AZUR-1: FDA Approves Dostarlimab in dMMR/MSI-H Locally Advanced Rectal Cancer

At a Glance

AZUR-1 Key Takeaways

Study Design

Global, multicenter, open-label, single-arm, registrational phase 2 trial of dostarlimab-gxly (Jemperli) 500 mg IV Q3W x 9 cycles (6 months) in 154 patients with untreated stage II/III dMMR/MSI-H locally advanced rectal cancer. (FDA notice; GSK release, Oct 19, 2026)

Primary Endpoint: cCR12 by Independent Central Review

cCR12 by independent central review (ICR, primary endpoint): 47% (54/116) of 116 ICR-evaluable patients. Separately, FDA reports 38 patients (33%) with cCR by ICR but under 12 months of follow-up, and 44 (38%) with near CR at data cutoff (categories as reported by FDA). Investigator-assessed cCR12: 68% (95% CI 60-76) of 144 evaluable patients. ORR 79% (95% CI 71-85) by ICR and 82% (95% CI 75-88) by investigator. Median follow-up 26.3 months (AZUR-1, FDA notice); no patient with cCR12, cCR or near CR had progressed. [Source: FDA approval notice, Oct 19, 2026] Full interim data were presented at ESMO 2026 (LBA87, October 25, 2026; see the ESMO 2026 results below).

cCR12 47% (ICR, primary) - 68% (investigator) - FDA notice

ESMO 2026 Interim Analysis (LBA87, Annals of Oncology)

Presented by Andrea Cercek on October 25, 2026, with a simultaneous Annals of Oncology paper (DCO 20-Apr-2026; median follow-up 26.3 months, range 2–36). Primary endpoint, cCR12 by independent central review: 47% (54/116), with 38 more patients in cCR still being followed toward 12 months; the presented slides call the ICR analysis 75% mature (investigator analysis 94% mature). Investigator-assessed cCR12 (secondary): 68% (98/144). Exploratory composite cCR12 (investigator) + pCR: 76% (110/144); 12 of 15 patients who had surgery after dostarlimab alone had a pCR. 98% of patients who reached cCR stayed in cCR for at least 12 months, and no recurrences were reported among patients in cCR or pCR. 71% (110/154) were managed without further treatment after dostarlimab alone; 26% (40/154) received additional standard-of-care treatment. Grade ≥3 immune-mediated adverse events: 3% (4 patients). Single-arm interim analysis. (ESMO 2026 abstract LBA87; Annals of Oncology, Oct 25, 2026; Cercek, ESMO 2026 slides)

ESMO 2026: cCR12 47% ICR (primary) · 68% investigator · 76% cCR12 + pCR

Safety

Serious adverse reactions 20%; most common adverse reactions fatigue (32%), rash (22%), diarrhea (18%) and pruritus (17%); permanent discontinuation for adverse reactions 3% (GSK press release, Oct 19, 2026). Prescribing-information warnings and precautions: immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic HSCT, embryo-fetal toxicity (FDA notice). GSK press release, Oct 19, 2026 → FDA notice →

Prior Data Context

The landmark investigator-led, multicenter MSK study (NCT04165772) reported 100% clinical complete response in the first 12 patients treated with dostarlimab alone (Cercek et al., NEJM 2022). The ASCO 2024 update (LBA3512) reported cCR in all 42 patients who completed treatment, with sustained cCR of 12+ months in 24 patients (median follow-up 26.3 months for that subset, ASCO 2024). In the FDA's 2026 review of this study (50 treated), cCR12 was 93% (95% CI 82-99) in evaluable patients (denominator not stated by FDA). (NEJM 2022; JCO LBA3512, ASCO 2024; FDA approval notice, Oct 19, 2026)

Regulatory Status

FDA accelerated approval granted October 19, 2026 - dostarlimab-gxly (Jemperli, GSK) for adults with stage II or III locally advanced rectal cancer that is MSI-H or dMMR, as determined by an FDA-authorized test for solid tumors. The FDA approved about four months ahead of its goal date (FDA notice); the PDUFA date had been February 2027 (AnaptysBio release; GSK's Aug 24 Priority Review announcement). Pathways: Priority Review; Breakthrough Therapy designation; Real-Time Oncology Review; Assessment Aid; Project Orbis (Health Canada, Israel MoH, Swissmedic, UK MHRA - reviews ongoing); FDA Commissioner's National Priority Review Voucher (CNPV) pilot program. No specific companion diagnostic named. Dostarlimab also received a separate accelerated approval on August 17, 2021 for adults with dMMR recurrent or advanced solid tumors (as determined by an FDA-approved test) that progressed on or following prior treatment and who have no satisfactory alternative treatment options (GARNET; FDA notice, Aug 17, 2021). FDA notice, Aug 17, 2021 → FDA notice →

FDA approved Oct 19, 2026 - accelerated approval

Sponsor & Drug

GSK. Dostarlimab-gxly (Jemperli), a PD-1 inhibitor. Organ-preserving immunotherapy-only approach that may allow selected dMMR/MSI-H rectal cancer patients to avoid chemotherapy, radiation and surgery (17% underwent surgery and 8% received additional therapy in AZUR-1; FDA notice).

Regulatory Milestone

FDA Accelerated Approval - October 19, 2026

FDA APPROVED Jemperli (dostarlimab-gxly) monotherapy, stage II/III MSI-H/dMMR locally advanced rectal cancer

On October 19, 2026, the FDA granted accelerated approval to dostarlimab-gxly (Jemperli, GSK) for adults with stage II or III locally advanced rectal cancer that is microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR), as determined by an FDA-authorized test for solid tumors. The FDA approved about four months ahead of its goal date (FDA notice); the PDUFA date had been February 2027 (AnaptysBio release; GSK's Aug 24 Priority Review announcement). [Source: FDA approval notice, 10/19/2026; AnaptysBio release, 10/19/2026; GSK Priority Review announcement, Aug 24, 2026]

Efficacy basis - AZUR-1 (NCT05723562), 154 treated patients: the primary endpoint, sustained clinical complete response at 12 months (cCR12) by independent central review (ICR), was 47% (54/116; 95% CI 37-56 per GSK's release) in 116 ICR-evaluable patients [Source: FDA notice 10/19/2026; GSK press release 10/19/2026]. The FDA notice prints the interval as 27%-56%. Separately, FDA reports 38 patients (33%) with cCR by ICR but under 12 months of follow-up, and 44 (38%) with near CR at data cutoff (categories as reported by FDA). Investigator-assessed cCR12: 68% (95% CI 60-76) in 144 evaluable patients. ORR: 79% (95% CI 71-85) by ICR and 82% (95% CI 75-88) by investigator. Disposition: 110 patients (71%) received dostarlimab alone with no further treatment and no progression; 26 (17%) had surgery; 13 (8%) received additional systemic therapy or radiation; 1 (0.6%) progressed without further treatment; 4 (2.5%) withdrew or were lost to follow-up. Of 15 patients who had surgery after dostarlimab alone for imaging suggesting incomplete response, 12 had a pathological complete response. Median follow-up 26.3 months (AZUR-1, FDA notice); no patient with cCR12, cCR or near CR experienced disease progression. [Source: FDA approval notice, 10/19/2026]

Supporting study - NCT04165772 (investigator-led, multicenter, MSK-led; 50 treated; same regimen): cCR12 93% (95% CI 82-99) in evaluable patients (denominator not stated by FDA); ORR 100% (95% CI 93-100); no patient received chemoradiation or rectal cancer surgery. Of 27 patients followed at least 3 years, 1 had a local recurrence treated with lymphadenectomy, 1 withdrew and 1 died of causes unrelated to the disease under study. [Source: FDA approval notice, 10/19/2026]

Safety: serious adverse reactions in 20% of patients; most common adverse reactions fatigue (32%), rash (22%), diarrhea (18%) and pruritus (17%); permanent discontinuation for adverse reactions in 3%. [Source: GSK press release, 10/19/2026 - not in the FDA notice] Prescribing-information warnings and precautions: immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic HSCT, embryo-fetal toxicity. [Source: FDA notice]

Dosing: 500 mg IV every 3 weeks until disease progression or unacceptable toxicity, for up to 9 cycles. Review pathways: Priority Review; Breakthrough Therapy designation; Real-Time Oncology Review (RTOR); Assessment Aid; Project Orbis (concurrent review with Health Canada, Israel's Ministry of Health, Swissmedic and the UK MHRA - those reviews ongoing); FDA Commissioner's National Priority Review Voucher (CNPV) pilot program. No specific companion diagnostic was named - the indication requires MSI-H/dMMR status as determined by an FDA-authorized test for solid tumors. [Source: FDA notice]

Update: the full AZUR-1 interim analysis was presented at ESMO 2026 in Madrid (LBA87, October 25, 2026); see the ESMO 2026 results. [Source: AnaptysBio release (GlobeNewswire), 10/19/2026, which reproduces GSK's announcement; GSK's own release states only that the data will be presented at the ESMO Congress in October 2026]

Source: FDA approval notice (2026-10-19) → · GSK press release (2026-10-19) · ClinicalTrials.gov NCT05723562

Approval-Day KOL Reaction

What global KOLs said on approval day

Verbatim physician posts captured on October 19, 2026, in the hours after the FDA notice. Posts are shown in full; media, company and institutional accounts are tracked but not shown as voices.

Oncology Brothers@OncBrothers

Dostarlimab (IV q3 wks, 9 cycles) is now @FDA ✅ for locally advanced (Stg II/III) MSI-H/dMMR rectal cancer off Ph II AZUR-1 study: - 71% got IO alone (no additional Rx) - Clinical CR for 12 mos: 47% (no progression at 26.3mos median f/u) - Surgery/Chemo free option! #gism

988 views 9 likes 3 RTs 2026-10-19

ilyas sahin, MD@ilyassahinMD

FDA grants accelerated approval to dostarlimab for locally advanced rectal cancer that is microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR)

684 views 8 likes 0 RTs 2026-10-19

Nicholas Hornstein@GIMedOnc

🚨 FDA approval for dostarlimab in locally advanced dMMR/MSI-H rectal cancer! This was based on AZUR-1, with full data coming at @myESMO. #ESMO26 No recurrences among responders after more than 2 years of median follow-up! We know immunotherapy works, and when patients respond, those responses can be incredible. I’ve been using immunotherapy with curative intent in these patients, and I haven’t been disappointed. The fact that we’re potentially curing solid tumors with systemic therapy alone, without chemotherapy, radiation, or surgery, is magical. Looking forward to the full data and seeing this approach become more broadly available to patients. @OncoAlert @Onco_Nexus @TheGutOncLab

459 views 15 likes 6 RTs 2026-10-19

ESMO 2026 KOL Reaction

What physicians said about the ESMO 2026 data

Physician posts on the AZUR-1 presentation (LBA87) and Annals of Oncology paper, newest first. Every post is shown in full and verbatim and links to the original on X.

What physicians debated

Investigator vs central review. Several physicians flagged the gap between the 68% investigator-assessed cCR12 and the 47% central-review primary endpoint: Jose Tapia marked it with a question, Allan Pereira and Rishabh Jain listed the less mature central review among their caveats, and Jeff Ryckman led with the central-review figure as the registry primary. Before ESMO, Mustafa Özdoğan separated the 71% (110/154) count from the primary endpoint.

Single-arm design and follow-up. Nicholas Hornstein argued that a randomized comparison with TNT/TME is not equitable for these patients and suggested the investigator figure may understate eventual response, citing PET, biopsy and ctDNA in his own practice; Allan Pereira named late local regrowth as the number to watch at a median follow-up of 26 months. Each post is shown in full below.

Allan Pereira, MD, PhD@DrAllanPereira

🔥 AZUR-1 Phase 2, Annals of Oncology (ESMO LBA87) AZUR-1 is a global, single-arm, Phase 2 trial of 💊 Dostarlimab 500 mg q3w for 9 cycles in adults with 🎯 Untreated stage II/III dMMR/MSI-H rectal cancer 👥 154 enrolled, 144 with ≥12 mo follow-up ✅ Sustained cCR at 12 mo: 68% (investigator) ✅ cCR 1y after end of treatment + pCR: 76% 🔁 98% of cCRs held ≥12 mo, no recurrences in responders ⚠️ Single arm, central review less mature This is the full dataset behind the accelerated approval we covered on October 20, and it holds up. 2 in 3 pts keep their rectum with a PD-1 antibody alone, and no one in complete response has recurred so far. Two caveats: it is single-arm, and the investigator read runs ahead of central review, which the authors say is less mature. With a median follow-up of 26 months, late local regrowth is the number to watch. Everyone must test MMR on every rectal biopsy before anyone starts total neoadjuvant therapy. #CRC #RectalCancer #dMMR #ESMO26 #GIOnc https://t.co/Zyg0Eo2gI2

144 views 0 likes 0 RTs 2026-10-25

Ana K. Valenzuela@anakvalenzuelav

🔥 AZUR-1: A new era in organ preservation! #ESMO2026 ✅ A new standard of care for patients with localized dMMR/MSI-H rectal cancer! ✅✅ 154 patients enrolled in the first global, multicenter cohort! ✅✅✅ Dostarlimab monotherapy for 6 months —cCR (98) + pCR (12/15): 76% 🔥 —98% maintained cCR for >12 months! 👉 FDA accelerated approval granted on October 19, 2026! Congratulations to @AndreaCercek and colleagues! 👏👏👏

153 views 1 likes 1 RTs 2026-10-25

Nieves Martinez Lago MD PhD@DraMartinezLago

#ESMO26 🧬 AZUR-1 | dMMR/MSI-H rectal cancer 📖 Simultaneous publication in Annals of Oncology! 👥 154 pts | Dostarlimab alone 🎯 12-mo sustained cCR: 68% ✅ cCR + pCR: 76% 🔒 98% maintained cCR ≥12 mo ⚠️ G≥3 immune AEs: 3% 🚀 A new era of organ preservation! 🔗 https://t.co/cUt7PemuXU @OncoAlert

408 views 9 likes 5 RTs 2026-10-25

Nicholas Hornstein@GIMedOnc

AZUR-1 delivers. #ESMO26 Phase 2, single arm. Dostarlimab x 9 cycles (6 months) in untreated stage II/III dMMR/MSI-H rectal cancer, 154 patients. Cercek's 49-patient NEJM cohort gone global. No control arm, because randomizing these patients to TNT/TME isn't equitable. cCR12 (complete response held 12+ months, no further treatment): 68% by investigator.   26% needed additional treatment 10% went to surgery 68% is likely lower than reality since many patients probably just needed more time to radiographically respond. Using PET/Biopsy/ctDNA, especially ctDNA, is incredibly helpful in my practice to identify patients who can avoid TME even if a fibrotic tumor remains as they often do. FDA already gave accelerated approval (way to steal the ESMO thunder) last week which leads me to my next point. Obvious new standard of care. You should go to oncology jail if you don't treat MSI-H with IO. @OncoAlert @TheGutOncLab @Onco_Nexus

2.1K views 51 likes 23 RTs 2026-10-25

Jose Tapia@TapiaJC1

.#AZUR-1 Dorstalimab (~6mo) #RectalCancer . -12mo-cCR 68% -12mo-cCR/pCR 76% -ICR vs INV ❓ -surgery 10%, Subseq Tx 26% Important: T4 26% & Low-Rectum 40%. Great results. #ESMO26 @OncoAlert https://t.co/u6U8Q1fDaz

274 views 5 likes 4 RTs 2026-10-25

Dr Rishabh Jain@DrRishabhOnco

🚨 RECTAL CANCER WITHOUT CHEMO, RADIATION OR SURGERY? 🌍 AZUR-1 | #ESMO26 📖 Concomitant publication in Annals of Oncology! Dostarlimab in 154 patients with stage II/III dMMR/MSI-H rectal cancer: 🔥 68% sustained clinical CR ≥12 months 🔥 76% sustained cCR + pCR 🔥 98% maintained cCR ≥12 months ✅ No recurrences reported among patients achieving cCR/pCR! 💡 Could immunotherapy make organ preservation the new standard? ⚠️ Single-arm interim results; central review remains immature. @myesmo @ESMO_open @ASCO @oncoalert #ESMO26 #RectalCancer #Immunotherapy

756 views 13 likes 6 RTs 2026-10-25

Nieves Martinez Lago MD PhD@DraMartinezLago

#ESMO26 🧬 AZUR-1 | Phase II 👥 154 pts | dMMR/MSI-H LARC 💊 Dostarlimab × 9 cycles 🎯 cCR: 71% (110/154) ✅ 12-mo sustained cCR: 68% (98/144) 📈 cCR12 + pCR: 76% 🚀 98% durable cCR; no recurrences 🏥 71% avoided additional SOC ⚠️ G≥3 immune AEs: 3% 💡 Promising organ preservation strategy! @OncoAlert

560 views 13 likes 8 RTs 2026-10-25

Paolo Ciracì@p_ciracimd

Results from the AZUR-1 trial: dostarlimab monotherapy in dMMR/MSI-H LARC #ESMO26 @OncoAlert https://t.co/5L5SabWBnW

363 views 8 likes 5 RTs 2026-10-25

Yakup Ergün@dr_yakupergun

#ESMO26 | AZUR-1 Treating rectal cancer with dostarlimab—without ChT, RT or surgery! Organ preservation in dMMR/MSI-H locally advanced rectal cancer is exactly the kind of progress we want to see in oncology. The FDA granted accelerated approval for this indication on October 19, 2026. Credit where it’s due: a major advance with a direct impact on patients’ lives👏👏

707 views 6 likes 2 RTs 2026-10-25

Jeff Ryckman@jryckman3

AZUR-1 (LBA87): Single-arm dostarlimab 500 mg q3w x9 in dMMR/MSI-H LARC. cCR12 by central review, the registry primary: 47% (54/116). Investigator-assessed: 68% among 144 pts. ICR confirmed cCR later, with different evaluable populations. The dostarlimab-alone surveillance path avoids RT, chemo and surgery. #ESMO26 #OncTwitter https://t.co/rOJbf5J8i8

352 views 4 likes 0 RTs 2026-10-24

Mustafa Özdoğan, MD@ozdogan_md

Precision note: 110/154 (71%) is FDA's count of patients with no further treatment and no progression at cutoff. The primary endpoint, cCR12 by independent review, was 47% (54/116; 95% CI 37-56%); investigator-assessed 68% (98/144). Full AZUR-1 data at #ESMO26.

81 views 1 likes 0 RTs 2026-10-20

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Influence Leaders

Top KOLs Discussing AZUR-1

Andrea Cercek (Memorial Sloan Kettering) presented AZUR-1 at ESMO 2026 (LBA87, October 25). The invited discussant was David Tougeron (Poitiers); his rationale slide is in Key Slides.

Andrea Cercek

@AndreaCercek

ESMO 2026 presenter

ilyas sahin, MD

@ilyassahinMD

3.1K impressions

Ibrahim Halil SAHIN, MD

@IbrahimSahinMD1

2.8K impressions

Dr. Cathy Eng

@CathyEngMD

1.7K impressions

Jaume Capdevila

@Ja_Capdevila

936 impressions

Vivek Subbiah, MD

@VivekSubbiah

491 impressions

ilyas sahin, MD@ilyassahinMD

Could some rectal cancer patients skip chemotherapy, radiation, and surgery? The FDA has granted priority review to dostarlimab (a PD-1 immunotherapy) for untreated stage II–III dMMR/MSI-H locally advanced rectal cancer, with a decision expected by February 2027. The application is based on the global Phase 2 AZUR-1 study (n=154), where 6 months of dostarlimab alone met the primary endpoint of sustained clinical complete response at ≥12 months (cCR12). This builds on the landmark MSK NEJM experience showing striking complete-response rates in this biomarker-defined group. As a reminder, dMMR/MSI-H accounts for only about 5–10% of rectal cancers. AZUR-1 is single-arm, and priority review is not approval. Still, biomarker-driven organ preservation moving toward a regulatory label is a major milestone. ✅

3.1K views 34 likes 6 RTs 2026-08-24

Conference Presentations

AZUR-1 Key Slides & Visuals

ESMO 2026 slides

Slides from ESMO 2026 (Madrid) as photographed and shared on X by physicians, newest first. Each post is shown verbatim; click any slide to enlarge, and open the OCR text under each post. All ESMO 2026 AZUR-1 slides in the KOL Pulse slide library →

Allan Pereira, MD, PhD @DrAllanPereira

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 ESMO 2026 discussant slide by David Tougeron: the rationale for non-operative management of dMMR rectal cancer, citing the 49-patient MSK cohort (shared by Allan Pereira, MD, PhD, @DrAllanPereira)

[Slide 1] AZUR-1: the rationale Non-operative management (NOM) of dMMR tumours • 49 patients with rectal adenocarcinoma • 9 cycles of dostarlimab • Median follow-up of 30 months • 100% cCR • RFS at 2 years was 96% Prof David Tougeron | ESMO Congress 2026 Cercek A et al. NEJM 2025

Ana K. Valenzuela @anakvalenzuelav

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 ESMO 2026 title slide: Clinical complete response with dostarlimab monotherapy, first results from the global registrational AZUR-1 trial, Cercek et al. (1 of 2) (shared by Ana K. Valenzuela, @anakvalenzuelav)

AZUR-1 ESMO 2026 slide: high rate of cCR12 + pCR with dostarlimab alone (76%, 110/144) (2 of 2) (shared by Ana K. Valenzuela)

[Slide 1] Clinical Complete Response With Dostarlimab Monotherapy in dMMR/MSI-H Locally Advanced Rectal Cancer: First Results From the Global Registrational AZUR-1 Trial Andrea Cercek1, Jean-Baptiste Bachet2, Gunnar Folprecht3, Hideaki Bando4, Jenny Seligmann5, Naureen Starling6, María del Carmen Riesco Martínez7, Pilar García Alfonso8, Denis Smith9, Lisa Salvatore10,11, Encarna Gonzalez Flores12, Emmanuel Mitry13, Eric Chen14, Jaume Capdevila15, Federica Morano16, Susana Roselló Keränen17, Neda Stjepanovic18, Zsolt Szijgyarto19, Luis A. Diaz, Jr1, Jeanine M.L. Roodhart20 1Memorial Sloan Kettering Cancer Center, New York, NY, USA; 2Sorbonne University, Pitié Salpêtrière Hospital, Paris, France; 3Technical University Dresden/Medical Faculty Carl Gustav Carus, Dresden, Germany; 4National Cancer Center Hospital East, Kashiwa-shi, Chiba, Japan; 5University of Leeds, Leeds, UK; 6Royal Marsden NHS Foundation, London, UK; 7Hospital Universitario 12 de Octubre, Madrid, Spain; 8Hospital General Universitario Gregorio Marañón, Faculty of Medicine, Complutense University of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; 9CHU Haut Lévêque, Pessac, France; 10Università Cattolica del Sacro Cuore, Rome, Italy; 11Comprehensive Cancer Center, Fondazione Policlinico Universitario Agostino Gemelli, IRCCS Rome, Rome, Italy; 12Hospital Universitario Virgen de las Nieves, Instituto de Investigación Biosanitaria IBS, Granada, Spain; 13Institut Paoli-Calmettes, Marseille, France; 14Princess Margaret Cancer Centre, Toronto, Canada; 15Vall Hebron University Hospital and Vall Hebron Institute of Oncology (VHIO), Barcelona, Spain; 16Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; 17Hospital Clínico Universitario, INCLIVA Biomedical Research Institute, University of Valencia, Valencia, Spain; 18GSK, Baar, Switzerland; 19GSK, London, UK; 20University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands [Slide 2] High rate of cCR12 + pCR was observed with dostarlimab alone cCR12 = Patients who achieved cCR after dostarlimab monotherapy and maintained for ≥12 mo with no additional treatment Legend: cCR with 12 months follow up (n=98) | nCR (n=3) | SD (n=10) | PD (n=8) | Late cCR (n=8) | *pCR after dostarlimab alone (n=12) | PR (n=13) | N/A (n=10) | cCR with <12 months follow up (n=10) cCR with <12 mo follow-up (n=10) | cCR with ≥12 months follow-up* (n=98) | Non-cCR12 (n=46) End of treatment response (N=154) cCR12 (n=98) + pCR (n=12): 76% (110/144) †Patients who were not evaluable (n=4) have been pooled with those who were N/A (n=6): four patients did not reach end of treatment response assessment and did not initiate SOC treatment; six patients did not undergo end of treatment response assessment but were recorded as continuing on study and received SOC. cCR, clinical complete response; cCR12, clinical complete response for ≥12 months; mo, months; N/A, not available; nCR, near complete response; pCR, pathological complete response; PD, progressive disease; PR, partial response; SD, stable disease; SOC, standard of care. Dr Andrea Cercek

Nieves Martinez Lago MD PhD @DraMartinezLago

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 ESMO 2026 slide: response swimmer/bar figure: EOT response and cCR12 by investigator and ICR (shared by Nieves Martinez Lago MD PhD)

Nicholas Hornstein @GIMedOnc

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 study design graphic (planned N=150): phase 2 study design, inclusion and exclusion criteria and endpoints, dostarlimab in dMMR/MSI-H rectal cancer (shared by Nicholas Hornstein, @GIMedOnc)

[Slide 1] AZUR-1: Phase 2 Study A single-arm, open label study of dostarlimab monotherapy in participants with untreated stage 2/3 MMR-D/MSI-H locally advanced rectal cancer. Inclusion criteria1 • Adults aged ≥ 18 years • Histologically confirmed stage II–III (T3–T4, N0, or T any, N+), locally advanced rectal cancer • Radiologically and endoscopically evaluable disease • ECOG PS 0–1 • Tumor that can be categorized as dMMR or MSI-H by local or central assessment Exclusion criteria1 • Distant metastatic disease • Prior radiation therapy, systemic therapy, or surgery for the management of rectal cancer • Tumor-caused symptomatic bowel obstruction • Participant has any history of interstitial lung disease or pneumonitis • Any irAE of Grade ≥ 3, immune-related severe neurologic events, exfoliative dermatitis of any grade, or myocarditis from prior immunotherapy • Malignancy that has progressed or required active treatment ≤ 2 years Overview of Study Design Phase 2, open-label, single-arm study1-2 (N = 150) Dostarlimab 500 mg IV Q3W × 9 cycles → EOT response assessment → < cCR: SoC, +/− surgery (if needed); cCR: Non-operative management 6 weeks | 12 weeks Disease assessments: • 6 weeks, 12 weeks, EOT, then – Q4 months in Years 1–3 – Q6 months in Years 4–5 Endpoints1 Primary: • Proportion who sustain cCR for 12 months by ICR Secondary: • Sustained cCR24 by ICR for 24 and 36 months • EFS by INV at 3 years • cCR by INV at 12, 24, and 36 months • ORR by ICR at post-intervention disease assessment • Organ preservation rate at 3 years • DSS and DSS at 5 years • OS and OS at 5 years • Safety (AE, SAE, irAE, study discontinuations, and deaths) • PK parameters • Antidrug antibodies against dostarlimab

Jose Tapia @TapiaJC1

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 ESMO 2026 slide: investigator vs central review cCR12 (68% INV vs 47% ICR), Dr Andrea Cercek (shared by Jose Tapia)

[Slide 1] Investigator-assessed cCR is achieved earlier than by central review cCR12 (INV): 98/144 68% cCR12 (ICR): 54/116 47% Legend: cCR with <12 mo follow-up | cCR with ≥12 mo follow-up | Non-cCR/pCR cCR12 by INV 94% mature cCR12 by ICR 75% mature *No subsequent systemic treatment or radiotherapy after completing dostarlimab. cCR, clinical complete response; cCR12, clinical complete response for ≥12 months; ICR, independent central review; INV, investigator; mo, months; nCR, near complete response; pCR, pathologic complete response. Dr Andrea Cercek

Nieves Martinez Lago MD PhD @DraMartinezLago

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 ESMO 2026 slide — response data: end-of-treatment cCR 71% (110/154) waterfall (1 of 3) (shared by Nieves Martinez Lago MD PhD)

AZUR-1 ESMO 2026 slide: cCR12 + pCR 76% (110/144) (livestream capture) (2 of 3) (shared by Nieves Martinez Lago MD PhD)

[Slide 1] 10:15 - 11:45 Proffered paper: Gastrointestinal tumours, lower digestive CHAIR: GUILLERMO ARGILES MARTINEZ High rate of clinical complete responses (cCR) was observed after dostarlimab alone Legend: cCR (n=102); Late cCR (n=8)*; nCR (n=9); PR (n=15); SD (n=10); N/A (n=10); PD (n=8) Y axis: cCR, nCR, PR, SD, N/A†, PD cCR: 66% (n=102) | nCR: 6% (n=9) | PR: 10% (n=15) | SD: 6% (n=10) | N/A: 7% (n=10)† | PD: 5% (n=8) End of treatment response (N=154) cCR 71% (110/154) *8 patients converted from nCR/PR to cCR at any time; †Patients who were not evaluable (n=4) have been pooled with those who were N/A (n=6): four patients did not reach end of treatment response assessment and did not initiate SOC treatment; six patients did not undergo end of treatment response assessment but were recorded as continuing on study and received SOC. cCR, clinical complete response; N/A, not available; nCR, near complete response; pCR, pathological complete response; PD, progressive disease; PR, partial response; SD, stable disease. Dr Andrea Cercek ALMERIA AUDITORIUM - HALL 9 [Slide 2] 10:15 - 11:45 Proffered paper: Gastrointestinal tumours, lower digestive CHAIR: GUILLERMO ARGILES MARTINEZ High rate of cCR12 + pCR was observed with dostarlimab alone cCR12 = Patients who achieved cCR after dostarlimab monotherapy and maintained for ≥12 mo with no additional treatment Legend: cCR with 12 months follow up (n=98); pCR after dostarlimab alone (n=12); nCR (n=3); PR (n=13); SD (n=10); N/A (n=10); PD (n=8); Late cCR (n=8); cCR with <12 months follow up (n=10) cCR with <12 mo follow-up (n=10) | cCR with ≥12 months follow-up* (n=98) | Non-cCR12 (n=46) End of treatment response (N=154) cCR12 (n=98) + pCR (n=12): 76% (110/144) [Footnotes: N/A pooling and abbreviations, small print] Dr Andrea Cercek ALMERIA AUDITORIUM - HALL 9 [Slide 3] 10:15 - 11:45 Proffered paper: Gastrointestinal tumours, lower digestive CHAIR: GUILLERMO ARGILES MARTINEZ Safety profile was consistent with prior studies of dostarlimab Dostarlimab median number of cycles 9 (range 2–9) N=154 AEs (≥10% of patients) | Gr 1–2 | ≥Gr 3 Any dostarlimab-related AE, n (%) | 98 (64) | 15 (10) Pruritus | 21 (14) | 0 Hypothyroidism | 19 (12) | 0 Fatigue | 16 (10) | 1 (<1) Immune-mediated AEs (≥2% of patients) | Gr 1–2 | ≥Gr 3 Any immune-mediated AE, n (%) | 32 (21) | 4 (3)|| Hypothyroidism | 12 (8) | 0 Arthralgia | 3 (2) | 0 Hyperthyroidism | 3 (2) | 0 SAEs* | Any causality | Dostarlimab related† Any treatment-emergent SAE, n (%) | 31 (20) | 8 (5) SAEs of clinical interest Intestinal obstruction‡ | 3 (2) | 0 Rectal stenosis | 2 (1) | 0 Intestinal perforation§ | 2 (1) | 0 Among adverse events related to dostarlimab: • 3 (2%) patients discontinued treatment¶ • No fatal AEs DCO 20 April 2026. [Footnotes small print: SAE definition; AEs considered related at investigator discretion; obstruction at primary tumour site in 2 patients with response; perforation includes large intestinal perforation (n=1) and procedural intestinal perforation (n=1); ≥Gr3 immune-mediated includes Grade 3 adrenal insufficiency (n=1), Grade 4 diabetic ketoacidosis (n=1), Grade 3 lichen planus (n=1) and Grade 3 hepatitis (n=1); discontinuations: hepatitis (n=1), amylase increase (n=1) and lichen planus (n=1) - partially legible] Dr Andrea Cercek ALMERIA AUDITORIUM - HALL 9

Paolo Ciracì @p_ciracimd

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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Results from the AZUR-1 trial: dostarlimab monotherapy in dMMR/MSI-H LARC #ESMO26 @OncoAlert https://t.co/5L5SabWBnW

AZUR-1 ESMO 2026 slide: patient disposition - Dr Andrea Cercek (shared by Paolo Ciracì)

[Slide 1] Patient disposition Assessed for eligibility N=165 Screening failures (n=11) • Ineligible (n=10) • Withdrew (n=1) Received dostarlimab monotherapy N=154 (full analysis set) • Completed (n=136) • Discontinued prematurely (n=18)* Did not reach response assessment (n=4) • Withdrew (n=3) • Died (n=1) NOM after dostarlimab 71% (110/154) Additional SOC treatment after dostarlimab 26% (40/154) Lost to follow-up post SOC (n=5) • Withdrew (n=1) • Died (n=4)† On study and in follow-up 94% (145/154) PD post SOC (n=2) On study with no evidence of PD after dostarlimab ± SOC 93% (143/154)‡ *Premature discontinuations included adverse event (n=4), physician decision (n=6), PD (n=6), withdrawal by patient (n=1), other (n=1). †One patient refused SOC and died without evidence of having received any additional treatment. ‡Two patients refused SOC, as recommended after EOT disease assessment, had local progression and then received additional treatment (immunotherapy n=1; CRT n=1); no further PD noted during or following additional treatments. CRT, chemoradiotherapy; DCO, data cut-off; EOT, end of treatment; NOM, non-operative management; PD, progressive disease; SOC, standard of care. Dr Andrea Cercek

Yakup Ergün @dr_yakupergun

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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AZUR-1 ESMO 2026 slide: durable cCR swimmer plot (n=100 with >=12 mo follow-up) - Dr Andrea Cercek (1 of 4) (shared by Yakup Ergün)

AZUR-1 ESMO 2026 slide — response data: cCR12 by investigator 68% (98/144) waterfall - Dr Andrea Cercek (2 of 4) (shared by Yakup Ergün)

AZUR-1 ESMO 2026 slide: assessment of response, clinical complete response definition by examination, endoscopy and MRI, Andrea Cercek (3 of 4) (shared by Yakup Ergün, @dr_yakupergun)

AZUR-1 ESMO 2026 slide: trial design, Andrea Cercek (4 of 4) (shared by Yakup Ergün, @dr_yakupergun)

[Slide 1] Durable responses were observed in patients who achieved cCR Patients achieving cCR (INV) after dostarlimab monotherapy among patients with ≥12 months follow-up (n=100) cCR (n=100) 98% of cCRs were durable with no recurrences (2 patients with cCR elected for surgery and had pCR) Legend: Time from enrolment to start of cCR12 follow-up; In follow up with sustained cCR; Ongoing follow up (further response assessment pending); cCR reported prior to EOT; EOT; Patients with cCR who elected for surgery Months (0-40) cCR, clinical complete response; cCR12, clinical complete response for ≥12 months; EOT, end of treatment; INV, investigator; pCR, pathological complete response Dr Andrea Cercek [Slide 2] High rate of cCR12 was observed with dostarlimab alone cCR12 = Patients who achieved cCR after dostarlimab monotherapy and maintained for ≥12 mo with no additional treatment Legend: cCR with <12 mo follow-up (n=10); cCR with ≥12 mo follow-up (n=98); Non-cCR12 (n=46); Late cCR (n=8) 2 patients who achieved a cCR at EOT response assessment elected for surgery (both pCR) so could not achieve cCR12 Y axis: cCR/pCR, nCR, PR, SD, N/A†, PD cCR with <12 mo follow-up (n=10) | cCR with ≥12 months follow-up* (n=98) | Non-cCR12 (n=46) Patients evaluable for cCR12 = 144 cCR12 by INV: 68% (98/144) *Sufficient follow-up for cCR12 analyses required 12 months of follow-up and adequate disease assessments according to the scheduled assessment plan (i.e., a patient with a cCR may have completed 12 months of follow-up but would still not be cCR12-evaluable if the required disease assessments were not performed). †Patients who were not evaluable (n=4) have been pooled with those who were N/A (n=6): four patients did not reach end of treatment response assessment and did not initiate SOC treatment; six patients did not undergo end of treatment response assessment but were recorded as continuing on study and received SOC. cCR, clinical complete response; cCR12, clinical complete response for ≥12 months; EOT, end of treatment; mo, months; N/A, not available; nCR, near complete response; pCR, pathological complete response; PD, progressive disease; PR, partial response; SD, stable disease; SOC, standard of care. Dr Andrea Cercek [Slide 3] Assessment of response: Clinical complete response (cCR) Clinical complete response (cCR): concordant examination, endoscopy and MRI Clinical examination + Endoscopy ✓ Normal digital rectal examination ✓ No visible residual rectal tumor + Rectal MRI ✓ No residual diffusion restriction on DWI; scar on T2-weighted imaging ✓ Target lymph nodes decrease to <5 mm in short-axis diameter* [Images: Endoscopy and MRI, Baseline → Complete response] *The <5 mm threshold is source-specific and should be applied within the study assessment protocol, not treated as a standalone universal guarantee of nodal sterilization. cCR, clinical complete response; DWI, diffusion-weighted imaging; MRI, magnetic resonance imaging. Dr Andrea Cercek [Slide 4] AZUR-1 trial design Global Phase 2 single-arm study of dostarlimab monotherapy for dMMR/MSI-H locally advanced rectal cancer Patients with dMMR/MSI-H LARC → Dostarlimab treatment → EOT response assessment → Post-dostarlimab management based on INV assessment → Efficacy endpoints for interim analysis ✓ Stage II to III (T3–T4, N0, or T any, N+) ✓ dMMR/MSI-H by local or central assessment ✓ No prior treatment for rectal cancer ✓ No tumour-caused symptomatic bowel obstruction N=154 Dostarlimab 500 mg IV Q3W x 9 cycles Endoscopy and MRI/CT 21 days after last dose (+7 days) cCR → NOM† (surveillance without further treatment) <cCR → NOM† (surveillance without further treatment) or SOC (ChT/RT/surgery) (per investigator discretion) iCR/nCR* (second assessment loop) Primary/secondary: cCR12 by ICR/ cCR12 by INV Exploratory: cCR12 (INV) + pCR Note, cCR12 and pCR achieved after dostarlimab alone *Patients with near CR (nCR; defined as those with significant reduction in tumour burden but with some residual disease) or incomplete CR (iCR; defined as all responses less than nCR that are not progressive disease, including those with PR and SD) will have the option for a second clinical response evaluation 4–8 weeks after the initial evaluation, at the discretion of the investigator and the patient. If the patient reaches cCR, they may enter the nonoperative management period; if the response is less than cCR, patients will either proceed with SOC or surveillance without further treatment per investigator discretion. †Endoscopy, rectal MRI, and CT CAP Q4M in Years 1–2 and Q6M in Years 3–5. cCR12, clinical complete response for ≥12 months; iCR, incomplete clinical response; ICR, independent central review; INV, investigator; nCR, near complete response; NOM, nonoperative management. Dr Andrea Cercek

Yakup Ergün @dr_yakupergun

AZUR-1 · ESMO 2026 slides

Oct 25, 2026 · ESMO 2026

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#ESMO26 | AZUR-1 Global, single-arm trial of dostarlimab in dMMR/MSI-H LARC (n=154). 🔹 cCR sustained ≥12 mo: 68% (INV), 47% (ICR; 38 additional pts in cCR awaiting 12-mo follow-up) 🔹 cCR12 + pCR: 76% (including surgical pCR) 🔹 71% remained progression-free without additional SOC treatment. 🔹 Median follow-up: 26.3 mo; no recurrences after cCR/pCR to date. The FDA already granted accelerated approval on October 19, 2026.

AZUR-1 ESMO 2026 programme screenshot: LBA87 abstract - dostarlimab monotherapy cCR in dMMR/MSI-H LARC (Andrea Cercek) (shared by Yakup Ergün)

[Slide 1] LBA87 - Clinical complete response with dostarlimab monotherapy in dMMR/MSI-H locally advanced rectal cancer (LARC): First results from the global registrational AZUR-1 trial Speakers Andrea Cercek (New York, United States of America, NY) Lecture Time 11:00 - 11:10 Abstract Background Multimodal treatment with chemotherapy, radiation and surgery is a standard of care (SOC) for LARC associated with significant toxicity/morbidity. After TNT, the range of clinical complete response (cCR) is 21–41%. dMMR/MSI-H tumours are exceptionally responsive to PD-1 blockade: in a small study, neoadjuvant dostarlimab treatment led to durable cCRs and eliminated the need for SOC in most patients (pts) with LARC. AZUR-1 (NCT05723562) is a global single-arm trial and the first registrational study evaluating the clinical benefit of dostarlimab monotherapy in pts with dMMR/MSI-H LARC. Methods Dostarlimab 500 mg was administered IV every 3 weeks for 9 cycles. Key endpoints include rate of sustained cCR for 12 months (cCR12) following end of treatment (EOT) with dostarlimab alone by investigator (INV) and independent central review (ICR), and composite rate of cCR12 (INV) + pathological CR (pCR). Results At data cutoff (DCO, 20 April 2026), 154 pts were enrolled and median follow-up was 26.3 months (range 2–36). Of 144 pts with ≥12 months follow-up, 68% achieved cCR12 (INV). Of 15 pts who underwent surgery after dostarlimab alone, 12 (80%) had pCR, resulting in a cCR12+pCR rate of 76%. Fewer pts were cCR12-evaluable by ICR, primarily due to cCR being confirmed later by ICR after initial EOT evaluation. Of pts evaluable by ICR, 47% (54/116) achieved cCR12, with 38 pts in cCR and being followed for cCR12 at DCO. 98% of pts who achieved cCR remained in cCR for ≥12 months by INV or ICR, with no recurrences to date for pts who achieved cCR or pCR. Overall, 93% of patients are in surveillance with no evidence of disease progression after treatment (dostarlimab ± SOC) and 71% achieved this outcome with dostarlimab alone. The safety profile was acceptable: 88% of pts completed all 9 cycles of dostarlimab and Grade ≥3 immune-mediated AEs occurred in 4 pts. Conclusions In this AZUR-1 interim analysis, 68% of pts achieved cCR12 and 76% achieved cCR12+pCR with dostarlimab alone with no disease recurrences to date. These durable responses indicate the potential to eliminate the need for chemotherapy, radiation and surgery, and redefine the curative-intent treatment paradigm for pts with dMMR/MSI-H LARC.

KOL-Made Infographics

Physician-authored summary graphics from ESMO 2026 · click to enlarge

AZUR-1 summary graphic made by Jeff Ryckman: design schema and cCR12 47% by central review, 68% by investigator, pCR 80% after surgery (shared by Jeff Ryckman, @jryckman3) — @jryckman3 · Oct 24, 2026 · ESMO 2026

AZUR-1 Top Tweets

ilyas sahin, MD@ilyassahinMD

3.1K views 34 likes 6 RTs 2026-08-24

Ibrahim Halil SAHIN, MD@IbrahimSahinMD1

✳️The AZUR-1 trial, testing the efficacy of dostarlimab for patients with MMR-D/MSI-H rectal cancer, is now open and enrolling at @UPMCHillmanCC ‼️ ✳️This trial will serve to patients in with #lynch syndrome and rectal cancer or those with sporadic MMR-D Rectal Cancer‼️ Please feel to reach out ‼️ @stacy_hurt @manjuggm @CrcTrialsChat @TheColonClub @colontown @CCAREfightlynch

2.8K views 37 likes 12 RTs 2024-02-09

Dr. Cathy Eng@CathyEngMD

@AndreaCercek 🤩announced at #ESMOGI2026 phase 2 AZUR-1 will be presented at @myESMO #ESMO2026 which was created to validate her original single center Dostarlimab data in #rectal #cancer. Looking forward to the results! #CancerResearch @GSK_US @OncoAlert

1.7K views 34 likes 14 RTs 2026-07-01

Jaume Capdevila@Ja_Capdevila

A Phase 2, Single-Arm, Open-Label Study with Dostarlimab Monotherapy in Participants with Untreated Stage II/III dMMR/MSI-H Locally Advanced Rectal Cancer (AZUR-1) @GrupoTTD @VHIO @GSK https://t.co/Qe9CxQRD6E

936 views 16 likes 6 RTs 2025-03-18

Vivek Subbiah, MD@VivekSubbiah

FDA Grants Priority Review to Dostarlimab for dMMR/MSI-H Locally Advanced Rectal Cancer | OncLive https://t.co/DyRWydmPht

491 views 9 likes 3 RTs 2026-08-24

Trial Background

About the AZUR-1 Trial

AZUR-1 is a global, multicenter, open-label, single-arm, registrational phase 2 trial evaluating dostarlimab-gxly (Jemperli) monotherapy in 154 patients with previously untreated stage II/III dMMR/MSI-H locally advanced rectal cancer. The trial was designed by Andrea Cercek, MD, at Memorial Sloan Kettering Cancer Center to confirm her landmark 2022 NEJM findings showing 100% clinical complete response (cCR) in 12 patients treated with dostarlimab alone. AZUR-1 met its primary endpoint of sustained clinical complete response at 12 months (cCR12) by independent central review, demonstrating that a clinically significant proportion of participants had no detectable signs of cancer for at least one year after treatment (GSK), with data continuing to mature.

ClinicalTrials.gov NEJM 2022 (Prior Study) GSK Press Release

ilyas sahin, MD@ilyassahinMD

3.1K views 34 likes 6 RTs 2026-08-24

Study Design

Trial Methodology & Results

Study Design

Single-arm, open-label, registrational phase 2 trial. Patients received dostarlimab 500 mg IV every 3 weeks for 9 cycles over 6 months. At end of treatment, patients with cCR entered non-operative management (NOM); those without cCR proceeded to standard of care with or without surgery.

Population

Adults 18 years or older with histologically confirmed stage II to III (T3-T4, N0, or T any, N+) locally advanced rectal cancer, with radiologically and endoscopically evaluable disease and dMMR/MSI-H status confirmed by local or central assessment. Exclusions included distant metastases, prior rectal cancer therapy, interstitial lung disease, and recent active malignancy.

Interventions

Dostarlimab-gxly (Jemperli) 500 mg IV Q3W for 9 cycles (6 months). This PD-1 inhibitor monotherapy approach aims to eliminate the need for chemoradiation and surgery in selected dMMR/MSI-H rectal cancer patients.

Endpoints

Primary: proportion of patients sustaining clinical complete response for 12 months (cCR12) by independent central review (ICR). Secondary: cCR24 and cCR36 by ICR, cCR12 by investigator, 3-year event-free survival (EFS), disease-specific survival (DSS), organ preservation rate, overall survival (OS), objective response rate (ORR), safety, and PK parameters.

Lead Investigator

Andrea Cercek, MD, Memorial Sloan Kettering Cancer Center. Section Head of Colorectal Cancer; co-director, Center for Young Onset Colorectal and Gastrointestinal Cancer.

Clinical Complete Response (cCR12) - Primary Endpoint

Per the FDA approval notice (October 19, 2026): cCR12 by independent central review (ICR), the primary endpoint, was 47% (54/116) in 116 ICR-evaluable patients. Separately, FDA reports 38 patients (33%) with cCR by ICR but under 12 months of follow-up, and 44 (38%) with near CR at data cutoff (categories as reported by FDA). Investigator-assessed cCR12 was 68% (95% CI 60-76) in 144 evaluable patients. ORR was 79% (95% CI 71-85) by ICR and 82% (95% CI 75-88) by investigator. Of 154 treated patients, 110 (71%) received dostarlimab alone with no further treatment and no progression. Median follow-up 26.3 months (AZUR-1, FDA notice); no patient with cCR12, cCR or near CR had progressed. [Source: FDA approval notice, Oct 19, 2026] The full interim analysis was presented at ESMO 2026 (LBA87) and is summarized in the next block.

cCR12 47% by ICR (primary) - 68% by investigator
Source: FDA approval notice, Oct 19, 2026 · GSK press release, Oct 19, 2026

ESMO 2026: First Results From the Global AZUR-1 Trial (LBA87; Interim Analysis, DCO 20-Apr-2026)

Andrea Cercek presented the interim analysis in the lower-digestive proffered paper session at ESMO 2026 (Madrid, October 25, 2026), with a simultaneous paper in Annals of Oncology (doi:10.1016/j.annonc.2026.10.1280). At the data cutoff of April 20, 2026, 154 patients had received dostarlimab 500 mg IV every 3 weeks for 9 cycles; median follow-up was 26.3 months (range 2–36). 88% completed all 9 cycles (abstract; median 9 cycles, range 2–9, on the safety slide).

Endpoint hierarchy. The registered primary endpoint is cCR12 by independent central review (ICR). The abstract and paper lead with investigator-assessed cCR12 and the composite cCR12 + pCR. Fewer patients were cCR12-evaluable by ICR, mainly because ICR confirmed cCR at later time points than investigators did; the presented slide is titled “Investigator-assessed cCR is achieved earlier than by central review.”

Endpoint	Result	Context	Source
cCR12 by independent central review (primary endpoint)	47% (54/116); 95% CI 37–56 on the ESMO slide. The FDA notice prints 27–56; GSK’s Oct 19 release prints 37–56	ICR analysis 75% mature; 38 patients in cCR still being followed for cCR12	Abstract; slides
cCR12 by investigator (secondary)	68% (98/144); 95% CI 60–76	Investigator analysis 94% mature	Abstract; slides
Composite cCR12 (investigator) + pCR (exploratory)	76% (110/144)	98 cCR12 + 12 pCR after surgery following dostarlimab alone	Abstract; slides
pCR after surgery following dostarlimab alone	80% (12/15)		Abstract
End-of-treatment cCR	71% (110/154)	102 cCR at end of treatment + 8 late conversions from nCR/PR	Slides
Durability	98% of patients in cCR stayed in cCR ≥12 months	No recurrences reported among patients in cCR or pCR	Abstract; Annals
Managed with dostarlimab alone (non-operative management)	71% (110/154)	Additional standard-of-care treatment 26% (40/154); on study with no progression after dostarlimab ± SOC 93% (143/154)	Slides; abstract

Safety (Cercek, ESMO 2026 slide, DCO 20-Apr-2026): dostarlimab-related adverse events led to discontinuation in 3 patients (2%); there were no fatal dostarlimab-related adverse events. The patient-disposition slide records 5 deaths (1 before the end-of-treatment response assessment; 4 in the additional standard-of-care branch, including 1 patient who refused standard-of-care treatment). SAEs of clinical interest were intestinal obstruction (3; 2%), rectal stenosis (2; 1%) and intestinal perforation (2; 1%), none considered dostarlimab-related.

Safety (N=154)	Grade 1–2 (or any)	Grade ≥3
Any dostarlimab-related AE	98 (64%)	15 (10%)
Any immune-mediated AE	32 (21%)	4 (3%)
Treatment-emergent SAE, any cause / dostarlimab-related	31 (20%) / 8 (5%)	—

The investigators conclude that the durable responses indicate the potential to avoid chemotherapy, radiation and surgery in dMMR/MSI-H locally advanced rectal cancer. AZUR-1 is single-arm, the ICR analysis is still maturing, and follow-up is a median of about two years. The October 19, 2026 FDA accelerated approval (above) was based on the FDA’s review of this trial.

cCR12 47% by ICR (primary) · 68% by investigator · 76% cCR12 + pCR · DCO 20-Apr-2026

ESMO 2026 abstract LBA87 · Annals of Oncology, Oct 25, 2026 · Cercek, ESMO 2026 slides (photographed by physicians; see Key Slides)

Prior MSK Study (NCT04165772): 100% cCR in 42 Patients (ASCO 2024)

In the landmark investigator-led, multicenter MSK study, the first 12 patients treated with dostarlimab monotherapy all achieved clinical complete response (Cercek et al., NEJM 2022). The ASCO 2024 update (LBA3512) reported cCR in all 42 patients who completed treatment, with sustained cCR of 12+ months in 24 patients (median follow-up 26.3 months for that subset, ASCO 2024). In the FDA's 2026 review (50 treated): cCR12 93% (95% CI 82-99) in evaluable patients (denominator not stated by FDA); ORR 100% (95% CI 93-100); no patient received chemoradiation or rectal cancer surgery as part of LARC treatment, and of 27 patients followed at least 3 years, one had a local recurrence treated with lymphadenectomy. (Cercek et al., NEJM 2022; JCO LBA3512, ASCO 2024; FDA approval notice, Oct 19, 2026)

100% cCR in 42/42 patients (prior MSK study, ASCO 2024 LBA3512)
Source: Cercek et al., NEJM 2022 · JCO LBA3512 (ASCO 2024) · FDA approval notice, Oct 19, 2026

Safety

Per the GSK approval release (October 19, 2026): serious adverse reactions occurred in 20% of patients; the most common adverse reactions were fatigue (32%), rash (22%), diarrhea (18%) and pruritus (17%); 3% permanently discontinued for adverse reactions. The FDA notice lists prescribing-information warnings for immune-mediated adverse reactions, infusion-related reactions, complications of allogeneic HSCT and embryo-fetal toxicity. [Source: GSK release 10/19/2026; FDA notice 10/19/2026] In the prior MSK study (NCT04165772), common any-grade adverse events reported at the ASCO 2024 update (LBA3512) included pruritus (13%), rash/dermatitis (21%), diarrhea (9%), nausea (9%), fatigue (11%), fever (6%), and hypothyroidism (11%).

Serious adverse reactions 20% · discontinuation 3% (GSK 10/19/2026)
Source: GSK press release, Oct 19, 2026 · FDA approval notice, Oct 19, 2026

Clinical Implications

✓ FDA accelerated approval October 19, 2026. Dostarlimab-gxly (Jemperli) is now approved for adults with stage II/III MSI-H/dMMR locally advanced rectal cancer (as determined by an FDA-authorized test for solid tumors), which GSK describes as the first and only immunotherapy approved in this setting, offering selected patients a path that may avoid chemotherapy, radiation and surgery - in AZUR-1, 71% of 154 treated patients received dostarlimab alone with no further treatment and no progression (FDA notice). GSK announced on August 24, 2026 that the FDA had accepted the sBLA for Priority Review. The FDA approved about four months ahead of its goal date (FDA notice); the PDUFA date had been February 2027 (AnaptysBio release; GSK's Aug 24 Priority Review announcement). Dostarlimab previously received Breakthrough Therapy and Fast Track designations in this setting (per GSK). This approach builds on Cercek's landmark MSK study (NCT04165772): 100% cCR in the first 12 patients (NEJM 2022) and in all 42 patients who completed treatment at the ASCO 2024 LBA3512 update. Full AZUR-1 interim data are expected at ESMO 2026.

Major Media & Publications

AZUR-1 in the News

FDA

FDA grants accelerated approval to dostarlimab for locally advanced rectal cancer

U.S. FDAOct 19, 2026

PRESS

Jemperli (dostarlimab) approved in US as first and only immunotherapy for adults with MSI-H/dMMR locally advanced rectal cancer

GSKOct 19, 2026

PRESS

Jemperli (dostarlimab) Approved in the U.S. as First and Only Immunotherapy for Adults with MSI-H/dMMR Locally Advanced Rectal Cancer

AnaptysBio (GlobeNewswire)Oct 19, 2026

MEDIA

FDA Approves Dostarlimab for dMMR/MSI-H Locally Advanced Rectal Cancer

OncLiveOct 19, 2026

MEDIA

FDA Approves Dostarlimab in Previously Untreated Locally Advanced Rectal Cancer

CancerNetworkOct 19, 2026

MEDIA

FDA Approves Jemperli for dMMR Locally Advanced Rectal Cancer

CUREOct 19, 2026

PRESS

Jemperli (dostarlimab-gxly) Accepted for Priority Review by the US FDA for dMMR/MSI-H Locally Advanced Rectal Cancer

GSKAug 24, 2026

MEDIA

FDA Grants Priority Review to Dostarlimab for dMMR/MSI-H Locally Advanced Rectal Cancer

OncLiveAug 24, 2026

MEDIA

Dostarlimab Achieves Sustained Clinical Complete Responses in dMMR/MSI-H Rectal Cancer

OncLiveJul 13, 2026

MEDIA

Dostarlimab Yields Sustained Complete Responses in dMMR/MSI-H Rectal Cancer

CancerNetworkJul 13, 2026

PUB

PD-1 Blockade in Mismatch Repair-Deficient, Locally Advanced Rectal Cancer

NEJMJun 2022

PUB

Durable Complete Responses to PD-1 Blockade Alone in dMMR Locally Advanced Rectal Cancer

JCO (ASCO 2024)Jun 2024

Frequently Asked Questions

AZUR-1 FAQ

What is the AZUR-1 trial?

AZUR-1 is a global, multicenter, open-label, single-arm, registrational phase 2 trial evaluating dostarlimab-gxly (Jemperli) monotherapy in 154 patients with previously untreated stage II/III dMMR/MSI-H locally advanced rectal cancer. It was designed to confirm the landmark findings of Andrea Cercek's MSK study showing 100% clinical complete response with PD-1 blockade alone.

What did AZUR-1 show at ESMO 2026?

At ESMO 2026 (LBA87, October 25, 2026; Annals of Oncology), the interim analysis (data cutoff April 20, 2026; median follow-up 26.3 months) reported cCR12 by independent central review, the primary endpoint, of 47% (54/116), with 38 more patients in cCR still being followed. Investigator-assessed cCR12 was 68% (98/144) and the exploratory composite of cCR12 plus pathological complete response was 76% (110/144). 98% of patients who reached cCR stayed in cCR for at least 12 months, no recurrences were reported among patients in cCR or pCR, and 71% (110/154) were managed with dostarlimab alone. Grade 3 or higher immune-mediated adverse events occurred in 3% (4 patients). The trial is single-arm and the central-review analysis is still maturing.

Did AZUR-1 meet its primary endpoint?

Yes, per GSK, with ICR cCR12 data still maturing. Per the FDA notice, cCR12 by ICR was 47% (54/116) in 116 ICR-evaluable patients (sustained clinical complete response at 12 months by independent central review, the primary endpoint). Separately, FDA reports 38 patients (33%) with cCR by ICR but under 12 months of follow-up, and 44 (38%) with near CR at data cutoff (categories as reported by FDA). Investigator-assessed cCR12 was 68% (95% CI 60-76) in 144 evaluable patients. ORR was 79% by ICR and 82% by investigator. With a median follow-up of 26.3 months (AZUR-1, FDA notice), no patient with cCR12, cCR or near CR had progressed. Full interim data were presented at ESMO 2026 (LBA87, October 25, 2026) and published in Annals of Oncology.

Is dostarlimab FDA-approved for rectal cancer?

Yes. On October 19, 2026, the FDA granted accelerated approval to dostarlimab-gxly (Jemperli, GSK) for adults with stage II or III locally advanced rectal cancer that is MSI-H or dMMR, as determined by an FDA-authorized test for solid tumors. The FDA approved about four months ahead of its goal date (FDA notice); the PDUFA date had been February 2027 (AnaptysBio release; GSK's Aug 24 Priority Review announcement). The approval is based on AZUR-1 (NCT05723562; cCR12 by independent central review, the primary endpoint, 47% (54/116); 68% by investigator) and the supporting study NCT04165772 (investigator-led, multicenter, MSK-led; 50 treated): cCR12 93% (95% CI 82-99) in evaluable patients (denominator not stated by FDA). Recommended dose: 500 mg IV every 3 weeks for up to 9 cycles. Reviewed under Priority Review, Breakthrough Therapy, Real-Time Oncology Review, Project Orbis and the FDA Commissioner's National Priority Review Voucher (CNPV) pilot program. Dostarlimab also received a separate accelerated approval on August 17, 2021 for adults with dMMR recurrent or advanced solid tumors (as determined by an FDA-approved test) that progressed on or following prior treatment and who have no satisfactory alternative treatment options (GARNET; FDA notice, Aug 17, 2021). FDA notice, Aug 17, 2021 → FDA notice →

How does AZUR-1 differ from the original Cercek study?

The original MSK study (Cercek et al., NEJM 2022; NCT04165772) was an investigator-led, multicenter study of 12 patients (later expanded to 42) that achieved 100% cCR with dostarlimab alone. AZUR-1 is the global, multicenter, registrational phase 2 trial with 154 patients that served as the basis of the October 19, 2026 accelerated approval.

What is the significance of the non-operative management approach?

With the October 19, 2026 accelerated approval, dostarlimab-gxly became what GSK describes as the first and only immunotherapy approved for adults with stage II/III MSI-H/dMMR locally advanced rectal cancer, offering selected patients a path that may avoid chemotherapy, radiation and surgery - in AZUR-1, 71% of 154 treated patients received dostarlimab alone with no further treatment and no progression (FDA notice). The GSK release quotes AZUR-1 principal investigator Andrea Cercek, MD, describing the results as showing the potential for “a fundamentally different treatment approach” in this biomarker-defined population; avoiding chemoradiation and surgery may spare patients their long-term quality-of-life impacts, including effects on bowel, urinary and sexual function, and fertility (GSK press release, Oct 19, 2026).

Physician Opinions

Key KOL Sentiments - AZUR-1

KOL	Comment	Sentiment	Impressions
Oncology Brothers @OncBrothers · FDA approval day	Dostarlimab (IV q3 wks, 9 cycles) is now @FDA ✅ for locally advanced (Stg II/III) MSI-H/dMMR rectal cancer off Ph II AZUR-1 study: - 71% got IO alone (no additional Rx) - Clinical CR for 12 mos: 47% (no progression at 26.3mos median f/u) - Surgery/Chemo free option! #gism	POSITIVE	988
ilyas sahin, MD @ilyassahinMD · FDA approval day	FDA grants accelerated approval to dostarlimab for locally advanced rectal cancer that is microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR)	NEUTRAL	684
Nicholas Hornstein @GIMedOnc · FDA approval day	🚨 FDA approval for dostarlimab in locally advanced dMMR/MSI-H rectal cancer! This was based on AZUR-1, with full data coming at @myESMO. #ESMO26 No recurrences among responders after more than 2 years of median follow-up! We know immunotherapy works, and when patients respond, those responses can be incredible. I’ve been using immunotherapy with curative intent in these patients, and I haven’t been disappointed. The fact that we’re potentially curing solid tumors with systemic therapy alone, without chemotherapy, radiation, or surgery, is magical. Looking forward to the full data and seeing this approach become more broadly available to patients. @OncoAlert @Onco_Nexus @TheGutOncLab	POSITIVE	459
Dr. Cathy Eng	@AndreaCercek 🤩announced at #ESMOGI2026 phase 2 AZUR-1 will be presented at @myESMO #ESMO2026 which was created to validate her original single center Dostarlimab data in #rectal #cancer. Looking forward to the results! #CancerResearch @GSK_US @OncoAlert	POSITIVE	1.7K
ilyas sahin, MD	Could some rectal cancer patients skip chemotherapy, radiation, and surgery? The FDA has granted priority review to dostarlimab (a PD-1 immunotherapy) for untreated stage II–III dMMR/MSI-H locally advanced rectal cancer, with a decision expected by February 2027. The application is based on the global Phase 2 AZUR-1 study (n=154), where 6 months of dostarlimab alone met the primary endpoint of sustained clinical complete response at ≥12 months (cCR12). This builds on the landmark MSK NEJM experience showing striking complete-response rates in this biomarker-defined group. As a reminder, dMMR/MSI-H accounts for only about 5–10% of rectal cancers. AZUR-1 is single-arm, and priority review is not approval. Still, biomarker-driven organ preservation moving toward a regulatory label is a major milestone. ✅	POSITIVE	3.1K
Ibrahim Halil SAHIN, MD	✳️The AZUR-1 trial, testing the efficacy of dostarlimab for patients with MMR-D/MSI-H rectal cancer, is now open and enrolling at @UPMCHillmanCC ‼️ ✳️This trial will serve to patients in with #lynch syndrome and rectal cancer or those with sporadic MMR-D Rectal Cancer‼️ Please feel to reach out ‼️ @stacy_hurt @manjuggm @CrcTrialsChat @TheColonClub @colontown @CCAREfightlynch	NEUTRAL	2.8K
Jaume Capdevila	A Phase 2, Single-Arm, Open-Label Study with Dostarlimab Monotherapy in Participants with Untreated Stage II/III dMMR/MSI-H Locally Advanced Rectal Cancer (AZUR-1) @GrupoTTD @VHIO @GSK https://t.co/Qe9CxQRD6E	NEUTRAL	936
Vivek Subbiah, MD	FDA Grants Priority Review to Dostarlimab for dMMR/MSI-H Locally Advanced Rectal Cancer \| OncLive https://t.co/DyRWydmPht	NEUTRAL	491

Compiled and reviewed by the KOL Pulse research team, led by Brian Shields, Founder, KOL Pulse. Last updated October 26, 2026 (ESMO 2026 LBA87 data, slides and physician reactions).

AZUR-1 Trial

AZUR-1 Key Takeaways

Study Design

Primary Endpoint: cCR12 by Independent Central Review

ESMO 2026 Interim Analysis (LBA87, Annals of Oncology)

Safety

Prior Data Context

Regulatory Status

Sponsor & Drug

FDA Accelerated Approval - October 19, 2026

FDA APPROVED Jemperli (dostarlimab-gxly) monotherapy, stage II/III MSI-H/dMMR locally advanced rectal cancer

What global KOLs said on approval day

What physicians said about the ESMO 2026 data

What physicians debated

Track oncology’s top KOLs in your specialty

Top KOLs Discussing AZUR-1

AZUR-1 Key Slides & Visuals

ESMO 2026 slides

More slides on this page

AZUR-1 Top Tweets

About the AZUR-1 Trial

Trial Methodology & Results

Study Design

Population

Interventions

Endpoints

Lead Investigator

Clinical Complete Response (cCR12) - Primary Endpoint

ESMO 2026: First Results From the Global AZUR-1 Trial (LBA87; Interim Analysis, DCO 20-Apr-2026)

Prior MSK Study (NCT04165772): 100% cCR in 42 Patients (ASCO 2024)

Safety

Clinical Implications

AZUR-1 in the News

AZUR-1 FAQ

What is the AZUR-1 trial?

What did AZUR-1 show at ESMO 2026?

Did AZUR-1 meet its primary endpoint?

Is dostarlimab FDA-approved for rectal cancer?

How does AZUR-1 differ from the original Cercek study?

What is the significance of the non-operative management approach?

Key KOL Sentiments - AZUR-1

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