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. (GSK Press Release, Jul 2026)
Primary Endpoint: cCR12 Met
AZUR-1 met its primary endpoint of sustained clinical complete response at 12 months (cCR12) by independent central review. GSK reported results represent a substantial improvement compared to historical standard of care. Full numerical data will be presented at ESMO 2026. (GSK Press Release, Jul 2026)
Primary endpoint met - cCR12 achievedPrior Data Context
The landmark MSK phase 2 study (Cercek et al., NEJM 2022) demonstrated 100% clinical complete response in all 42 patients treated with dostarlimab alone, with sustained cCR of 12+ months in 24 patients at median 26.3 months follow-up. No grade 3+ adverse events. (NEJM 2022; JCO LBA3512, ASCO 2024)
Regulatory Status
Investigational for this specific indication. FDA Priority Review granted August 24, 2026 (PDUFA February 2027). Breakthrough Therapy and Fast Track designations previously granted. Submitted under Project Orbis. Dostarlimab has existing tumor-agnostic approval for dMMR recurrent/advanced solid tumors (August 2021). (GSK Press Release, Aug 2026)
Investigational - Priority Review PDUFA Feb 2027Sponsor & Drug
GSK. Dostarlimab-gxly (Jemperli), a PD-1 inhibitor. Organ-preserving immunotherapy-only approach - potentially eliminating chemotherapy, radiation, and surgery for selected dMMR/MSI-H rectal cancer patients.
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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 significant proportion of participants had no detectable signs of cancer for at least one year after treatment.
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. ECOG performance status 0-1. 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
AZUR-1 met its primary endpoint, demonstrating a meaningful and sustained clinical complete response rate at 12 months (cCR12) with no detectable signs of cancer for at least one year. GSK reported that AZUR-1 results represent a substantial improvement compared to the historical standard of care. Detailed response kinetics, durability metrics, and full cCR12 rates will be disclosed at a scientific congress later in 2026 (confirmed for ESMO 2026).
Primary endpoint cCR12 metSource: GSK Press Release, Aug 24, 2026
Prior MSK Study: 100% cCR in 42 Patients
In the landmark prior MSK study, all 42 patients treated with dostarlimab monotherapy achieved clinical complete response. Updated data (ASCO 2024, LBA3512) showed sustained cCR of 12+ months in 24 patients at median 26.3 months follow-up. No patient required chemotherapy, radiation, or surgery. No grade 3+ adverse events occurred. (Cercek et al., NEJM 2022; JCO 2024)
100% cCR in 42/42 patients (prior study, NEJM 2022)Source: Cercek et al., NEJM 2022
Safety
In interim data, the safety and tolerability profile of dostarlimab-gxly was generally consistent with its well-characterized and manageable safety profile observed across solid tumors. No new safety signals were identified. In the prior MSK phase 2 study (Cercek et al., NEJM 2022), no grade 3 or higher adverse events occurred. Common any-grade AEs in the prior study included pruritus (13%), rash/dermatitis (21%), diarrhea (9%), nausea (9%), fatigue (11%), fever (6%), and hypothyroidism (11%).
Consistent, manageable safety profileSource: GSK Press Release, Aug 24, 2026
Clinical Implications
If approved, dostarlimab-gxly would become the first immunotherapy specifically indicated to potentially eliminate or delay the need for chemotherapy, radiation, and surgery in selected patients with dMMR/MSI-H locally advanced rectal cancer. The FDA granted Priority Review to the sBLA on August 24, 2026, with a PDUFA target action date of February 2027. Dostarlimab previously received Breakthrough Therapy and Fast Track designations in this setting. This approach builds on Cercek's landmark NEJM 2022 study showing 100% cCR in all 42 patients treated. AZUR-1 is INVESTIGATIONAL for this specific indication.
AZUR-1 in the News
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.
Did AZUR-1 meet its primary endpoint?
Yes. AZUR-1 met its primary endpoint of sustained clinical complete response at 12 months (cCR12) by independent central review. GSK reported that results represent a substantial improvement compared to the historical standard of care. Full data will be presented at ESMO 2026.
Is dostarlimab FDA-approved for rectal cancer?
Not yet for this specific indication. The FDA granted Priority Review to the sBLA on August 24, 2026, with a target action date of February 2027. Dostarlimab previously received Breakthrough Therapy and Fast Track designations for dMMR/MSI-H locally advanced rectal cancer. It has existing FDA approval for dMMR recurrent/advanced solid tumors (tumor-agnostic, August 2021).
How does AZUR-1 differ from the original Cercek study?
The original MSK study (Cercek et al., NEJM 2022) was a single-center study of 12 patients (later expanded to 42) that achieved 100% cCR with dostarlimab alone. AZUR-1 is the multicenter, global, registrational confirmatory trial with 154 patients designed to validate these results across multiple centers and support FDA approval.
What is the significance of the non-operative management approach?
If approved, dostarlimab-gxly would become the first immunotherapy specifically indicated to potentially eliminate the need for chemotherapy, radiation, and surgery for selected patients with dMMR/MSI-H locally advanced rectal cancer. This organ-preserving approach could fundamentally change the treatment paradigm, avoiding the significant long-term quality-of-life impacts associated with chemoradiation and surgery, including effects on bowel, urinary, and sexual function, and fertility.
Key KOL Sentiments - AZUR-1
Compiled and reviewed by the KOL Pulse research team, led by Brian Shields, Founder, KOL Pulse. Last updated 2026-08-24.