What is the PANKU-Breast01 trial?

PANKU-Breast01 (BL-B01D1-306, NCT06343948) is a Phase III, randomized, open-label study in China of iza-bren (izalontamab brengitecan) versus chemotherapy of physician’s choice in 383 patients with previously treated HR+/HER2- advanced breast cancer. The primary endpoint is progression-free survival. See Trial Design.

What did PANKU-Breast01 show?

Iza-bren met its primary endpoint, improving progression-free survival over chemotherapy (HR 0.41; ESMO 2026 LBA50, data cutoff 21 Jul 2026); OS was immature. PFS, response and safety figures with sources: At a Glance.

Iza-bren (izalontamab brengitecan, BL-B01D1) is an investigational EGFR×HER3 bispecific antibody-drug conjugate developed by SystImmune/Biokin and, outside China, jointly with Bristol Myers Squibb. It is not FDA-approved. See At a Glance.

Is iza-bren FDA-approved for breast cancer?

No. Iza-bren is investigational in the United States. Its FDA Breakthrough Therapy Designation is in previously treated EGFR-mutated NSCLC, not breast cancer. See At a Glance.

How does PANKU-Breast01 differ from PANKU-Breast02?

PANKU-Breast01 (BL-B01D1-306) enrolled HR+/HER2- breast cancer; PANKU-Breast02 (BL-B01D1-307, NCT06382142) enrolled triple-negative breast cancer. They are separate Phase III trials of the same drug.

PANKU-Breast01: Iza-Bren PFS 8.18 vs 4.01 Months at ESMO 2026 (LBA50)

Physician Reactions · ESMO 2026

Physician reactions to the LBA50 results

Full, verbatim posts from physicians on X during ESMO 2026 week (October 22–24, 2026), newest first and linked to the originals. Most cite the PFS gain; several point to hematologic toxicity, immature OS, the China-only population, and where iza-bren would sit next to other ADCs.

Erika Hamilton, MD, FASCO@ErikaHamilton9

#PANKUBreast01 Ph III results for iza bren (bispecific EGFR/HER3 ADC) vs TPC chemo, in previously treated HR +/HER- MBC 🔹mPFS: 4.0 vs. 8.1 mo, HR 0.41 🔹 ORR: 20% vs 40% 🔹 DoR: 4.2 vs. 6.9 mo 🔹 ILD: only 1.1% & all grade 1/2 #ESMO26 #ESMOAmbassadors https://t.co/ikHLXiLHX1

349 views 6 likes2 RT 2026-10-23

MV Chandrakanth@ChandrakanthMv

🚨 PANKU-Breast01 | ESMO 2026 | LBA50 TWO TARGETS. DOUBLE THE PFS. BUT WHAT ABOUT SURVIVAL? Phase III trial of izalontamab brengitecan (iza-bren), a bispecific EGFR/HER3 ADC, in previously treated HR+/HER2− advanced breast cancer. 🔹 N = 383 | Iza-bren vs physician's choice chemotherapy 🔹 Median PFS: 8.18 vs 4.01 months 🔹 HR 0.41 — 59% lower hazard of progression or death 🔹 ORR: 40.5% vs 20.2% 🔹 ILD: 1.1%, all grade 1–2 ⚠️ OS immature. Optimal ADC sequencing remains unresolved. TAKE-HOME Dual EGFR/HER3 targeting nearly doubles median PFS, but an overall survival advantage remains unproven. 📖 Ref: Lan B et al. PANKU-Breast01. ESMO 2026; LBA50. @myESMO @OncoAlert #MVOnco #ESMO2026 #BreastCancer #ADC

333 views 0 likes1 RT 2026-10-23

Yakup Ergün@dr_yakupergun

#ESMO26 | PANKU-Breast01 In HR+/HER2− mBC, after CDK4/6i and 1–2 prior chemotherapy lines: Iza-bren vs chemotherapy: PFS: 8.2 vs 4.0 months (HR 0.41); ORR: 40.5% vs 20.2% https://t.co/izrdBxO77a https://t.co/iDkohswiRI

262 views 2 likes1 RT 2026-10-23

Stephanie Graff, MD, FACP, FASCO@DrSGraff

Iza-bren shows significant mPFS of 8.2 mos vs 4.0 mos , HR=0.41 #ESMO26 @OncoAlert https://t.co/Dk2JusQLRi

247 views 6 likes5 RT 2026-10-23

Paolo Tarantino@PTarantinoMD

🇨🇳 PANKU-Breast01: the HER3-EGFR bispecific TOPO1 ADC Iza-Bren improved PFS vs chemo in HR+/HER2- MBC (OS immature). High rate of hematologic toxicity, with ~50% G3+ anemia, neutropenia and thrombocytopenia, and most patients requiring dose reductions⚠️. #ESMO26 #ESMOAmbassadors https://t.co/f1zn2X0bpe

240 views 1 likes2 RT 2026-10-23

Kazuki Nozawa, MD@kazuki_nozawa

PANKU-Breast01 #ESMO26 Iza-bren (EGFRxHER3-ADC) significantly improved PFS vs chemotherapy in pretreated HR+/HER2− advanced breast cancer (8.2 vs 4.0 months; HR 0.41). ORR doubled (40.5% vs 20.2%), with manageable safety (ILD 1.1%). OS remains immature. https://t.co/EfZyLTGV02

228 views 3 likes3 RT 2026-10-23

Sara Tolaney@stolaney1

PANKU-Breast01 HR+ MBC, prior cdk 4/6i, 1-2 prior chemo Iza-bren vs TPC ~70% 1 prior chemo PFS 8.2 vs 4.0 mo, HR 0.41 p<0.0001 ORR 40.5% vs 20.2% DOR 6.9 mo vs 4.2 mo OS immature Most tox: heme tox, primary GCSF was not required @OncoAlert #ESMO26 https://t.co/zdUlK7U21Q

220 views 4 likes6 RT 2026-10-23

Matteo Lambertini, MD PhD@matteolambe

Oral abstract #BreastCancer session at #ESMO26: results from PANKUbreast01 published in @TheLancet shoring efficacy of bispecific ADC #IzaBren in pretreated patients with HR+/HER2- advanced disease @OncoAlert @myESMO https://t.co/QJy9STIjLz

187 views 5 likes5 RT 2026-10-23

Philippe Aftimos, MD @aftimosp

PANKU-Breast01 🇨🇳: dual EGFR and HER3 ADC Iza-Bren vs TPC in HR+/HER2- pre-treated MBC: 🔹 Median PFS improvement with Iza-bren: 8.2 vs 4 months (HR 0.41) 🔹 OS immature 🔸 More grade 3 AEs with Iza-bren #ESMO26 #ESMOAmbassadors @myESMO @PTarantinoMD @E_de_Azambuja https://t.co/ORpXqVnLMk

171 views 2 likes2 RT 2026-10-23

Sherene Loi, MD@LoiSher

#ESMO2026 Panku-breast01 Izabren sig. improves PFS in met HR+HER2 post CDK4i #BreastCancer 👏New targets 🎈impressive ORR too ➡️broadly comparable to DB04 - here all HER2 But 🎈haem tox Still have the what next issue 🤷🏻‍♀️ Online publication in @TheLancetOncol #ESMOAmbassadors #bcsm @OncoAlert @myESMO

151 views 4 likes4 RT 2026-10-23

Elisa Agostinetto@ElisaAgostinett

At #ESMO26 proffered paper session 1️⃣ on #breastcancer Iza-bren ⬆️ PFS vs TPC in pretreated HR+ HER2-neg mBC Simultaneous publication in @TheLancetOncol @OncoAlert https://t.co/2dTssDG8tq

140 views 5 likes6 RT 2026-10-23

Elisabetta Bonzano MD, PhD@to_be_elizabeth

📌 Proffered paper 1: Breast cancer, early and advanced stage ✨PANKU-Breast01: Randomized Phase III Study of Izalontamab Brengitecan in Previously Treated Unresectable Locally Advanced or Metastatic HR+/HER2- Breast Cancer Presented by ✨ Bo Lan 👉🏻In this pre-specified analysis, iza-bren demonstrated a statistically significant and clinically meaningful improvement in PFS vs TPC in previously treated HR+/HER2-BC, meeting the primary endpoint. 👉🏻Iza-bren demonstrated an improved confirmed ORR and more durable response than TPC. #ESMO26 🇪🇸 @OncoAlert #OncoAlertAF

139 views 4 likes5 RT 2026-10-23

Gaia Griguolo@GaiaGriguolo

PANKU-Breast01 presented at #ESMO26 Iza-bren vs CT in HR+/HER2- after ET and 1 or 2 lines of CT ✅️ significantly improved PFS Mostly hematologic toxicity, 1% ILD events @OncoAlert https://t.co/Xwo7yVmiTM

124 views 4 likes5 RT 2026-10-23

Aya Mohamed | MSc, MD 🎗@Dr_Oncologista

PANKU-Breast01 | #ESMO26 Iza-bren significantly improved PFS in pretreated HR+/HER2− advanced #BreastCancer vs physician’s choice chemotherapy (8.2 vs 4.0 months; HR 0.41). @OncoAlert #bcsm https://t.co/FS1TSa1cLo

62 views 8 likes5 RT 2026-10-23

Evandro de Azambuja, MD, PhD@E_de_Azambuja

Iza-bren improves PFS compared to standard chemo in pts with HR+ HER2 neg MBC after 1-2 lines of CT for metastatic disease #ESMO26 #ESMOAmbassadors #ESMOcommunity @myESMO https://t.co/h8TrfHlQel

58 views 1 likes1 RT 2026-10-23

Carmen Criscitiello@CarmenCriscit

PANKU-Breast01 at #ESMO26: izalontamab brengitecan, an EGFR×HER3 bispecific ADC, doubled PFS vs physician's-choice chemo in pretreated HR+/HER2- MBC (8.2 vs 4.0 mo, HR 0.41). A new target pairing after CDK4/6 - promising, though a Chinese-only population. #ESMOAmbassadors @myESMO https://t.co/s4PYcCD56O

29 views 0 likes0 RT 2026-10-23

Yakup Ergün@dr_yakupergun

𝕏

#ESMO26 | PANKU-Breast01 In HR+/HER2− mBC, the EGFR/HER3 bispecific ADC (iza-bren): PFS: 8.18 vs 4.05 months (HR 0.41). Grade ≥3 TRAEs: 40.5% vs 20.2%. OS remains immature. An impressive PFS benefit. However, in an era when ADCs such as T-DXd and SG are already in use, superiority over chemotherapy alone is not enough. Another treatment option… The added value of bispecific targeting, particularly its efficacy after other TOP1-ADCs, remains uncertain. These are the key data needed to define its place in treatment sequencing.

Context: in the LBA50 abstract in this post (data cutoff 21 Jul 2026), 40.5% vs 20.2% is the BICR-confirmed objective response rate; grade 3 or higher TRAEs were 85.3% vs 65.8% on the presented safety slide. Median PFS by BICR was 8.18 vs 4.01 months (HR 0.41).

1.8K views 7 likes2 RT 2026-10-23

Yakup Ergün@dr_yakupergun

𝕏

I’ve added the PANKU-Breast01 results to Dr. Barbara Pistilli’s excellent original slide👇 https://t.co/9DABg8HFkl https://t.co/iBIMpJWeSe

1.7K views 24 likes15 RT 2026-10-23

Kristina Jankovic, MD@JankovicK

𝕏

🚨 #ESMO26 | PANKU-Breast01 🇨🇳 Izalontamab brengitecan (iza-bren), an EGFR×HER3 bispecific ADC, significantly improved PFS 🆚 physician’s choice chemotherapy in HR+/HER2− advanced #BreastCancer after endocrine therapy, CDK4/6i and 1–2 chemotherapy lines. 🔹 mPFS: 8.2 🆚 4.0 months (HR 0.41) 🔹 Confirmed ORR: 40.5% 🆚 20.2% 🔹 OS remains immature ⚠️ Grade ≥3 TRAEs: 85% 🆚 66%, predominantly haematological. 🎯 Promising efficacy in a heavily pretreated population; toxicity and validation beyond China remain key considerations. 📖 Simultaneously published in @TheLancet : https://t.co/2ccmyPJSO4 @OncoAlert @myESMO

320 views 2 likes5 RT 2026-10-23

Mali Barbi, MD MSc | Breast & Gyn Oncologist@DrBarbiOnc

𝕏

#PANKUBreast01: iza-bren, an EGFR x HER3 bispecific ADC with a TOPO1 payload, vs chemo in HR+/HER2- MBC n=383. PFS 8.2 vs 4.0 mo, HR 0.41. ORR 40.5% vs 20.2%. A real result, and it enrolled HER2 0, 1+ and 2+, so no HER2 test gates it. In clinic it lands in a space already holding T-DXd, Dato-DXd and sacituzumab. All TOPO1. Iza-bren is a new target, not a new mechanism. The number I want is how many patients had a prior ADC, and how they did. #bcsm #ESMO26 @myESMO

200 views 2 likes1 RT 2026-10-23

Prof. Dr. Ahmet Dirican@dr_dirican

𝕏

#ESMO26 | Impressive results with a next-generation bispecific ADC! Phase III PANKU-Breast01: EGFR×HER3-targeting iza-bren improved median PFS in HR+/HER2− metastatic breast cancer (8.2 vs 4.0 months; HR 0.41). However, grade ≥3 treatment-related AEs reached 85.3%. Key questions: Do ESR1, PIK3CA, or PTEN alterations influence response? What is the impact of prior ADC exposure? #ESMO26 #BreastCancer #ADC @myESMO @oncodaily @OncoAlert

180 views 1 likes0 RT 2026-10-23

Sara Soliman, MD@sara_soliman7

𝕏

#ESMO26 | PANKU-Breast01 Phase III: iza-bren, an EGFR×HER3 bispecific ADC, vs chemotherapy in previously treated HR+/HER2− advanced BC (N=383). ▪️ mPFS: 8.2 vs 4.0 months HR 0.41 (95% CI 0.33–0.53); P<0.0001 ▪️ ORR: 40.5% vs 20.2% ▪️ OS immature ▪️ Grade ≥3 TRAEs predominantly hematologic; ILD 1.1% (grade 1–2) Promising efficacy. Key question: where will it fit in ADC sequencing? 🔹 𝗕𝗠𝗦’𝘀 𝗼𝗻𝗴𝗼𝗶𝗻𝗴 𝗜𝗭𝗔𝗕𝗥𝗜𝗚𝗛𝗧-𝗕𝗿𝗲𝗮𝘀𝘁𝟬𝟭 𝘪𝘻𝘢-𝘣𝘳𝘦𝘯 𝘪𝘯 𝘢 𝘥𝘪𝘧𝘧𝘦𝘳𝘦𝘯𝘵 𝘱𝘰𝘱𝘶𝘭𝘢𝘵𝘪𝘰𝘯: 1𝘓 𝘢𝘥𝘷𝘢𝘯𝘤𝘦𝘥 𝘛𝘕𝘉𝘊 𝘰𝘳 𝘌𝘙-𝘭𝘰𝘸/𝘏𝘌𝘙2− 𝘉𝘊 𝘪𝘯𝘦𝘭𝘪𝘨𝘪𝘣𝘭𝘦 𝘧𝘰𝘳 𝘢𝘯𝘵𝘪–𝘗𝘋-(𝘓)1 𝘵𝘩𝘦𝘳𝘢𝘱𝘺. #Breastcancer #ADCs #PANKUBreast01

57 views 0 likes1 RT 2026-10-23

Dr Amol Akhade@SuyogCancer

🚨 ESMO 2026 | PANKU-Breast01 (LBA50) #esmo26 Impressive phase III results for izalontamab brengitecan (iza-bren), a bispecific EGFR/HER3 ADC, in previously treated MBC HR +ve Her2 -ve Iza-bren vs physician's choice chemotherapy: 🔹 Median PFS: 8.18 vs 4.01 months 🔹 HR 0.41 (95% CI 0.33–0.53; p<0.0001) 🔹 ORR: 40.5% vs 20.2% 🔹 Median DoR: 6.93 vs 4.21 months 🔹 ILD: 1.1% (all grade 1–2) 🔹 OS: Immature A remarkable 59% reduction in the hazard of progression or death, with manageable toxicity. Another ADC enters the increasingly crowded HR+/HER2− breast cancer landscape. @OncBrothers @myESMO @OncoAlert

1.2K views 9 likes2 RT 2026-10-22

Physician sentiment

Physician	Date	Sentiment	Post (verbatim)
Aya Mohamed \| MSc, MD 🎗 @Dr_Oncologista	Oct 23, 2026	● POSITIVE	PANKU-Breast01 \| #ESMO26 Iza-bren significantly improved PFS in pretreated HR+/HER2− advanced #BreastCancer vs physician’s choice chemotherapy (8.2 vs 4.0 months; HR 0.41). @OncoAlert #bcsm https://t.co/FS1TSa1cLo
Carmen Criscitiello @CarmenCriscit	Oct 23, 2026	● POSITIVE	PANKU-Breast01 at #ESMO26: izalontamab brengitecan, an EGFR×HER3 bispecific ADC, doubled PFS vs physician's-choice chemo in pretreated HR+/HER2- MBC (8.2 vs 4.0 mo, HR 0.41). A new target pairing after CDK4/6 - promising, though a Chinese-only population. #ESMOAmbassadors @myESMO https://t.co/s4PYcCD56O
Elisabetta Bonzano MD, PhD @to_be_elizabeth	Oct 23, 2026	● POSITIVE	📌 Proffered paper 1: Breast cancer, early and advanced stage ✨PANKU-Breast01: Randomized Phase III Study of Izalontamab Brengitecan in Previously Treated Unresectable Locally Advanced or Metastatic HR+/HER2- Breast Cancer Presented by ✨ Bo Lan 👉🏻In this pre-specified analysis, iza-bren demonstrated a statistically significant and clinically meaningful improvement in PFS vs TPC in previously treated HR+/HER2-BC, meeting the primary endpoint. 👉🏻Iza-bren demonstrated an improved confirmed ORR and more durable response than TPC. #ESMO26 🇪🇸 @OncoAlert #OncoAlertAF
Sherene Loi, MD @LoiSher	Oct 23, 2026	● NEUTRAL	#ESMO2026 Panku-breast01 Izabren sig. improves PFS in met HR+HER2 post CDK4i #BreastCancer 👏New targets 🎈impressive ORR too ➡️broadly comparable to DB04 - here all HER2 But 🎈haem tox Still have the what next issue 🤷🏻‍♀️ Online publication in @TheLancetOncol #ESMOAmbassadors #bcsm @OncoAlert @myESMO
Philippe Aftimos, MD  @aftimosp	Oct 23, 2026	● NEUTRAL	PANKU-Breast01 🇨🇳: dual EGFR and HER3 ADC Iza-Bren vs TPC in HR+/HER2- pre-treated MBC: 🔹 Median PFS improvement with Iza-bren: 8.2 vs 4 months (HR 0.41) 🔹 OS immature 🔸 More grade 3 AEs with Iza-bren #ESMO26 #ESMOAmbassadors @myESMO @PTarantinoMD @E_de_Azambuja https://t.co/ORpXqVnLMk
Gaia Griguolo @GaiaGriguolo	Oct 23, 2026	● POSITIVE	PANKU-Breast01 presented at #ESMO26 Iza-bren vs CT in HR+/HER2- after ET and 1 or 2 lines of CT ✅️ significantly improved PFS Mostly hematologic toxicity, 1% ILD events @OncoAlert https://t.co/Xwo7yVmiTM
Matteo Lambertini, MD PhD @matteolambe	Oct 23, 2026	● POSITIVE	Oral abstract #BreastCancer session at #ESMO26: results from PANKUbreast01 published in @TheLancet shoring efficacy of bispecific ADC #IzaBren in pretreated patients with HR+/HER2- advanced disease @OncoAlert @myESMO https://t.co/QJy9STIjLz
Kazuki Nozawa, MD @kazuki_nozawa	Oct 23, 2026	● POSITIVE	PANKU-Breast01 #ESMO26 Iza-bren (EGFRxHER3-ADC) significantly improved PFS vs chemotherapy in pretreated HR+/HER2− advanced breast cancer (8.2 vs 4.0 months; HR 0.41). ORR doubled (40.5% vs 20.2%), with manageable safety (ILD 1.1%). OS remains immature. https://t.co/EfZyLTGV02
Elisa Agostinetto @ElisaAgostinett	Oct 23, 2026	● POSITIVE	At #ESMO26 proffered paper session 1️⃣ on #breastcancer Iza-bren ⬆️ PFS vs TPC in pretreated HR+ HER2-neg mBC Simultaneous publication in @TheLancetOncol @OncoAlert https://t.co/2dTssDG8tq
Paolo Tarantino @PTarantinoMD	Oct 23, 2026	● NEUTRAL	🇨🇳 PANKU-Breast01: the HER3-EGFR bispecific TOPO1 ADC Iza-Bren improved PFS vs chemo in HR+/HER2- MBC (OS immature). High rate of hematologic toxicity, with ~50% G3+ anemia, neutropenia and thrombocytopenia, and most patients requiring dose reductions⚠️. #ESMO26 #ESMOAmbassadors https://t.co/f1zn2X0bpe
Yakup Ergün @dr_yakupergun	Oct 23, 2026	● NEUTRAL	#ESMO26 \| PANKU-Breast01 In HR+/HER2− mBC, after CDK4/6i and 1–2 prior chemotherapy lines: Iza-bren vs chemotherapy: PFS: 8.2 vs 4.0 months (HR 0.41); ORR: 40.5% vs 20.2% https://t.co/izrdBxO77a https://t.co/iDkohswiRI
Stephanie Graff, MD, FACP, FASCO @DrSGraff	Oct 23, 2026	● POSITIVE	Iza-bren shows significant mPFS of 8.2 mos vs 4.0 mos , HR=0.41 #ESMO26 @OncoAlert https://t.co/Dk2JusQLRi
Sara Tolaney @stolaney1	Oct 23, 2026	● NEUTRAL	PANKU-Breast01 HR+ MBC, prior cdk 4/6i, 1-2 prior chemo Iza-bren vs TPC ~70% 1 prior chemo PFS 8.2 vs 4.0 mo, HR 0.41 p<0.0001 ORR 40.5% vs 20.2% DOR 6.9 mo vs 4.2 mo OS immature Most tox: heme tox, primary GCSF was not required @OncoAlert #ESMO26 https://t.co/zdUlK7U21Q
Evandro de Azambuja, MD, PhD @E_de_Azambuja	Oct 23, 2026	● POSITIVE	Iza-bren improves PFS compared to standard chemo in pts with HR+ HER2 neg MBC after 1-2 lines of CT for metastatic disease #ESMO26 #ESMOAmbassadors #ESMOcommunity @myESMO https://t.co/h8TrfHlQel
Erika Hamilton, MD, FASCO @ErikaHamilton9	Oct 23, 2026	● POSITIVE	#PANKUBreast01 Ph III results for iza bren (bispecific EGFR/HER3 ADC) vs TPC chemo, in previously treated HR +/HER- MBC 🔹mPFS: 4.0 vs. 8.1 mo, HR 0.41 🔹 ORR: 20% vs 40% 🔹 DoR: 4.2 vs. 6.9 mo 🔹 ILD: only 1.1% & all grade 1/2 #ESMO26 #ESMOAmbassadors https://t.co/ikHLXiLHX1
MV Chandrakanth @ChandrakanthMv	Oct 23, 2026	● NEUTRAL	🚨 PANKU-Breast01 \| ESMO 2026 \| LBA50 TWO TARGETS. DOUBLE THE PFS. BUT WHAT ABOUT SURVIVAL? Phase III trial of izalontamab brengitecan (iza-bren), a bispecific EGFR/HER3 ADC, in previously treated HR+/HER2− advanced breast cancer. 🔹 N = 383 \| Iza-bren vs physician's choice chemotherapy 🔹 Median PFS: 8.18 vs 4.01 months 🔹 HR 0.41 — 59% lower hazard of progression or death 🔹 ORR: 40.5% vs 20.2% 🔹 ILD: 1.1%, all grade 1–2 ⚠️ OS immature. Optimal ADC sequencing remains unresolved. TAKE-HOME Dual EGFR/HER3 targeting nearly doubles median PFS, but an overall survival advantage remains unproven. 📖 Ref: Lan B et al. PANKU-Breast01. ESMO 2026; LBA50. @myESMO @OncoAlert #MVOnco #ESMO2026 #BreastCancer #ADC
Dr Amol Akhade @SuyogCancer	Oct 22, 2026	● POSITIVE	🚨 ESMO 2026 \| PANKU-Breast01 (LBA50) #esmo26 Impressive phase III results for izalontamab brengitecan (iza-bren), a bispecific EGFR/HER3 ADC, in previously treated MBC HR +ve Her2 -ve Iza-bren vs physician's choice chemotherapy: 🔹 Median PFS: 8.18 vs 4.01 months 🔹 HR 0.41 (95% CI 0.33–0.53; p<0.0001) 🔹 ORR: 40.5% vs 20.2% 🔹 Median DoR: 6.93 vs 4.21 months 🔹 ILD: 1.1% (all grade 1–2) 🔹 OS: Immature A remarkable 59% reduction in the hazard of progression or death, with manageable toxicity. Another ADC enters the increasingly crowded HR+/HER2− breast cancer landscape. @OncBrothers @myESMO @OncoAlert
Yakup Ergün @dr_yakupergun	Oct 23, 2026	● POSITIVE	#ESMO26 \| PANKU-Breast01 In HR+/HER2− mBC, the EGFR/HER3 bispecific ADC (iza-bren): PFS: 8.18 vs 4.05 months (HR 0.41). Grade ≥3 TRAEs: 40.5% vs 20.2%. OS remains immature. An impressive PFS benefit. However, in an era when ADCs such as T-DXd and SG are already in use, superiority over chemotherapy alone is not enough. Another treatment option… The added value of bispecific targeting, particularly its efficacy after other TOP1-ADCs, remains uncertain. These are the key data needed to define its place in treatment sequencing.
Yakup Ergün @dr_yakupergun	Oct 23, 2026	● POSITIVE	I’ve added the PANKU-Breast01 results to Dr. Barbara Pistilli’s excellent original slide👇 https://t.co/9DABg8HFkl https://t.co/iBIMpJWeSe
Kristina Jankovic, MD @JankovicK	Oct 23, 2026	● POSITIVE	🚨 #ESMO26 \| PANKU-Breast01 🇨🇳 Izalontamab brengitecan (iza-bren), an EGFR×HER3 bispecific ADC, significantly improved PFS 🆚 physician’s choice chemotherapy in HR+/HER2− advanced #BreastCancer after endocrine therapy, CDK4/6i and 1–2 chemotherapy lines. 🔹 mPFS: 8.2 🆚 4.0 months (HR 0.41) 🔹 Confirmed ORR: 40.5% 🆚 20.2% 🔹 OS remains immature ⚠️ Grade ≥3 TRAEs: 85% 🆚 66%, predominantly haematological. 🎯 Promising efficacy in a heavily pretreated population; toxicity and validation beyond China remain key considerations. 📖 Simultaneously published in @TheLancet : https://t.co/2ccmyPJSO4 @OncoAlert @myESMO
Mali Barbi, MD MSc \| Breast & Gyn Oncologist @DrBarbiOnc	Oct 23, 2026	● NEUTRAL	#PANKUBreast01: iza-bren, an EGFR x HER3 bispecific ADC with a TOPO1 payload, vs chemo in HR+/HER2- MBC n=383. PFS 8.2 vs 4.0 mo, HR 0.41. ORR 40.5% vs 20.2%. A real result, and it enrolled HER2 0, 1+ and 2+, so no HER2 test gates it. In clinic it lands in a space already holding T-DXd, Dato-DXd and sacituzumab. All TOPO1. Iza-bren is a new target, not a new mechanism. The number I want is how many patients had a prior ADC, and how they did. #bcsm #ESMO26 @myESMO
Prof. Dr. Ahmet Dirican @dr_dirican	Oct 23, 2026	● POSITIVE	#ESMO26 \| Impressive results with a next-generation bispecific ADC! Phase III PANKU-Breast01: EGFR×HER3-targeting iza-bren improved median PFS in HR+/HER2− metastatic breast cancer (8.2 vs 4.0 months; HR 0.41). However, grade ≥3 treatment-related AEs reached 85.3%. Key questions: Do ESR1, PIK3CA, or PTEN alterations influence response? What is the impact of prior ADC exposure? #ESMO26 #BreastCancer #ADC @myESMO @oncodaily @OncoAlert
Sara Soliman, MD @sara_soliman7	Oct 23, 2026	● POSITIVE	#ESMO26 \| PANKU-Breast01 Phase III: iza-bren, an EGFR×HER3 bispecific ADC, vs chemotherapy in previously treated HR+/HER2− advanced BC (N=383). ▪️ mPFS: 8.2 vs 4.0 months HR 0.41 (95% CI 0.33–0.53); P<0.0001 ▪️ ORR: 40.5% vs 20.2% ▪️ OS immature ▪️ Grade ≥3 TRAEs predominantly hematologic; ILD 1.1% (grade 1–2) Promising efficacy. Key question: where will it fit in ADC sequencing? 🔹 𝗕𝗠𝗦’𝘀 𝗼𝗻𝗴𝗼𝗶𝗻𝗴 𝗜𝗭𝗔𝗕𝗥𝗜𝗚𝗛𝗧-𝗕𝗿𝗲𝗮𝘀𝘁𝟬𝟭 𝘪𝘻𝘢-𝘣𝘳𝘦𝘯 𝘪𝘯 𝘢 𝘥𝘪𝘧𝘧𝘦𝘳𝘦𝘯𝘵 𝘱𝘰𝘱𝘶𝘭𝘢𝘵𝘪𝘰𝘯: 1𝘓 𝘢𝘥𝘷𝘢𝘯𝘤𝘦𝘥 𝘛𝘕𝘉𝘊 𝘰𝘳 𝘌𝘙-𝘭𝘰𝘸/𝘏𝘌𝘙2− 𝘉𝘊 𝘪𝘯𝘦𝘭𝘪𝘨𝘪𝘣𝘭𝘦 𝘧𝘰𝘳 𝘢𝘯𝘵𝘪–𝘗𝘋-(𝘓)1 𝘵𝘩𝘦𝘳𝘢𝘱𝘺. #Breastcancer #ADCs #PANKUBreast01

Conference Presentations

PANKU-Breast01 Key Slides

ESMO 2026 slides

Presented by Bo Lan, MD (LBA50, Proffered Paper Session, Oct 23, 2026), as photographed and shared by physicians. Each slide appears once, from the physician post with the widest reach. Click any image to enlarge; full transcriptions are under “View OCR Text”.

Dr Amol Akhade @SuyogCancer · #ESMO26 · Oct 22, 2026

LBA50 abstract (programme site): background, methods, results and conclusions

View post on X ↗

Dr Amol Akhade shared the ESMO 2026 LBA50 abstract: PANKU-Breast01 title, speaker Bo Lan, and background on iza-bren, an EGFR x HER3 bispecific antibody-drug conjugate

Dr Amol Akhade shared the ESMO 2026 LBA50 abstract methods: eligibility, 1:1 randomization to iza-bren or treatment of physician's choice, PFS by BICR as primary endpoint

Dr Amol Akhade shared the ESMO 2026 LBA50 abstract results and conclusions: PFS by BICR, ORR, duration of response, safety and ILD for iza-bren vs TPC

[Image 1] Proffered Paper session LBA50 - PANKU-Breast01: Randomized phase III study of izalontamab brengitecan (iza-bren) in previously treated unresectable locally advanced or metastatic (LA/M) hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) Speakers Bo Lan (Beijing, China) Lecture Time 14:35 - 14:45 [Abstract] Background Although first-line endocrine therapy plus CDK4/6 inhibitors has improved clinical outcome of HR+/HER2- BC, patients (pts) inevitably develop resistance and survival outcomes remain poor with subsequent therapy. Iza-bren is a first-in-class bispecific antibody-drug conjugate (ADC) against EGFR and HER3, containing a potent topoisomerase I inhibitor payload (Ed-04). --- [Image 2] Methods Eligible pts had unresectable LA/M HR+/HER2- BC (HR+, ER≥1% and/or PR≥1%; HER2-, IHC 0, 1+, or 2+/ISH-), progressed after at least 1L of endocrine therapy and 1 or 2L prior chemotherapy, and had previously received CDK4/6 inhibitors and taxanes. Pts were randomized 1:1 to receive iza-bren (2.5 mg/kg D1D8 Q3W) or TPC (eribulin, capecitabine, gemcitabine, or vinorelbine). The primary endpoint was PFS by blinded independent central review (BICR). Secondary endpoint included OS. The pre-planned final analysis for PFS serves as the interim analysis for OS. --- [Image 3] Results As of Jul 21, 2026, a total of 383 pts were randomized and treated (iza-bren/TPC, 190/193). Median follow-up for PFS was 15.24 vs 13.63 mo (iza-bren/TPC). Iza-bren significantly improved PFS by BICR vs TPC; mPFS was 8.18 mo (95% CI, 6.93-8.58) vs 4.01 mo (95% CI, 2.92-4.30) (HR, 0.41; 95% CI, 0.33-0.53; P<0.0001). OS was immature at the interim analysis, and no detrimental effect was observed. The cORR by BICR was 40.5% with iza-bren vs 20.2% with TPC, and mDOR was 6.93 vs 4.21 mo, respectively. Grade ≥3 TRAEs were predominantly hematologic in nature. TRAEs were manageable with standard supportive care, and only 1.6% of pts discontinued iza-bren treatment due to TRAEs. Adjudicated ILD occurred in 2 (1.1%) pts with iza-bren (grade 1 or 2). No new safety signals were identified. Conclusions The study met its primary endpoint at the prespecified analysis. Iza-bren demonstrated a statistically significant and clinically meaningful improvement in PFS vs TPC in previously treated HR+/HER2- BC. The safety profile was manageable and consistent with previous studies. The results support iza-bren as a new standard of care option in this population in China.

Erika Hamilton, MD, FASCO @ErikaHamilton9 · #ESMO26 · Oct 23, 2026

Bo Lan, LBA50: study design, PFS by BICR (primary endpoint) and antitumor responses

View post on X ↗

Erika Hamilton, MD, FASCO shared the PANKU-Breast01 study design slide: open-label phase III at 72 centers in China, N=383 randomized 1:1 to iza-bren 2.5 mg/kg D1D8 Q3W or TPC, primary endpoint PFS by BICR

Erika Hamilton, MD, FASCO shared the PANKU-Breast01 PFS by BICR Kaplan-Meier slide: median 8.2 vs 4.0 months, HR 0.41 (0.33-0.53), iza-bren vs TPC

Erika Hamilton, MD, FASCO shared the PANKU-Breast01 antitumor responses slide: confirmed ORR 40.5% vs 20.2% by BICR, waterfall plots, median DOR 6.9 vs 4.2 months, OS not mature

PFS by BICR, primary endpoint (mITT; data cut-off July 21, 2026; median PFS follow-up 15.2 months)

Arm	N	Events	Median PFS, mo (95% CI)	6 mo	9 mo	12 mo
Iza-bren	190	130	8.2 (6.9–8.6)	62.8%	41.8%	26.5%
TPC	193	159	4.0 (2.9–4.3)	24.2%	14.4%	9.2%
HR 0.41 (95% CI 0.33–0.53), stratified Cox model; P<0.0001, one-sided stratified log-rank test. Subjects at risk at 0/3/6/9/12/15/18/21/24 mo: 190/138/97/63/38/22/12/4/0 vs 193/96/34/17/10/4/2/1/0.

Source: ESMO 2026 LBA50 slide (Bo Lan), as shared on X by Erika Hamilton, Oct 23, 2026. Landmark rates are the values printed on the curve. Iza-bren is investigational and not FDA approved.

[Image 1] PANKU-Breast01 Study Design An open-label, multicenter, randomized, phase III study conducted at 72 study centers across China Key eligibility criteria • Unresectable LA/M HR+/HER2- BC (HR+, ER≥1% and/or PR≥1%; HER2-, IHC 0, IHC 1+, or IHC 2+/ISH-) • Progressed after at least 1 line of endocrine therapy • 1 or 2 lines of prior chemotherapy • Previously received CDK4/6 inhibitors and taxanes • Measurable lesion per RECIST v1.1 • ECOG PS 0-1 R 1:1 N=383 Iza-bren 2.5 mg/kg D1D8 Q3W TPC • Eribulin, D1D8 Q3W • Capecitabine, BID, Q3W • Gemcitabine, D1D8 Q3W • Vinorelbine, D1D8 Q3W Stratified by • Previous lines of chemotherapy (1 line vs 2 lines) • CNS metastases (Yes vs No) • HER2 expression (IHC 0 vs IHC 1+ vs IHC 2+/ISH-) Treatment until Disease progression per RECIST v1.1 or intolerable toxicity Primary endpoint: PFS (BICR) Key secondary endpoint: OS H_PFS α=0.025 → H_OS α=0 Other secondary endpoints • PFS (INV) • ORR (BICR & INV) • DCR (BICR & INV) • DOR (BICR & INV) • Safety, PK, Immunogenicity Note: Iza-bren was dosed with 10% compensation per protocol; eribulin 1.4 mg/m² on days 1 and 8 Q3W; capecitabine 1000-1250 mg/m², BID from days 1 to 14 Q3W; gemcitabine 1000 mg/m² on days 1 and 8 Q3W; vinorelbine 25 mg/m² on days 1 and 8 Q3W. ECOG PS, Eastern Cooperative Oncology Group performance status; Q3W, every 3 weeks; D, day; PFS, progression-free survival; BICR, blinded independent central review; OS, overall survival; INV, investigator assessed; ORR, objective response rate (confirmed); DCR, disease control rate; DOR, duration of response. Bo Lan, MD Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo] --- [Image 2] Survival-curve slide: the printed values are in the numbers table above. --- [Image 3] Antitumor Responses Iza-bren (N=190) | TPC (N=193) Best overall response, n (%) PR: 77 (40.5) | 39 (20.2) Non-CR/Non-PD: 3 (1.6) | 3 (1.6) SD: 84 (44.2) | 81 (42.0) PD: 16 (8.4) | 61 (31.6) NE: 10 (5.3) | 9 (4.7) ORR, % (95% CI): 40.5 (33.5, 47.9) | 20.2 (14.8, 26.6) Difference, % (95% CI): 20.2 (11.2, 29.0) Odds ratio (95% CI): 2.7 (1.7, 4.3) DCR, % (95% CI): 86.3 (80.6, 90.9) | 63.7 (56.5, 70.5) CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; NE, not evaluable [Waterfall plot] Iza-bren mDOR = 6.9 mo — 77.9% of patients (148/190) had tumor shrinkage and the median (range) shrinkage (%) was -37.4 (-89.9, -0.1). [Waterfall plot] TPC mDOR = 4.2 mo — 60.6% of patients (117/193) had tumor shrinkage and the median (range) shrinkage (%) was -24.5 (-90.7, -0.1). Y-axis: Best Change from Baseline (%) • OS data not mature*: Median follow-up 17.8 months, and no detrimental effect was observed • The study is continuing to the next planned analysis for OS *: Information fraction: 62.8% BICR-assessed confirmed ORR was doubled in iza-bren versus TPC with longer durability of response. Data cut off: July 21, 2026 Bo Lan, MD Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo]

Yakup Ergün @dr_yakupergun · #ESMO26 · Oct 23, 2026

Bo Lan, LBA50: safety summary

View post on X ↗

Yakup Ergün shared the PANKU-Breast01 safety summary slide: TRAEs, grade 3 or higher TRAEs, treatment-related SAEs, TRAEs leading to death, discontinuation, dose reduction and interruption, iza-bren vs TPC

[Image 1] Safety Summary [Table] Iza-bren (N = 190) | TPC (N = 193) TRAEs, n (%): 189 (99.5) | 188 (97.4) ≥Grade 3 TRAEs, n (%): 162 (85.3) | 127 (65.8) Treatment-related SAEs, n (%): 79 (41.6) | 22 (11.4) TRAEs leading to death, n (%): 2 (1.1) | 1 (0.5) TRAEs leading to treatment discontinuation, n (%): 3 (1.6) | 2 (1.0) TRAEs leading to dose reduction, n (%): 123 (64.7) | 55 (28.5) TRAEs leading to dose interruption, n (%): 107 (56.3) | 73 (37.8) • Median (range) duration of treatment, mo: – Iza-bren: 7.3 (0.3, 22.5) – TPC: 4.3 (0.3, 26.0) • Median (range) number of treatment cycles: – Iza-bren: 10 (1, 30) – TPC: 6 (1, 37) • Iza-bren had a manageable safety profile. The rate of treatment discontinuation due to TRAEs was low (1.6%) vs TPC (1.0%). • TRAEs leading to death occurred in 2 patients (1.1%) receiving iza-bren and in 1 patient (0.5%) receiving TPC. TRAE, treatment related adverse events. Safety data based on the safety analysis set. TRAEs leading to death occurred in 2 patients (1.1%) receiving iza-bren: Death (unknown cause) and Pneumonia. TRAEs leading to death occurred in 1 patient (0.5%) receiving TPC: Sepsis. Data cut off: July 21, 2026 Bo Lan, MD Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo]

Sara Tolaney @stolaney1 · #ESMO26 · Oct 23, 2026

Discussant Fumikata Hara: PANKU-Breast01 among ADC trials in HR+/HER2− MBC, and “three trials, three clinical decisions”

View post on X ↗

Sara Tolaney shared discussant Fumikata Hara's slide comparing ADC trials in HR+/HER2- metastatic breast cancer by N, setting, line, PFS and PFS HR, including iza-bren in PANKU-Breast01 (cross-trial, not head-to-head)

Sara Tolaney shared discussant Fumikata Hara's conclusions slide: three trials, three clinical decisions, for B-42, NATALEE and PANKU-Breast01

[Image 1] PANKU-BREAST01: IZA-BREN ADC TRIALS IN HR+/HER2− METASTATIC BREAST CANCER ADC / TRIAL | N* | POPULATION / SETTING | LINE | PFS (mo) | PFS HR (95% CI) T-DXd · DB06 | 866** | HER2-low / ultralow; no prior chemo | 1L | 13.2 / 8.1 | 0.62 (0.51–0.74) T-DXd · DB04 | 494 | HER2-low; 1–2 prior chemo | 2–3L | 10.1 / 5.4 | 0.51 (0.40–0.64) Dato-DXd · TROPION-B01 | 732 | HR+/HER2−; 1–2 prior chemo | 2–3L | 6.9 / 4.9 | 0.63 (0.52–0.76) SG · ASCENT-07 | 690 | HR+/HER2−; no prior chemo | 1L | 8.3 / 8.3 | 0.85 (0.69–1.05) SG · TROPiCS-02 | 543 | HR+/HER2−; 2–4 prior chemo | 3–5L | 5.5 / 4.0 | 0.66 (0.53–0.83) sac-TMT · OptiTROP-B02 | 399 | HR+/HER2−; 1–4 prior chemo | 2–5L | 8.3 / 4.1 | 0.35 (0.26–0.48) Iza-bren · PANKU-B01 | 383 | HR+/HER2−; 1–2 prior chemo | 2–3L | 8.2 / 4.0 | 0.41 (0.33–0.53) *N randomized (DB04 HR+ subset); lines refer to metastatic chemotherapy. PANKU prior ADC exposure: NR. **DB06 HR 0.62 is HER2-low cohort (n=713), not all 866. T-DXd is an established early ADC option for HER2-low/ultralow disease; iza-bren needs sequencing evidence [source footnote line, small: DB06 NEJM 2024; DB04 NEJM 2022; TROPION-B01 JCO 2025; TROPiCS-02 JCO 2022; ASCENT-07 SABCS 2025; OptiTROP-B02 ESMO 2025 LBA?; PANKU ESMO 2026 - partially illegible] Fumikata Hara Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo] --- [Image 2] CONCLUSIONS THREE TRIALS — THREE CLINICAL DECISIONS TRIAL | KEY EVIDENCE | CLINICAL IMPLICATION B-42 At year 5 | Reduced recurrence with extended letrozole; no OS benefit detected | At year 5, individualize AI extension by late-recurrence risk and tolerability—not a routine 10 years. NATALEE At diagnosis | Sustained iDFS benefit; clinically meaningful, although descriptive, OS signal | Offer 3-year ribociclib selectively; weigh absolute risk against toxicity. PANKU-Breast01 At relapse | Large PFS gain vs chemotherapy; substantial hematologic toxicity | Do not assume efficacy after prior TOP1 ADCs; sequencing and marrow toxicity remain key. The right treatment, for the right patient, for the right duration — and in the right sequence [footer illegible] [ESMO Congress Madrid 2026 logo]

Paolo Tarantino @PTarantinoMD · #ESMO26 · Oct 23, 2026

Bo Lan, LBA50: TRAEs in ≥30% of patients

View post on X ↗

Paolo Tarantino shared the PANKU-Breast01 slide of treatment-related adverse events occurring in 30% or more of patients, by grade, iza-bren vs TPC, with notes on G-CSF use, neutropenic fever and adjudicated ILD

[Image 1] TRAEs in ≥ 30% of Patients TRAEs with Frequency ≥ 30% Iza-bren (N=190) vs TPC (N=193) [Butterfly bar chart, Incidence (%), Preferred Term] Preferred terms (top to bottom): Anaemia; Leukopenia; Thrombocytopenia; Neutropenia; Alopecia; Asthenia; Nausea; AST increased; Decreased appetite; Constipation; Hypoalbuminaemia; ALT increased; Lymphocyte count decreased; Diarrhoea; Hypokalaemia; Stomatitis; Hypertriglyceridaemia [Bar value labels, read top-to-bottom in photo order; small, perspective-skewed, row alignment uncertain] Iza-bren (Grade ≥3 | Grade 1-2): 49.5 | 44.8; 48.4 | 38.4; 46.3 | 38.4; 53.7 | 25.8; 0.5 | 52.7; 13.2 | 36.3; 2.6 | 43.7; 0.5 | 37.9; 2.1 | 34.7; — | 35.8; — | 35.8; 1.1 | 34.2; 13.7 | 17.9; 3.2 | 27.9; 7.4 | 23.7; 2.1 | 28.4; 1.6 | 28.4 TPC (Grade 1-2 | Grade ≥3): 56.5 | 6.2; 44.6 | 40.4; 31.1 | 5.7; 32.1 | 54.9; 43.0; 19.7 | 2.6; 24.4 | 0.5; 34.7 | 2.1; 13.5; 21.8; 11.4; 36.2 | 1.6; 10.9 | 5.7; 7.3; 6.2; 5.7 | 0.5; 19.6 | 3.6 Legend: Iza-bren | Grade 1-2; Iza-bren | Grade ≥3; TPC | Grade 1-2; TPC | Grade ≥3 Most common TRAEs were hematological, including anemia, thrombocytopenia and neutropenia, which were effectively managed through standard supportive measures including growth factor support, dose delay and dose reductions, which allowed majority of patients to continue iza-bren treatment with low discontinuation rate. Primary G-CSF prophylaxis is not mandatory. Grade ≥3 anemia resolved in a median of 6 days in the iza-bren arm. Grade ≥3 neutropenia and thrombocytopenia generally resolved within 2 and 3 days in the iza-bren arm. Neutropenic fever (7.9%) and grade 3 or higher infections (4.7%) were low in the iza-bren arm. Non-hematologic AEs were mostly low grade; alopecia was the most common in both groups (53.2% with iza-bren and 43.0% with TPC), followed by asthenia (49.5% and 22.3%, respectively). Adjudicated treatment-related ILD occurred in two patients (1.1%) in the iza-bren arm (one case of grade 1 and one case of grade 2). None in the TPC arm. Data cut off: July 21, 2026 Bo Lan, MD Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo]

Sara Tolaney @stolaney1 · #ESMO26 · Oct 23, 2026

Bo Lan, LBA50: conclusions

View post on X ↗

Sara Tolaney shared the PANKU-Breast01 conclusions slide: PFS 8.2 vs 4.0 months HR 0.41, confirmed ORR 40.5% vs 20.2%, DOR 6.9 vs 4.2 months, OS immature, discontinuation 1.6%, adjudicated ILD 1.1%

[Image 1] Conclusions • In this pre-specified analysis, iza-bren demonstrated a statistically significant and clinically meaningful improvement in PFS vs TPC in previously treated HR+/HER2- BC, meeting the primary endpoint. • Iza-bren demonstrated an improved confirmed ORR and more durable response than TPC. • OS is immature at this interim analysis, no detrimental effect was observed. • The safety profile of iza-bren was manageable and consistent with previous studies. – TRAEs leading to discontinuation (1.6%) were low. – The incidence of adjudicated ILD was 1.1% PFS (Median): Iza-bren 8.2 mo | TPC 4.0 mo | HR: 0.41, 95% CI: 0.33 - 0.53 cORR: Iza-bren 40.5% | TPC 20.2% | Difference: 20.2%, 95% CI: 11.2 - 29.0 DOR (Median): Iza-bren 6.9 mo | TPC 4.2 mo The results support iza-bren as a potential new standard of care option in this population. Bo Lan, MD Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo]

Gaia Griguolo @GaiaGriguolo · #ESMO26 · Oct 23, 2026

Bo Lan, LBA50: baseline characteristics

View post on X ↗

Gaia Griguolo shared the PANKU-Breast01 baseline characteristics slide: age, prior chemotherapy lines, CNS metastases, HER2 expression, prior CDK4/6 inhibitor duration and ECOG status by arm

[Image 1] Baseline Characteristics | | Iza-bren (N = 190) | TPC (N = 193) | Median (range) age, years | 54.0 (33.0, 71.0) | 54.0 (27.0, 70.0) Age group (years), n (%) < 65 | 166 (87.4) | 172 (89.1) ≥ 65 | 24 (12.6) | 21 (10.9) Previous chemotherapy lines, n (%) 1 line | 135 (71.1) | 139 (72.0) 2 lines | 55 (28.9) | 54 (28.0) CNS metastases, n (%) Yes | 4 (2.1) | 3 (1.6) No | 186 (97.9) | 190 (98.4) HER2 expression, n (%) IHC 0 | 64 (33.7) | 66 (34.2) IHC 1+ | 73 (38.4) | 74 (38.3) IHC 2+/ISH- | 53 (27.9) | 53 (27.5) | | Iza-bren (N = 190) | TPC (N = 193) | Duration of prior CDK-inhibitor use ≥ 12 months, n (%) | 93 (48.9) | 103 (53.4) Prior (neo)adjuvant therapy, n (%) | 152 (80.0) | 149 (77.2) Prior anthracycline use, n (%) | 152 (80.0) | 160 (82.9) Duration of endocrine therapy in advanced disease ≥ 6 months, n (%) | 162 (85.3) | 164 (85.0) Progression within 6 months after (neo)adjuvant chemotherapy, n (%) | 16 (8.4) | 18 (9.3) Baseline liver metastasis, n (%) | 136 (71.6) | 137 (71.0) ECOG PS, n (%) 0 | 68 (35.8) | 69 (35.8) 1 | 122 (64.2) | 124 (64.2) De novo metastasis at initial diagnosis, n (%) | 33 (17.4) | 42 (21.8) Previous radiotherapy, n (%) | 106 (55.8) | 103 (53.4) Data cut off: July 21, 2026 Bo Lan, MD Content of this presentation is copyright and responsibility of the author. Permission is required for re-use. [ESMO Congress Madrid 2026 logo]

The Lancet @TheLancet · #ESMO26 · Oct 23, 2026

Simultaneous publication: The Lancet, first pageJournal post

View post on X ↗

The Lancet shared the first page of the PANKU-Breast01 article, Izalontamab brengitecan for HR+/HER2- breast cancer in China: a randomised, phase 3 trial (Bo Lan et al.)

[Image 1] EUROPEAN SOCIETY FOR MEDICAL ONCOLOGY (ESMO) CONGRESS 2026 Articles Izalontamab brengitecan for HR+/HER2– breast cancer in China (PANKU-Breast01): a randomised, phase 3 trial Bo Lan*, Yehui Shi*, Xiying Shao*, Fan Wu*, Shusen Wang*, Weimin Xie, Qingyuan Zhang, Quchang Ouyang, Jiuwei Cui, Xiaoling Ling, Haijun Yu, Huihui Li, Xianjun Tang, Sijuan Ding, Chunfang Hao, Bing Zhao, Yang Li, Hua Yang, Min Yan, Guohui Han, Xujuan Wang, Fanfan Li, Peijian Peng, Chang Gong, Yunjiang Liu, Junlan Guo, Yongmei Yin, Man Li, Yue'e Teng, Jiuda Zhao, Yongli Gao, Jingfen Wang, Jing Luo, Xinghua Han, Xiaoping Li, Bin Liu, Shuqun Zhang, Bihui Li, Lei Yang, Sa Xiao, Hai Zhu, Yi Zhu, Binghe Xu, for the PANKU-Breast01 Investigators† Summary Background Patients with heavily pretreated hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2–) breast cancer have few treatment options. Izalontamab brengitecan (iza-bren) is a first-in-class, epidermal growth factor receptor and HER3 bispecific antibody–drug conjugate that contains a potent topoisomerase I inhibitor payload (Ed-04). The aim of PANKU-Breast01 was to compare the efficacy and safety of iza-bren versus chemotherapy in patients with pretreated HR+/HER2– breast cancer. Published Online October 23, 2026 https://doi.org/10.1016/S0140-6736(26)02096-9 *Co-first authors †Investigators are listed in the appendix (pp 2–5) [The Lancet crossmark/access icons]

KOL-made infographics#ESMO26

Summary graphics designed by physicians, not conference slides. Click to enlarge.

MV Chandrakanth KOL-made infographic: PANKU-Breast01 LBA50 headline, iza-bren PFS result — @ChandrakanthMv

MV Chandrakanth KOL-made infographic, part 1: PANKU-Breast01 design, PFS, ORR and duration of response — @ChandrakanthMv

MV Chandrakanth KOL-made infographic, part 2: PANKU-Breast01 safety, OS immaturity and ADC landscape — @ChandrakanthMv

PANKU-Breast01 Key Takeaways

ESMO 2026 results — LBA50 (October 23, 2026)

Bo Lan presented LBA50 in the Proffered Paper session (breast cancer) on Friday, October 23, 2026, 14:35–14:45, at ESMO 2026 in Madrid. The results were published the same day in The Lancet. The trial ran at 72 centers in China.

Results, from the abstract (ESMO 2026 LBA50 abstract, data cutoff 21 Jul 2026):

Patients: 383 randomized and treated (iza-bren 190, chemotherapy 193). Median PFS follow-up 15.24 vs 13.63 months.
PFS by BICR (primary endpoint): median 8.18 months (95% CI 6.93–8.58) vs 4.01 months (95% CI 2.92–4.30); HR 0.41 (95% CI 0.33–0.53); P<0.0001.
Response: confirmed ORR by BICR 40.5% vs 20.2%; median duration of response 6.93 vs 4.21 months.
Overall survival: immature at this interim analysis; the abstract reports no detrimental effect.
Safety: grade ≥3 TRAEs were predominantly hematologic; 1.6% of patients discontinued iza-bren because of TRAEs; adjudicated ILD in 2 patients (1.1%) on iza-bren, grade 1 or 2. The abstract does not report the overall grade ≥3 TRAE rate.

Safety, from the presentation slides (ESMO 2026 LBA50 presentation, Bo Lan, data cutoff 21 Jul 2026; slide photos posted on X by @PTarantinoMD), iza-bren vs chemotherapy:

Grade ≥3 TRAEs 85.3% vs 65.8%; treatment-related serious AEs 41.6% vs 11.4%
TRAEs leading to dose reduction 64.7% vs 28.5%; to dose interruption 56.3% vs 37.8%; to discontinuation 1.6% vs 1.0%
TRAEs leading to death: 2 patients (1.1%) vs 1 patient (0.5%)
Grade ≥3 neutropenia 53.7%, anemia 49.5%, leukopenia 48.4%, and thrombocytopenia 46.3% with iza-bren. The slide states primary G-CSF prophylaxis is not mandatory.

The presentation slide and the BMS press release round median PFS to 8.2 vs 4.0 months. Some posts on X restate figures differently; the values above are taken from the abstract text and the presentation slides as labelled. The abstract concludes that the results support iza-bren “as a new standard of care option in this population in China.”

Sources: ESMO 2026 LBA50 abstract · The Lancet publication · SystImmune / BMS press release (Oct 23, 2026) · ClinicalTrials.gov NCT06343948

Topline result — Aug 26, 2026

Iza-bren met the primary endpoint of PFS at a pre-specified interim analysis, per Biokin’s announcement. No numbers were released with the topline; the full results followed at ESMO 2026 (above).

The drug

Iza-bren (izalontamab brengitecan, BL-B01D1) is a bispecific antibody-drug conjugate targeting both EGFR and HER3. It is developed by SystImmune (a Biokin subsidiary) and, outside China, jointly with Bristol Myers Squibb under an exclusive license. The FDA has granted Breakthrough Therapy Designation in previously treated EGFR-mutated NSCLC — not in breast cancer. SystImmune / BMS press release

Regulatory

⚠ Iza-bren is investigational and not FDA approved in any indication. PANKU-Breast01 was conducted in China; applicability of its results to regulatory filings outside China has not been announced.

PANKU-Breast01 Trial