Clinical Complete Response with Dostarlimab Monotherapy in dMMR/MSI-H Locally Advanced Rectal Cancer: First Results from the Global AZUR-1 Trial.

Authors

Andrea Cercek, Jean-Baptiste Bachet, Gunnar Folprecht, Hideaki Bando, Jenny Seligmann, Naureen Starling, Maria Carmen Riesco-Martinez, Pilar Garcia Alfonso, Denis Smith, Lisa Salvatore, Encarna Gonzalez Flores, Emmanuel Mitry, Eric Chen, Jaume Capdevila Castillon, Federica Morano, Susana Roselló Keränen, Francine Aubin, Carlos López López, Sara Lonardi, Gary Buchschacher, Christoph Roderburg, Marco Gerlinger, Dominik Modest, Volker Heinemann, Thorsten Oliver Goetze, Takeshi Kato, Young Suk Park, Géraldine Perkins, Frédéric Lemay, Michael Vickers, Zsolt Szijgyarto, Neda Stjepanovic, Sina Haftchenary, Luis A Diaz, Jeanine M L Roodhart

Published in

Annals of oncology : official journal of the European Society for Medical Oncology. Oct 25, 2026. Epub Oct 25, 2026.

Abstract

Multimodal treatment with chemotherapy, radiation, and surgery for locally advanced rectal cancer (LARC) is a standard of care (SOC) associated with significant toxicity/morbidity. After TNT, clinical complete response (cCR) ranges between 21-41%, highlighting the need for novel approaches. dMMR/MSI-H tumors are exceptionally responsive to PD-1 blockade: in a pilot study, patients with dMMR/MSI-H LARC achieved durable responses after neoadjuvant dostarlimab. AZUR-1 is the first global registrational study evaluating dostarlimab monotherapy in adults with previously untreated stage II/III dMMR/MSI-H LARC.
Dostarlimab 500 mg was administered intravenously Q3W for 9 cycles. Key endpoints include rate of sustained cCR for 12 months (cCR12) following end of treatment (EOT) with dostarlimab alone by investigator and independent central review (ICR), and composite rate of cCR12 (INV) + pathological CR (pCR).
At data cutoff (April 20, 2026), 154 patients were enrolled (median follow-up [range]: 26.3 [2-36] months). Of 144 patients with ≥12 months follow-up, 68% achieved cCR12 (INV). pCR was achieved in 12/15 patients (80%) who underwent surgery after dostarlimab alone: cCR12+pCR rate was 76%. cCR12 (ICR) was less mature than investigator, as first cCR (ICR) was identified at later timepoints. 98% who achieved cCR maintained cCR for ≥12 months. Overall, 93% of patients were on study with no evidence of disease progression after treatment (dostarlimab ± SOC); 71% achieved this outcome with dostarlimab alone. There were no reported recurrences for patients in cCR or pCR. Safety was acceptable; grade ≥3 immune-mediated AEs occurred in 4 (3%) patients. PROs showed meaningful improvements from baseline to EOT for several domains.
In this AZUR-1 interim analysis, 68% of patients achieved cCR12 and 76% achieved cCR12+pCR with dostarlimab alone and had no disease recurrences. These durable responses indicate the potential to eliminate the need for current SOC and redefine the curative-intent treatment paradigm with dostarlimab in dMMR/MSI-H LARC.
NCT05723562.

PMID:
42927858
Bibliographic data and abstract were imported from PubMed on 26 Oct 2026.

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