Clinical Complete Response with Dostarlimab Monotherapy in dMMR/MSI-H Locally Advanced Rectal Cancer: First Results from the Global AZUR-1 Trial
In brief
Dostarlimab alone brought 12-month complete responses to 68% of rectal cancer patients
In this interim analysis, 68% of 144 patients with at least 12 months of follow-up had a clinical complete response sustained for 12 months after dostarlimab alone; the combined rate of sustained clinical or surgical complete response was 76%. No recurrences were reported among patients with complete responses, but longer follow-up and more mature independent review are needed to clarify whether treatment can replace standard care.
- Journal
- Annals of oncology : official journal of the European Society for Medical Oncology (Q1)
- Published
- 25 October 2026
- Study design
- Unclassified
- Evidence level
- Level 5, Expert Opinion (CEBM 5)
- Authors
- Andrea Cercek, Jean-Baptiste Bachet, Gunnar Folprecht, Hideaki Bando, Jenny Seligmann, Naureen Starling, et al.
- PMID
- 42927858
- DOI
- 10.1016/j.annonc.2026.10.1280
Why clinicians should know about it
- Picked for Radiation Oncology (paper of the day, 27 October 2026): Evaluates complete response enabling potential radiation omission in rectal cancer
Abstract
BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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. TRIAL REGISTRATION NUMBER: NCT05723562.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.