Clinical complete response with dostarlimab monotherapy in dMMR/MSI-H locally advanced rectal cancer (LARC): First results from the global registrational AZUR-1 trial

doi:10.1016/j.annonc.2026.10.1280

AZUR-1

Patient / Population Intervention / Exposition Vergleich Endpunkt

In patients with dMMR/MSI-H locally advanced rectal cancer, dostarlimab monotherapy achieved a clinical complete response sustained for 12 months by investigator assessment in 68% of evaluable patients without chemotherapy, radiation or surgery.

N

154Patienten

Design

Global single-arm registrational trial of dostarlimab monotherapy for 9 cycles in patients with dMMR/MSI-H locally advanced rectal cancer (NCT05723562).

Endpunkt

Rate of sustained clinical complete response for 12 months after end of treatment (cCR12) with dostarlimab alone, by investigator and by independent central review, and the composite rate of cCR12 (investigator) plus pathological complete response (pCR).

ErgebniscCR12 by investigator with dostarlimab alone in 68% of 144 patients with ≥12 months follow-up. Composite cCR12+pCR rate 76%, with pCR in 12 of 15 patients (80%) who underwent surgery after dostarlimab alone. By independent central review cCR12 in 47% (54/116), with 38 patients in cCR and still being followed for cCR12 at data cutoff. Of patients who achieved cCR, 98% remained in cCR for ≥12 months by investigator or central review, with no recurrences to date after cCR or pCR. 93% of patients are in surveillance with no evidence of disease progression after dostarlimab ± SOC and 71% after dostarlimab alone. Median follow-up 26.3 months (range 2-36). 88% completed all 9 cycles; Grade ≥3 immune-mediated AEs occurred in 4 patients.

Cercek A, Bachet J, Folprecht G, et al. Annals of Oncology. 2026. 10.1016/j.annonc.2026.10.1280

Diskussion & Kritik

This interim analysis shows a high and so far durable rate of clinical complete response with dostarlimab alone in dMMR/MSI-H locally advanced rectal cancer, with no recurrences reported after cCR or pCR. It is a single-arm study with no comparator, and the central review rate (47% of 116) is well below the investigator rate (68% of 144), with 38 patients still being followed for cCR12. Median follow-up is 26.3 months, and organ preservation is reported only as surveillance status at an interim analysis, so durability beyond this point is not yet known. The abstract gives no survival, distant recurrence or long-term functional and quality-of-life outcomes, and reports safety only as completion of treatment and the number of grade ≥3 immune-mediated events.