Study
| Phase 2, single-arm, multicenter study (NCT04165772) |
| Patients with stage I-III dMMR solid tumors amenable to curative surgery, including rectal and nonrectal sites |
| Neoadjuvant dostarlimab 500 mg IV every 3 weeks for 6 months (9 cycles) |
Efficacy
| Clinical complete response: 84/103 pts (82%) who completed treatment |
| Nonoperative management: 82/103 pts (80%) |
| 2-yr recurrence-free survival: 92% (95% CI, 86–99) |
| 2-yr RFS in rectal cancer cohort: 96% (95% CI, 90–100) |
| 2-yr RFS in nonrectal cohort: 85% (95% CI, 70–100) |
| Median follow-up for recurrence: 20.0 mos (range, 0–60.8) |
Safety
| Grade ≥3 AEs: diabetes (1 pt), lung infection (1 pt), hypothyroidism (1 pt), encephalitis (1 pt), neutropenia (1 pt), febrile neutropenia (1 pt) |
| Most common: fatigue (23%), rash/dermatitis (21%), pruritus (19%) |
N Engl J Med 2025; published online Apr 27
Cercek A,Foote MB,Rousseau B Nonoperative Management of Mismatch Repair–Deficient Tumors
http://doi.org/10.1056/NEJMoa2404512
Reviewed by Ulas D. Bayraktar, MD on May 4, 2025
