Rectal Cancer · Cancer Warriors

Rectal Cancer

Dostarlimab (Jemperli), a PD-1-blocking immunotherapy, has shown unprecedented results in treating locally advanced mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H) rectal cancer, with 100% clinical complete response (cCR) rates in multiple studies.

Phase II Study (NCT04165772): A landmark trial led by Memorial Sloan Kettering Cancer Center (MSK) found that all 12 patients treated with neoadjuvant dostarlimab achieved a clinical complete response, with no evidence of tumor after 6 months of treatment, and no need for chemotherapy, radiation, or surgery.

Updated 2024 Data (ASCO): An expanded analysis of 42 patients confirmed a 100% sustained clinical complete response with a median follow-up of 26.3 months. No patients experienced disease recurrence or required additional therapy.

Key Outcomes:

No evidence of disease confirmed via MRI, endoscopy, digital rectal exam, and PET scans.

No grade 3 or higher adverse events reported.

Durable responses observed for over 2 years, with no local or distant recurrences.

Regulatory Status: The US FDA granted Breakthrough Therapy Designation to dostarlimab for this indication in December 2024, based on the remarkable results.

Ongoing Research: The AZUR-1 trial (NCT05723562) is a global, phase II registrational study evaluating dostarlimab monotherapy as a first-line treatment for untreated dMMR/MSI-H locally advanced rectal cancer, with the goal of confirming these findings in a larger cohort.

This treatment offers a paradigm shift by potentially eliminating the need for life-altering surgery, chemoradiation, and their associated long-term side effects, especially for young patients and those in childbearing years.

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