• DOI:10.1056/NEJMoa2201445
• Corpus ID: 249395846

PD-1 Blockade in Mismatch Repair-Deficient, Locally Advanced Rectal Cancer.

@article{Cercek2022PD1BI,
  title={PD-1 Blockade in Mismatch Repair-Deficient, Locally Advanced Rectal Cancer.},
  author={Andrea Cercek and Melissa A Lumish and Jenna Sinopoli and Jill Weiss and Jinru Shia and Michelle F Lamendola-Essel and Imane El Dika and Neil H. Segal and Marina Shcherba and Ryan Sugarman and Zsofia K. Stadler and Rona Yaeger and J. Joshua Smith and Beno{\^i}t Rousseau and Guillem Argil{\'e}s and Miteshkumar Patel and Avni Mukund Desai and Leonard B. Saltz and Maria Widmar and Krishna Iyer and Janie Y Zhang and Nicole Gianino and Christopher Crane and Paul B. Romesser and Emmanouil P. Pappou and Philip P. Paty and Julio Garcia-Aguilar and Mithat Gonen and Marc J. Gollub and Martin R. Weiser and Kurt A. Schalper and Luis A. Diaz},
  journal={The New England journal of medicine},
  year={2022}
}

• A. Cercek, M. Lumish, +29 authors L. Diaz
• Published 5 June 2022
• Medicine
• The New England journal of medicine

BACKGROUND
Neoadjuvant chemotherapy and radiation followed by surgical resection of the rectum is a standard treatment for locally advanced rectal cancer. A subset of rectal cancer is caused by a deficiency in mismatch repair. Because mismatch repair-deficient colorectal cancer is responsive to programmed death 1 (PD-1) blockade in the context of metastatic disease, it was hypothesized that checkpoint blockade could be effective in patients with mismatch repair-deficient, locally advanced rectal cancer.

METHODS
We initiated a prospective phase 2 study in which single-agent dostarlimab, an anti-PD-1 monoclonal antibody, was administered every 3 weeks for 6 months in patients with mismatch repair-deficient stage II or III rectal adenocarcinoma. This treatment was to be followed by standard chemoradiotherapy and surgery. Patients who had a clinical complete response after completion of dostarlimab therapy would proceed without chemoradiotherapy and surgery. The primary end points are sustained clinical complete response 12 months after completion of dostarlimab therapy or pathological complete response after completion of dostarlimab therapy with or without chemoradiotherapy and overall response to neoadjuvant dostarlimab therapy with or without chemoradiotherapy.

RESULTS
A total of 12 patients have completed treatment with dostarlimab and have undergone at least 6 months of follow-up. All 12 patients (100%; 95% confidence interval, 74 to 100) had a clinical complete response, with no evidence of tumor on magnetic resonance imaging, 18F-fluorodeoxyglucose-positron-emission tomography, endoscopic evaluation, digital rectal examination, or biopsy. At the time of this report, no patients had received chemoradiotherapy or undergone surgery, and no cases of progression or recurrence had been reported during follow-up (range, 6 to 25 months). No adverse events of grade 3 or higher have been reported.

CONCLUSIONS
Mismatch repair-deficient, locally advanced rectal cancer was highly sensitive to single-agent PD-1 blockade. Longer follow-up is needed to assess the duration of response. (Funded by the Simon and Eve Colin Foundation and others; ClinicalTrials.gov number, NCT04165772.).