GSK Jemperli Trial Shows No Evidence of Disease in 100% of Rectal Cancer Patients

GSK plc announced updated results from a phase II study evaluating Jemperli (dostarlimab) as a first-line treatment for locally advanced mismatch repair deficient (dMMR) rectal cancer. The trial demonstrated a 100% clinical complete response rate in 42 patients who completed dostarlimab treatment, with no evidence of tumors detected via imaging, endoscopy, and rectal exam.

The data, presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting, builds on earlier findings. In the initial 24 patients, the complete response was sustained with a median follow-up of 26.3 months. These findings were first presented at ASCO 2022 and published in The New England Journal of Medicine.

Hesham Abdullah, Senior Vice President, Global Head Oncology, R&D at GSK, called the results remarkable and a step towards understanding dostarlimab's potential in this curative-intent setting. GSK is also evaluating dostarlimab in ongoing AZUR-1 and AZUR-2 registrational studies for certain colorectal cancers.

The standard of care for dMMR/microsatellite instability-high (MSI-H) locally advanced rectal cancer involves chemotherapy and radiation followed by surgery. While this often yields initial positive outcomes, nearly one-third of patients eventually die from distant metastasis. Furthermore, the standard treatment can lead to long-term side effects impacting quality of life, including bowel, urinary, and sexual dysfunction, as well as secondary cancers and infertility.

Dostarlimab is not currently approved anywhere for the frontline treatment of locally advanced dMMR rectal cancer. GSK is advancing studies, including the AZUR clinical trial program, to evaluate dostarlimab in patients with advanced or metastatic dMMR/MSI-H colorectal cancer.