by Dr. C.H. Weaver M.D. 3/2019
An early phase clinical trial evaluating dostarlimab in women with recurrent or advanced endometrial cancer appears promising. These data were presented at the 2019 Society for Gynecologic Oncology (SGO) Annual Meeting on Women’s Cancer in Honolulu, Hawaii.
Endometrial cancer (EC) is the most common gynecologic malignancy in the U.S. but there are limited treatment options for women whose disease progresses on or after first-line therapy. EC can be classified as microsatellite stable (MSS/75%) or microsatellite instability-high (MSI-H/25%) and no effective treatments are currently available for either group.
Dostarlimab (TSR-042) is a humanized anti-programmed death (PD)-1 monoclonal antibody that binds with high affinity to the PD-1 receptor and effectively blocks its interaction with the ligands PD-L1 and PD-L2. Dostarlimab is a novel precision cancer immunotherapy drugs that helps to restore the body’s immune system in fighting cancer by releasing checkpoints that cancer uses to shut down the immune system. PD-1 and PD -L1 are proteins that inhibit certain types of immune responses, allowing cancer cells to evade an attack by the body’s immune cells. Dostarlimab works similar to other checkpoint inhibitors.
Key Study Findings From GARNET
A total of 125 women with recurrent EC were treated with Dostarlimab 500 mg once every 3 weeks for 4 doses, followed by 1000 mg once every 6 weeks until disease progression. Patients were MSI-H (33%), MSS (63%) and unknown MSI-status (4%).
Treatment with dostarlimab monotherapy resulted in a clinically meaningful response rate in recurrent EC who progressed on or after a platinum-based regimen regardless of MSI status. The overall response rates in the MSI-H population, and MSS population was 53%, 63% and 47%, respectively. At the time of data cutoff, treatment was still ongoing in 84% of responders, with 89% of the responders (33 of 37) having been on treatment for more than six months and 49% of responders (18 of 37) having been on treatment for more than one year.
Dostarlimab is not currently approved for use anywhere in the world but submission to regulatory authorities is planned for later in 2019.