Arn Unpacks Dostarlimab Approval for Patients With dMMR Advanced Endometrial Cancer

Courtney R. Arn, APRN-CNP

The FDA has granted regular approval to dostarlimab-gxly (Jemperli) following the review of updated clinical data for adult patients with mismatch repair–deficient (dMMR) recurrent or advanced endometrial cancer who have progressed on or following a prior platinum-containing regimen in any settings and are not eligible for curative surgery or radiation.¹ According to Courtney R. Arn, APRN-CNP, the immunotherapy demonstrated encouraging efficacy results in the clinical trial setting.

Patients (n = 141) receiving the anti–PD-1 monoclonal antibody in the GARNET trial (NCT02715284), which supported the regular approval, achieved an overall response rate (ORR) of 45.4% (95% CI, 37.0%-54.0%). The median duration of response was not reached; among responders, 85.9% had a response lasting at least 12 months and 54.7% had a response of 24 months or longer.

“The recent data from the phase 1 GARNET study—with the ORR rate of 45%—is very exciting data and has very promising results,” Arn told Oncology Nursing News®. “They have produced a statistically significant ORR compared with other immunotherapy agents or other chemotherapy agents, and overall, [there are] relatively similar safety warnings and precautions.”

Arn, a nurse practitioner in the Division of Gynecologic Oncology at The Ohio State University Wexner Medical Center and The James Comprehensive Cancer Center, discussed treating patients with dostarlimab and what nurses should be monitoring when administering the agent to patients.

Oncology Nursing News®: Since the accelerated approval of dostarlimab in 2021, what has been your experience with dostarlimab in practice?

Previously dostarlimab received accelerated approval based on ORR and duration of response. Most recently, the regular approval, supported by data from the phase 1 GARNET trial which [showed] a complete response rate of 15% and nearly 30% partial response [rate]. Since the accelerated approval, and most recently the regular approval, we’ve been excited about using dostarlimab for patients who have recurrent or advanced endometrial cancer who are MMR deficient.

We have had a lot of experience with dostarlimab—both on clinical trials and as part of standard of care. I do not think that dostarlimab specifically has any more challenges compared [with] other immunotherapy options. The safety data and warnings and precautions are relatively similar to other immunotherapy agents. We do test all our patients for MMR status; if they did not have it done on their initial biopsy, then at the time of their hysterectomy our pathologist will test every specimen for MMR status.

What do you consider the best nursing practices when administering this agent?

As far as nursing practice goes, there are a few key takeaways. [It’s important to be] making sure [that] you’re doing a very good baseline assessment, [and that] patients don’t have any autoimmune disorders that would exclude them from being treated with immunotherapy. Make sure you’re checking baseline labs [such as] liver [and] kidney function; for preexisting diabetes or thyroid disorders before starting therapy; and closely monitoring labs on treatment, [in addition to] monitoring their symptoms at every single visit.

One of the important things with immunotherapy is there’s no set time for when these toxicities can kick in; it can be after the first cycle, it can be after being on therapy for 1 to 2 years, and even if a patient has been on the same regimen for over 1 year, make sure that you’re continuing to assess for any possible immune associated toxicity at every visit and that they’re aware of when to be calling if they do develop any new symptoms. Not only that, but patients are able to develop immune-associated toxicities several weeks or even months after stopping therapy, so if a patient has completed immunotherapy and they call with new symptoms keep in mind that if their most recent treatment was with immune therapy, you’re ruling out any possible immune toxicities.

What is important to discuss with patients during treatment with dostarlimab?

Making sure that [you’re] continuing to monitor [patients] and education is important prior to initiating therapy with immunotherapy. Make sure you’re counseling your patient on the possible risks or adverse effects and going through head-to-toe possible adverse effects that could occur and give them warnings and precautions of reasons that they should be contacting the office if they do develop those symptoms. [I recommend] intervening quickly as soon as you start to have any concern for immune-associated toxicity, make sure that you’re fully assessing them, ruling it out, treating it appropriately, and monitoring them at every single visit, [along with] holding treatment when needed.

Reference

FDA grants regular approval to dostarlimab-gxly for dMMR endometrial cancer. FDA. February 9, 2023. Accessed March 16, 2023. https://www.fda.gov/drugs/resources-information-approved-drugs/