GSK’s Oncology Drug Acquired from Tesaro Notches Accelerated Approval for Endometrial Cancer

On April 22nd, GSK announced that its antibody, Jemperli (dostarlimab) received the FDA’s accelerated approval. The PD-1 inhibitor is approved for treating mismatch repair-deficient (dMMR) recurrent or advanced endometrial cancer in adult women who have progressed following prior platinum-based chemotherapy.

Cancer Recurrence – A Tough Challenge

Endometrial cancer is described as cancer that forms in the inner lining of the uterus called the endometrium. It is the sixth most common cancer in women worldwide.

Based on biomarkers, endometrial cancers are classified either as mismatch repair-deficient/microsatellite instability-high (dMMR/MSI-H) or mismatch repair-proficient/microsatellite stable. In 2019, the FDA approved Eisai’s Lenvima (lenvatinib) plus Merck and Co.’s PD-1 inhibitor, Keytruda (pembrolizumab) combination therapy for advanced endometrial cancer that is not dMMR/MSI-H.

If detected early, endometrial cancer is often curable by surgical removal of the uterus. But if cancer has spread to other organs, patients are usually treated using radiation or chemotherapy. Yet, 1 in 4 women experiences recurrence of cancer. Currently, there is no effective first-line therapy for those whose cancer has returned following chemotherapy.

“Unfortunately, as many as 60,000 women are diagnosed with endometrial cancer in the US each year, and these women currently have limited treatment options if their disease progresses on or after first-line therapy,” said Dr. Hal Barron, Chief Scientific Officer and President R&D, GSK.

“Today’s approval of JEMPERLI by the FDA has the potential to transform the treatment landscape for these women and demonstrates our continued commitment to helping patients with gynecologic cancers,” he added.

Phase 1 GARNET Trial

The accelerated approval is an outcome of positive primary trial endpoints, overall response rate (ORR), and duration of response (DOR) observed from the dMMR endometrial cancer cohort of the ongoing GARNET trial.

Results showed that the 71-patient study registered an ORR of 42.3% with a complete response rate of 12.7% and a partial response rate of 29.6%. Among patients who responded, 93.3% demonstrated a DOR of 6 months or more. Fatigue/asthenia, nausea, diarrhea, anemia, and constipation were the most commonly reported side effects.

“We applaud GSK and their ongoing efforts to support women with endometrial cancer, the most common gynecologic malignancy in the US and the sixth most common cancer in women worldwide. For many women whose disease is dMMR and has progressed after platinum-based chemotherapy, the approval of JEMPERLI brings a new treatment option to an underserved patient population,” said Dr. Sue Friedman, Executive Director of Facing Our Risk of Cancer Empowered (FORCE).

Jemperli was originally generated by AnaptysBio and subsequently developed by Tesaro, Inc. GSK got hold of the drug through its $5.1 billion acquisition of Tesaro in 2018.

Jemperli will receive continued FDA approval if it registers clinical benefit in confirmatory trials.

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Author

Rajaneesh K. Gopinath