ESMO: In PD-1 battle GSK waged on Merck, Jemperli appears to show survival edge over Keytruda in lung cancer

Last year, a first-of-its-kind head-to-head clinical trial between two PD-1 inhibitors went in GSK’s favor. Now, the British pharma has some new patient survival data to celebrate.

Compared with Merck’s market-leading Keytruda, GSK’s Jemperli demonstrated a 25% lower risk of death in patients with newly diagnosed nonsquamous non-small cell lung cancer (NSCLC), according to new data unveiled today, Oct. 20, at the European Society for Medical Oncology (ESMO) 2023 Congress.

The data come from an updated analysis of the phase 2 PERLA trial, which was the first global, head-to-head study of two PD-1 inhibitors.

The number doesn’t bear statistical significance, because the trial wasn’t designed to show superiority. It does, however, further prove that Jemperli behaves in a similar way as Keytruda does, Hesham Abdullah, M.D., who leads GSK’s oncology drug development, said in an interview with Fierce Pharma.

“I think what it probably does is it gives us certainly additional confidence in how we think about life cycle management opportunities and combinations with that type of backbone,” Abdullah said of Jemperli’s overall survival result.

The overall survival win adds to previous positive results in which Jemperli produced a numerically better tumor response rate and time to tumor progression compared with Keytruda.

The new update showed that patients who took Jemperli and chemo lived a median 19.4 months, versus 15.9 months in the Keytruda-chemo group. By the time of the data cutoff, about half of the trial population had died.

Previously, Jemperli’s performance was less impressive in PD-L1-negative patients. This time, the GSK drug did numerically better than Keytruda on overall survival across PD-L1 subgroups. In the PD-L1-negative group, Jemperli takers lived a median 20.8 months, versus 16.1 months for Keytruda. The numbers were 18 months and 15.9 months for the drugs, respectively, in PD-L1-positive patients. Jemperli’s advantage, however, looks less clear in those with tumor PD-L1 expression between 1% to 49%.

GSK has moved forward with a phase 3 trial that combines Jemperli and the chemotherapy docetaxel with or without its experimental TIM-3 inhibitor cobolimab in NSCLC patients who have progressed on first-line treatment of the combination of a PD-1/L1 inhibitor and chemo. That trial is expected to read out toward the second half of 2024, Abdullah said.

Matching up to Keytruda in NSCLC bodes well for Jemperli. Thanks in large part to its NSCLC leadership, Keytruda in 2022 sold a whopping $20.9 billion globally. By comparison, Jemperli, with small indications in previously treated, mismatch repair-deficient (dMMR) solid tumors, brought in only 21 million pounds sterling in sales last year.

Despite the positive head-to-head data in NSCLC, Jemperli seemed to have performed worse than Keytruda in their separate trials when it comes to staving off disease progression in primary advanced or first recurrent endometrial cancer with mismatch repair-proficient tumors.

Patient follow-up frequency and different recruitment criteria may have affected the two readouts—from Jemperli’s RUBY trial and Keytruda’s NRG-GY018 in endometrial cancer, Abdullah explained.

At ESMO, investigators also shared additional analyses from RUBY among patients with different mutations as well as analysis of time to second disease progression or death.

Based on the RUBY data, GSK has already won the FDA’s approval to market Jemperli as a first-line treatment for dMMR endometrial cancer. GSK is now awaiting additional overall survival data next year to see whether an expansion in the overall population is possible, Abdullah said. Only about a third of patients in the RUBY trial had died by the time of the previous analysis.