The mesothelioma approval for the Keytruda combination regimen potentially unlocks a $12 billion market opportunity, according to a recent report from research firm IMARC Group.
The FDA on Wednesday approved a new indication for Merck’s blockbuster cancer therapy Keytruda (pembrolizumab), adding pleural mesothelioma to the already-extensive list of malignancies that the PD-1 inhibitor can be used for.
Wednesday’s label expansion covers the use of Keytruda with pemetrexed and platinum chemotherapy to treat adult patients with unresectable advanced or metastatic malignant pleural mesothelioma, a type of cancer that originates in the linings of the chest and the lungs. The Keytruda-based regimen can be used in the frontline setting in this indication.
“We’re pleased to offer a new first-line treatment option for adult patients with unresectable advanced or metastatic malignant pleural mesothelioma, a disease where prognoses are generally poor,” Gregory Lubiniecki, vice president of oncology clinical research at Merck Research Laboratories said in a statement.
The pharma’s application for Keytruda in this indication was backed by findings from the Phase II/III KEYNOTE-483 trial, which enrolled 440 patients for its late-stage phase, regardless of their PD-L1 expression levels. The Keytruda regimen was compared against pemetrexed and cisplatin or carboplatin. The FDA accepted Merck’s filing in May 2024 and granted in Priority Review.
Results from KEYNOTE-483 showed that Merck’s PD-1 blocker yielded significant survival benefit for patients, cutting the risk of death by 21%. Median overall survival (OS) was 17.3 months in patients who received the Keytruda combo, as compared to 16.1 months in patients treated with chemotherapy alone.
The Keytruda regimen also led to significantly better progression-free survival, reducing the likelihood death or disease progression by 20% versus chemotherapy alone. Overall response rate was likewise significantly better in the combo treatment arm.
In terms of safety, Keytruda’s side effects in KEYNOTE-483 were broadly consistent with what had been established in previous studies. However, Merck in its announcement emphasized that immune-mediated events can occur in any organ system during or after treatment with Keytruda. These episodes can be severe or fatal, according to the pharma.
Wednesday’s mesothelioma approval for Keytruda opens up a multibillion-dollar opportunity for Merck. According to an August 2024 report from research and consulting firm IMARC Group, the malignant mesothelioma market is expected to exceed $12 billion in value by 2034. From 2024 to 2034, the space is expected to hit a compound annual growth rate of 6.5%.
Another player in the mesothelioma space is Bristol Myers Squibb with its own PD-1 blocker Opdivo (nivolumab), which was approved as a first-line treatment for malignant pleural mesothelioma in August 2020, in combination with the anti-CTLA-4 therapy Yervoy (ipilimumab). According to the IMARC report, there is a “robust pipeline” of other developmental therapies for mesothelioma, and the space is expected to grow even more rapidly as the industry adopts a more personalized and targeted approach to treatment and increases its focus on early detection.
