Last month, the U.S. Food & Drug Administration (FDA) approved a new drug, known as Keytruda, to treat non-small cell lung cancer (NSCLC) that has metastasized (spread to other parts of the body). In a press release announcing the fast-track approval, the FDA stated that the new drug would give doctors a better opportunity to treat patients who may benefit by using Keytruda, which has the generic name pembrolizumab.
Pembrolizumab targets cellular pathways called PD-1/PD-L1, which are proteins located within certain types of cancer cells and the body’s immune cells. Drugs like Keytruda help boost the body’s natural immune system to fight against the cancerous cells.
Previously, Keytruda was approved to treat instances of advanced melanoma in combination with an immunotherapy drug, ipilimumab. One other drug that targets PD-1/PD-L1, Opdivo, has been approved to fight a certain type of NSCLC known as squamous non-small cell lung cancer. The approval of Keytruda expands the availability of drugs targeting this pathway and offers a more direct way to fight additional types of NSCLC.
Pembrolizumab and Mesothelioma
While the new FDA approval is tied specifically to lung cancer, this is also great news for mesothelioma patients.
Approximately 20% to 40% of mesothelioma cancers express the PD-L1 protein targeted by pembrolizumab. Sarcomatoid cell mesothelioma is particularly liable to express PD-L1.
A recent study (KEYNOTE-028) shows that pembrolizumab may have some positive effects for those who are suffering from this mesothelioma, a deadly cancer whose only known cause is exposure to asbestos. In that study, as described by Dr. Evan W. Alley during a recent conference, 25 mesothelioma patients took pembrolizumab biweekly with additional assessments made at eight-week intervals. After the trial period, the overall disease control rate was an astounding 76%, with 12 patients showing stable disease and 7 patients exhibiting partial responses to the treatment. Dr. Alley described these results as “quite encouraging.”
The Future of Keytruda
Additional studies are going on to determine other potential effects of Keytruda on different forms of cancer.
Just within the last week Merck – the maker of Keytruda – and Eli Lilly announced an expansion to their collaborative efforts at studying the combined effects of Keytruda and Alimta, a commonly prescribed chemotherapy drug. The new study builds on positive results from a previous study, which were delivered earlier this year during the 16th World Congress on Lung Cancer and which focused on nonsquamous NSCLC. As part of the expanded collaboration, Phase I and Phase III studies will look at how other drugs work with pembrolizumab to combat NSCLC and multiple tumors. Since Alimta has long been approved to treat mesothelioma, it’s possible that this expanded partnership will help bring us closer to a more effective treatment of mesothelioma.
In the long run, the promises of Keytruda are still under investigation. However, while there is still plenty of additional study to occur, emerging treatments like Keytruda offer plenty of hope in an area where hope is often hard to come by.