The U.S. Food and Drug Administration (FDA) recently granted approval for immunotherapy drugs Keytruda and Opdivo to fight non-small cell lung cancer, raising the hopes of patients with malignant pleural mesothelioma.
Drugmakers Merck & Co. and Bristol-Myers Squibb manufacture Keytruda (pembrolizumab) and Opdivo (nivolumab), respectively. Both drugs target PD-1 and PD-L1, specific proteins that block a body’s immune system from attacking the cancer cells.
Those same proteins were identified in a subset of mesothelioma patients with the shortest survival times.
The University of Chicago Comprehensive Cancer Center recently started the only phase II mesothelioma clinical trial for Keytruda. Meanwhile, the Netherlands Cancer Institute in Amsterdam announced in July the first mesothelioma clinical trial for Opdivo.
Both drugs were already approved for other cancers, and they are now being tested in numerous clinical trials across the U.S. Opdivo has shown a promising response rate with cancers of the bladder, kidney, head and neck.
Cancer researchers believe that immunotherapy drugs, such as Keytruda and Opdivo, can be utilized most effectively in a combined effort, also known as synergy, with other drugs as adjuvant treatment to eliminate remaining cancer cells after surgery.
For example, the FDA approved Opdivo in 2014 for use in combination with Yervoy, a skin cancer drug, as an immunotherapy strategy for advanced melanoma.
“I would expect the FDA to extend approval of that combination for certain cases of lung cancer,” Dr. Raymond Wong, former staff scientist at the Pacific Meso Center, told Asbestos.com. “This could set the stage for its use in mesothelioma.”
In clinical trials, Opdivo showed a unique ability to extend the lives of lung cancer patients with metastatic disease.
The FDA earlier this year approved the drug for the treatment of patients with advanced squamous non-small cell lung cancer (NSCLC). The agency’s October approval added non-squamous NSCLC to its list of approved uses.
Regulators approved Keytruda a few days ahead of Opdivo for NSCLC in combination with a diagnostic test designed to determine the amount of PD-L1 expression.
A trial that included 61 NSCLC patients, who also showed significant PD-L1 expression, determined the effectiveness of Keytruda. Tumors shrank in 41 percent of patients treated. The effectiveness ranged from 2.1 months to 9 months before regression.
The clinical trial in Chicago follows a smaller study performed at the University of Pennsylvania Cancer Center. In that trial, Keytruda shrank or stopped the growth of mesothelioma tumors in 19 of the 25 patients who received it.
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Although there are major differences between lung cancer and pleural mesothelioma, the FDA approval has sparked hope within the mesothelioma community.
An estimated 158,000 people are expected to die in the U.S. from lung cancer in 2015, according to the National Cancer Institute. It is the leading cause of cancer death, eclipsing breast, prostate and colorectal cancers combined.
Mesothelioma is a rare and aggressive cancer diagnosed in an estimated 3,000 people annually in the U.S. The rarity has made it difficult to study, raise research funds and conduct clinical trials to advance treatment options.
Standard treatment today for mesothelioma remains a combination of surgery, chemotherapy and radiation — also known as multimodal therapy. The rise of immunotherapy research with other cancers has heightened mesothelioma awareness.
“Long-term, the trend is finding effective combinations of different immunotherapies,” Wong said. “One way to look at it is that the PD-1/PD-L1 drugs might become the new ‘common denominator’ of cancer therapy, to which additional immunotherapies are added for synergistic effect.”