Merck & Co’s anticipated immunotherapy pembrolizumab is likely to be approved before October by the U.S. Food and Drug Administration (FDA) as a treatment for melanoma, making it the first anti-Programmed Death receptor/ligand (PD-1/L1) antibody commercially available for use in the clinic.
PD-1/PD-L1 are immune checkpoints exponentially targeted in the development of new immunotherapies against several types of cancers, since they are crucial for an efficient anti-tumoral immune response by T cells.
While the majority of anti-cancer drugs aim to directly kill cancer cells, immuno-oncology drugs enhance the body’s own ability to recognize and destroy cancer cells, resulting in immunological memory that lasts for a longer time and can prevent cancer recurrence.
Companies like Bristol-Myers Squibb, Roche Holding AG and AstraZeneca Plc, all have similar experimental drugs in their pipeline research and are racing towards an FDA approval to treat different types of cancer.
This new class of melanoma immunotherapeutic drugs is likely to generate more than $30 billion in annual sales worldwide by 2025.
Merck’s objective is to sell its PD-1 drug for patients whose skin cancer does not respond to treatment with Yervoy, a Bristol-Myers immunotherapy targeting CTLA-4, a receptor expressed on the surface of T cells and that acts as an “off” switch when activated by tumors.
So far, clinical studies have proven pembrolizumab can shrink tumors in about a third of patients with late-stage melanoma.
“My hope is that over the next five to 10 years, we will be curing over half of melanoma patients,” Dr. Steven O’Day, director of the Los Angeles Skin Cancer Institute said in a Reuters interview.
“If we have pembrolizumab approved, it makes a big difference. About a third of those patients will have a chance of a durable, long-lasting response,” added Dr. Antoni Ribas, professor of hematology-oncology at the University of California, Los Angeles, and a pembrolizumab trial lead investigator in the same interview.
In addition to melanoma, PD-1 inhibitors are also being studied for the treatment of different types of cancer, including lung cancer, one of the biggest targets of this drug.
Bristol is submitting lung cancer data to the FDA on a rolling basis and wants to be first in the market with its nivolumab (anti-PD-1) and Yervoy (anti-CTLA-4) combination immunotherapy for lung cancer, a story recently covered by Immuno-Oncology News.
“We believe a combination of immuno-oncology agents represents the best chance for patients to achieve long-term survival,” Michael Giordano, head of development, oncology and immunology, said in the Reuters interview.
Even though Merck is not studying pembrolizumab in combination with its own experimental drugs, it has ongoing studies with drugs from Amgen and other companies, and is conducting a study of PD-1 in combination with its older melanoma drug Sylatron.
While combination therapies usually result in a better outcome, they first need to be analyzed as a monotherapy, to fully understand their potential benefits and possible risks.