A new kind of cancer drug has been approved by the Food and Drug Administration (FDA).

According to the agency's news release, "The U.S. Food and Drug Administration today granted accelerated approval to Keytruda (pembrolizumab) for treatment of patients with advanced or unresectable melanoma who are no longer responding to other drugs."

Keytruda, marketed by Merck & Co., is the first of its kind as it "blocks a cellular pathway known as PD-1, which restricts the body's immune system from attacking melanoma cells," the press announcement stated.  

"Keytruda is the sixth new melanoma treatment approved since 2011, a result of promising advances in melanoma research," said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research.

"Many of these treatments have different mechanisms of action and bring new options to patients with melanoma."

The agency recalls the five earlier approved melanoma treatments which include ipilimumab (2011), peginterferon alfa-2b (2011), vemurafenib (2011), dabrafenib (2013), and trametinib (2013).

Keytruda is a genetically engineered drug that is part of an emerging class of antibody-based drugs, noted The Washington Post.

This new approach to cancer treatment opens up a new range of treatment opportunities for both melanoma and other types of cancers, as well.

"This is really opening up a whole new avenue of effective therapies previously not available," quoted The New York Times of Dr. Louis M. Weiner, director of the Georgetown Lombardi Comprehensive Cancer Center in Washington and a spokesman for the American Association for Cancer Research. "It allows us to see a time when we can treat many dreaded cancers without resorting to cytotoxic chemotherapy."

In terms of the price, Merck estimates that the cost to the average U.S. patient will be in the range of $12,500 per month or $150,000 annually and will be given in a three-week interval, noted Bloomberg. This means that the average treatment will just a bit over six months.

Many in the field of cancer research are hailing the new drug as a game changer.

"For patients who have not responded to prior therapies, this drug now provides a very real chance to shrink their tumors and the hope of a lasting response to treatment," said Dr. Antoni Ribas, the study's principal investigator and a professor of medicine in the division of hematology-oncology at the David Geffen School of Medicine at UCLA, per News Medical.

"Keytruda embodies Merck's unwavering commitment to pursue breakthrough science to help people who are facing the most challenging diseases," Merck CEO Ken Frazier said in a statement via Bloomberg. "We are grateful to the people with advanced melanoma who participated in our trials, and the scientific and medical community for the shared effort that has led to the accelerated approval of Keytruda."