Cancer Immunotherapy

Cancer kills more than 8 million people a year, and the number of new cases is expected to grow to 22 million by the 2030s. That gives urgency to scientists’ hopes for so-called immunotherapies, new drugs that harness the body’s defense system to attack cancer cells. While forms of the treatments have been around for decades, they once worked against just a few malignancies. New immunotherapies can target a wider range of cancers, including tumors of the lung and kidney as well as several blood cancers. Some drugs teach the immune system how to recognize and fight cancers, while others disable the mechanisms that cancers employ to defend themselves. The potential: long-lasting therapies for difficult cancers that can enhance existing treatments. The market for cancer immunotherapies could reach $35 billion a year.

The U.S. Food and Drug Administration has approved a number of immunotherapies. Drugs in a class called checkpoint blockers help to take the brakes off the immune system, unleashing the body’s killer T-cells to hunt down cancer. Merck & Co’s Keytruda has been approved to treat advanced melanoma, an aggressive form of skin cancer, as well as several other malignancies. Former President Jimmy Carter is the most high-profile patient to have taken the drug. While checkpoint blockers have dramatically improved survival for some advanced cancer patients, only a fraction survive beyond five years, and researchers are still struggling to understand what makes those few different. AstraZeneca Plc. shocked investors in July when its combination of a checkpoint inhibitor with another immunotherapy drug failed to slow disease progression in lung cancer patients any better than chemotherapy. Another type of immunotherapy, known as CAR-T, works by re-engineering a patient’s T-cells to make them better cancer fighters. The FDA for the first time approved such a therapy, made by Novartis AG, in August, and another made by Kite Pharma Inc. is expected to follow later in the year. Initial demand is expected to exceed supply, which would force doctors into the heartbreaking position of deciding which patients gets treatment. While trial results have been impressive, the potent treatments can also cause dangerous side effects. Juno Therapeutics Inc. halted a trial after patients died of brain swelling. So far the approach has been limited to blood cancers. Expanding into solid tumors remains a hurdle.