The early success of an experimental drug from Bristol-Myers Squibb Co. that’s designed to unleash the body’s immune-system defenses against cancer sets the stage for an industry wide race to produce similar treatments.
The drug shrank tumors in people with advanced lung, kidney and skin cancer in 18 percent to 28 percent of patients, depending on the illness, who had failed on other therapies, according to data from a 296-patient trial reported June 2 at the American Society of Clinical Oncology meeting in Chicago.
The findings hint that therapies like the Bristol drug, that prompt killer T-cells to eliminate invaders, may work against many tumors, said James Allison, an immunologist at Memorial Sloan-Kettering Cancer Center in New York.
“There is no reason to think that all cancers might not be susceptible to immune therapy,” Allison said by telephone, noting that the human immune system can wipe out whole organs when it rejects a transplant.
Drugmakers and scientists have been trying to find ways to boost the immune system against cancer for decades, with little successes until recently.
In 2010, Dendreon Corp.’s Provenge, a prostate cancer treatment, was approved in the U.S. as the first therapy designed to train the body’s immune system to attack tumor cells as if they were a virus. Last year, Bristol-Myers immune boosting antibody Yervoy was approved for advanced melanoma.
Now “the whole idea of immunotherapy is really blossoming,” said David Chang, a vice president for Amgen Inc., which is testing immune-boosting treatments for melanoma and leukemia, in an interview at the oncology conference. “It is going to be the next wave in cancer treatments.”
In the 1990s, Allison did pioneering work that led to Yervoy. At that point, many researchers were skeptical that the concept would work in people, he said. Just a few years ago, when he gave talks to doctors at cancer meetings, the room would only be half full, he said.
At the weekend’s oncology conference Allison discussed data from Bristol’s trial and studies of competing immune drugs in a hall packed with researchers, doctors, and industry officials.
Bristol-Myers’s Yervoy was a milestone for the New York-based company, the first drug proven to extend the survival of advanced melanoma patients. The therapy blocks a molecular off-switch on the immune cells that keeps them from attacking cancer. It has been shown in studies to shrink melanoma in 10 percent to 15 percent of patients.
The newest Bristol drug, BMS-936558, is an antibody that blocks a different immune system off-switch, called PD-1. Many types of tumors act to keep the off-switch in place to protect themselves from the immune system.
Lung, Kidney, Skin Cancer
Results from the company-sponsored trial reported at the cancer meeting showed Bristol-Myers’s anti-PD-1 drug shrank tumors in 18 percent of lung cancer patients, 27 percent of kidney cancer patients and 28 percent of melanoma patients.
Based on the findings, Bristol-Myers plans to begin a final set of trials of the treatment in lung and kidney cancer this year, and in melanoma by early next year, said Michael Giordano, a Bristol-Myers senior vice president, in a phone interview.
Immune therapy will become “a new paradigm in the way cancers are treated,” he said.
Maureen O’Grady, 59, of Milford, Connecticut was diagnosed in January 2009 with lung cancer that had spread to her liver and both kidneys. By June 2010, the disease had also moved into to her heart despite several rounds of chemo and experimental drugs. “It was all over the place,” she said in a telephone interview. “My prognosis was poor.”
‘Teach Your Body’
Scott Gettinger, O’Grady’s doctor at Yale Cancer Center in New Haven, Connecticut, gave her a choice of two experimental drug trials, including the Bristol anti-PD-1 drug that might “teach your body to recognize cancer.” She chose the PD-1 drug and, within two months, her tumors started to shrink.
They have remained under control ever since then. The remaining lesions may just be dead tissue, O’Grady said.
“It has extended my life and given me a second chance,” she said in a phone interview. “Everybody is very happy I am still here.”
Potential rivals to Bristol-Myers include Merck & Co., Roche Holding AG, Teva Pharmaceutical Industries Ltd. and GlaxoSmithKline Plc, all of which are in early stages of testing drugs that work by similar mechanisms.
The new class of drugs “is definitely a revolution in the making,” said Keith Flaherty, head of developmental cancer therapeutics for Massachusetts General Hospital in Boston and a co-investigator on the study.
A promising aspect of new immune-boosting therapies is that they may work for long periods of time, said Suzanne Topalian, a professor of surgery and oncology at Johns Hopkins University School of Medicine in Baltimore and a lead author on the study.
According to the results, 20 patients on the Bristol-Myers PD-1 drug had tumor responses that have lasted a year or more. This stands in contrast to existing drugs that hit mutated genes on cancer cells. These often stop working in a matter of months as the tumors become resistant, Topalian said in a phone interview before the meeting.
Some patients who responded to BMS-936558 have now gone off therapy without their tumors regrowing, Topalian said.
The immune system “has a memory component that continues to hold to the tumor in check” even after therapy is stopped, she said in the phone interview.
A downside of boosting the immune system against cancer is that it may also attack normal tissue. Three patients in the trial died from lung inflammation linked to the drug, according to the results.
There haven’t been any deaths since Bristol started a program to aggressively treat patients who showed signs of the lung inflammation, said Fouad Namouni, the Bristol-Myers vice president who is leading the testing program for BMS-936558, in a phone interview.
In addition to lung, kidney and melanoma patients, the Bristol-Myers drug trial also included people with advanced colon cancer and prostate cancer. None of those patients experienced major tumor shrinkage, for reasons that aren’t clear.