In a small new trial, a form of treatment based on the body's immune system appears to be helping patients with Hodgkin lymphoma for whom other treatments had failed.
A therapy that liberates the immune system to attack cancer cells drove Hodgkin lymphoma (HL) into complete or partial remission in fully 87 percent of patients with resistant forms of the disease who participated in an early-phase clinical trial, investigators at Dana-Farber Cancer Institute and partnering institutions report in a study published today in the New England Journal of Medicine and simultaneously presented at the annual meeting of the American Society of Hematology (ASH) in San Francisco.
The disease "kills more than 1,000 people in the U.S. each year and is one of the rare cancers more common in young adults than in older patients," said one expert, Dr. Joshua Brody, director of the Lymphoma Immunotherapy Program at the Icahn School of Medicine at Mount Sinai, in New York City.
"Many people may know of actor Michael C. Hall, of television's 'Dexter,' who battled the disease in 2010," said Brody, who was not involved in the new study.
He stressed that Hodgkin lymphoma is often responsive to chemotherapy. However, in the minority of patients who do not respond to standard treatment, the disease is typically considered incurable and fatal.
The success of the agent, nivolumab, in this study has prompted the U.S. Food and Drug Administration to designate it a "breakthrough therapy" for treating relapsed HL, and a large, multinational Phase 2 trial is now under way.
"What makes these results especially encouraging is that they were achieved in patients who had exhausted other treatment options," said the study's co-senior author, Margaret Shipp, MD, chief, Division of Hematologic Neoplasia at Dana-Farber. "We're also excited by the duration of responses to the drug: the majority of patients who had a response are still doing well more than a year after their treatment."
The study involved 23 patients with relapsed or treatment-resistant HL, a cancer of white blood cells called lymphocytes. Although relatively uncommon - with less than 10,000 new cases each year in the U.S. - it is one of the most frequent cancers in children and young adults. While the disease can often be treated successfully with current therapies, up to a quarter of all patients eventually have a relapse.
"Nivolumab is a novel therapy which blocks the protein PD-1 -- a 'brake pedal' of certain immune cells," Brody explained. "This allows patients' immune systems to attack their own cancer -- an old concept which has shown unprecedented results in recent years."
Following treatment, four of the patients had no detectable tumor left and the tumors in 16 other patients had shrunk to less than half of their original size, the researchers said. Six months after treatment, 86 percent of patients were alive and continued to show response to the therapy. One year after treatment, most of the patients continued to do well.
About 20 percent of the patients had serious treatment-related side effects, but none of them were life-threatening, the study's authors said.
According to the researchers, the new findings have led the U.S. Food and Drug Administration to designate nivolumab as a "breakthrough therapy" for patients with relapsed Hodgkin lymphoma, and a large phase 2 trial is currently under way.
That's encouraging news, Brody said, because the patient pool in the current study is small. "Moving forwards, ongoing studies will assess the true efficacy and safety of this approach in larger studies," he said.
Side effects could be a stumbling block, as well. "As the therapy can increase anti-tumor immune responses it may also cause potentially dangerous anti-self-immune responses," Brody said. "Examples of this -- such as inflammation of the pancreas -- did occur, though only two patients had to discontinue therapy due to side effects."
Nevertheless, these early results are promising, he said.
"Even this early hint of remarkable results suggests that patients' immune systems will be the next powerful tool in fighting this type of cancer," Brody said.