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.
Hodgkin lymphoma -- a cancer of white blood cells called lymphocytes -- is one of the most common cancers in children and young adults in the United States, with about 10,000 new cases occurring each year. While current therapies are often successful in treating the disease, up to one-fourth of patients eventually suffer a relapse, experts say.
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 new study involved 23 such patients. According to researchers at Dana-Farber Cancer Institute, in Boston, more than one-third of the patients had tried -- and ultimately failed -- at least six lines of treatment. Four-fifths of the patients had also undergone stem cell transplant therapy in hopes of curing their disease, but also failed.
The new phase 1 trial involved a drug called nivolumab, a therapy that frees the immune system to attack cancer cells.
"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.
"What makes these results especially encouraging is that they were achieved in patients who had exhausted other treatment options," study co-senior author Dr. Margaret Shipp, chief of the division of hematologic neoplasia at Dana-Farber Cancer Institute, said in an institute news release.
"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," she added.
The study was published Dec. 6 in the New England Journal of Medicine to coincide with its expected presentation on Saturday at the annual meeting of the American Society of Hematology, in San Francisco.
The study received funding from Bristol-Myers Squibb, which markets nivolumab, as well as funding from the U.S. National Institutes of Health.
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.