Long-term rituximab therapy cuts mantle-cell lymphoma death rate over 4 years

By Gene Emery

NEW YORK (Reuters Health) - A team of researchers in France says three years of rituximab maintenance therapy, given every 2 months for 3 years, cuts the 4-year death rate from mantle-cell lymphoma nearly in half.

The rate of overall survival was 89% among rituximab recipients versus 80% in the observation group (P=0.04). All 240 study participants (ages 18-65) had already undergone autologous stem-cell transplantation for their cancer, which is generally regarded as incurable. For older patients, a transplant isn't usually regarded as a good option.

The rates of event-free survival were 79% with rituximab versus 61% with observation (P=0.001). Median follow-up was 50.2 months.

"I think this will change practice for transplanted patients," chief author Dr. Steven Le Gouill, a hematologist at the Center for Research in Oncology and Immunology at the University of Nantes, told Reuters Health in a telephone interview.

Roche and Amgen paid for the study, published online September 27 in The New England Journal of Medicine.

Mantle-cell lymphoma represents about 6% of non-Hodgkin lymphoma cases in adults. An estimated 4,200 new U.S. cases are reported each year according to the Leukemia and Lymphoma Society. It's unusual to not have a relapse after treatment.

All the patients in the Le Gouill study had stage II, III or IV disease and were eligible for an autologous stem-cell transplant. For induction therapy they used the R-DHAP chemotherapy regimen, followed by R-BEAM treatment for consolidation therapy.

After the transplant, half the group received 375 mg of intravenous rituximab per square meter of body-surface area every 2 months for 3 years. (The drug is also part of the induction therapy and preparation for transplantation.)

The researchers chose 3 years as the length of treatment because, with other lymphomas, 2 years of maintenance therapy seems to work well. "Mantle-cell disease is much more aggressive, so we hypothesized we would need more maintenance therapy," Dr. Le Gouill said. "We wanted something that had a beginning and an end. Three years was a good balance."

Among the deaths in the study, lymphoma was the major cause, for 8 people in the rituximab group and 16 in the observation group.

Neutropenia, the most common side effect, was seen in 12.1% of the rituximab maintenance patients and 2.9% of the observation group between 12 and 36 months of follow-up.

Rituximab treatment not only prevented relapses, it "was associated with a low risk of major infection," the researchers concluded. "Whether maintenance therapy with rituximab improves outcomes in patients who are treated with other (chemotherapy) regimens is unknown."

SOURCE: http://bit.ly/2yzrWl0

N Engl J Med 2017.

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