Ibrutinib, Rituximab for Patients With CLL Superior to Standard Chemoimmunotherapy

A combination of ibrutinib and rituximab for patients with chronic lymphocytic leukemia (CLL) is superior to current treatment, according to results of a phase 3 trial published recently.

As compared with standard chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab, the ibrutinib-rituximab combination led to longer progression-free survival, as well as overall survival. The authors also said the combination treatment is better tolerated and is less toxic that standard chemoimmunotherapy. While the current CLL treatment standard works for many patients, it is also toxic, causing severe myelosuppression and creating a risk of infections due to immunosuppression of T cells.

In the trial, 89.4% of those treated with the ibrutinib—rituximab combination had not seen their disease progress after 3 years, compared with 72.9% of those who had the traditional combination.

The study randomized a total of 529 patients, giving 354 patients the ibrutinib-rituximab combination and 175 the chemoimmunotherapy regimen. After 33.6 months, the hazard ratio (HR) for the study drug combination for PFS or death was 0.35 (95% CI, 0.22-0.56; P <.001). For OS, the study drug combo had an HR of 0.17 (95% CI, 0.05-0.54; P <.001). All patients were aged 70 years or younger.

Infections were less common in the patients taking ibrutinib—rituximab (37 patients compared with 32 patients). Both groups had a similar rate of serious adverse events. Patients taking the 2-drug combination also reported less fatigue.

The ibrutinib—rituximab combination was especially beneficial for patients without immunoglobulin heavy-chain variable region mutation, a group that historically did not respond as well to the standard treatment regimen.

Patients will likely see a new standard of care, according to the lead author.

“These results will fully usher the treatment of chronic lymphocytic leukemia into a new era,” Tait Shanafelt, MD, professor of medicine at Stanford, said in a statement. “It seems likely that, in the future, these patients will be able to forego chemotherapy altogether.”

Reference

Shanafelt TD, Wang XV, Kay NE, et al. Ibrutinib—rituximab or chemoimmunotherapy for chronic lymphocytic leukemia. N Engl J Med. 2019;381:432-43. Doi: 10.1056/NEJMoa1817073.