Drug Regimen Found More Effective Than Chemoimmunotherapy for Patients With CLL

A new study published in the New England Journal of Medicine has found that an ibrutinib-rituximab regimen had a higher overall survival (OS) in patients with previously untreated chronic lymphocytic leukemia (CLL).

According to the American Cancer Society, CLL is the most common leukemia in adults and starts in the cells that become lymphocytes, a type of white blood cells in the bone marrow. In 2019 alone, there were approximately 21,000 new cases of CLL in the United States. The current standard treatment regimen includes chemotherapy; however, data regarding the efficacy of treatment with other treatments, such as ibrutinib-rituximab, have been limited.

In the phase 3 trial, researchers randomly assigned patients who were 70 years of age or younger with previously untreated CLL to receive either ibrutinib and rituximab for 6 cycles (after a single cycle of ibrutinib monotherapy), followed by ibrutinib until disease progression, or 6 cycles of chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab.

Of the 529 patients in the study, 354 were assigned to receive ibrutinib-rituximab and 175 were assigned to chemoimmunotherapy. After a follow-up of 34 months, the researchers found that ibrutinib-rituximab was favorable over chemoimmunotherapy. The drug regimen also achieved a superior OS and progression-free survival (PFS) (98.8% vs. 91.5% and 90.7% vs. 62.5%, respectively). Approximately 87.7% of patients achieved a 3-year PFS in the ibrutinib-rituximab group compared with 88.0% with chemoimmunotherapy alone.

The incidence of adverse events of grade 3 or higher was similar in the 2 groups (80.1% for those who received ibrutinib-rituximab and 79.7% who received chemoimmunotherapy), whereas infectious complications of grade 3 or higher were less common with ibrutinib-rituximab than with chemoimmunotherapy.

The findings were a part of the study’s interim analysis.

Reference

• Shanafelt T, Wang X, Kay N, et al. Ibrutinib—Rituximab or Chemoimmunotherapy for Chronic Lymphocytic Leukemia. The New England Journal of Medicine 2019; 381:432-443. Published August 1, 2019. https://www.nejm.org/doi/full/10.1056/NEJMoa1817073. Accessed August 19, 2019.

DOI: 10.1056/NEJMoa1817073;

• Chronic Lymphocytic Leukemia (CLL). American Cancer Society website. https://www.cancer.org/cancer/chronic-lymphocytic-leukemia.html. Accessed August 19, 2019.