Ibrutinib-Venetoclax Produces High MRD-Negative Rates in CLL/SLL

Medscape Medical News
26 Jun, 2020 ,

In patients with previously untreated chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), a once-daily oral regimen of ibrutinib and venetoclax was associated with deep molecular remissions in both bone marrow and peripheral blood, including in patients with high-risk disease, according to investigators in phase 2 CAPTIVATE MRD trial.

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In patients with previously untreated chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), a once-daily oral regimen of ibrutinib and venetoclax was associated with deep molecular remissions in both bone marrow and peripheral blood, including in patients with high-risk disease, according to investigators in phase 2 CAPTIVATE MRD trial.

Intention-to-treat analysis of 164 patients with CLL/SLL treated with the combination of ibrutinib (Imbruvica) and venetoclax (Venclexta) showed a 75% rate of minimal residual disease (MRD) negativity in peripheral blood and a 68% rate of MRD negativity in bone marrow among patients who received up to 12 cycles of the combination, reported Tanya Siddiqi, MD, of City of Hope National Medical Center, Duarte, Calif., and colleagues.

"This phase 2 study supports the synergistic antitumor activity of the combination with notable deep responses across multiple compartments," she said in an oral presentation during the virtual annual congress of the European Hematology Association.

Not Ready to Change Practice

A hematologist/oncologist who was not involved in the study said that the data from CAPTIVATE MRD look good, but it's still not known whether concurrent or sequential administration of the agents is optimal and whether other regimens may be more effective in the first line.

"I think this is promising, but the informative and practice-changing study would be to compare this combination to ibrutinib monotherapy or to venetoclax and obinutuzumab, and that's actually the subject of the next large German cooperative group study, CLL17," said Catherine C. Coombs, MD, assistant professor of medicine at the University of North Carolina, and the UNC Lineberger Cancer Center, Chapel Hill.

She noted that the combination of venetoclax and obinutuzumab (Gazyva) is also associated with high rates of MRD negativity in the first-line setting, and that use of this regimen allows clinicians to reserve ibrutinib or acalabrutinib (Calquence) for patients in the relapsed setting.

Prerandomization Results

Dr. Siddiqi presented pre-randomization results from the MRD cohort of the CAPTIVATE trial (NCT02910583), which is evaluating the combination of ibrutinib and venetoclax for the depth of MRD response. Following 12 cycles of the combinations, patients in this cohort are then randomized based on confirmed MRD status, with patients who are MRD negative randomized to maintenance with either ibrutinib or placebo, and patients with residual disease (MRD positive) randomized to maintenance with either ibrutinib alone or with venetoclax.

 

A total of 164 patients with previously untreated CLL/SLL and active disease requiring treatment who were under age 70 and had good performance status were enrolled. Following an ibrutinib lead-in period with the drug given at 420 mg once daily for three cycles of 28 days, the patients were continued on ibrutinib, and were started on venetoclax with a ramp-up to 400 mg once daily, for 12 additional cycles.

As planned, patients were assessed after 15 cycles for tumor lysis syndrome (TLS) risk assessment, MRD, and hematologic, clinical, imaging, and bone marrow exams for a response.