Ninety percent of fit patients with previously untreated chronic lymphocytic leukemia (CLL) responded to treatment with obinutuzumab in combination with chemotherapy, according to the results of a subgroup analysis of the nonrandomized, phase 3b GREEN study.

The study assigned 124 patients to receive obinutuzumab 1000 mg plus fludarabine and cyclosphosphamide (G-FC).

Among the patients who responded, almost half (46.4%) achieved a complete response and another 43.6% achieved a partial response. Minimal residual disease was negative in 64.3% of patients when measured by peripheral blood and 35.7% when measured by bone marrow. Among patients with IGHV mutations, minimal residual disease (MRD) negativity was 96.6% in peripheral blood and 66.7% in bone marrow.

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With a median follow-up of longer than 2 years, the 2-year progression-free survival was 91%. According to the researchers, these results suggest that this treatment regimen is clinically active in this patient population.

The majority of patients experienced at least 1 adverse event. The most common adverse events were neutropenia, nausea, pyrexia, thrombocytopenia, anemia, vomiting, and diarrhea. Grade 3 or worse adverse events were also common, occurring in 87.1% of patients. The most common grade 3 or worse events were neutropenia, thrombocytopenia, anemia, leukopenia, febrile neutropenia, and pneumonia.

Ten percent of patients discontinued treatment because of adverse events. Four adverse events resulted in death.

“G-FC represents a promising treatment option for young, fit patients with previously untreated CLL who are eligible for potent chemoimmunotherapy,” the researchers wrote. “Moreover, G-FC could hold potential as an effective ‘backbone’ of combination therapies with new compounds, such as ibrutinib; such a regimen (G-FC plus ibrutinib) is already showing favorable efficacy in a phase 2 trial as first-line treatment for fit CLL patients with mutated IGHV.”

Disclosure: Many of the authors of the original study reported conflicts of interest with various pharmaceutical companies. For a full list of disclosures, please refer to the original study.

Reference                                                                                    

Bosch F, Cantin G, Cortelezzi A, et al. Obinutuzumab plus fludarabine and cyclophosphamide in previously untreated, fit patients with chronic lymphocytic leukemia: a subgroup analysis of the GREEN study [published online August 27, 2019]. Leukemia. doi:10.1038/s41375-019-0554-1