Combining obinutuzumab and chlorambucil in unfit patients with chronic lymphocytic leukemia

The study evaluated the effectiveness of combining obinutuzumab (Gazyva) and chlorambucil (Leukeran) (O-Clb) to treat physically unfit patients with chronic lymphocytic leukemia (CLL). The authors found that O-Clb is a safe and effective initial treatment for unfit patients with low-risk CLL in a real-world setting.

Frontline therapy is the initial treatment given in cancer. Patients with CLL benefited from frontline therapy with O-Clb in clinical trials. However, older patients with other medical problems are generally excluded from planned clinical trials. Treatment effects also differ between trials and real-world medical practice. The real-world effectiveness of O-Clb in unfit patients with CLL is unclear.

The medical records of 437 patients with CLL from 13 countries were assessed. Genetic defects in del(11q22.3) gene were among 18.7% of patients. An unchanged IGHV gene was observed in 64.4% of patients. Both were characteristics of high-risk CLL. 408 patients received O-Clb and 29 patients received obinutuzumab alone (O-monotherapy), as frontline treatment. The average follow-up time was 14.1 months.

An overall treatment response was seen in 80.3% of patients. Complete response (CR) or absence of all clinical symptoms of cancer was reached in 169 (38.7%) patients. 182 (41.6%) patients experienced a partial response (a 50% or partial reduction in cancer symptoms).  

Patients were estimated to survive without cancer for 27.6 months on average. Patients treated with O-Clb combination had a 62% higher survival without cancer growing or spreading compared to those treated with O-monotherapy. 61.8% of patients on O-Clb and 52.8% of patients on O-monotherapy survived without cancer’s progression. 

Patients with high-risk CLL, enlarged lymph nodes and a low dose of obinutuzumab had shorter survival without cancer progression. Such patients also failed to achieve CR. Overall 88% of patients survived for 2 years after therapy. Patients treated with O-Clb had a 74% better overall survival than patients with O-monotherapy. The safety of O-Clb was similar to that of the earlier clinical trials.

The study concluded that O-Clb is a safe and effective way to treat unfit patients with low-risk CLL in the real-world. 

The study was retrospective, meaning that it looked back in time to analyze data. The number of patients on O-monotherapy was also much lower than patients in O-Clb.