Long term outcomes for venetoclax plus rituxumab in relapsed chronic lymphocytic leukemia

This study aimed to investigate the long-term outcomes of venetoclax and rituximab (VR) treatment in patients with relapsed/refractory (r/r) chronic lymphocytic leukemia (CLL). 

This study concluded that this treatment had long-term effectiveness in these patients.  

Bendamustine plus rituximab (BR) is a standard treatment combination used in patients with relapsed or refractory (unresponsive) CLL. However, many patients, particularly those with genetic abnormalities, can still have disease progression. 

Venetoclax (Venclexta) is a targeted therapy used for the treatment of r/r CLL. It has been shown good effectiveness in patients with genetic abnormalities. Adding immunotherapy drug rituximab (Rituxan) for a fixed period of time to venetoclax has been shown to improve progression-free survival (PFS) when compared to BR in patients with r/r CLL). The long-term outcomes and response to further therapies after VR in these patients were unknown. 

This study involved 389 patients with r/r CLL. 194 patients were treated with VR and 195 were treated with BR. Patients were followed up for an average of 48 months. 

The 4-year PFS rate for the VR group was 57.3% compared to 4.6% for the BR group. VR was associated with an 81% lower risk of disease progression compared to BR. 85.3% of patients in the VR group were alive at 4 years compared to 66.8% in the BR group. VR was associated with a 59% lower risk of mortality compared to BR. 

Undetectable minimal residual disease (MRD) at the end of combination treatment led to better PFS compared to patients who were MRD positive in both groups. MRD positive means there are cancer cells detected after treatment. More patients in the VR group who had genetic abnormalities were MRD-positive.

Patients in the VR group who received ibrutinib (Imbruvica) treatment after progression had a response rate of 100%. Patients in the VR group who were treated after progression with a venetoclax-based regimen had a response rate of 55%.  

This study concluded that the effectiveness of VR is sustained in patients with r/r CLL patients and is durable in patients who achieve undetectable MRD. 

This study was funded by Genentech and AbbVie, the manufacturer of venetoclax.