Biopharmaceutical firm AbbVie has presented the updated results of a Phase Ib trial, which demonstrated patients with relapsed/refractory chronic lymphocytic leukemia (CLL) taking venetoclax in combination with rituximab had an overall response rate (ORR) of 84%.

Venetoclax is an investigational oral B-cell lymphoma-2 (BCL-2) inhibitor that is being assessed to treat patients with various cancer types. It is being developed in partnership with Genentech and Roche.

The BCL-2 protein is said to prevent apoptosis of some cells, including lymphocytes, and can be expressed in some cancer types.

AbbVie oncology development vice-president Dr Gary Gordon said: "AbbVie’s goal is to develop treatments that can help patients with hard-to-treat cancers.

"Combining the potential of venetoclax with rituximab is just one example of how we are investigating combination therapy."

The Phase Ib, open-label, dose-escalation, multicentre and international study evaluated the maximum tolerated dose and safety of venetoclax combined with rituximab in patients with relapsed/refractory CLL or small lymphocytic leukemia (SLL).

The secondary objectives of the study comprised pharmacokinetics and preliminary efficacy.

AbbVie said that the trial’s ORR was 84%, of the 49 patients assessed, including 20 patients achieving a complete response and 21 patients achieving a partial response (PR), one nodular.

In the trial, six patients achieved complete response with incomplete bone marrow recovery (CRi).

In this year, venetoclax received breakthrough therapy designation from the US Food and Drug Administration (FDA) to treat CLL in previously treated (relapsed/refractory) patients with the 17p deletion genetic mutation.

Image: High-power magnification (1000 X) of a Wright’s stained peripheral blood smear showing chronic lymphocytic leukemia (CLL). Photo: courtesy of Mary Ann Thompson.