of venetoclax (Venclexta)
Photo courtesy of AbbVie
Health Canada has issued a Notice of Compliance with Conditions (NOC/c) for the BCL-2 inhibitor venetoclax (Venclexta™).
This means venetoclax is conditionally approved for use in patients with previously treated chronic lymphocytic leukemia (CLL) who have 17p deletion or no other available treatment options.
An NOC/c is authorization to market a drug with the condition that the sponsor perform additional studies to verify a clinical benefit.
The NOC/c policy is designed to provide access to:
- Drugs that can treat serious, life-threatening, or severely debilitating diseases
- Drugs that can treat conditions for which no drug is currently marketed in Canada
- Drugs that provide a significant increase in efficacy or significant decrease in risk when compared to existing drugs marketed in Canada.
Venetoclax (previously ABT‐199) is being developed by AbbVie and Genentech, a member of the Roche Group. The drug is jointly commercialized by the companies in the US and by AbbVie outside of the US.
Venetoclax is currently under evaluation in phase 3 trials for the treatment of relapsed, refractory, and previously untreated CLL.
Phase 2 trial
Results from a phase 2 trial of venetoclax in CLL (M13-982, NCT01889186) were published in The Lancet Oncology in June. The trial enrolled 107 patients with relapsed or refractory CLL and 17p deletion.
Patients received venetoclax at 400 mg once daily following a weekly ramp-up schedule for the first 5 weeks. The primary endpoint was overall response rate, as determined by an independent review committee.
At a median follow-up of 12.1 months, 85 patients had responded to treatment, for an overall response rate of 79%.
Eight patients (8%) achieved a complete response or complete response with incomplete count recovery, 3 (3%) had a near-partial response, and 74 (69%) had a partial response. Twenty-two patients (21%) did not respond.
At the time of analysis, the median duration of response had not been reached. The same was true for progression-free survival and overall survival. The progression-free survival estimate for 12 months was 72%, and the overall survival estimate was 87%.
The incidence of treatment-emergent adverse was 96%. The most frequent grade 3/4 adverse events were neutropenia (40%), infection (20%), anemia (18%), and thrombocytopenia (15%).
The incidence of serious adverse events was 55%. The most common of these events were pyrexia (7%), autoimmune hemolytic anemia (7%), pneumonia (6%), and febrile neutropenia (5%).
Grade 3 laboratory tumor lysis syndrome (TLS) was reported in 5 patients during the ramp-up period only. Three of these patients continued on venetoclax, but 2 patients required a dose interruption of 1 day each.
In the past, TLS has caused deaths in patients receiving venetoclax. In response, AbbVie stopped dose-escalation in patients receiving the drug and suspended enrollment in phase 1 trials.
However, researchers subsequently found that a modified dosing schedule, prophylaxis, and patient monitoring can reduce the risk of TLS.
