AbbVie, a global biopharmaceutical company, announced that the US Food and Drug Administration (FDA) accepted AbbVie's New Drug Application (NDA) granting priority review for venetoclax for the treatment of chronic lymphocytic leukemia (CLL) in adults who have received at least one prior therapy, including patients with 17p deletion. With priority review, the FDA's goals include a faster timeline for review of six months, compared to 10 months for the standard review period.

Additionally, AbbVie announced the European Medicines Agency (EMA) has validated its Marketing Authorisation Application (MAA) for venetoclax for the treatment of patients with chronic lymphocytic leukemia (CLL) with 17p deletion or TP53 mutation.

Venetoclax is an inhibitor of the B-cell lymphoma-2 (BCL-2) protein being developed in partnership with Genentech and Roche to treat CLL. Venetoclax is believed to lead some cells, including some cells with CLL, to undergo apoptosis, or cell death.

The FDA granted venetoclax Breakthrough Therapy designation (BTD) in April 2015 for the treatment of CLL in previously treated patients with the 17p deletion genetic mutation, underscoring the potential for venetoclax to provide substantial improvement over current therapies in this difficult to treat patient population.

"The FDA acceptance and EMA validation of AbbVie's Venetoclax submissions mark a major step forward as we work to become a global leader in oncology, providing new therapies for patients with cancer," said Michael Severino, M.D., executive vice president of research and development and chief scientific officer, AbbVie. "Patients are always our number one priority and we accelerated our efforts to bring venetoclax, the first BCL-2 inhibitor, to patients with CLL in need of new therapies, including those with 17p deletion who typically have a poor prognosis."

The NDA and MAA are supported by pivotal data from a phase 2, open-label study of venetoclax in patients with relapsed/refractory CLL with 17p deletion, a genetic variation in CLL associated with a poor patient prognosis. In August 2015, AbbVie announced the phase 2 study met its primary endpoint of achieving an overall response rate, according to an assessment by an independent review committee. The safety profile was similar to other venetoclax studies and no unexpected safety signals were reported.

Venetoclax is an investigational oral B-cell lymphoma-2 (BCL-2) inhibitor being evaluated for the treatment of patients with various cancer types. The BCL-2 protein prevents apoptosis (programmed cell death) of some cells, including lymphocytes, and can be over expressed in some cancer types. Venetoclax is designed to selectively inhibit the function of the BCL-2 protein. Venetoclax is being developed in collaboration with Genentech and Roche. Together, the companies are committed to BCL-2 research with venetoclax, which is currently being evaluated in Phase 3 clinical trials for the treatment of relapsed/refractory CLL, along with studies in several other cancers. Venetoclax is an investigational compound and its safety and efficacy have not been evaluated by the FDA or any other health authority. According to the FDA, BTD is intended to expedite the development and review of drugs for serious or life-threatening conditions. The criteria for BTD includes preliminary clinical evidence, demonstrating a drug may have substantial improvement on at least one clinically significant endpoint compared to available therapies.

CLL is a slow-progressing cancer of the bone marrow and blood in which the bone marrow makes too many lymphocytes, a type of white blood cell. It is the most common leukemia diagnosed in adults in western countries.

The 17p deletion mutation is a genomic alteration in which a part of chromosome 17 is absent. Approximately 3-10 per cent of CLL patients are found to have the 17p deletion mutation at diagnosis, and it occurs in 30-50 per cent of patients with relapsed/refractory CLL. The median life expectancy for CLL patients with 17p deletion is less than 2-3 years. Chromosome 17 contains the TP53 gene6, which is involved in regulating the division and death of normal cells. Deletion of 17p or mutations in TP53 are associated with rapid disease progression and short survival.

The phase 2, multicenter, international, open label clinical trial was designed to evaluate the efficacy and safety of venetoclax monotherapy in CLL patients with 17p deletion who relapsed or who were refractory to existing therapies. The study enrolled 158 patients, 107 in the main study cohort evaluating efficacy, and 50 patients in the safety expansion cohort.

The primary efficacy endpoint was overall response rate and the safety evaluations were the number and percentage of patients who experienced treatment-related adverse events, changes in physical exam findings, including vital signs, changes in clinical laboratory test results and changes in cardiac assessment findings. Secondary efficacy outcome measures included complete remission rate, partial remission rate, duration of response, overall survival and progression-free survival, among others.