The Food and Drug Administration has halted enrollment in trials of venetoclax (Venclexta) for multiple myeloma.
The move comes after a review of data from the phase 3 BELLINI trial, which pitted venetoclax against placebo in relapsed and refractory multiple myeloma patients on a background of bortezomib and low-dose dexamethasone. Venetoclax is not approved for the treatment of multiple myeloma; the agency said that patients using the drug for approved indications should continue use of the drug.
There were 41/194 deaths (21.1%) in the venetoclax arm, versus 11/97 (11.3%) in the placebo group; 13 of the deaths in the venetoclax arm (32%) and 1 death in the placebo arm (9%) were treatment related. Sepsis, pneumonia, and cardiac arrest were the most common treatment-related causes of death in the venetoclax group; 8 of the 13 deaths (62%) were due to infection.
The FDA estimated that the drug doubled the risk of death compared to placebo.
The agency warned against off-label use of venetoclax for multiple myeloma, and noted that the drug “is safe and effective for its approved uses,” which include second-line treatment of chronic lymphocytic leukemia and small lymphocytic lymphoma in adults, as well as newly-diagnosed acute myeloid leukemia in adults age 75 years or older or who have contraindications to standard chemotherapy.
There are more than 10 trials in the United States of venetoclax for multiple myeloma, and most of them have been suspended, including BELLINI.
Patients already enrolled in the trial can remain on treatment, but they must re-consent to the trial. The FDA “will be working directly with sponsors of Venclexta, as well as other investigators conducting clinical trials in patients with multiple myeloma, to determine the extent of the safety issue,” the agency said in a statement.
Abbvie, which is developing venetoclax in partnership with Roche, noted in its own press release that the drug otherwise outperformed placebo in BELLINI, both in progression-free survival (22.4 months versus 11.5 months), and in overall (82% versus 68%) and partial (59% versus 36%) response rates.
Severe grade 3-5 toxicity and serious adverse event rates were similar in the two study arms, as was the overall incidence of infections (79.8% versus 77.1%). However, the incidence of pneumonia was 20.7% with venetoclax, versus 15.6% with placebo.
“We will continue working with the FDA and worldwide regulatory agencies to determine appropriate next steps for the multiple myeloma program,” Michael Severino, MD, AbbVie vice chairman and president, said in the press release.
Venetoclax binds and inhibits the B-cell lymphoma-2 protein, which prevents some blood cancer cells from undergoing programmed cell death.