follicular lymphoma
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The US Food and Drug Administration (FDA) has accepted for priority review the new drug application (NDA) for duvelisib, a dual PI3K delta/gamma inhibitor.
With this NDA, Verastem, Inc., is seeking full approval of duvelisib for the treatment of relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and accelerated approval of the drug for the treatment of relapsed or refractory follicular lymphoma (FL).
The FDA expects to make a decision on the NDA by October 5, 2018.
The FDA aims to take action on a priority review application within 6 months of receiving it, rather than the standard 10 months.
The agency grants priority review to applications for products that may provide significant improvements in the treatment, diagnosis, or prevention of serious conditions.
The application for duvelisib is supported by data from DUO™, a randomized, phase 3 study of patients with relapsed or refractory CLL/SLL, and DYNAMO™, a phase 2 study of patients with refractory indolent non-Hodgkin lymphoma.
Phase 3 DUO trial
Results from DUO were presented at the 2017 ASH Annual Meeting in December.
This study included 319 CLL/SLL patients who were randomized 1:1 to receive either duvelisib (25 mg orally twice daily) or ofatumumab (initial infusion of 300 mg followed by 7 weekly infusions and 4 monthly infusions of 2000 mg).
The study’s primary endpoint was met, as duvelisib conferred a significant improvement in median progression-free survival (PFS) over ofatumumab.
Per an independent review committee, the median PFS was 13.3 months with duvelisib and 9.9 months with ofatumumab (hazard ratio=0.52; P<0.0001). Duvelisib maintained a PFS advantage in all patient subgroups analyzed.
The overall response rate was 73.8% with duvelisib and 45.3% with ofatumumab (P<0.0001). The complete response rate was 0.6% in both arms.
Overall survival (OS) was similar in the duvelisib and ofatumumab arms (hazard ratio=0.99; P=0.4807). The median OS was not reached in either arm.
The most common grade 3 or higher adverse events (AEs)—in the duvelisib and ofatumumab arms, respectively—were neutropenia (30% vs 17%), anemia (13% vs 5%), diarrhea (15% vs 1%), pneumonia (14% vs 1%), and colitis (12% vs 1%).
Thirty-five percent of patients discontinued duvelisib due to an AE.
Severe opportunistic infections occurred in 6% of duvelisib recipients—bronchopulmonary aspergillosis (n=4), fungal infection (n=2), Pneumocystis jirovecii pneumonia (n=2), and cytomegalovirus colitis (n=1).
There were 4 deaths related to duvelisib—staphylococcal pneumonia (n=2), general physical health deterioration (n=1), and sepsis (n=1).
Phase 2 DYNAMO trial
Results from DYNAMO were presented at the 22nd EHA Congress (abstract S777) in June 2017.
This trial enrolled patients with indolent non-Hodgkin lymphoma whose disease was refractory to both rituximab and chemotherapy or radioimmunotherapy.
There were 83 patients with FL. They had a median of 3 prior anticancer regimens (range, 1-10).
The patients received duvelisib at 25 mg orally twice daily until disease progression or unacceptable toxicity.
The overall response rate, per an independent review committee, was 43%. One patient achieved a complete response, and 35 had a partial response. The median duration of response was 7.9 months.
The median PFS was 8.3 months, and the median OS was 27.8 months.
The most common grade 3 or higher AEs were neutropenia (22%), anemia (13%), diarrhea (16%), lipase increase (10%), and thrombocytopenia (9%).
There were 2 serious opportunistic infections—Pneumocystis pneumonia and fungal pneumonia.
There were 3 deaths attributed to duvelisib—toxic epidermal necrolysis/sepsis syndrome (n=1), drug reaction/eosinophilia/systemic symptoms (n=1), and pneumonitis/pneumonia (n=1).