Patients with relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) who failed prior Arzerra (ofatumumab) treatment achieved robust and durable responses after switching to duvelisib, Verastem Oncology announced.
Results from the Phase 3 crossover extension study IPI-145-12 (NCT02049515) were recently presented at the 23rd Congress of the European Hematology Association (EHA) in Stockholm, Sweden. The poster was titled, “The Efficacy of Duvelisib Monotherapy Following Disease Progression on Ofatumumab Monotherapy in Patients with Relapsed/Refractory CLL or SLL in a Phase 3 Crossover Extension Study.”
Duvelisib, Verastem’s lead treatment candidate, is an investigational oral therapy that inhibits phosphoinositide-3-kinase (PI3K)-delta and PI3K-gamma — two enzymes that promote the survival and growth of malignant B- and T-cells.
Researchers believe that blocking the activity of these two enzymes weakens malignant B- and T-cells by disrupting their interactions with the microenvironment, improving disease outcome.
Recently, the Phase 3 DUO trial (NCT02004522) examined the effectiveness of duvelisib versus Arzerra in patients with relapsed or refractory CLL/SLL. In the trial, duvelisib maintained patients without signs of disease progression for about 3.4 months longer than Arzerra, reducing the risk of disease progression or death by nearly half.
For patients with confirmed disease progression after Arzerra treatment in the DUO trial, Verastem designed the open-label, crossover extension study IPI-145-12, which gave patients the option to receive duvelisib instead.
The trial enrolled 89 patients with relapsed or refractory CLL/SLL who voluntarily received 25 mg of duvelisib twice a day until disease progression, intolerance, death, or study withdrawal — with a median exposure of 32 weeks — after being treated with Arzerra in DUO.
The objective response rate for patients treated with duvelisib in the crossover study was 73% compared with 28% with previous Arzerra treatment in DUO. Patients treated with duvelisib also remained progression-free for 15 months — approximately six months longer — than with the Arzerra regimen.
“The DUO crossover extension data presented build upon the previously reported positive Phase 3 DUO study results and further support duvelisib’s potential as an oral treatment option for patients with relapsed or refractory CLL/SLL,” Diep Le, MD, PhD, chief medical officer of Verastem Oncology, said in a press release.
“Duvelisib monotherapy also demonstrated a manageable safety profile, with results from this study consistent with the well-characterized safety profile of duvelisib monotherapy in previous studies. It is encouraging to see such a robust response to duvelisib monotherapy, similar to response observed in the parent DUO study, in patients that had failed an additional line of therapy and needed a new treatment option,” he said.