PI3Kδ/γ inhibitor generates rapid responses in CLL

Serious AEs in more than 1 patient included diarrhea (n=3), colitis (n=2), dehydration (n=2), pneumonia (n=2), and pneumonitis (n=2).

The AEs leading to treatment discontinuation were increased ALT/AST, dehydration, and spinal stenosis (all in 1 patient), as well as arthritis, pneumonitis, colitis, diarrhea, and stomatitis.

“We tend to see the transaminitis and the pneumonitis earlier, and then the late toxicity tends to be the diarrhea and colitis,” Dr O’ Brien said. “The one toxicity where I would not be inclined to try and re-treat a patient is pneumonitis, but I do think colitis can be successfully re-treated.”

Pharmacodynamic studies show very rapid inhibition of phosphorylated AKT following treatment, which is sustained throughout the whole first cycle. And following 1 cycle of duvelisib, there is near-complete inhibition of CLL proliferation, as evidenced by the reduction in Ki67.

Given these data, the investigators recommended further development of duvelisib in treatment-naïve CLL.

*Information in the abstract differs from that presented at the meeting.