Duvelisib bests ofatumumab as monotherapy for treatment of CLL/SLL

The investigators pointed out that duvelisib treatment was particularly effective in eliciting a lymph node response—85.0% compared to 15.7% with ofatumumab as assessed by IRC (P<0.0001).

Median overall survival was not reached in either arm. The 12-month probability of survival was 86% for both treatments.

Safety

Median treatment exposure was almost twice as long in the duvelisib arm because ofatumumab treatment was not allowed to exceed 12 doses as specified in the prescribing information.

The investigators explained this resulted in a longer adverse event (AE) reporting period for duvelisib.

One hundred twenty-four duvelisib-treated patients discontinued treatment, most commonly due to AEs (35%), disease progression (22%), subject withdrawal (8%), and death (8%).

All ofatumumab-treated patients discontinued treatment by the time of data cutoff, and 67% had completed treatment as per protocol. Others discontinued due to disease progression (20%), subject withdrawal (5%), and AEs (4%).

Eight (5%) duvelisib patients crossed over to ofatumumab therapy at the time of disease progression, and 89 (57%) ofatumumab-treated patients crossed over to duvelisib.

Nearly all patients in both arms experienced an AE.

The most common hematologic malignancies with duvelisib and ofatumumab, respectively, occurring in 10% or more patients were neutropenia (33%, 21%), anemia (23%, 10%), and thrombocytopenia (15%, 6%).

The most common nonhematologic AES with duvelisib were diarrhea (51%), pyrexia (29%), nausea (23%), and cough (21%).

With ofatumumab, the most common nonhematologic AES were infusion-related reaction (19%), cough (14%), and diarrhea, rash, and fatigue (12% each).

Grade 3 or greater AEs occurred in 87% of duvelisib-treated patients and 48% in the ofatumumab arm.

The most common grade 3 or greater events with duvelisib were neutropenia (30%), diarrhea (15%), pneumonia (14%), and anemia (13%).

With ofatumumab, only neutropenia (17%) of grade 3 or higher occurred in 10% or more patients.

Severe immune-related toxicities with duvelisib included colitis (12%) and pneumonitis, alanine transaminase (ALT) or aspartate transaminase (AST) increase (3% each). The events were managed with dose interruptions and steroid therapy for pneumonitis or colitis. All reported events resolved, and none was fatal.

Infectious AEs occurred more frequently with duvelisib, 69% compared to 43% in the ofatumumab arm. Pneumonia (18%) and upper respiratory tract infection (16%) were the most common events.

Three patients in the duvelisib arm and 1 in the ofatumumab arm contracted Pneumocystis jirovecii.

The most frequently reported serious AE was pneumonia (duvelisib 15%; ofatumumab 3%).

Nineteen fatal AEs occurred in patients on the duvelisib arm, 4 of which were related to the study drug: staphylococcal pneumonia (n = 2), sepsis (n=1), and general health deterioration (n = 1).

Seven fatal AEs occurred in patients on the ofatumumab arm, although none was attributed to ofatumumab.

The DUO trial was sponsored by Verastem Oncology and Infinity Pharmaceuticals , Inc.