Phase 2 study of the safety and efficacy of umbralisib in patients with CLL who are intolerant to BTK or PI3Kδ inhibitor therapy.

Journal Article (Journal Article;Multicenter Study)

Intolerance is the most common reason for kinase inhibitor (KI) discontinuation in chronic lymphocytic leukemia (CLL). Umbralisib, a novel highly selective phosphatidylinositol 3-kinase δ (PI3Kδ)/CK1ε inhibitor, is active and well tolerated in CLL patients. In this phase 2 trial (NCT02742090), umbralisib was initiated at 800 mg/d in CLL patients requiring therapy, who were intolerant to prior BTK inhibitor (BTKi) or PI3K inhibitor (PI3Ki) therapy, until progression or toxicity. Primary end point was progression-free survival (PFS). Secondary end points included time to treatment failure and safety. DNA was genotyped for CYP3A4, CYP3A5, and CYP2D6 polymorphisms. Fifty-one patients were enrolled (44 BTKi intolerant and 7 PI3Kδi intolerant); median age was 70 years (range, 48-96), with a median of 2 prior lines of therapy (range, 1-7), 24% had del17p and/or TP53 mutation, and 65% had unmutated IGHV. Most common adverse events (AEs) leading to prior KI discontinuation were rash (27%), arthralgia (18%), and atrial fibrillation (16%). Median PFS was 23.5 months (95% CI, 13.1-not estimable), with 58% of patients on umbralisib for a longer duration than prior KI. Most common (≥5%) grade ≥3 AEs on umbralisib (all causality) were neutropenia (18%), leukocytosis (14%), thrombocytopenia (12%), pneumonia (12%), and diarrhea (8%). Six patients (12%) discontinued umbralisib because of an AE. Eight patients (16%) had dose reductions and were successfully rechallenged. These are the first prospective data to confirm that switching from a BTKi or alternate PI3Ki to umbralisib in this BTKi- and PI3Ki-intolerant CLL population can result in durable well-tolerated responses.

Full Text

Duke Authors

Cited Authors

  • Mato, AR; Ghosh, N; Schuster, SJ; Lamanna, N; Pagel, JM; Flinn, IW; Barrientos, JC; Rai, KR; Reeves, JA; Cheson, BD; Barr, PM; Kambhampati, S; Lansigan, F; Pu, JJ; Skarbnik, AP; Roeker, L; Fonseca, GA; Sitlinger, A; Hamadeh, IS; Dorsey, C; LaRatta, N; Weissbrot, H; Luning Prak, ET; Tsao, P; Paskalis, D; Sportelli, P; Miskin, HP; Weiss, MS; Svoboda, J; Brander, DM

Published Date

  • May 20, 2021

Published In

Volume / Issue

  • 137 / 20

Start / End Page

  • 2817 - 2826

PubMed ID

  • 33259589

Pubmed Central ID

  • PMC8574211

Electronic International Standard Serial Number (EISSN)

  • 1528-0020

Digital Object Identifier (DOI)

  • 10.1182/blood.2020007376


  • eng

Conference Location

  • United States