Idelalisib (PI3Kδ inhibitor) therapy for patients with relapsed/refractory chronic lymphocytic leukemia: A Swedish nation‐wide real‐world report on consecutively identified patients

• Published in: European journal of haematology 2023-11, Vol.111 (5), p.715-721
• Main Authors: Mattsson, Agnes, Sylvan, Sandra Eketorp, Axelsson, Per, Ellin, Fredrik, Kjellander, Christian, Larsson, Karin, Lauri, Birgitta, Lewerin, Catharina, Scharenberg, Christian, Tätting, Love, Johansson, Hemming, Österborg, Anders, Hansson, Lotta
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; Chronic lymphocytic leukemia; CLL; Colitis; idelalisib; Inflammatory bowel disease; inhibitor; Leukemia; Medicin och hälsovetenskap; PI3K & delta; PI3Kδ inhibitor; real-world; Rituximab; Survival; Toxicity
• ISSN: 0902-4441; 1600-0609; 1600-0609
• DOI: 10.1111/ejh.14065

Objectives We examined the efficacy and toxicity of the PI3Kδ inhibitor idelalisib in combination with rituximab salvage therapy in consecutively identified Swedish patients with chronic lymphocytic leukemia (CLL). Methods and Results Thirty‐seven patients with relapsed/refractory disease were included. The median number of prior lines of therapy was 3 (range 1–11); the median age was 69 years (range 50–89); 22% had Cumulative Illness Rating Scale (CIRS) >6 and 51% had del(17p)/TP53 mutation. The overall response rate was 65% (all but one was partial response [PR]). The median duration of therapy was 9.8 months (range 0.9–44.8). The median progression‐free survival was 16.4 months (95% CI: 10.4–26.3) and median overall survival had not been reached (75% remained alive at 24 months of follow‐up). The most common reason for cessation of therapy was colitis (n = 8, of which seven patients experienced grade ≥3 colitis). The most common serious adverse event was grade ≥3 infection, which occurred in 24 patients (65%). Conclusions Our real‐world results suggest that idelalisib is an effective and relatively safe treatment for patients with advanced‐stage CLL when no other therapies exist. Alternative dosing regimens and new PI3K inhibitors should be explored, particularly in patients who are double‐refractory to inhibitors of BTK and Bcl‐2.