Retrospective Analysis of the Impact of Adverse Event-Triggered Idelalisib Interruption and Dose Reduction on Clinical Outcomes in Patients With Relapsed/Refractory B-Cell Malignancies.

BACKGROUND: Idelalisib is a phosphatidylinositol 3-kinase δ inhibitor approved for relapsed/refractory follicular lymphoma, a type of indolent non-Hodgkin lymphoma (iNHL), and chronic lymphocytic leukemia (CLL). Idelalisib-triggered adverse events (AEs) may be managed with treatment interruption and/or dose reduction, potentially extending therapy duration and increasing the likelihood of continued response. PATIENTS AND METHODS: Post hoc analyses were conducted to evaluate clinical outcomes after AE-induced idelalisib interruption for 125 patients with iNHL and 283 with CLL. RESULTS: Progression-free survival (PFS) was longer for patients with iNHL who experienced ≥ 2 interruptions versus those with 0 interruptions who discontinued idelalisib or study because of AEs (hazard ratio 0.33; P = .0212). Both PFS and overall survival were longer for patients with CLL with ≥ 2 interruptions versus 0 interruptions in those who discontinued therapy because of an AE (hazard ratio PFS 0.50, overall survival 0.41; P < .005). Clinical benefits persisted for patients with CLL who experienced treatment interruption after receiving idelalisib for ≥ 6 months. Supplementing interruption with dose reduction did not worsen clinical outcomes. However, time off therapy of ≥ 8% may diminish the clinical benefit of treatment interruption. CONCLUSION: Idelalisib interruption and dose reduction were associated with enhanced clinical outcomes for patients with relapsed/refractory iNHL or CLL who experienced an AE, supporting this management strategy when indicated.

No increased bleeding events in patients with relapsed chronic lymphocytic leukemia and indolent non-Hodgkin lymphoma treated with idelalisib.

The advent of novel B-cell receptor pathway targeting agents like ibrutinib dramatically changed management of B-cell malignancies. However, with concomitant anticoagulation (AC) and antiplatelet (AP) therapy, ibrutinib is associated with increased bleeding. This post hoc analysis aimed to determine the role of AC/AP therapy in patients with idelalisib-treated B-cell malignancies and to establish if it contributes to increased bleeding events. Data from two idelalisib trials (rituximab ± idelalisib in chronic lymphocytic leukemia [CLL] and idelalisib monotherapy in indolent non-Hodgkin lymphoma [iNHL]) were analyzed. Antithrombotic therapy was common (36%-63%), with comparable bleeding incidence across treatment groups (14%-19%; p = 0.56). Bleeding events of grade ≥3 occurred in 0.9% and 3.2% of the idelalisib-treated CLL and iNHL cohorts, respectively. Our findings demonstrate no increase in bleeding events with simultaneous AC/AP treatment and idelalisib use. Hemorrhagic risk is prevalent in these patients and an important consideration when evaluating available treatment options. ClinicalTrials.gov identifiers: NCT01539512 and NCT01282424.