A Dose Escalation Study Of Ibrutinib With Lenalidomide For Relapsed And Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma

Introduction: Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is dependent upon dysregulated signaling through the B-cell receptor (BCR) pathway. Bruton’s tyrosine kinase (BTK) mediates BCR signaling, and inhibition of BTK with ibrutinib, a selective, irreversible BTK inhibitor, is effective and well tolerated for patients (pts) with relapsed/refractory CLL/SLL. However, complete remissions (CRs) are infrequent, mechanisms of resistance to single-agent ibrutinib have been identified, and the duration of response beyond 3 years is unknown. Lenalidomide, a multi-functional immunomodulatory agent, is active in CLL/SLL, but limited by tumor flare reactions, which occur secondary to B-cell activation. Ibrutinib and lenalidomide modulate several key overlapping factors involving the CLL tumor microenvironment, and therefore a phase 1 combination study with lenalidomide dose escalation was undertaken.