Dr. Eyre on Resistance to BTK Inhibition in MCL

Toby Eyre, MCBhB, MRCP, consultant hematologist at Oxford University Hospitals NHS Trust, discusses resistance to BTK inhibition in mantle cell lymphoma (MCL).

In a study presented at the 2018 European Hematology Association Congress, venetoclax (Venclexta) monotherapy induced an overall response rate (ORR) of 60% in patients with poor-risk relapsed/refractory MCL previously treated with a BTK inhibitor. Patients who develop resistance to BTK inhibitors are a big unmet need in MCL, explains Eyre, accounting for approximately 30% of the overall population.

In a phase II study with ibrutinib (Imbruvica) monotherapy (NCT01236391), the ORR in relapsed/refractory patients was 68%, with a complete response of 21%, which left approximately 30% of patients with no suitable treatment alternatives. Additionally, the progression-free survival was just over 1 year, suggesting that many of the patients who do respond to the inhibitor will experience relapse. Within 1 or 2 years of BTK inhibitor therapy, the majority of patients will require another line of therapy, explains Eyre.