Clinical Trial to Evaluate the Efficacy and Safety of Pirtobrutinib With Rituximab in Patients With Mantle Cell Lymphoma

The current evidence obtained from clinical trials exploring the incorporation of BTK inhibitors in first-line treatment of MCL points toward a clear significant improvement in both patient responses and progression-free survival. Until new data from randomized clinical trials become available, the inclusion of new combinations of BTK inhibitors with chemoimmunotherapy or with new targeted combinations alone, remains a matter of debate. In addition, there is some concern regarding the additional toxicity associated with some of these combinations, which could be ameliorated by a fixed duration of treatment or by the use of newer generation BTK inhibitors, associated with significantly better tolerability. The new non-covalent BTK inhibitor pirtobrutinib has recently shown more promising activity in MCL relapsed/refractory to prior covalent BTK inhibitors therapy, and also with very favourable safety profile (3% of discontinuations due to drug-induced adverse events). Pirtobrutinib could be a very interesting drug to be tested in the upfront setting to try to sort out the significant toxicity more frequently observed with covalent BTK inhibitors. Indeed, indolent clinical forms of MCL that represent around 20% of new MCL diagnosis could be particularly suitable to receive pirtobrutinib as a first-line treatment in combination with rituximab in order to maximize responses and the rate of undetectable molecular minimal residual disease while improving the treatment tolerance. This combination could also limit treatment duration, except for MRD detectable and TP53 mutated cases, according to the data shown in the IMCL-2015 trial. By testing pirtobrutinib in combination with rituximab in a population of indolent MCL patients, the investigators aim to improve and refine the potential new standard treatment for this particular subset of MCL patients. Moreover, the Sponsor plan to conduct a clinical study that will allow not only a deep molecular MRD analysis but also a thorough biological study with different bulk and single-cell level multi-omic platforms in order to gain insight into pirtobrutinib performance in indolent clinical forms of MCL. For this purpose, the Sponsor have designed a multicenter, international, open-label, phase II clinical to assess the efficacy of pirtobrutinib in combination with rituximab in patients with indolent MCL.