The purpose of the phase 1 part of this study is to evaluate how well pirtobrutinib is tolerated and what side effects may occur. The phase 2 part of the study will further investigate efficacy and safety of multiple pirtobrutinib dosages versus placebo. The study drug will be administered orally in participants with Primary Immune Thrombocytopenia (ITP). Blood tests will be performed to check how much pirtobrutinib gets into the bloodstream and how long it takes the body to eliminate it. The study will last up to approximately 16 weeks for phase 1 dose-escalation and 28 weeks for phase 2 dose-optimization, excluding screening.
Phase 1 trials primarily test safety and dosing in a small number of participants (typically 20–100). Results do not yet speak to efficacy. FDA approval is typically many years away from this stage.
Phase 2 trials begin testing efficacy in a larger patient group (100–300). This is often where biotech binary events occur — positive Phase 2 data can significantly advance a company's pipeline narrative, while failures can be terminal for a program.
Currently recruiting: the trial is enrolling patients. A data readout is not expected until after enrollment closes and the follow-up period is complete.
Eli Lilly and Company (LLY) is the sponsoring company for this trial. BiotechSign currently grades this company C (54/100) based on composite catalyst signals across its full pipeline. This trial is one data point in that overall catalyst picture.