This study will be conducted in 2 parts. Part 1 will evaluate LOXO-338 as monotherapy. If safety and initial evidence of efficacy of LOXO-338 monotherapy are confirmed, part 2 will evaluate the combination of LOXO-338 with the highly selective, noncovalent Bruton's tyrosine kinase (BTK) inhibitor, pirtobrutinib (LOXO-305).
The purpose of this study is to find out whether the study drug, LOXO-338, is safe and effective in patients with advanced blood cancer. Patients must have already received standard therapy. The study may last up to approximately 3 years.