Discovery of 1H-pyrazolo[3,4-d]pyrimidin-4-ylamine derivatives as potent PI3Kδ/BTK dual-target inhibitors for the treatment of B-cell lymphoma.

B-cell lymphoma (BCL) is a hematological system malignant tumor with a relatively high incidence, and PI3Kδ and BTK play an important role in the development of BCL. In the preliminary investigation, we found that when the PI3K inhibitor and the BTK inhibitor were used in combination, the therapeutic effect was greater than that of single-drug administration at both cell and animal levels. Therefore, dual-target inhibitors of PI3Kδ and BTK were expected to potentially achieve improved therapeutic window for BCL. Here, we designed and synthesized 30 compounds, among which compound 27 showed high inhibitory activity against both targets at the kinase level (IC50-PI3Kδ = 9.0 nM, IC50-BTK = 17.3 nM). Furthermore, at the cellular level, the inhibitory activity of 27 against JeKo-1 and H9 cells (IC50-JeKo-1 = 1.6 μM, IC50-H9 = 5.8 μM) was comparable to or exceeded that of the positive drug alone and in combination. Western blot analysis confirmed that compound 27 potently suppressed phosphorylation of BTK, PI3Kδ and their downstream effectors. In addition, compound 27 showed reduced cytotoxicity in H9c2 cardiomyocytes (LD50 = 247.3 μM) compared to the positive. Preliminary pharmacokinetic studies in rats revealed favorable plasma exposure profiles. These preliminary results collectively identified compound 27 as a promising lead candidate for further development against BCL.