selpercatinib + rifampin

This is a combination of **selpercatinib**, a potent and highly selective small-molecule inhibitor of the rearranged during transfection (RET) receptor tyrosine kinase (RET kinase inhibitor), and **rifampin**, a classic antibiotic and a strong inducer of cytochrome P450 3A (CYP3A) enzymes. Selpercatinib is primarily indicated for the treatment of cancers with RET gene alterations, such as non-small cell lung cancer (NSCLC) with RET fusion-positive mutations, medullary thyroid cancer (MTC) with RET mutations, and advanced thyroid cancers with RET fusions. It works by selectively inhibiting the RET kinase, preventing downstream signaling involved in tumor growth and progression. Rifampin, while mainly an antimycobacterial agent for diseases like tuberculosis, is included here for its role as a pharmacokinetic modulator: co-administration with selpercatinib is contraindicated or not recommended because rifampin strongly induces CYP3A, leading to a significant reduction (up to ~87% in AUC) in selpercatinib systemic exposure, potentially causing loss of efficacy or treatment failure. There is no therapeutic clinical indication for the intentional combination of selpercatinib and rifampin; this combination represents a clinically relevant drug-drug interaction rather than an intended treatment regimen[1][3].

Brand names

Rifadin

Other names

selpercatinibRET kinase inhibitorrifampicin