selumetinib + temsirolimus

Selumetinib + temsirolimus is a combination of two targeted small-molecule inhibitors used in experimental cancer therapy. **Selumetinib** is an oral, potent, and highly selective allosteric inhibitor of MEK1/2, key kinases in the RAS/RAF/MEK/ERK (MAPK) signaling pathway, which is constitutively activated in many cancers. **Temsirolimus** is an intravenous inhibitor of mammalian target of rapamycin (mTOR), a key regulator of cell growth and proliferation. Temsirolimus inhibits the mTOR pathway, but resistance can arise via feedback activation of MAPK signaling. The rationale for this combination is to synergistically inhibit tumor growth by concurrently blocking both the MAPK and mTOR pathways, potentially overcoming resistance seen with monotherapies. This combination has been studied in advanced solid tumors, including soft tissue sarcoma and leiomyosarcoma, but remains investigational. The combination shows some activity in leiomyosarcoma, with a favorable progression-free survival benefit for this subgroup, along with specific adverse effects including mucositis, lymphopenia, neutropenia, and anemia[1][2][3].