RecruitingPhase 2Drug trialSelinexor Plus Gemcitabine in Selected Advanced Soft-tissue Sarcoma (SeliSarc)Phase I-II, non-randomized, single-arm, open-label, multicenter, international clinical trial. Patients with advanced soft-tissue sarcoma (leiomyosarcoma or malignant peripheral nerve sheath tumor) will receive selinexor in combination with gemcitabine.