Phase I Study Of Sirolimus Plus Gemcitabine In Patients With Advanced Solid Tumors: A Spanish Group For Research On Sarcomas (Geis) Study

3096 Background: In preclinical studies, combination of sirolimus with gemcitabine enhances apoptosis in vitro and increases anti-tumor efficacy in vivo. Methods: Patients with advanced solid tumors, age 18-70 years, no prior mTOR inhibitor or gemcitabine, ECOG PS 0-1, and adequate hematological, renal and hepatic function, were enrolled in this phase I study to assess safety, tolerability, pharmacokinetics (PK), and to identify the dose limiting toxicity (DLT), maximum tolerated dose (MTD) and recommended dose (RD) of the combination of sirolimus and gemcitabine. A 3+3 dose escalation design with cohorts of 3-6 patients was used. Sirolimus was given po continuously. Gemcitabine was given iv 10mg/m2/minute on days 1 and 8 every 3 weeks. Dose levels 1, 2 and 3 corresponded to sirolimus 2, 2 and 5mg/24h plus gemcitabine 800, 1000 and 1000mg/m2 respectively. After observing DLTs at higher dose level and poorer mTOR signaling inhibition at lower doses, a new cohort of sirolimus 5mg/24h plus gemcitabine 800 mg...