A phase I study of daily everolimus plus low-dose weekly cisplatin for patients with advanced solid tumors

Preclinical studies demonstrate synergistic anti-tumor activity with the combination of everolimus and cisplatin. We conducted a phase I study to establish the recommended phase II of oral everolimus to be given with low-dose weekly intravenous cisplatin.

Part A used a standard 3 + 3 dose escalation scheme. There were 4 planned dose levels of everolimus: 2.5, 5, 7.5, and 10 mg/day. Subjects received oral everolimus during days 1-21 and cisplatin 20 mg/m(2) intravenously (fixed dose) on days 1, 8, and 15 of a 28-day cycle. Pharmacokinetic (PK) blood samples were collected on day 1 and day 8 of cycle 1 in Part A. After the phase II recommended dose was established (Part A), 6 additional subjects were enrolled in an expansion cohort (Part B). Response was assessed by RECIST q 2 cycles for all subjects.

Thirty patients were enrolled (18 male, 12 female) and 29 were treated. Median age was 61 years (31-79) and the median number of prior cytotoxic chemotherapy regimens was 2 (0-3). Eighty-three percent of subjects had received prior RT. DLTs occurred at dose level 1 (sudden death of unclear cause in a patient with melanoma metastatic to liver) and dose level 2 (bowel obstruction). No DLTs occurred at dose levels 3 and 4. The most common adverse events (≥grade 3) among 28 patients evaluable for toxicity were lymphopenia (36%), hyperglycemia (11%), fatigue (11%), and venous thrombosis (11%). PK analysis of everolimus demonstrated dose-proportional increases in C (max) (mean 91.9 ng/ml) and AUC(0-INF) (mean 680.5 h*ng/ml) at dose level 4. Three partial responses were seen (metastatic pulmonary carcinoid, n = 2; metastatic sinus carcinoma, n = 1). Prolonged stable disease ≥6 cycles occurred in subjects with pulmonary carcinoid, oropharyngeal squamous cell carcinoma, basal cell carcinoma, papillary thyroid carcinoma, and esthesioneuroblastoma (n = 1 each).

The phase II recommended dose is everolimus 10 mg/day (days 1-21) + cisplatin 20 mg/m(2) (days 1, 8, and 15) of a 28-day cycle. PK data demonstrate dose-proportional increases in exposure, as previously described for everolimus monotherapy. Anti-tumor activity was observed in several tumor types.