Yu, Xiang‐Qing

TPS2618 Background: MEDI-573 is an investigational dual-targeting human antibody that neutralizes IGF-I/-II ligands and inhibits IGF‑1R and insulin receptor-A (IR-A) signaling pathways. By sparing IR-B and its hybrid receptors, MEDI-573 may achieve antitumor activity without perturbing glucose homeostasis. Objectives of this phase 1 dose-escalation and expansion study are to evaluate safety and determine the maximum tolerated dose (MTD), optimal biologically effective dose, pharmacokinetics, pharmacodynamics, and immunogenicity of MEDI-573 in adult patients with solid tumors. Methods: Patients with advanced solid tumors, Karnofsky status ≥60, and adequate organ function were treated with escalating doses of MEDI-573 IV once weekly (0.5 to 15 mg/kg) or every 3 weeks (30 or 45 mg/kg q3w) using a 3+3 design. Three patients per dose level were evaluated for safety. A biomarker-rich dose-expansion arm tested weekly 5 or 15 mg/kg MEDI‑573 in patients with advanced bladder cancer. Results: Preliminary data are presented for 43 patients (25 M, 18 F), median age 64 years. No dose-limiting toxicities or serious toxicity patterns occurred at any dose level. Drug-related adverse events occurring in ≥10% of patients were fatigue (28%), decreased appetite (23%), nausea (16%), diarrhea (14%), and anemia (12%); the majority were ≤ grade 2. Perturbations in insulin and growth hormone were not observed. Clinically significant changes in serum glucose were rare. The MTD was not reached after completely enrolling patients through the highest dose, 45 mg/kg IV q3w. Serum exposure of MEDI-573 increased with increasing dose. Full suppression of IGF‑I/-II was achieved with weekly and q3w dosing. No neutralizing antibodies against MEDI‑573 were detected. Of 43 patients, 8 (19%) had stable disease ≥12 weeks. The longest exposure was 21 months in a patient with well-differentiated liposarcoma. Conclusions: MEDI-573 demonstrated an acceptable safety profile at all doses tested. No dose-limiting toxicity or serious toxicities, including those related to glucose homeostasis, were detected. These preliminary results support further clinical development.

Abstract Purpose: This phase I, multicenter, open-label, single-arm, dose-escalation, and dose-expansion study evaluated the safety, tolerability, and antitumor activity of MEDI-573 in adults with advanced solid tumors refractory to standard therapy or for which no standard therapy exists. Experimental Design: Patients received MEDI-573 in 1 of 5 cohorts (0.5, 1.5, 5, 10, or 15 mg/kg) dosed weekly or 1 of 2 cohorts (30 or 45 mg/kg) dosed every 3 weeks. Primary end points included the MEDI-573 safety profile, maximum tolerated dose (MTD), and optimal biologic dose (OBD). Secondary end points included MEDI-573 pharmacokinetics (PK), pharmacodynamics, immunogenicity, and antitumor activity. Results: In total, 43 patients (20 with urothelial cancer) received MEDI-573. No dose-limiting toxicities were identified, and only 1 patient experienced hyperglycemia related to treatment. Elevations in levels of insulin and/or growth hormone were not observed. Adverse events observed in >10% of patients included fatigue, anorexia, nausea, diarrhea, and anemia. PK evaluation demonstrated that levels of MEDI-573 increased with dose at all dose levels tested. At doses >5 mg/kg, circulating levels of insulin-like growth factor (IGF)-I and IGFII were fully suppressed. Of 39 patients evaluable for response, none experienced partial or complete response and 13 had stable disease as best response. Conclusions: The MTD of MEDI-573 was not reached. The OBD was 5 mg/kg weekly or 30 or 45 mg/kg every 3 weeks. MEDI-573 showed preliminary antitumor activity in a heavily pretreated population and had a favorable tolerability profile, with no notable perturbations in metabolic homeostasis. Clin Cancer Res; 20(18); 4747–57. ©2014 AACR.