Rational molecularly targeted combinations: A parallel-arm phase I trial of the humanized anti-IGF-1R antibody dalotuzumab (D) in combination with the allosteric AKT inhibitor MK-2206 or the gamma secretase inhibitor MK-0752, in patients with advanced solid tumors.

Abstract

3027 Background: Two rational strategies to interrogate the IGF-1R pathway were investigated in this parallel-arm phase I trial: 1) vertical inhibition with D and MK-2206 to potentiate PI3K pathway targeting, 2) horizontal crosstalk inhibition with D and MK-0752 to exert effects against cellular proliferation, angiogenesis and stem cell propagation. Methods: Patients (pts) with advanced solid tumors and no prior exposure to agents of the same targets were eligible. Dose escalation was based on a modified toxicity probability interval method (Ji et al, 2010). Arm A is comprised of fixed D dose of 10 mg/m2 IV weekly plus MK-2206 at escalating doses of 90-200 mg PO weekly. Arm B is comprised of fixed MK-0752 dose of 1800 mg PO weekly plus D at escalating doses of 7.5-10 mg/m2 IV weekly. Each cycle = 4 weeks in both arms. Primary objectives were to determine DLT and RP2D of these combinations. Results: 30 patients were enrolled in the dose escalation phase (18 in Arm A and 12 in Arm B) with: median age = 56 (range 36-74); M:F = 13:17; ECOG 0:1 = 12:18; primary diagnosis = colorectal (CRC) (9), NSCLC (3), others (17); prior metastatic regimens = 3 (range 1-4). In Arm A, 1/6 DLT was observed with MK-2206 at 135 mg (G3 serum sickness-like reaction); 2/3 DLTs with MK-2206 at 200 mg (G4 leukopenia/neutropenia; G3 rash). No other G4 or worse adverse events (AEs) were observed. RP2D of Arm A = D 10mg/m2 IV weekly and MK-2206 150 mg PO weekly. Other common AEs in Arm A included: fatigue, rash and nausea. In Arm B, 2/6 DLTs were observed with D at 10 mg/m2 (G3 rash; G3 nausea/vomiting). RP2D of Arm B = D 10mg/m2 IV weekly and MK-0752 at 1800 mg PO weekly based on Ji et al. Other common AEs in Arm B included: anorexia, nausea and fatigue. No PR was observed and SD > 4 months occurred in 4 pts (all in Arm A). PK analyses are ongoing. Conclusions: Targeted combinations of D with MK-2206 or with MK-0752 were both tolerable. Expansion cohorts based on biomarker selection are underway, specifically ovarian cancer with high IGF1 expression/low RAS score for Arm A; and KRAS wild-type CRC with high IGF1/low IGF2 expression for Arm B.