Phase I study of procaspase-activating compound-1 (PAC-1) in the treatment of advanced malignancies.

BACKGROUND: Procaspase-3 (PC-3) is overexpressed in multiple tumour types and procaspase-activating compound 1 (PAC-1) directly activates PC-3 and induces apoptosis in cancer cells. This report describes the first-in-human, phase I study of PAC-1 assessing maximum tolerated dose, safety, and pharmacokinetics. METHODS: Modified-Fibonacci dose-escalation 3 + 3 design was used. PAC-1 was administered orally at 7 dose levels (DL) on days 1-21 of a 28-day cycle. Dose-limiting toxicity (DLT) was assessed during the first two cycles of therapy, and pharmacokinetics analysis was conducted on days 1 and 21 of the first cycle. Neurologic and neurocognitive function (NNCF) tests were performed throughout the study. RESULTS: Forty-eight patients were enrolled with 33 completing ≥2 cycles of therapy and evaluable for DLT. DL 7 (750 mg/day) was established as the recommended phase 2 dose, with grade 1 and 2 neurological adverse events noted, while NNCF testing showed stable neurologic and cognitive evaluations. PAC-1's t1/2 was 28.5 h after multi-dosing, and systemic drug exposures achieved predicted therapeutic concentrations. PAC-1 clinical activity was observed in patients with neuroendocrine tumour (NET) with 2/5 patients achieving durable partial response. CONCLUSIONS: PAC-1 dose at 750 mg/day was recommended for phase 2 studies. Activity of PAC-1 in treatment-refractory NET warrants further investigation. CLINICAL TRIAL REGISTRATION: Clinical Trials.gov: NCT02355535.

Phase I Study of IGF-Methotrexate Conjugate in the Treatment of Advanced Tumors Expressing IGF-1R.

OBJECTIVES: Insulin-like growth factor-methotrexate (IGF-MTX) is a conjugate of methotrexate and 765IGF, a variant of IGF-1 with high affinity for insulin-like growth factor type 1 receptor. The study aim was to determine the maximum tolerated dose of IGF-MTX in refractory solid organ and hematologic malignancies expressing insulin-like growth factor type 1 receptor. MATERIALS AND METHODS: This phase I trial used a modified toxicity probability interval design with 5 cohort dose levels, and expansion cohort at maximum tolerated dose. IGF-MTX was given intravenously over 90 minutes on days 1, 8, and 15 of a 28-day cycle. RESULTS: A total of 17 patients were enrolled. The highest tolerated dose tested was 0.80 µEq/kg with dose-limiting toxicity of grade 3 hypoglycemia. Drug-related grade 3 and 4 toxicities included abdominal pain (26%), hypoglycemia (10%), and hypotension (10%). Of the 15 evaluable for response, 3 patients (20%) had stable disease, including the patient with Hodgkin lymphoma with stable disease for 12 cycles of therapy. IGF-MTX concentrations declined rapidly, with half-lives of 5.2 to 14 minutes for the initial distribution phase and 6.5 to 7.5 hours for the terminal elimination phase. Higher IGF-R1 expression did not correlate with better outcome. CONCLUSIONS: IGF-MTX is well tolerated. IGF-MTX pharmacokinetics suggest rapid cellular uptake. The activity of IGF-MTX in Hodgkin lymphoma should be explored.

Phase I Study of Aurora A Kinase Inhibitor Alisertib (MLN8237) in Combination With Selective VEGFR Inhibitor Pazopanib for Therapy of Advanced Solid Tumors.

OBJECTIVES: Pazopanib is a multikinase angiogenesis inhibitor. Alisertib is a highly selective inhibitor of mitotic Aurora A kinase. There is preclinical evidence that mitosis-targeting agents exhibit antiangiogenic effects. Thus, the combination of these 2 agents may have a synergistic effect on tumor vasculature. The primary objective of this study is to determine the optimal tolerated dose (OTD) for alisertib and pazopanib. MATERIALS AND METHODS: This phase 1b study evaluated the OTD of alisertib twice a day, on days 1 to 7 with pazopanib, once a day, continuously in a 21-day cycle, both taken orally. Disease response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1 every 2 cycles. OTD cohort was expanded to assure safety and perform pharmacokinetics analysis. RESULTS: A total of 27 patients received treatment. Seventy-seven percent of the patients had received at least 3 prior chemotherapy regimens. Dose-limiting toxicities occurred in dose level (DL) 2+ (grade 4 thrombocytopenia and grade 3 mucositis) and DL 3 (grade 3 liver transaminases elevation and grade 3 abdominal pain). The OTD was determined to be DL 2: alisertib 20 mg twice daily and pazopanib 600 mg daily. Pharmacokinetic analysis revealed that clearance of alisertib was reduced by ∼40% in the presence of pazopanib compared with clearance in the absence of pazopanib. Fourteen patients had stable disease and 2 patients had a partial response. CONCLUSIONS: The combination of alisertib with pazopanib demonstrates manageable safety and early clinical evidence of antitumor activity in patients with advanced malignancies (NCT01639911).