Phase 1, open-label, dose escalation, safety, and pharmacokinetics study of ME-344 as a single agent in patients with refractory solid tumors

Abstract

Background: The current phase 1, open-label, dose escalation study was conducted to establish the safety, tolerability, pharmacokinetic profile, and preliminary antitumor activity of the novel mitochondrial inhibitor ME-344 in patients with refractory solid tumors.

Methods: Patients with refractory solid tumors were treated in a 3 + 3 dose escalation design. ME-344 was administered via intravenous infusion on days 1, 8, and 15 of the first 28-day cycle and weekly thereafter. Pharmacokinetics was assessed on days 1 and 15 of the first cycle.

Results: A total of 30 patients (median age, 65 years; 67% of whom were female) received ME-344. There were 5 dose-limiting toxicities reported. Four patients developed grade 3 neuropathy (2 patients each at doses of 15 mg/kg and 20 mg/kg) and 1 patient treated at a dose of 10 mg/kg developed a grade 3 acute myocardial infarction (toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.03]). The maximum tolerated dose (MTD) was defined as 10 mg/kg weekly. The most common adverse events were nausea, dizziness, and fatigue. At the MTD of 10 mg/kg, the maximal plasma concentration (Cmax) was 25.8 µg/mL and the area under the concentration curve from time zero to infinity was 25.9 hour*µg/mL. One patient with small cell lung cancer achieved a partial response for ≥ 52 weeks. Four patients had prolonged stable disease (1 patient each with urothelial carcinoma [47 weeks], carcinoid tumor [≥ 40 weeks], cervical leiomyosarcoma [39 weeks], and cervical cancer [≥ 31 weeks]).

Conclusions: The once-weekly administration of ME-344 was generally well tolerated in the current study, a first-in-human study; dose-limiting neuropathy was noted, but not at the MTD. Exposures at the 10-mg/kg dose level suggest a sufficient therapeutic index. The preliminary clinical activity as a monotherapy supports the further clinical development of ME-344 in combination with chemotherapy.

Keywords: ME-344; first-in-human; maximum tolerated dose (MTD); mitochondrial inhibitor; phase 1; refractory solid tumors.

Figure 1

Relationship between ME-344 dose versus day 1 and day 15 area under the concentration curve (AUC) is shown.

Figure 2

ME-344 plasma concentration on day 1 versus time is shown.

Figure 3

Computed tomography images from a patient with small cell lung cancer at (A) baseline and (B) week 52 are shown.

Figure 4

Duration of prior therapy compared with ME-344 dosing in patients achieving a partial response or stable disease is shown. SCLC indicates small cell lung cancer; NSCLC, non-small cell lung cancer.