A Phase 1b study of the OxPhos inhibitor ME-344 with bevacizumab in refractory metastatic colorectal cancer.

Antiangiogenic drugs may cause vascular normalization and correct hypoxia in tumors, shifting cells to mitochondrial respiration as the primary source of energy. In turn, the addition of an inhibitor of mitochondrial respiration to antiangiogenic therapy holds potential to induce synthetic lethality. This study evaluated the mitochondrial inhibitor ME-344 in combination with bevacizumab in patients with refractory metastatic colorectal cancer (mCRC). Patients were eligible if they had disease progression after standard therapies, adequate hematologic, hepatic and renal function, and no contraindications to bevacizumab. ME-344 was administered intravenously on days 1, 8 and 15 and bevacizumab on days 1 and 15 of 28-day cycles until disease progression or intolerance. The primary efficacy endpoint was progression-free survival (PFS) at week 16. In the 23 patients enrolled, the median age was 58 years, median number of prior lines of therapy was 4, and median interval from last therapy was 3 months. The most common adverse events (all grades/grade ≥ 3) were fatigue (48%/13%), abdominal pain (35%/4%), diarrhea (30%/4%) and constipation (30%/0%). No patient had an objective response; 9 patients (39%) achieved stable disease. The 16-week PFS was 30.6% (95% confidence interval [CI]: 12.2-51.3), the median PFS was 1.9 months (95% CI: 1.6-4.7), and the median overall survival was 6.7 months (95% CI: 3.4-not reached). ME-344 plus bevacizumab was well tolerated. Disease control was limited in this heavily pretreated patient population. Additional investigations in earlier lines are indicated, and extended-release ME-344 formulations may provide longer drug exposure to maximize benefit. (Trial registration number ClinicalTrials.gov NCT05824559. Registration date 22 March 2022).