Clinical safety and efficacy of novel antifungal, fosmanogepix, for the treatment of candidaemia: results from a Phase 2 trial

Abstract

Background: Fosmanogepix is a first-in-class antifungal targeting the fungal enzyme Gwt1, with broad-spectrum activity against yeasts and moulds, including multidrug-resistant fungi, formulated for intravenous (IV) and oral administration.

Methods: This global, multicenter, non-comparative study evaluated the safety and efficacy of fosmanogepix for first-line treatment of candidaemia in non-neutropenic adults. Participants with candidaemia, defined as a positive blood culture for Candida spp. within 96 h prior to study entry, with ≤2 days of prior systemic antifungals, were eligible. Participants received fosmanogepix for 14 days: 1000 mg IV twice daily on Day 1, followed by maintenance 600 mg IV once daily, and optional switch to 700 mg orally once daily from Day 4. Eligible participants who received at least one dose of fosmanogepix and had confirmed diagnosis of candidaemia (<96 h of treatment start) composed the modified intent-to-treat (mITT) population. Primary efficacy endpoint was treatment success at the end of study treatment (EOST) as determined by the Data Review Committee. Success was defined as clearance of Candida from blood cultures with no additional antifungal treatment and survival at the EOST.

Results: Treatment success was 80% (16/20, mITT; EOST) and Day 30 survival was 85% (17/20; 3 deaths unrelated to fosmanogepix). Ten of 21 (48%) were switched to oral fosmanogepix. Fosmanogepix was well tolerated with no treatment-related serious adverse events/discontinuations. Fosmanogepix had potent in vitro activity against baseline isolates of Candida spp. (MICrange: CLSI, 0.002-0.03 mg/L).

Conclusions: Results from this single-arm Phase 2 trial suggest that fosmanogepix may be a safe, well-tolerated, and efficacious treatment for non-neutropenic patients with candidaemia, including those with renal impairment.

Figure 1.

Study schematic. Time period (<96 h) to complete eligibility assessments started at the time that the sample for the blood culture positive for Candida was collected. EOST may be the same as EOT for those participants who do not step-down to fluconazole or alternative antifungal therapy. EOST, end of study treatment; EOT, end of treatment; FMGX, fosmanogepix; IV, intravenous; PO, oral.

Figure 2.

Participant disposition. AE, adverse event; FMGX, fosmanogepix; ITT, intent-to-treat; mITT, modified intent-to-treat.