Phase 1b safety and pharmacokinetics of intravenous and oral fosmanogepix in patients with acute myeloid leukaemia and neutropenia.

OBJECTIVES: Fosmanogepix (APX001), a first-in-class, intravenous (IV) and oral (PO) antifungal prodrug, is being developed to treat invasive fungal diseases (IFDs). Manogepix (APX001A; active moiety) targets fungal glycosylphosphatidylinositol-anchored cell wall transfer protein 1, inhibiting cell wall synthesis causing loss of viability. This open-label, multicentre, Phase 1b study in patients with AML and neutropenia (absolute neutrophil count <500 cells/µL; >10 days) undergoing chemotherapy aimed to assess tolerability, safety and pharmacokinetics (PK) of IV and PO fosmanogepix. METHODS: Of 21 adult AML patients undergoing remission induction chemotherapy, 10 received IV fosmanogepix (600 mg; q24h) and 11 received oral fosmanogepix (500 mg; q24h) over 14 days, with a 28 day follow-up. Patients also received remission induction chemotherapy [sequential high-dose cytarabine and mitoxantrone (S-HAM) or 7 + 3 regimen] for AML and IFD prophylaxis (posaconazole). A two-compartmental PK model from previous studies in healthy volunteers was fitted to manogepix plasma data. RESULTS: Of 26 fosmanogepix-related adverse events (AEs; IV: 14; PO: 12) in 9 (42.9%) patients [IV: 5 (50%); PO: 4 (36.4%)], none were serious or resulted in fosmanogepix discontinuation. Most frequently occurring fosmanogepix-related AEs were Grade 1/2 nausea [four events in three patients (14.3%)]; vomiting, ALT increase, and delirium [two events; two patients (9.5%) each]. One patient experienced fosmanogepix-related Grade 3 hypertension. Dose-corrected geometric mean ratio of AUC (PO-to-IV) was 95%. Elimination half-lives (∼2 days) were consistent with prior studies in healthy volunteers. CONCLUSIONS: Fosmanogepix was safe and well tolerated in AML patients with neutropenia receiving remission induction chemotherapy. Safety and PK profiles were comparable to healthy volunteers.

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

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.