Antifungal drugs don’t get much love in biotech.
Oncology gets the conferences and the headlines. Rare disease gets the orphan designations and the premium pricing. Antifungals get… amphotericin B, which has been around since 1958, hammers your kidneys, and is still standard of care for the worst invasive infections because nothing better has come along.
That’s genuinely embarrassing for the field. Invasive mould infections kill 30 to 80 percent of immunocompromised patients depending on the pathogen, the patient, and the speed of treatment. We’ve had decades to do better. The pipeline has produced some new azoles and echinocandins, but the polyene class (the one amphotericin belongs to) has barely advanced.
Elion Therapeutics just dosed the first patient in the TREAT-1 Phase 2 trial of turletricin (EL219), a next-generation polyene antifungal designed to keep amphotericin’s broad fungicidal activity while losing the toxicity that limits its use.
The trial is structured smart. It’s evaluating turletricin as early antifungal therapy in patients with suspected and confirmed invasive mould infection, the population where empiric treatment matters most because diagnostic confirmation often comes too late. Standard of care comparator. 80 patients. The kind of design that, if positive, can support a registration filing.
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The FDA agrees this matters. Turletricin already has Qualified Infectious Disease Product (QIDP) designation and Fast Track designation, both of which speed up review and add five years of market exclusivity on top of standard patent protection. Those designations don’t come easy. The bar is unmet need plus serious infection plus a credible mechanism.
The mechanism is the interesting part. Polyene antifungals work by binding ergosterol in fungal cell membranes, creating pores that lyse the cell. The problem with amphotericin is that it binds cholesterol in human cell membranes too, which is what causes the renal toxicity, infusion reactions, and the rest. Elion’s approach is to engineer the binding selectivity so the drug strongly prefers ergosterol over cholesterol. Keep the broad-spectrum killing, lose the human off-target effects.
If they pull it off, this could replace amphotericin B as the standard for severe invasive mould infections, including aspergillosis, mucormycosis, and rare emerging pathogens. That’s a sizeable hospital antifungal market, particularly with rising rates of resistant Candida auris infections and post-COVID mucormycosis surges.
The competitive setup isn’t crowded. F2G is developing olorofim, a novel orotomide antifungal that has had FDA back-and-forth but is finally moving toward approval. Cidara Therapeutics has rezafungin (an echinocandin) approved. Scynexis has ibrexafungerp. None of these are direct polyene replacements.
Elion is also presenting clinical data at ESCMID Global, Europe’s major infectious disease conference. That suggests there’s already supporting Phase 1 evidence the company is ready to share with the prescriber community.
Boring? Sure. Antifungals will never have the headline appeal of CAR-T or AI drug discovery. But the people who get invasive aspergillosis aren’t reading TechCrunch. They’re in ICU beds, hoping the drug they get works.
For them, a better polyene is a very big deal.
