Antifungal resistance is a theme we keep coming back to on this blog, for the plain reason that it keeps getting worse. The number of antifungal drug classes we have is tiny — you can count them on one hand — and fungi have been steadily learning to evade all of them. So the arrival of a genuinely new antifungal, one that kills fungi in a way none of the existing drugs do, is real news. A study just published in Annals of Internal Medicine puts one such drug through its paces.
The drug: olorofim
Olorofim is the first member of a new antifungal class called the orotomides. Instead of attacking the fungal cell membrane or wall (the way azoles, echinocandins, and terbinafine do), olorofim blocks an enzyme called dihydroorotate dehydrogenase (DHODH), which fungi need to build the pyrimidines that make up their DNA and RNA. Choke off that supply and the fungus can’t replicate.
The key word is new. Because olorofim’s target is completely different from every currently approved antifungal, fungi that have become resistant to the existing drugs generally haven’t seen anything like it — so it can work where the standard options have failed. That’s the whole point of a new mechanism.
The study
The trial focused on a difficult disease: refractory disseminated coccidioidomycosis — better known as Valley fever, a fungal infection (from Coccidioides species) that’s endemic to the dry southwestern United States and parts of Central and South America. “Disseminated” means it has spread beyond the lungs; “refractory” means the usual antifungal drugs had already failed.
In this single-group, open-label, Phase 2b study of 41 patients (aged 16 and up), olorofim — given alone or alongside conventional therapy — produced clinical improvement in roughly 73–76% of patients over 84 days, with responses often sustained through a year of treatment. That’s a strong signal in a group of patients who had essentially run out of good options.
The response varied sensibly by how hard the case was:
- ~80% improvement in patients without central nervous system infection,
- ~65% in those with CNS infection but no implanted devices,
- ~42% in the hardest cases, with implanted devices.
On safety, the most common problem was elevated liver enzymes — manageable with monitoring and dose adjustments, though it led one patient (about 2%) to stop treatment. Liver monitoring will clearly be part of using this drug.
The honest limitation: there was no comparison group, so this establishes promise, not proof. That’s what the later, controlled trials are for.
Why this matters — even far from Valley fever country
Valley fever isn’t a Malaysian disease; you won’t catch Coccidioides here. So why post about it?
Because the significance of olorofim isn’t really about this one infection — it’s about the new mechanism, and what that mechanism could eventually reach. Olorofim and drugs like it have broad activity against molds and hard-to-treat fungi that our current arsenal struggles with: Aspergillus, Scedosporium, Lomentospora, and others.
And there’s a piece of this that lands much closer to home for a dermatology clinic. Over the last few years, dermatologists across Asia — including in our region — have been seeing terbinafine-resistant ringworm, driven largely by an aggressive dermatophyte called Trichophyton indotineae. These are itchy, widespread, stubborn tinea infections that don’t clear with the usual first-line pills the way they used to. The core problem is exactly the one olorofim was built to solve: fungi that have outgrown our existing drugs. A pipeline that produces genuinely new antifungal mechanisms is the pipeline that eventually gives dermatology better tools against resistant ringworm and resistant nail fungus.
The caveats, plainly
- Olorofim isn’t approved yet — it’s investigational, and this study is one step (an important one) on a longer road.
- It hasn’t been studied specifically for skin or nail fungal infections — its development so far is aimed at serious invasive mold and systemic infections. The dermatology relevance is about the class and the mechanism, not an approved skin indication.
- When new antifungals do arrive, they’ll be reserved, at first, for exactly the “tough cases” in the heading — resistant, refractory, or invasive infections — not routine athlete’s foot.
Still: the first genuinely new antifungal class in about twenty years, showing real benefit in patients who had nothing left to try, is worth being glad about. For the resistant fungal infections we’re increasingly seeing, help is — slowly — on the way.