Spiral Therapeutics has closed a $27 million Series B round—a financing that quietly signals how device makers and drug developers are beginning to blur the lines in one of medicine's most challenging anatomical frontiers: the inner ear.
The round, announced April 14, 2026, and led by Gund Investment, included an unusual mix of participants. Advanced Bionics, the cochlear implant subsidiary of Swiss hearing giant Sonova, put in capital and signed on for a research collaboration announced the same day. An unnamed global pharmaceutical company also participated, alongside returning backers Ferring Ventures and Uni-Bio Science Group. For the South San Francisco biotech, the money matters less than the partnership roster—a device heavyweight willing to explore precision pharmacology at the point of implant surgery.
The Advanced Bionics tie-up asks a deceptively straightforward question: could delivering drugs directly to the cochlea during implantation improve hearing outcomes for patients receiving cochlear implants? It's the kind of practical mashup that has eluded the field for years. Advanced Bionics brings decades of expertise in electrode arrays and auditory nerve stimulation. Spiral contributes its Minimally-Invasive Cochlear System—MICS, in industry shorthand—a platform engineered to deliver therapeutics to the cochlea with durability and precision that older approaches lacked.
Inheriting Otonomy's Unfinished Work
Spiral didn't start here. The company acquired key assets from Otonomy in January 2023, picking up rights and data for three programs: OTO-104, a sustained-release dexamethasone formulation; OTO-510, an otoprotectant; and OTO-413, a brain-derived neurotrophic factor candidate. At the time, Otonomy had stumbled through late-stage setbacks, and Spiral saw an opening—intellectual property at a discount, with clinical learnings already baked in.
That acquisition gave Spiral a foothold in hearing-loss pharmacology just as cochlear implant makers were beginning to think beyond hardware. The convergence wasn't inevitable, but it was becoming harder to ignore. Implants restore hearing for many, but they don't address underlying biology. Drugs, delivered with precision at the right moment, might.
A Ménière's Bet
The Series B arrives roughly 18 months after Spiral wrapped a Phase 1b/2a trial of SPT-2101—a 6% dexamethasone long-acting gel—in patients with Ménière's disease. The company successfully completed the study as of September 30, 2024, presenting statistically significant reductions in overall vertigo at the 2024 AAO-HNS annual meeting in September, a data set that gave investors enough confidence to write checks.
Ménière's is miserable. The chronic inner ear disorder brings debilitating episodes of vertigo, tinnitus, and progressive hearing loss. The National Institute on Deafness and Other Communication Disorders estimates about 615,000 Americans live with it; roughly 45,500 new cases are diagnosed each year. Current treatments are scattershot—diuretics, dietary changes, occasionally destructive surgeries. A well-tolerated, office-based intervention that actually works would be something of a breakthrough, though perhaps that's overstating things given how early the data remain.
SPT-2101 is delivered via microendoscopy to the round window membrane in an office setting, where it provides therapeutic exposure for about two months. A feasibility study published in 2024 confirmed precise placement in all subjects, which is no small feat in such delicate anatomy. The next step is a registrational trial, and this financing is explicitly intended to get there—though specific timelines, including IND milestones or first-patient-in dates, weren't disclosed.
Platform Ambitions
Beyond Ménière's, Spiral has broader aims. The company intends to expand MICS and advance neurotrophic programs targeting the underlying pathobiology of hearing loss, not just symptoms. The global burden is staggering: more than 1.5 billion people live with some degree of hearing loss, according to the World Health Organization, with 430 million experiencing disabling impairment. Spiral's neurotrophic programs—anchored by those Otonomy assets—aim at disease modification, a higher bar than symptomatic relief but potentially a more defensible market position if it works.
The company, founded in 2016 by CEO Hugo Peris, has kept a lean profile. LinkedIn suggests a headcount in the single digits, though that may shift as the Series B capital flows in. A previous $8.25 million raise in January 2023 got SPT-2101 into Phase 2; this round is meant to carry it across the finish line.
What Comes Next
Proceeds will fund three priorities: advancing SPT-2101 toward a pivotal Ménière's trial, expanding the MICS delivery platform, and executing the Advanced Bionics collaboration. The identity of the "major global pharmaceutical company" participating in the round remains undisclosed—a detail that will likely surface in future regulatory filings or partnership press releases, as these things tend to.
For now, Spiral has capital, a device partner with real cochlear-implant reach, and early clinical data suggesting its lead asset can quiet the vertigo storms of Ménière's disease. Whether precision drug delivery to the inner ear can graduate from feasibility to commercial reality is the question that will define the next twelve to eighteen months. It's a high-risk space, both anatomically and commercially. But the convergence of devices and drugs has a certain logic to it—assuming the biology cooperates.
