SEATTLE, WASHINGTON — Sound Pharmaceuticals has presented a new analysis of Phase 3 clinical trial data showing significant improvements in hearing thresholds and speech understanding among patients with Ménière’s disease treated with its investigational oral drug, SPI-1005.
The findings, presented at the 2026 American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) Annual Meeting in Los Angeles, suggest the treatment may warrant further investigation for sudden sensorineural hearing loss (SSNHL). According to the company, the presentation received the meeting’s Best in Scientific Orals recognition.
The new findings build on Sound Pharmaceuticals’ ongoing clinical development of SPI-1005 for Ménière’s disease. In July, the company announced completion of enrollment in a separate Phase 3 open-label study designed to gather additional safety data supporting longer-term treatment. The latest analysis, however, draws on the earlier randomized, placebo-controlled STOPMD-3 trial and examines hearing outcomes that may have implications for sudden sensorineural hearing loss.
Phase 3 Analysis Shows Improvements in Hearing Thresholds
The analysis drew on a multicenter, randomized Phase 3 trial involving 221 adults with definite Ménière’s disease. Participants received either SPI-1005 at a dose of 400 mg twice daily or placebo for 28 days, with hearing assessments conducted at baseline and at 28, 56, and 84 days.
Researchers evaluated hearing improvements across three or four low-to-mid frequencies using pure-tone audiometry, as well as changes in speech understanding measured by a Words-in-Noise (WIN) test. The findings were based on a post-hoc analysis, meaning the specific comparisons were conducted after the original study design rather than being designated as primary trial endpoints.
According to the AAO-HNS scientific abstract, the per-protocol analysis included 191 participants, with 95 in the active-treatment group and 96 receiving placebo.
At 84 days, the researchers reported:
- Three-frequency hearing improvement: 32.6% of SPI-1005 recipients achieved an average improvement of at least 10 dB across 500, 1,000, and 2,000 Hz, compared with 11.5% of placebo recipients (p=0.0004).
- Four-frequency hearing improvement: 33.7% of treated participants achieved an average improvement of at least 10 dB across 250, 500, 1,000, and 2,000 Hz, compared with 9.3% receiving placebo (p<0.0001).
- Words-in-Noise performance: 42.1% of treated participants improved by at least four correctly identified words, compared with 27.1% in the placebo group (p=0.0336).
The analysis also examined participants with an average sensorineural hearing loss of at least 30 dB at baseline. In this subgroup, researchers reported significant differences favoring SPI-1005 for several hearing measures, although not every speech-understanding comparison reached conventional statistical significance.
During a subsequent open-label extension, researchers reported that improvements in hearing thresholds and Words-in-Noise performance continued among some participants through 12 months of treatment. However, the absence of a concurrent placebo comparison during the extension limits conclusions about sustained treatment effects.
Potential Implications for Sudden Sensorineural Hearing Loss
Sudden sensorineural hearing loss typically develops over a period of 72 hours or less and is considered an urgent medical condition. Corticosteroids, administered orally or through intratympanic injection, are commonly used in its management.
Sound Pharmaceuticals believes the hearing improvements observed in patients with Ménière’s disease could support investigating SPI-1005 for SSNHL. Both conditions can involve unilateral sensorineural hearing loss affecting lower frequencies, although their underlying causes and clinical courses may differ.
Importantly, the new analysis does not establish that SPI-1005 is effective for treating sudden sensorineural hearing loss. The underlying Phase 3 trial enrolled patients with Ménière’s disease, and additional clinical studies involving patients specifically diagnosed with SSNHL would be necessary to determine whether the drug offers benefits for that indication.
“We are honored to receive this recognition from the AAO-HNS and thank the reviewing committee,” said Dr. Jonathan Kil, Co-Founder and CEO of Sound Pharmaceuticals.
In its October 19 announcement, Sound Pharmaceuticals highlighted the statistically significant differences observed between treatment and placebo groups across several hearing measures and follow-up periods.
About SPI-1005 and Its Development
SPI-1005 is an investigational oral anti-inflammatory drug containing ebselen, a compound designed to mimic and increase the activity of glutathione peroxidase (GPx), an enzyme system involved in protecting cells against oxidative stress.
The company is studying the treatment for several inner-ear conditions, including Ménière’s disease, noise-induced hearing loss, tinnitus, and hearing-related complications associated with certain antibiotics and chemotherapy drugs.
In late 2025, the U.S. Food and Drug Administration granted SPI-1005 Breakthrough Therapy Designation for hearing loss associated with Ménière’s disease. The drug had previously received Fast Track Designation for that condition. These regulatory designations are intended to facilitate the development and review of promising investigational therapies and do not constitute FDA approval.
According to Sound Pharmaceuticals, 15 ongoing and completed SPI-1005 clinical trials have enrolled more than 980 patients across multiple indications.
While the latest Phase 3 analysis adds to the evidence supporting further investigation of SPI-1005 for inner-ear disorders, its potential role in treating sudden sensorineural hearing loss remains to be established through dedicated clinical research.
About Sound Pharmaceuticals
Sound Pharmaceuticals is a privately held biotechnology company based in Seattle, Washington, developing investigational treatments for hearing and balance disorders. Its lead candidate, SPI-1005, is being evaluated across several neurotologic indications. For more information, visit soundpharma.com.
Source: Sound Pharmaceuticals
