Otonomy, Inc. announced that the OTO-313 Phase 2 trial in tinnitus demonstrated no clinically meaningful benefit versus placebo for primary and secondary endpoints across all timepoints. The randomized, double-blind, placebo-controlled Phase 2 trial enrolled 153 patients with persistent, unilateral tinnitus of at least moderate severity. Patients were randomized 1:1 to a single intratympanic injection of OTO-313 (n=77) or placebo (n=76) and followed for 4 months.

The primary endpoint was a responder analysis based on the proportion of patients who reported a clinically meaningful improvement, defined as a reduction of 13 points or more in the Tinnitus Functional Index (TFI), from baseline to both Months 1 and 2 following treatment. The trial failed to meet this primary endpoint as well as secondary endpoints for the total study population. Although OTO-313 did show a higher response rate than placebo in a prospectively defined patient subgroup with tinnitus duration of less than 6 months (population studied in Phase 1/2 trial), the overall results do not support further development of OTO-313.

The company's clinical focus shifts to OTO-413 for the treatment of hearing loss. Positive Phase 2a results for OTO-413 were announced in April 2022, which corroborated findings from an earlier Phase 1/2 study. In addition, enrollment is complete for evaluation of higher dosing with top-line results expected in the fourth quarter of 2022.