It comes down to design. In clinical studies, it is important to be able to measure outcomes objectively. Since tinnitus is primarily subjective - it makes it more difficult to measure. This also makes the design of the study more costly while at the same time putting up more obstacles for a successful conclusion.
Obalto has asked HEI to continue to be a principal investigator in the research so we will continue working on various studies to help get the pill into the clinical and through the remaining clinical studies.
The pill was originally called the bomb blast pill. Primarily I'd say because scientists rarely have a knack for marketing
and also because that was what we originally were studying. However, unlike most other drug development companies we pursued other possibilities as the data prompted. That when we found that it not only prevented hearing loss if administered within 24 hours of the trauma but would recover hearing as well if administered weeks later after the damage from the trauma had set in. Once again following the data, we thought it might be helpful in tinnitus. So we did studies on animals, a model (that cannot be replicated for humans), and found that it was successful for acute tinnitus and one study that measured chronic tinnitus! Again, following the data, we discovered that the drug also has some amazing effects on the build-up of toxic TAU proteins in the auditory nerve. It stopped it cold. This has implications for Alzheimer's, Parkinson's. ALS, and other neurodegenerative diseases.
The short answer is that it all comes down to research design that can control variables and be measured objectively.