Digital therapeutics · Tinnitus
Oto
A London company selling app delivered cognitive behavioural therapy for tinnitus, first to patients and now through audiology clinics. Its largest randomised trial stopped enrolling in 2024 and the results are still unpublished.
One question
Ed Farrar tells audiologists to ask one question first. “When your tinnitus is bad, what is the emotion you feel?”
Anger, frustration or sadness means the patient has the kind of tinnitus his company is built for. Annoying but not limiting means they probably do not need intensive therapy.
That sorting question is the thesis. Oto does not try to remove the sound. It tries to change what the sound does to the person.
The gap it is aimed at
Tinnitus has no cure. About 15 percent of UK adults live with it, and for a minority it wrecks sleep, concentration and mood. The protocol for Oto’s own trial, published in PLOS ONE in January 2024, puts the state of play flatly: “The tinnitus treatment with the strongest evidence base is Cognitive Behavioural Therapy (CBT)”.
Getting that therapy is the hard part. NICE guideline NG155, from March 2020, tells clinicians to consider a stepped approach for adults whose tinnitus still affects their wellbeing after tinnitus support. The first step it names is “digital tinnitus-related cognitive behavioural therapy (CBT) provided by psychologists”. On sound therapy, the same guideline says only this: “The committee were unable to make recommendations for practice in this area.” Oto bundles both.
The access gap has a number on it. In May 2024 University of Michigan researchers reported Apple Hearing Study results from more than 160,000 participants. Fewer than 2.1 percent had chosen cognitive and behavioural therapy for their tinnitus. Noise machines, at 28 percent, were far more common.
Two military doctors with ringing ears
Farrar finished medical school in 2015 and joined the Royal Air Force meaning to train as a surgeon. He developed mild tinnitus in service and habituated to it fast. Many of the service men and women he treated did not.
He recalled thinking that “we’ve got an opportunity to use the skills we’ve learned as doctors, and also in the military to create a digital scalable solution for tinnitus”. His co-founder George Leidig was a Royal Navy doctor whose tinnitus was worse than his.
They incorporated on 27 September 2019 as Arbita Analytics Ltd and renamed the company Oto Health Ltd on 6 April 2020. Anna Pugh, a hearing therapist who wanted an app and could not build one, answered a LinkedIn post and became the clinical voice of the product. Jameel Muzaffar, an ENT surgeon, joined the board on 6 April 2021 and is chief scientific officer.
From subscription to clinic
The app launched in January 2021 with CBT, mindfulness, relaxation and a sound library. In January 2022 Oto announced a pre-seed of £510,000 and a place in Y Combinator’s Winter 2022 batch, reported then as one of only 15 UK health technology companies the accelerator had taken since 2005. That July it closed a seed round led by Octopus Ventures.
The product then was a seven day free trial and a monthly subscription. That is no longer the business. In a February 2026 trade interview Farrar said: “In the US, Oto is only available through providers.” The company now sells Oto Pro, a package for audiology practices with a compliance dashboard, provider training and an assigned Oto audiologist. Its pricing page in July 2026 put a basic plan without devices at $500 to $1,000, set by the clinic.
The pivot is coherent. A consumer subscription sets an app against a patient’s scepticism. A clinic bundle puts it next to an audiologist who has already been believed.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Flinders University RCT | 96 Australian adults, wait list control, registered as ACTRN12623001138673, published July 2025. Mean Tinnitus Functional Index fell 9 points more than control at 6 months (p = .006, 95% CI 2 to 16). A drop of 13 points or more, the clinically meaningful threshold, was reached by 32 percent of the Oto group and 12 percent of controls. Dropout 21 percent. | Public record |
| Feasibility study | 62 adults randomised, published July 2025. Retention 87 percent. A clinically meaningful TFI reduction in 16 percent of Oto users and 7 percent of non users. Oto users showed no significant change over 3 months; the non user group got significantly worse. | Public record |
| DEFINE, as registered | ISRCTN99577932. Open label non inferiority trial of the app against therapist delivered therapy. Target 196, final enrolment 210. Primary outcome TFI at 6 months. Sponsor listed as Oto Health Ltd, industry, commercial. Funders Innovate UK and Oto Health. End date December 2024. | Public record |
| DEFINE results | As of the registry record updated 6 August 2026, the only linked papers are the 2024 protocol and a 2025 paper on trial methods. No results paper. Oto’s research page says results are in peer review. | Not published |
| DEFINE, as marketed | An NHS Innovation Accelerator listing states the trial showed non inferiority and that “Around 64% of participants achieved clinically meaningful improvement in tinnitus distress in the DEFINE trial.” No peer reviewed source for either figure was found. | Ahead of the record |
| How many were in DEFINE | The registry and a 2025 methods paper both put enrolment at 210. In a February 2026 interview Oto’s Dr Joseph Salem said: “We randomized 120 participants to either the Oto digital therapeutic or one-to-one face-to-face CBT with expert therapists.” | Figures differ |
| How independent the trials are | Oto markets “Two independent university RCTs.” Its research page discloses that “Both academic trials of Oto were partially funded by Oto Health Ltd, alongside non-commercial co-funders.” Oto’s chief scientific officer co-authored both papers. | Company-stated |
| NHS hospital trial | NCT06623123, sponsored by East and North Hertfordshire NHS Trust with corporate funding from Oto Health Ltd. 160 planned, Oto against tinnitus retraining therapy. Started June 2024, primary completion estimated June 2025, still listed as recruiting with no update since October 2024. | Public record |
| Regulatory status | No FDA clearance, approval or de novo record was found for Oto. By comparison the FDA granted a de novo to Neuromod’s Lenire in March 2023, creating product code QVN under 21 CFR 874.3410. Oto states DTAC and DSPT readiness, which are NHS assurance standards, not authorisation by a regulator. | Nothing found |
| Reach and reimbursement | Over 2,500 users supported and an NHS England real world evaluation across several integrated care boards, per the accelerator listing. A 2022 release called Oto the first reimbursed digital tinnitus app in the US. No coverage record was found. | Company-stated |
Read plainly: Oto has more published trial evidence than almost any tinnitus app, and less than its marketing implies. The Australian trial is real and positive, but its average benefit of 9 points sits below the 13 point threshold the field calls clinically meaningful, and its comparator was a waiting list rather than a therapist. The feasibility study found Oto users held steady while untreated controls got worse, which is not the same as improvement. The trial that would settle the question stopped enrolling in 2024 and has been described in public with numbers no journal has yet checked.
What to watch
- The DEFINE results paper. Until it lands, the non inferiority claim rests on company statements, and two of them give different participant counts.
- NCT06623123 at East and North Hertfordshire NHS Trust, whose registry entry has not moved since October 2024 and whose estimated completion date has passed.
- Whether the NHS England evaluation becomes a commissioned pathway or stops at a pilot.
- How the clinic model holds up now that the customer is the audiologist, not the patient.
In their words
“When your tinnitus is bad, what is the emotion you feel?”
Edmund Farrar, co-founder, AudiologyOnline, 2026 · Company
“Oto is an adjunct, not a replacement.”
Edmund Farrar, AudiologyOnline, 2026 · Company
“The incidence of tinnitus is rising, and yet it is an isolating condition which is overlooked and traditionally poorly managed.”
George Leidig, co-founder, UKTN, 2022 · Independent
“I posted the other day that we’d now hit 100,000 sessions, which is I get very emotional about it.”
Anna Pugh, hearing therapist, This Week in Hearing podcast, 2022 · Interview
“The Oto team, however, refuse to habituate and instead are providing a 10x cheaper and more convenient way to help people manage their condition.”
Kamran Adle, Octopus Ventures, 2022 · Investor
“little limit on expansion to enable far more patients to be treated, whilst still maintaining much of the personalisation of therapy that tinnitus patients benefit from.”
Matthew Smith, chief investigator of DEFINE, Cambridge University Hospitals, quoted by Pharmaphorum, 2023 · Independent
“A large-scale randomized controlled trial is currently underway to further evaluate Oto’s effectiveness and app usability.”
Mui and colleagues, J Am Acad Audiol, 2025 · Peer reviewed
Related companies
Sources
- Public recordNICE guideline NG155, Tinnitus: assessment and management
- Public recordISRCTN99577932, DEFINE trial registration
- Public recordDEFINE: Protocol for a randomised controlled trial
- Public recordTowards digital solutions for tinnitus: a randomized controlled trial of the Oto smartphone application
- Public recordDigital Therapeutics in Tinnitus Care: A Feasibility Study of the Oto Smartphone Application
- Public recordClinicalTrials.gov NCT06623123 and HRA summary, IRAS 307486
- Public recordCompanies House record for Oto Health Ltd, 12231154
- Public recordForm D, Oto Health Inc., CIK 0001939605
- Public recordFDA device classification QVN, 21 CFR 874.3410, and Lenire registration listing
- Public recordApple Hearing Study shares preliminary insights on tinnitus
- IndependentUK tinnitus health startup scoops £510,000 and joins Y Combinator
- IndependentDigital health firm Oto raises $3.3m for tinnitus support tool
- InterviewApp Based Tinnitus Management: Ed Farrar and Anna Pugh of Oto
- CompanyBridging the Gap in Tinnitus Care, interview with Edmund Farrar and Joseph Salem
- CompanyOto research, professionals and pricing pages, and the Oto listing on the NHS Innovation Accelerator
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
