– Established cGMP manufacturing and development agreement with Catalent for otoferlin dual-vector gene therapy, DB-OTO – – Successfully completed the second tranche of an oversubscribed Series D financing and upsized Initial Public Offering raising approximately $165.3M in gross proceeds – BOSTON, May 13, 2021 (GLOBE NEWSWIRE) — Decibel Therapeutics (Nasdaq: DBTX), a clinical-stage biotechnology company dedicated to discovering and developing transformative treatments to restore and improve hearing and balance, today reported financial results for the first quarter ended March 31, 2021 and provided a corporate update. “The start of 2021 marked a pivotal time for Decibel as we successfully closed our upsized IPO. With this strong financial foundation, we are in a position to further advance our exciting pipeline of clinical, preclinical and discovery programs with the overarching goal of bringing the privileges of hearing and balance to people in need. In early 2021, we announced encouraging preclinical results on our lead gene therapy program, DB-OTO, for the treatment of people with otoferlin deficiency. We also established a critical cGMP manufacturing and development relationship with Catalent,” said Laurence Reid, Ph.D., Chief Executive Officer of Decibel. “Beyond DB-OTO, we remain encouraged by the progress in our gene therapy programs for congenital, monogenic hearing loss and look forward to announcing the program target for our AAV.104 program in 2021.” Company Highlights Closed Second Tranche of Series D Financing and Upsized Initial Public Offering: In February 2021, Decibel completed its Series D financing, closing the second tranche and receiving net proceeds of $27.4 million. Additionally, Decibel completed its Initial Public Offering (IPO) of 7,662,000 shares of common stock at a public offering price of $18.00 per share. Net proceeds from the offering, after deducting underwriting discounts and offering expenses, were approximately $124.8 million. Pipeline Progress Gene Therapies for Congenital, Monogenic Hearing Loss Continued Development of Lead Gene Therapy Program, DB-OTO, for Otoferlin (OTOF): In February 2021, Decibel established manufacturing capabilities for its lead gene therapy product candidate, DB-OTO. Under the new agreement, Catalent will provide Decibel with cGMP manufacturing and process and analytical development of DB-OTO.Presented New Preclinical Data on DB-OTO and Surgical Approach at the 44th Annual Association for Research in Otolaryngology Conference (ARO) and the Annual Scientific and Technology Conference of the American Auditory Society: In the first quarter of 2021, Decibel presented new preclinical findings to support the development of DB-OTO. Presentations highlighted data demonstrating that the Company’s proprietary dual vector technology and cell-selective promoter enabled expression of OTOF in hair cells and durably restored hearing in mice and drove highly selective expression of a reporter gene in hair cells of non-human primates across the cochlear length.On Track for DB-OTO Key Milestones in 2022: Decibel expects to submit an investigational new drug application (IND) with the U.S. Food and Drug Administration (FDA) and/or a Clinical Trials Application (CTA) in Europe and initiate a Phase 1/2 clinical trial for DB-OTO in pediatric patients with congenital hearing loss in 2022.Preclinical Pipeline Expansion Continues: Decibel expects to announce the program target for its AAV.104 discovery program in patients with autosomal recessive hearing disorders in 2021. Gene Therapies for Hair Cell Regeneration Preclinical Pipeline Expansion Continues: Decibel continues to advance DB-ATO and AAV.201, its gene therapy programs for regeneration of hair cells in the vestibule for the treatment of bilateral vestibulopathy, and its gene therapy program to regenerate hair cells in the cochlea for the treatment of sensorineural hearing loss. Based on findings from recently completed behavioral studies of DB-ATO, the Company did not see sufficient functional recovery to continue to move DB-ATO to development candidate in 2021. The Company plans to announce the program target for AAV.201 in 2022. Otoprotection Therapeutic Updated Timeline to Report Interim Results from Phase 1b Proof-of-Concept Trial of DB-020 for the Treatment of Cisplatin-Induced Hearing Loss: The reporting of interim results from the ongoing Phase 1b clinical trial of DB-020 in patients with cisplatin-induced hearing loss is now expected in the first half of 2022 due to continued impact of the COVID-19 pandemic on the pace of patient recruitment in the United States. Due to COVID-19 restrictions, sites in the United States have been delayed in recruiting, but are now open and actively recruiting for the trial, along with the active sites in Australia. First Quarter 2021 Financial Results: Cash Position: As of March 31, 2021, cash, cash equivalents and available-for-sale securities were $191.1 million, compared to $54.3 million as of December 31, 2020. The increase in cash, cash equivalents and available-for-sale securities was due to the sale of the Company’s Series D convertible preferred stock and common stock in the Company’s IPO completed in February 2021.Research and Development Expenses: Research and development expenses were $6.0 million for the first quarter of 2021, compared to $7.4 million for the first quarter of 2020. The decrease in research and development expenses for the first quarter of 2021 was primarily due to $1.8 million decrease in personnel-related costs due to reduced headcount, driven primarily by a reduction-in-force conducted in January 2020 and a $0.8 million decrease in expenses incurred for our DB-020 program driven by decreased activity as a result of delays due to the COVID-19 pandemic, partially offset by an increase of $1.2 million in other indirect research and development expenses.General and Administrative Expenses: General and administrative expenses were $4.9 million for the first quarter of 2021, compared to $4.2 million for the same period in 2020. The increase in general and administrative expenses for the first quarter of 2021 was primarily attributable to $1.0 million increase in professional fees, driven primarily by expenses related to consulting, accounting advisory and audit services incurred as a result of becoming a public company in February 2021. Financial Guidance: Based on its current operating and development plans, Decibel believes that its existing cash, cash equivalents and available-for-sale securities will fund its pipeline programs and operating expenses into 2024. About Decibel Therapeutics Decibel Therapeutics is a clinical-stage biotechnology company dedicated to discovering and developing transformative treatments to restore and improve hearing and balance, one of the largest areas of unmet need in medicine. Decibel has built a proprietary platform that integrates single-cell genomics and bioinformatic analyses, precision gene therapy technologies and expertise in inner ear biology. Decibel is leveraging its platform to advance gene therapies designed to selectively replace genes for the treatment of congenital, monogenic hearing loss and to regenerate inner ear hair cells for the treatment of acquired hearing and balance disorders. Decibel’s pipeline, including its lead gene therapy program, DB-OTO, to treat congenital, monogenic hearing loss, is designed to deliver on our vision of a world in which the privileges of hearing and balance are available to all. Forward-Looking Statements This press release contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this press release, including statements regarding Decibel’s strategy, future operations, prospects, plans, objectives of management, the therapeutic potential for Decibel’s product candidates and preclinical programs, the potential benefits of cell-selective expression, the expected timeline for submitting investigational new drug applications and achieving other planned milestones, expectations regarding the translation of preclinical findings to human disease and the sufficiency of Decibel’s existing cash resources for the period anticipated, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “might,” “objective,” “ongoing,” “plan,” “predict,” “project,” “potential,” “should,” or “would,” or the negative of these terms, or other comparable terminology are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Decibel may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in these forward-looking statements as a result of various important factors, including: uncertainties inherent in the identification and development of product candidates, including the conduct of research activities and the initiation and completion of preclinical studies and clinical trials, the timing of and Decibel’s ability to submit and obtain approval to initiate clinical development of its program candidates, whether results from preclinical studies will be predictive of the results of later preclinical studies and clinical trials, whether Decibel’s cash resources are sufficient to fund its foreseeable and unforeseeable operating expenses and capital expenditure requirements, uncertainties related to the impact of the COVID-19 pandemic on Decibel’s business and operations, as well as the risks and uncertainties identified in Decibel’s filings with the Securities and Exchange Commission (SEC), including those risks detailed under the caption “Risk Factors” in Decibel’s Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2021. In addition, the forward-looking statements included in this press release represent Decibel’s views as of the date of this press release. Decibel anticipates that subsequent events and developments will cause its views to change. However, while Decibel may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing Decibel’s views as of any date subsequent to the date of this press release. Condensed Consolidated Balance Sheets(unaudited) (in thousands) March 31, 2021 December 31, 2020Cash, cash equivalents and available-for-sale securities$191,077 $54,310 Total assets 207,086 67,285 Convertible preferred stock – 93,091 Total stockholders’ deficit (173,559) (162,689) Condensed Consolidated Statement of Operations(unaudited) (in thousands) For the three months ended March 31, 2021 March 31, 2020Operating expenses: Research and development $6,020 $7,436 General and administrative 4,883 4,178 Total Operating expenses 10,903 11,614 Loss from operations (10,903) (11,614)Other income: Interest income 33 79 Total other income, net 33 79 Net loss $(10,870) $(11,535) Investor Contact:Julie SeidelStern IR, Inc.julie.seidel@sternir.com Media Contact:Chris Railey Ten Bridge Communicationschris@tenbridgecommunications.com