Aura Biosciences, Inc.

Aura Biosciences, Inc. is a clinical-stage biotechnology company focused on developing precision therapies to treat solid tumors while preserving organ function. The company's core business model revolves around its lead candidate, belzupacap sarotalocan (bel-sar), a virus-like drug conjugate (VDC) in late-stage clinical development. Revenue generation is currently absent, with the company having incurred significant net losses since its inception, totaling $480.4 million ¹ as of December 31, 2025. The company's ability to generate revenue and achieve profitability is entirely dependent on the successful discovery, development, regulatory approval, and commercialization of its product candidates ².

The company's primary product candidate, bel-sar, is a novel VDC designed with a dual mechanism of action: direct cytotoxic payload delivery for acute necrosis and activation of a secondary immune-mediated response. Bel-sar consists of modified human papilloma virus (HPV) capsid proteins conjugated to hundreds of light-activated molecules. Its tumor-targeting specificity is driven by selective binding of virus-like particles (VLPs) to modified tumor-associated glycosaminoglycans (GAGs) expressed on tumor cell membranes, enabling precise tumor cell killing with minimal damage to healthy tissues upon light activation ³.

Bel-sar is in late-stage clinical development for the first-line treatment of adult patients with early choroidal melanoma, defined as small choroidal melanoma and/or indeterminate lesions. This indication represents a significant unmet need, as current standard of care (radiotherapy or enucleation) often leads to significant vision loss or total vision loss. The company is evaluating bel-sar in an ongoing global Phase 3 CoMpass trial for this indication. Early choroidal melanoma affects approximately 8,000 patients annually in the United States and Europe ⁴.

Beyond early choroidal melanoma, Aura Biosciences is expanding bel-sar's clinical development into other ocular oncology indications and bladder cancer. For ocular oncology, bel-sar is in an ongoing Phase 2 clinical trial for metastases to the choroid, which has an annual incidence rate of 20,000 patients in the United States and Europe ⁵. The company is also initiating a Phase 1 proof-of-concept trial for cancers of the ocular surface, including melanomas and squamous cell carcinomas, affecting 35,000 patients annually in the United States and Europe ⁶. In urologic oncology, bel-sar is in clinical development for non-muscle invasive bladder cancer (NMIBC), with an ongoing Phase 1b/2 trial evaluating additional doses and cycles in intermediate and high-risk NMIBC patients. The global market for bladder cancer is projected to exceed $8.0 billion ⁷ by 2032.

For the fiscal year ended December 31, 2025, Aura Biosciences reported a net loss of $106.2 million ⁸, compared to a net loss of $86.9 million ⁹ for the year ended December 31, 2024. Total operating expenses increased to $112.791 million ¹⁰ in 2025 from $96.116 million ¹¹ in 2024, primarily driven by higher research and development expenses. The company had cash and cash equivalents and marketable securities of $144.2 million ¹² as of December 31, 2025.

Year-over-year, research and development expenses increased by $16.998 million ¹³, rising from $73.302 million ¹⁴ in 2024 to $90.300 million ¹⁵ in 2025. This increase was mainly attributed to ongoing clinical and CRO costs associated with the progression of the global Phase 3 trial of bel-sar in early choroidal melanoma and higher personnel expenses. General and administrative expenses slightly decreased to $22.491 million ¹⁶ in 2025 from $22.814 million ¹⁷ in 2024, primarily due to reduced professional fees. Net cash used in operating activities was $84.742 million ¹⁸ in 2025, an increase from $79.805 million ¹⁹ in 2024.

During 2025, Aura Biosciences announced positive data from its Phase 1 trial in NMIBC (NCT05483868) and is advancing bel-sar's clinical development in NMIBC with an ongoing Phase 1b/2 trial. The company also completed a 2025 Follow-On Offering on May 16, 2025, issuing 11,735,565 shares of common stock, pre-funded warrants for up to 3,571,435 shares, and accompanying warrants for 3,826,750 shares, generating approximately $69.9 million ²⁰ in net proceeds. A new shelf registration statement on Form S-3 was filed on March 27, 2024, for up to $350.0 million ²¹ of securities, under which 1,055,362 shares of common stock were issued at a weighted average price of $6.36 ²² for aggregate gross proceeds of $6.7 million ²³ during 2025.

Aura Biosciences anticipates continued significant expenses and operating losses for the foreseeable future, as the company does not expect to generate any revenue from product sales in the near term. The ability to achieve profitability hinges on the successful development and commercialization of its product candidates, particularly bel-sar. The company's current operating plan indicates substantial doubt about its ability to continue as a going concern for at least twelve months following the filing of this Annual Report on Form 10-K, necessitating additional funding.

The primary growth area for Aura Biosciences is the advancement of bel-sar in early choroidal melanoma. The company expects to complete enrollment for its global Phase 3 CoMpass trial by mid-2026 ²⁴, with topline data for the 15-month primary endpoint anticipated in the second half of 2027 ²⁵. If approved, bel-sar would represent the first therapy for early choroidal melanoma as a potential first-line treatment option, with an addressable market opportunity of 11,000 patients diagnosed per year in the United States and Europe ²⁶. The company believes it can independently commercialize bel-sar in this indication due to a focused call point of approximately 50 ocular oncologists in the United States and 50 in Europe ²⁷.

Further growth is expected from expanding bel-sar into additional ocular oncology indications. The company continues to enroll patients in an ongoing Phase 2 clinical trial for metastases to the choroid, with early proof-of-concept data expected in 2026 ²⁸. This indication has an annual incidence rate of 20,000 patients in the United States and Europe ²⁹. Additionally, Aura Biosciences is initiating a Phase 1 proof-of-concept trial in Australia for cancers of the ocular surface, including melanomas and squamous cell carcinomas, with early data expected in 2026 ³⁰. This market represents 35,000 patients a year in the United States and Europe ³¹.

In urologic oncology, the company is advancing bel-sar in non-muscle invasive bladder cancer (NMIBC) with an ongoing Phase 1b/2 trial. Initial three-month clinical data from this trial are expected in mid-2026 ³². The company aims to establish bel-sar as an immune-based frontline treatment for NMIBC, either as an immune-ablative approach or as a neoadjuvant therapy prior to transurethral resection of bladder tumor (TURBT). The global market for bladder cancer is expected to be greater than $8.0 billion ³³ by 2032.

Operationally, research and development expenses are expected to increase for the foreseeable future as clinical development for bel-sar progresses and additional product candidates are discovered and developed. Later stages of clinical development generally entail higher costs due to increased trial size and duration. The company also anticipates increased general and administrative expenses as it builds out its team to support administrative, accounting, finance, communications, commercial strategy, legal, and business development efforts, along with additional costs associated with operating as a public company.

Planned capital allocation will involve financing operations through existing cash, cash equivalents, and marketable securities, supplemented by strategic financing opportunities such as collaboration agreements, future equity offerings, or debt financings. As of December 31, 2025, the company held $144.2 million ³⁴ in cash, cash equivalents, and marketable securities. Operating lease commitments total $24.346 million ³⁵, with $3.405 million ³⁶ due in less than one year, $10.834 million ³⁷ due in one to three years, $7.768 million ³⁸ due in three to five years, and $2.339 million ³⁹ due in more than five years. The company also has potential milestone payments under license agreements, including up to $0.7 million ⁴⁰ in development and regulatory milestones and $0.6 million ⁴¹ in sales milestones to NIH, and up to $21.0 million ⁴² in aggregate milestones to Clearside Biomedical upon specified regulatory, development, and commercial sales achievements.

Management has explicitly flagged structural headwinds and execution risks, including the need for substantial additional funding to finance operations, as existing capital is insufficient to fund bel-sar through regulatory approval. The company's ability to raise additional capital on acceptable terms is uncertain, and failure to do so could force delays, reductions, or termination of research and development programs or commercialization efforts. Furthermore, the company's auditors have issued a "going concern" audit opinion, highlighting substantial doubt about its ability to continue as an ongoing business for the next twelve months. Geopolitical and macro factors, such as global economic uncertainty, inflation, and conflicts like the Russia-Ukraine conflict and the conflict in the Middle East, could adversely affect business operations, supply chains, and the ability to raise capital. Changes in U.S. federal tax law, such as the One Big Beautiful Bill Act of 2025 (OBBBA), could also impact cash flow and tax liabilities.

Aura Biosciences faces significant risks, primarily stemming from its financial position, with substantial doubt about its ability to continue as a going concern due to accumulated net losses of $480.4 million ⁴³ as of December 31, 2025, and no product revenue to date. The company is heavily dependent on the success of bel-sar, its only product candidate, and any failure to obtain regulatory approval or achieve market acceptance would severely impair revenue generation. Regulatory risks are heightened by bel-sar being a novel biologic requiring multiple medical devices (SCS Microinjector and laser), increasing the complexity and potential for delays in the approval process. Delays in patient enrollment for clinical trials, particularly for rare diseases like early choroidal melanoma, could also impede development timelines. Furthermore, the company relies on third-party contract development and manufacturing organizations (CDMOs) and contract research organizations (CROs), exposing it to risks of supply shortages, manufacturing non-compliance, and performance failures. Commercialization risks include the challenge of achieving broad market acceptance, potential price competition, and unfavorable pricing regulations or reimbursement practices from governmental and private payors. Intellectual property protection is crucial, and challenges to patents or the inability to license necessary third-party intellectual property could undermine its competitive position. The company is also exposed to macroeconomic risks, including global economic uncertainty, inflation, and geopolitical conflicts, which could disrupt operations and capital markets. Cybersecurity risks, including data breaches and cyberattacks, pose threats to confidential information and could lead to significant liabilities and operational disruptions.

Management's message to shareholders emphasizes a clear vision to innovate cancer care by developing precision therapies that preserve organ function, with an initial strategic focus on ocular and urologic oncology. Key strategic priorities include completing the global Phase 3 CoMpass trial for bel-sar in early choroidal melanoma and pursuing FDA approval, with the goal of establishing it as a first-line treatment option. Management also prioritizes expanding bel-sar's development into additional ocular oncology indications, such as metastases to the choroid and cancers of the ocular surface, and advancing its development in non-muscle invasive bladder cancer. A further strategic objective is to continue evaluating bel-sar for other solid cancers based on its mechanism of action and to build operational capabilities for successful commercialization in ocular oncology, if approved. The company expects to complete enrollment for the Phase 3 trial by mid-2026 ⁴⁴ and anticipates topline data for the 15-month primary endpoint in the second half of 2027 ⁴⁵. Initial three-month clinical data from the Phase 1b/2 trial in NMIBC are expected in mid-2026 ⁴⁶.