Overview

We are a clinical-stage biopharmaceutical company developing a new class of immunotherapeutics based on our proprietary arenavirus platform. Our replicating and non-replicating technologies are engineered to induce robust and durable antigen-specific CD8+ T cell responses and pathogen-neutralizing antibodies. We believe our technologies can meaningfully leverage the human immune system for therapeutic purposes.

We are building a proprietary immuno-oncology pipeline utilizing our replicating technology. Our oncology portfolio includes two primary programs in development: eseba-vec (formerly HB-200) and HB-700. Eseba-vec is in clinical development for the treatment of Human Papillomavirus 16-positive (“HPV16+”) head and neck cancers. In November 2024, we announced that we will pause clinical development in the eseba-vec program, including an early termination of our ongoing Phase ¹⁄₂ clinical trial. We expect to focus primarily on progressing the phase 1-ready HB-700 program for the treatment of KRAS mutant cancers.

We are also developing infectious disease therapies in partnership with Gilead Sciences Inc. Our Hepatitis B (“HBV”) program, HB-400, and our Human Immunodeficiency Virus (“HIV”) program, HB-500, are developed in a partnership with Gilead.

In 2024, we implemented a Restructuring Plan to improve our cost structure and operating efficiency, which included a significant reduction in our workforce and the closing and consolidation of offices and laboratories. These actions were taken to align with our strategic refocus on the development of our oncology portfolio.

As of December 31, 2024, we had cash, cash equivalents and restricted cash of $39.9 million. We have incurred recurring losses and do not expect positive cash flows from operations in the foreseeable future. We will require substantial additional financing to fund our operations and development activities.

Impacts of Market Conditions on Our Business

Unfavorable economic conditions, such as heightened inflation, increased interest rates, and global macroeconomic factors, could negatively impact our ability to access capital and materially affect our business.

Components of Our Results of Operations

Our revenue to date has been derived from research collaboration and license agreements with Gilead and Roche. Our operating expenses consist of research and development, general and administrative, restructuring, and impairment costs.

Results of Operations

For the year ended December 31, 2024, we reported a net loss of $43.5 million, compared to a net loss of $81.6 million in 2023. The decrease in net loss was primarily due to higher revenue from collaboration and licensing agreements, partially offset by lower research and development expenses and impairment charges.

Liquidity and Capital Resources

As of December 31, 2024, we had $39.9 million in cash, cash equivalents and restricted cash. We have funded our operations to date primarily through public and private equity offerings, as well as payments from our collaboration agreements. We do not expect to generate revenue from product sales in the near future and will require substantial additional financing to fund our operations and development activities. There is substantial doubt about our ability to continue as a going concern.

Intellectual Property Licenses

We have entered into several license agreements with universities and research institutions to obtain exclusive, worldwide, royalty-bearing licenses for our arenavirus-based technologies. These agreements require us to pay royalties, milestone payments, and sublicensing fees.

Critical Accounting Policies and Estimates

Our critical accounting policies include revenue recognition from collaboration agreements, leasing, research and development costs, and stock-based compensation. We also recognize income from government grants and research incentives.