Cidara Therapeutics Announces Publication of CD388 Preclinical Data in Nature Microbiology

Insights

Biotechnology R&D Expert

The publication of CD388 preclinical data in Nature Microbiology represents significant scientific validation for Cidara's Cloudbreak platform. This is particularly noteworthy as publication in such a prestigious journal indicates rigorous peer review of their drug-Fc conjugate approach.

The preclinical data reveals three critical advantages: universal activity against influenza strains (including highly pathogenic H5N1), low resistance potential, and efficacy regardless of immune status. This last point addresses a critical unmet need, as current influenza vaccines provide suboptimal protection for immunocompromised patients.

Mechanistically, CD388 targets viral neuraminidase while leveraging the Fc domain for extended half-life - combining small molecule potency with antibody-like durability. This fundamental design appears to drive efficacy through direct antiviral activity rather than immune stimulation, explaining its effectiveness in immunocompromised models.

The advancement to a ~5,000 subject Phase 2b trial demonstrates confidence in the approach, though investors should recognize that preclinical success doesn't guarantee clinical outcomes. The timing during a "particularly severe" flu season offers ideal conditions for demonstrating efficacy, potentially enhancing the signal detection compared to milder seasons.

Healthcare Investment Analyst

This Nature Microbiology publication enhances Cidara's scientific credibility at a important time as the company approaches data readout from its Phase 2b NAVIGATE trial. The study's large size (~5,000 subjects) and the "particularly severe" 2024-2025 flu season create favorable conditions for demonstrating clinical benefit.

The influenza prevention market represents a substantial opportunity. Current vaccines show variable effectiveness (typically 40-60%) and require annual administration, while existing antivirals have limitations in prevention settings. CD388's single-dose, universal protection approach addresses clear market gaps, particularly for immunocompromised populations.

Beyond CD388 specifically, this publication validates Cidara's proprietary Cloudbreak platform, potentially increasing partnership interest across their pipeline. The drug-Fc conjugate approach represents a differentiated technology that could be applied to multiple infectious disease targets.

While this scientific validation is meaningful, investors should focus primarily on the upcoming Phase 2b results as the decisive near-term catalyst. Success would likely trigger significant value creation, while failure would raise questions about the platform's clinical translatability. The publication reduces scientific risk somewhat but does not eliminate the substantial clinical development risks ahead.

Data highlights potential of CD388 as a potent, universal antiviral for influenza prevention regardless of immune status

SAN DIEGO, March 17, 2025 (GLOBE NEWSWIRE) -- Cidara Therapeutics, Inc. (Nasdaq: CDTX), a biotechnology company using its proprietary Cloudbreak^® platform to develop drug-Fc conjugate (DFC) immunotherapies, today announced the publication of preclinical data assessing CD388, the company’s influenza DFC, in the peer-reviewed scientific journal Nature Microbiology. The article, entitled “Drug-Fc Conjugate CD388 targets influenza virus neuraminidase and is broadly protective in mice,” highlights the potential of CD388 as a potent, universal preventative for influenza A and B in healthy and high-risk populations.

“This publication, combined with the promising clinical data we’ve generated to date, further validates our Cloudbreak DFC platform and the potential of CD388 to offer universal protection against both seasonal and pandemic influenza strains,” said Jeffrey Stein, Ph.D., president and chief executive officer of Cidara. “While vaccines play a vital role in flu prevention, they do not offer sufficient protection, particularly for immune-compromised individuals, underscoring the critical need for a durable, broadly acting antiviral like CD388. We look forward to the results of our ~5,000 subject Phase 2b NAVIGATE study that is evaluating CD388 during the particularly severe 2024-2025 flu season.”

Les Tari, Ph.D., chief scientific officer of Cidara added, “DFCs are a unique drug modality with the potential to enhance the efficacy and safety of targeted small molecules, while combining them with the long half-lives of monoclonal antibodies. These preclinical data indicate that CD388’s efficacy is driven by the intrinsic antiviral activity of the drug, potentially enabling it to work as a long-term preventative against influenza regardless of immune status.”

Key Findings

• The publication describes CD388 and its potential for universal activity across influenza A and B viruses in cellular and animal models.
  • Administration of CD388 resulted in the following:
    • Potent, universal activity against all influenza A and B virus strains, including high pathogenicity strains like H5N1, also known as avian influenza or bird flu, and strains that are resistant to approved neuraminidase inhibitors
    • Low potential for resistance development
    • Efficacy at similar exposures in immune-competent and immune-compromised lethal challenge models in mice demonstrating that efficacy is driven predominantly by the intrinsic antiviral activity of CD388
      

CD388 is currently under clinical evaluation in the ~5000 patient Phase 2b NAVIGATE trial, evaluating CD388 for the single-dose prevention of seasonal influenza in healthy unvaccinated adult subjects.

About CD388
CD388 is an investigational drug-Fc conjugate (DFC) comprising multiple copies of a potent small molecule neuraminidase inhibitor stably conjugated to a proprietary Fc fragment of a human antibody. DFCs are not vaccines or monoclonal antibodies but are low molecular weight biologics which are designed to function as long-acting small molecule inhibitors. CD388 was designed to provide universal protection against all known strains of seasonal and pandemic influenza with the potential to provide season-long protection with a single subcutaneous or intramuscular administration. Importantly, because CD388 is not a vaccine, its activity is not reliant on an immune response and thereby is expected to be efficacious in individuals regardless of immune status. More information can be found at: https://www.cidara.com/cloudbreak/influenza/

About Cidara Therapeutics
Cidara Therapeutics is using its proprietary Cloudbreak^® platform to develop novel drug-Fc conjugates (DFCs) comprising targeted small molecules or peptides coupled to a proprietary human antibody fragment (Fc). Cidara’s lead DFC candidate, CD388, is a long-acting antiviral designed to achieve universal prevention of seasonal and pandemic influenza with a single dose by directly inhibiting viral proliferation. In June 2023, CD388 was granted Fast Track Designation by the U.S. Food and Drug Administration (FDA), and the Company announced completion of Phase 2b enrollment in December 2024. Additional DFCs have been developed for oncology and in July 2024 Cidara received IND clearance for CBO421 which is intended to target CD73 in solid tumors. Cidara is headquartered in San Diego, California. For more information, please visit www.cidara.com.

Forward-Looking Statements
This release contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and such forward-looking statements are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. “Forward-looking statements” describe future expectations, plans, results, or strategies and are generally preceded by words such as “anticipates,” “expect,” “intends,” “believes,” “may,” “plan” or “will”. Forward-looking statements in this release include, but are not limited to, statements related to the potential of and future plans for CD388, whether and when we will complete our Phase 2b NAVIGATE trial, and whether animal data will be predictive of safety or effectiveness of CD388 in prevention of influenza infection in humans. Such statements are subject to a multitude of risks and uncertainties that could cause future circumstances, events, or results to differ materially from those projected in the forward-looking statements, such as unanticipated delays in or negative results from Cidara’s clinical trials and other risks related to clinical development, delays in action by regulatory authorities, other obstacles on the enrollment of patients or other aspects of CD388 or other DFC development, the impacts of the realignment and restructuring being different than expected and other risks and uncertainties associated with Cidara’s business in general. These and other risks are identified under the caption “Risk Factors” in Cidara’s most recent Quarterly Report on Form 10-Q and other filings subsequently made with the SEC. All forward-looking statements contained in this press release speak only as of the date on which they were made and are based on management’s assumptions and estimates as of such date. Cidara does not undertake any obligation to publicly update any forward-looking statements, whether as a result of the receipt of new information, the occurrence of future events or otherwise.

INVESTOR CONTACT:
Brian Ritchie
LifeSci Advisors
(212) 915-2578
britchie@lifesciadvisors.com

MEDIA CONTACT:
Michael Fitzhugh
LifeSci Communications
mfitzhugh@lifescicomms.com

FAQ

What are the main findings of CD388's preclinical study published in Nature Microbiology?

CD388 showed universal activity against all influenza A and B strains, including H5N1 bird flu, with low resistance potential and efficacy in both immune-competent and immune-compromised models.

How many participants are involved in CDTX's Phase 2b NAVIGATE trial for CD388?

The Phase 2b NAVIGATE trial includes approximately 5,000 subjects evaluating CD388 for single-dose flu prevention.

What advantage does CD388 offer over traditional flu vaccines according to CDTX?

CD388 offers potential universal protection regardless of immune status, addressing the limitations of vaccines that may not provide sufficient protection for immune-compromised individuals.

What is the current development stage of Cidara's CD388 influenza treatment?

CD388 is currently in Phase 2b clinical trials, being evaluated during the 2024-2025 flu season for seasonal influenza prevention.