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Cidara Therapeutics Announces Initiation of Phase 2a Human Viral Challenge Trial to Evaluate CD388 for Universal Prevention of Influenza

By September 13, 2022No Comments

CD388 is a drug-Fc conjugate (DFC) from Cidara’s Cloudbreak® platform designed to help transform the standard of care for seasonal and pandemic influenza prevention

Study is being conducted in collaboration with Janssen

SAN DIEGO, Sept. 13, 2022 — Cidara Therapeutics, Inc. (Nasdaq: CDTX), a biotechnology company developing long-acting therapeutics designed to help improve the standard of care for patients facing serious diseases, today announced the initiation of its Phase 2a trial to evaluate the pre-exposure prophylactic activity of CD388 against influenza virus. CD388 is a highly potent, long-acting antiviral designed to deliver universal prevention of seasonal and pandemic influenza. The study is being conducted under an exclusive worldwide license and collaboration agreement with Janssen Pharmaceuticals, Inc. (Janssen), one of the Janssen Pharmaceutical Companies of Johnson & Johnson, to develop and commercialize Cidara’s Cloudbreak® drug-Fc conjugates (DFCs) for the prevention of seasonal and pandemic influenza.

The Phase 2a trial (NCT05523089), which dosed its first healthy volunteer on September 10th, is a single-center, randomized, double-blind, placebo-controlled, proof-of-concept study to assess the prophylactic antiviral activity, safety, tolerability and pharmacokinetics of CD388 against influenza via a human viral challenge (influenza) model, and to explore the impact of dose levels on efficacy. Multiple dose levels of CD388 will be evaluated in volunteers who will receive a single administration of CD388 or placebo prior to influenza viral challenge. The trial is expected to enroll up to 168 healthy adults.

“The initiation of this Phase 2a trial is an important milestone, as it represents the first study in which CD388’s prophylactic potential against influenza will be examined in humans,” said Jeffrey Stein, Ph.D., president and chief executive officer of Cidara. “Because of its mode of action, CD388 has the potential to enable universal influenza coverage against all viral strains for all people, including those with compromised immune systems. We look forward to announcing the findings next year, and continuing our collaboration with Janssen who will be spearheading late-stage development.”

Cidara’s Cloudbreak DFCs, which stably couple highly potent small molecules or peptides to a proprietary composition of a human antibody fragment (Fc), is a fundamentally novel approach to treat and prevent serious viral infections and cancers. For influenza, the long-acting CD388 DFC is designed to directly inhibit viral proliferation by targeting a conserved region on the viral envelope, potentially conferring universal prevention of Types A and B influenza with a single seasonal dose.

About Cloudbreak® DFCs
Cidara is developing a new generation of immunotherapeutic antivirals from its Cloudbreak platform that couple potent antivirals to a human antibody fragment (Fc). These highly potent, long-acting, drug-Fc conjugates (DFCs) directly inhibit viral proliferation while simultaneously engaging the immune system. In addition to the clinical-stage CD388 program for seasonal and pandemic influenza, Cidara is advancing DFC programs to target other life-threatening viruses, such as SARS-CoV-2, as well as immuno-oncology targets associated with multiple cancers.

About Influenza
Influenza (“the flu”) is a contagious viral infection that can cause mild to severe illness, sometimes resulting in death. It’s caused by influenza viruses that infect the nose, throat and lungs, and can put people, such as older people, children, and people with certain health conditions, at higher risk for complications.1 While today’s flu vaccines are credited with significant public health benefits and currently offer the best defense against infection, only about 48% of U.S. adults received a vaccine during the 2019-2020 influenza season.2 Every year, there are an estimated 1 billion cases of influenza, resulting in 290,000 to 650,000 influenza-related respiratory deaths.3

About Cidara Therapeutics
Cidara is developing long-acting therapeutics designed to improve the standard of care for patients facing serious diseases. The Company’s portfolio is comprised of new approaches aimed at transforming existing prevention and treatment paradigms, first with its lead Phase 3 antifungal candidate, rezafungin, in addition to drug-Fc conjugates (DFCs) targeting viral and oncology diseases from Cidara’s proprietary Cloudbreak platform. Cidara is headquartered in San Diego, California. For more information, please visit

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,” “may,” “plan” or “will”. Forward-looking statements in this release include, but are not limited to, statements related to the potential for influenza DFCs, including CD388, to provide universal protection against all influenza strains for an entire season, whether CD388 will be clinically effective in a range of patients including immunocompromised patients, whether Cidara will be able to complete the Phase 2a clinical trial for CD388, whether data generated in the Phase 2a trial will demonstrate that CD388 has prophylactic activity against influenza in humans, and whether preliminary results of the trial will be reported in 2023. 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 preclinical or clinical trials, delays in action by regulatory authorities due to limitations on inspections and other COVID-19-related effects, and impacts of the COVID-19 pandemic or other obstacles on the enrollment of patients or other aspects of CD388 development. 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 Securities and Exchange Commission. 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.

Brian Ritchie
LifeSci Advisors
(212) 915-2578

Patrick Bursey
LifeSci Communications
(203) 430-9545

  1. About Flu. Centers for Disease Control and Prevention. Available at: Last accessed January 2022.
  2. Flu Vaccination Coverage, United States, 2019-20 Influenza Season. Centers for Disease Control and Prevention. Available at: Last accessed January 2022.
  3. WHO launches new global influenza strategy. World Health Organization. Available at: Last accessed January 2022.

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