Icosavax Initiates Phase 1/1b Trial of VLP Vaccine Candidate Against Respiratory Syncytial Virus

- Phase 1/1b clinical trial will assess the safety and immunogenicity of IVX-121 in healthy adults, including older adults -

Seattle, Washington, UNITED STATES


SEATTLE, Sept. 09, 2021 (GLOBE NEWSWIRE) -- Icosavax, Inc. (NASDAQ: ICVX), a biopharmaceutical company leveraging its innovative virus-like particle (VLP) platform technology to develop vaccines against infectious diseases, today announced the initiation of a Phase 1/1b clinical trial of IVX-121, a VLP displaying a Respiratory Syncytial Virus (RSV) stabilized pre-fusion F antigen, in healthy adults and older adults. Assuming favorable results from the IVX-121 Phase 1/1b clinical trial and favorable preclinical data from its human Metapneumovirus (hMPV) VLP candidate, Icosavax plans to thereafter initiate a Phase 1 clinical trial of its IVX-A12 bivalent RSV/hMPV vaccine candidate. 

“I am delighted with the clinical progress Icosavax has recently made. The initiation of our second clinical trial in just three months bears testament to the concerted effort our team exerted in the development and manufacturing of our vaccine candidates,” said Adam Simpson, Chief Executive Officer of Icosavax. “As part of our core strategy, we plan to transition IVX-121, our RSV monovalent VLP candidate, into a combination vaccine with RSV and hMPV, IVX-A12. With the vision of creating combination VLP vaccines, we believe that developing a bivalent vaccine targeting two of the leading viral causes of pneumonia in older adults could represent a compelling offering for both providers and patients. Currently, neither RSV nor hMPV have approved vaccines; IVX-A12 has the potential to prevent disease caused by both viruses in a single shot.”

The Phase 1/1b clinical trial of IVX-121 is a randomized, observer-blind, placebo-controlled multi-center study designed to evaluate the safety and immunogenicity of three dose levels of non-adjuvanted and aluminum-adjuvanted IVX-121 in healthy adults, including older adults. The trial will inform the dose of IVX-121 to be evaluated in combination with the Icosavax hMPV VLP candidate IVX-241 for the anticipated Phase 1 clinical trial of the RSV/hMPV bivalent vaccine candidate IVX-A12.

The Phase 1 part of the trial is expected to enroll up to 90 healthy adults in Belgium. The Phase 1b part of the trial is expected to enroll up to 217 healthy older adults. It is anticipated that a subset of the older adult subjects will be followed for 12 months after vaccination to assess durability of immune response to IVX-121.

Following the completion of the Phase 1/1b clinical trial of IVX-121, Icosavax intends to shift its development of the VLP vaccine candidate for RSV to an RSV/hMPV bivalent combination vaccine strategy. The company plans to submit an investigational new drug application (IND) to the U.S. Food and Drug Administration (FDA) in the first half of 2022 and, thereafter, initiate a Phase 1 clinical trial of IVX-A12.

About Virus-Like Particles (VLP) Vaccines
VLPs enable multivalent display of antigens in a manner that closely resembles viruses but contain no genetic material. Approved vaccines that are derived from naturally occurring VLPs have shown efficacy when formulated as combination vaccines and have shown the ability to induce high and sustained levels (titers) of neutralizing antibodies (nAbs) in adults, which have generally been associated with protective immunity. However, VLPs engineered to display complex viral antigens have in general been difficult to develop or successfully manufacture at scale, limiting the pathogens that can be addressed by this approach. Icosavax’s VLP vaccine technology is designed to enable robust, durable and broad immune responses against a broader array of pathogens than has been possible with naturally occurring VLPs and to overcome the manufacturing challenges experienced with other VLP technologies. 

About IVX-121, RSV VLP Vaccine Candidate
IVX-121 targets respiratory syncytial virus (RSV), a major cause of viral pneumonia for which no vaccine has been FDA approved. IVX-121 incorporates a stabilized pre-fusion F antigen licensed from NIAID/NIH that has been previously studied in healthy adults (DS-Cav1;  Lancet 2021). RSV F is known to undergo major structural changes that allow viral entry into the host cell, and during that process, critical protective epitopes are lost. Protein design methods have stabilized pre-fusion F, leading to improved neutralizing responses in humans.

About Icosavax
Icosavax is a biopharmaceutical company leveraging its innovative VLP platform technology to develop vaccines against infectious diseases, with an initial focus on life-threatening respiratory diseases. Icosavax’s VLP platform technology is designed to enable multivalent, particle-based display of complex viral antigens, which it believes will induce broad, robust, and durable protection against the specific viruses targeted. Icosavax’s pipeline includes vaccine candidates targeting respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Icosavax was formed in 2017 to advance the breakthrough VLP technology from the Institute for Protein Design at the University of Washington with the goal to discover, develop, and commercialize vaccines against infectious diseases. Icosavax exclusively licensed the VLP technology for use in several fields, including RSV and hMPV, from the University of Washington. For SARS-CoV-2, Icosavax has a non-exclusive, worldwide (excluding South Korea) license from the University of Washington that will convert to an exclusive license in North America and Europe in 2025. Icosavax is located in Seattle.

Forward Looking Statements
Statements contained in this press release regarding matters that are not historical facts are forward-looking statements. The forward-looking statements are based on our current beliefs and expectations and include, but are not limited to: our expectations regarding the potential therapeutic benefits of our product candidates, including IVX-121 and IVX-A12, the expected timing to file an IND and initiate a clinical trial of IVX-A12 and the potential advantages of our VLP technology. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in our business, including, without limitation: the early stage of our development efforts; our VLP technology and our plan to pursue a combination bivalent RSV/hMPV VLP vaccine candidate, both of which are novel and unproven; potential delays in the commencement, enrollment, and completion of clinical trials and preclinical studies; our dependence on third parties in connection with manufacturing, research, and preclinical and clinical testing; unexpected adverse side effects or inadequate efficacy of our product candidates that may limit their development, regulatory approval, and/or commercialization; results from preclinical studies or early clinical trials not necessarily being predictive of future results and other risks described in our prior filings with the Securities and Exchange Commission (SEC), including under the heading “Risk Factors” in our Registration Statement on Form S-1 and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and we undertake no obligation to update such statements to reflect events that occur or circumstances that exist after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

Media Contact: 
Jessica Yingling, Ph.D.
Little Dog Communications Inc.
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Investor Contact: 
Laurence Watts
Gilmartin Group, LLC
laurence@gilmartinir.com
+1.619.916.7620