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Icosavax Initiates Phase I/Ib Trial of VLP Vaccine Candidate Against Respiratory Syncytial Virus

By September 13, 2021No Comments

Icosavax, Inc., a biopharmaceutical company leveraging its innovative virus-like particle (VLP) platform technology to develop vaccines against infectious diseases, announced the initiation of a Phase I/Ib 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.