Biopharmaceutical company AstraZeneca plc (STO:AZN) (LON:AZN) (Nasdaq:AZN) announced on Tuesday a definitive agreement to acquire Icosavax Inc (NASDAQ:ICVX), a US-based clinical-stage biopharmaceutical company developing vaccines against infectious diseases.

Icosavax's virus-like particle (VLP) platform incorporates antigen design capabilities and technology to enable multivalent, particle-based display of complex viral antigens, in order to induce broad, robust and durable protection against the specific viruses targeted.

This acquisition will build on AstraZeneca's existing capabilities in respiratory syncytial virus (RSV) prevention.

The deal includes Icosavax's lead investigational vaccine candidate, IVX-A12, a potential first-in-class Phase III-ready combination protein VLP vaccine targeting RSV and human metapneumovirus (hMPV). IVX-A12 addresses significant unmet needs in infectious diseases, particularly in adults aged 60 and older, as well as those with chronic conditions such as cardiovascular, renal and respiratory diseases.

Icosavax's proprietary technology, coupled with its leadership in protein design and VLP science, will augment AstraZeneca's late-stage pipeline for Vaccines & Immune Therapies. The acquisition is expected to facilitate the progression of IVX-A12 and other differentiated VLP vaccines for respiratory infections with a high disease burden.

Through a subsidiary, AstraZeneca will initiate a tender offer to acquire all outstanding shares of Icosavax at USD15.00 per share in cash. This deal, valued at approximately USD0.8bn, represents a 43% premium to Icosavax's closing market price on 11 December 2023 and a 73% premium to the 60-day volume-weighted average price (VWAP) before the announcement. Including contingent value payments, the total transaction value could reach approximately USD1.1bn, representing a 91% premium to the closing market price and a 130% premium to the 60-day VWAP.