AstraZeneca Plc (AZN  ) has agreed to acquire Icosavax Inc (ICVX  ) at $15.00 per share in cash at closing, plus a non-tradable contingent value right to receive up to $5.00 in cash, payable upon achievement of specified regulatory and net sales milestones.

The deal provides AstraZeneca access to experimental vaccines targeting common respiratory disease-causing viruses.

The upfront cash portion of the consideration represents an equity value of approximately $838 million, nearly a 43% premium over Icosavax's share price of $10.49 on Monday. The acquisition is expected to close in Q1 of 2024.

Icosavax has a protein virus-like particle platform technology used to develop vaccines against infectious diseases. Its initial focus is on respiratory diseases.

Concurrently, Icosavax released topline interim results for its Phase 2 study of IVX-A12, a combination virus-like particle (VLP) vaccine candidate targeting both respiratory syncytial virus (RSV) and human metapneumovirus (hMPV).

IVX-A12 induced robust immune responses against both RSV and hMPV at Day 28 across both formulations with and without adjuvant.

For unadjuvanted IVX-A12, IVX-A12 induced geometric mean titers (GMTs) in RSV-A neutralizing antibody titers (nAbs) of approximately 12,200 IU/mL compared to approximately 2,000 IU/mL for placebo.

GMTs in RSV-B nAbs of approximately 5,500 IU/mL versus approximately 1,300.

IVX-A12 induced GMTs in hMPV-A nAbs of approximately 1,600 assay units/mL compared to approximately 400 and around 15,300 versus approximately 6,700 in hMPV-B nAbs.

"With the addition of Icosavax's Phase 3-ready lead asset to our late-stage pipeline, we will have a differentiated, advanced investigational vaccine and a platform for further development of combination vaccines against respiratory viruses," said AstraZeneca's EVP, Vaccines & Immune Therapies, Iskra Reic.

Price Action: AZN stock is up 1.56% at $64.49, and ICVX shares are up 45.95% at $15.31 during the premarket session on the last check Tuesday.