Sanofi (SNY) has agreed to acquire Vigil Neuroscience (VIGL) in a cash transaction with an equity value of up to $600 million, the companies said late Wednesday.

Under the terms of the deal, Vigil shareholders will receive an upfront payment of $8 per share in cash plus a non-tradeable right to receive a possible additional $2 per share in cash following the first commercial sale of Alzheimer's therapy VG-3927 if achieved within a specific time period, the companies said.

Sanofi and Vigil said they expect the transaction to close in Q3.

Iluzanebart, Vigil's monoclonal antibody program, is not part of the Sanofi deal and will return to Amgen (AMGN), which was the original licensor, the companies said.