BioNTech SE said Thursday it will acquire fellow German biotechnology firm CureVac NV in an all-stock transaction valued at about $1.25 billion. CureVac shareholders are to receive approximately $5.46 in BioNTech American depositary shares for each CureVac share, representing a premium of roughly 34 percent to CureVac’s last closing price and 55 percent to its three-month volume-weighted average. The purchase will be carried out through a voluntary public exchange offer approved by both companies’ boards. The tie-up brings together two former rivals in the Covid-19 vaccine race and is aimed at accelerating BioNTech’s development of mRNA-based cancer therapies by adding CureVac’s clinical programs and manufacturing capabilities. CureVac stock jumped about 30 percent in pre-market trading after the announcement, while BioNTech shares edged higher. The companies expect the transaction to close later this year, subject to regulatory approvals and other customary conditions.