Bayer AG has agreed to buy the U.S. biotech company Asklepios BioPharmaceutical for as much as $4 billion, the companies announced.

Under the deal, Bayer agreed to pay $2 billion upfront and potentially another $2 billion if milestones are met for the privately held company.

“With this acquisition, Bayer significantly advances the establishment of a cell and gene therapy platform that can be at the forefront of breakthrough science, contributing to preventing or even curing diseases caused by gene defects and further driving company growth in the future,” Bayer chairman Werner Baumann said in a statement.

AskBio, which is based in North Carolina, is developing gene therapies for illnesses including Parkinson’s disease and congestive heart failure.

Bayer created a special business unit for cell and gene therapies. After closing, the company said AskBio would continue to operate independently in the CGT unit to preserve its entrepreneurial culture and nurture innovation.

Analysts at Morgan Stanley said the acquisition was a push by Bayer to bolster its pipeline. “However, the financial payment does seem relatively high for an asset that is unlikely to see any sales contribution for at least the next four years,” the said.

There had been concern among some analysts that Bayer did not have enough promising products in development to compensate for expected patent losses. “What we now have is a comprehensive pipeline,” Stefan Oelrich, chief executive of Bayer’s pharmaceutical branch, said. “I feel like things are really coming together on the pharma side.”

AskBio had been planning an initial public offering when it was approached by Bayer, chief executive officer Sheila Mikhail said. The company raised $225 million from TPG Capital and Vida Ventures last year in its first ever fundraising.

The deal is expected to close during the fourth quarter of 2020.

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