The deal also includes an additional payment of $360m (£296.2m) based on achievement of pre-defined development milestones.
The total investment in BlueRock is valued at around $1bn (£823m), as Bayer already holds a 40.8% stake.
Bayer pharmaceuticals division president and management board member Stefan Oelrich said: “This acquisition marks a major milestone on our path towards a leading position in cell therapy.
“In line with our strategy to ramp up our investments in technologies with breakthrough innovation potential, we have decided to build our cell therapy pipeline based on BlueRock Therapeutics’ industry-leading iPSC platform.”
BlueRock Therapeutics is a major engineered cell therapy company, which is involved in the development of regenerative medicines for intractable diseases.
With an investment of $225m (£185m), Bayer and Versant Ventures established BlueRock Therapeutics in 2016 to help advance several programmes into the clinic.
Leveraging a proprietary induced pluripotent stem cell (iPSC) platform, the company is currently developing engineered cell therapies in the fields of neurology, cardiology and immunology.
BlueRock’s cell differentiation technology is said to recapitulate the cell’s developmental biology to produce native cell therapies, which will be further engineered for additional function.
BlueRock’s major programme in Parkinson’s disease is expected to enter the clinic by the end of this year.
The deal allows Bayer to own full rights of BlueRock’s Cell + Gene platform, including a wide intellectual property portfolio and associated technology platform with iPSC technology, gene engineering and cell differentiation capabilities.
The deal is expected to be completed in the third quarter of this year.
BlueRock Therapeutics CEO Dr Emile Nuwaysir said: “We have built a premier cell therapy platform at BlueRock Therapeutics, with industry-leading R&D, process development and manufacturing capabilities.
“With the expertise and support of Bayer, we will be even better positioned to pursue the discovery, development and commercialization of revolutionary new cell therapies for patients suffering from diseases previously thought of as intractable.”