Merck & Co. has reached an agreement to acquire Tilos Therapeutics, a developer of monoclonal antibodies targeting the latent TGFβ complex.

The deal will see biopharma firm Merck acquire private Massachusetts-based biotech Tilos Therapeutics for up to $773 million (€683 million), including an undisclosed upfront payment and milestones.

Dean Li, senior vice president, discovery and translational medicine, Merck Research Laboratories, said in a statement the deal is evidence of the firm’s continued efforts to enhance its pipeline.

“Tilos has developed a compelling portfolio of candidates that employ a novel approach to modulating the potent signaling molecule TGFβ by binding to latency-associated peptide, with potential applications across a range of disease indications,” he said.

Tilos was founded by Boehringer Ingelheim Venture Fund and Partners Innovation Fund. Its anti-LAP – latency-associated peptide of TGFβ – antibodies have been shown to effectively reduce tumor growth in animal models and have been touted by the firm to be a new class of therapeutics in the treatment of cancer, fibrosis and autoimmunity.

The antibodies modify the microenvironment of a tumor by depleting LAP+ inhibitory cells, freeing the innate and adaptive immune responses to effectively clear the tumor.

They also inhibit TGFβ response, stabilizing the LAP-TGFβ complex and preventing the release of the active cytokine. This, the firm says, reduces leads to broad effects on tumor growth, reducing metastasis, immunosuppression, epithelial-to-mesenchymal transition and angiogenesis.

As all the candidates are in preclinical development, there are no manufacturing operations in play at his stage, a Merck spokesperson told this publication.