Under the agreement, Artios will receive $30 million in up-front and near-term payments, plus double-digit option fees and up to $860 million total milestones per target, Merck said in a statement.

Merck said it will have the right to opt into exclusive development and commercialization of compounds on up to eight targets.

The two companies will collaborate on DNA damage response (DDR) inhibitors, which are designed to block a cancer cell's ability to repair its genetic code and are seen as a promising new group of oncology therapies also pursued by British drugmaker AstraZeneca.

"Targeting DNA damage response has the potential to provide an important therapeutic option for many patients in need of new treatments," said Andree Blaukat, Head of Translational Innovation Platform Oncology & Immuno-Oncology at Merck KGaA.

Many cancer cells have a diminished ability to restore their DNA when it gets damaged during cell division, which is a driver behind cancerous mutations.

DNA damage response inhibitors are designed to block what remains of that DNA repair mechanism so that cancer cells fail to replicate and the tumor can no longer sustain itself.

Approved drugs in this class include AstraZeneca and Merck & Co's Lynparza as well as GlaxoSmithKline's Zejula.

Merck KGaA already has a number of DNA damage response drugs in early stages of clinical testing.

(Reporting by Caroline Copley and Ludwig Burger; Editing by Riham Alkousaa and Emelia Sithole-Matarise)