Bristol Myers Squibb Co. will pay SystImmune Inc. up to $8.4 billion for rights to co-develop and sell an experimental drug for lung and breast cancers, the latest in a string of large deals for a potent new class of oncology treatments.

The agreement includes an $800 million upfront payment to SystImmune and as much as $500 million in contingent near-term payments, Bristol said Monday in a statement. The rest of the payments will be based on whether the drug, called BL-B01D1, reaches regulatory and sales goals. It’s now in an early-stage study.

Data from early stage studies “demonstrate promising anti-tumor activity in patients with a range of solid tumors that had progressed after standard of care treatments,” Bristol said in the statement.

The collaboration will allow SystImmune to retain exclusive rights the drug in mainland China, while Bristol will gain an exclusive license for the rest of the world. Based in Redmond, Washington, SystImmune is a company of China-based Sichuan Biokin Pharmaceutical Co., according to its website.