June 2 (Reuters) - U.S. drugmaker Bristol Myers Squibb ( BMY )

announced on Monday a $1.5 billion upfront payment to

partner with Germany's BioNTech on an

experimental cancer drug, in a deal that could eventually exceed

$11 billion in value for BioNTech.

Bristol said it will co-develop and co-commercialize

BioNTech's drug, BNT327, for multiple solid tumor types.

The drug belongs to a class of next-generation

immunotherapies - which harness patients' immune systems to

target and fight disease - called bispecific antibodies. BNT327

targets 2 proteins, PD-L1 and VEGF-A.

"We are impressed by the innovation that BioNTech has

achieved to date and we look forward to partnering to accelerate

existing clinical trials and time to market, while expanding the

number of potential indications," Bristol Myers CEO Chris

Boerner said in a statement.

In addition to the initial payment, Bristol plans to pay

BioNTech up to $2 billion more in non-contingent anniversary

payments through 2028. BioNTech may also earn up to $7.6 billion

more in development, regulatory and commercial milestones,

Bristol said.

The companies will share global profits and losses from the

drug equally, and joint development and manufacturing costs will

also be shared on a 50/50 basis, subject to some exceptions.

BNT327 is currently being tested as a first-line treatment

in extensive stage small cell lung cancer and non-small cell

lung cancer. More than 1,000 patients have been treated with the

drug to date.