(Reuters) -Pfizer ( PFE ) has submitted a sweetened bid for obesity drug developer Metsera ( MTSR ), as its fight against rival Novo Nordisk escalates, Bloomberg News reported on Friday.

The new offer improves upon Pfizer's ( PFE ) earlier proposal for $86.20 a share including milestone payments, the Bloomberg report said, citing people familiar with the matter.

Reuters could not immediately verify the Bloomberg report.

Novo raised its offer for the U.S. biotech company on Thursday just hours after New York-based Pfizer ( PFE ) matched the Danish drugmaker's previous $10 billion proposal late on Wednesday.