FRANKFURT (Reuters) - A major cancer drug deal between Pfizer (>> Pfizer Inc.) and Germany's Merck KGaA (>> Merck KGaA) is exclusive with regard to the immunotherapy drugs involved, Merck said on Monday.

"This is an exclusive collaboration in the PD-1, PD-L1 space," said Belen Garijo, who will take over leadership of Merck's healthcare business from next year.

She added that the two sides could jointly decide to collaborate with third parties.

Garijo was speaking in a conference call after the German group announced the major cancer-drugs alliance with Pfizer.

(Reporting by Ludwig Burger; Editing by Georgina Prodhan)

Stocks treated in this article : Pfizer Inc., Merck KGaA