United Kingdom-based AstraZeneca agreed to acquire a 55% stake in Dutch Acerta Pharma in a $4 billion deal, the company announced on Thursday. The transaction's price tag breaks down into an initial $2.5 billion payment plus another $1.5 billion unconditional payment when Acerta's experimental drug, acalabrutinib, is approved for any indication in the U.S. or at the end of 2018, whichever comes first. AstraZeneca will have the option to buy the remaining stake in the company for about $3 billion at a later date. Acalabrutinib is being tested as a treatment for various types of leukemia, lymphoma and other cancers. The New England Journal of Medicine recently published positive results of early clinical testing of the drug, which is seen as a rival to Johnson & Johnson Inc.'s (JNJ) and AbbVie Inc.'s (ABBV) Imbruvica and as a potential blockbuster treatment. AstraZeneca shares were up 1.45% in London at 4,480 pence, for a total market value of around £56.8 billion or $85.4 billion. Thursday's deal announcement comes just a day after AstraZeneca revealed its $575 million deal to acquire respiratory drugs owned by Japan's Takeda Pharmaceutical Company.