(Adds details, analysts' comments, shares)
July 6 (Reuters) - Celgene Corp said it would buy a stake in BeiGene Ltd to help develop and commercialize the China-based cancer immunotherapy developer's treatment for solid tumor cancers, expanding its position in the field of immuno-oncology.
BeiGene's shares rose as much as 31.4 percent to an all-time high of $68.67 in afternoon trading on Thursday. Celgene's shares were marginally down.
The deal announced on Wednesday will complement Celgene's partnership with AstraZeneca Plc to develop durvalumab as a treatment for hematological malignancies and expand the drug developer's presence in China's untapped cancer market.
BeiGene's advanced tumor cancer therapy, BGB-A317, is a type of antibody that belongs to a new class of drugs called PD-1 or PD-L1 inhibitors that block a mechanism tumors use to evade detection from cancer-fighting cells.
The treatment has been tested in more than 500 patients, with initial data suggesting that it is well-tolerated and exhibits anti-tumor activity across a range of solid tumor types, the companies said.
"We believe Celgene's ability to combine approved therapies in-house with either durvalumab or BGB-A317 provides the company flexibility during development and commercialization," William Blair analyst Andy Hsieh said in a client note.
BeiGene will get $263 million in upfront license fees and $150 million in equity investment. The company will also be eligible to receive up to $980 million in development, regulatory and sales milestone payments.
This is a "shockingly good" deal for BeiGene as it monetizes a market that is virtually impenetrable to all but the largest pharma players in the cancer space, Baird analyst Brian Skorney said.
Last month, Hutchison China MediTech, the Shanghai-based drugmaker listed in London and commonly known as Chi-Med, filed a marketing application for its cancer drug fruquintinib with the China Food and Drug Administration.
Chi-Med is developing the treatment for advanced colorectal cancer in collaboration with U.S. drug developer Eli Lilly and Co.
BeiGene will acquire Celgene's operations in China and also license and assume commercial responsibility for Celgene's approved therapies - Abraxane, Revlimid and Vidaza - in the region.
Celgene will acquire 32.7 million of BeiGene's ordinary shares at $4.58, or $59.55 per BeiGene's American Depositary Shares (ADS), the companies said.
Up to Wednesday's close of $52.27, BeiGene's shares had gained about 72 percent this year. (Reporting by Divya Grover and Bhanu Pratap in Bengaluru; Editing by Amrutha Gayathri and Martina D'Couto)