InvestmentsTop Global NewsMarketsReal Estate US’s Pfizer to buy 9.9per cent of CStone Pharmaceuticals for US$200 million By financialnews_rlv83x - September 30, 2020 0 246 CStone Pharmaceuticals, which focuses on immuno-oncology medicines, said on Wednesday a unit of Pfizer Inc has agreed to buy 9.9per cent of the Hong Kong-listed biopharmaceutical firm for HKUS$1.55 billion (US$200.01 million).