For the week ending September 16, 2016, a combined $1.01 billion was spent on three pharmaceutical deals, one of which is also the largest pharmaceutical deal so far in September.

Horizon Pharma plc (NASDAQ: HZNP), which develops, acquires and commercializes medicines for the treatment of arthritis, pain, inflammatory and/or orphan diseases, acquired Raptor Pharmaceuticals Corp. (NASDAQ: RPTP) for approximately $800 million, or $9.00 per share. Raptor focuses on developing and commercializing transformative treatments for people affected by rare and debilitating diseases.

The transaction gives Horizon global rights to PROCYSBI® delayed-release capsules, used to treat nephropathic cystinosis, and QUINSAIR™ (aerosolized form of levofloxacin), used for the treatment of chronic pulmonary infections in patients with cystic fibrosis, with PROCYSBI® having strong patent protection through 2034. It also diversifies Horizon’s revenue with 11 medicines across orphan, rheumatology and primary care.

Horizon Pharma has stayed relatively quiet in 2016. Its only other acquisition this year was in April, when it paid $28 million for Boehringer Ingelheim’s interferon assets.