Gilead pays $4.3B for CymaBay, the biotech that never gave up on liver disease med

Gilead Sciences is bolstering its liver disease portfolio with the $4.3 billion acquisition of CymaBay Therapeutics, specifically for the primary biliary cholangitis (PBC) med seladelpar.

The deal follows a Big Pharma trend of picking up late-stage, validated assets. Seladelpar was submitted to the FDA to treat PBC with pruritus, or itching, without cirrhosis or with compensated cirrhosis in December 2023. The rare liver disease primarily affects women over 40 and is characterized by impaired bile flow and the accumulation of bile acids in the liver, causing an elevation of liver enzymes that can be dangerous.

Seladelpar was granted a priority review for the condition with a due date of Aug. 14 for a decision, according to a separate update from CymaBay this morning.

“We are looking forward to advancing seladelpar by leveraging Gilead’s long-standing expertise in treating and curing liver diseases,” said Gilead CEO Daniel O’Day in a Monday statement. “Building on the strong research and development work by the CymaBay team to date, we have the potential to address a significant unmet need for people living with PBC and expand on our existing broad range of transformational therapies.”

This will not be new territory for Gilead, which has a deep portfolio of HIV meds and has also previously tested GS-9674 for PBC. The med, now known as cilofexor, was unsuccessful in PBC and the related disease primary sclerosing cholangitis. Gilead is now testing cilofexor in combination with Novo Nordisk’s semaglutide for metabolic dysfunction-associated steatohepatitis (MASH—previously known as nonalcoholic steatohepatitis or NASH).

Seladelpar improved levels of serum alkaline phosphatase and bilirubin, as well as reduced itch, in a phase 3 trial that read out in September. The data teed up the regulatory filing.

It wasn’t smooth sailing for the med through the clinic, with seladelpar failing in MASH in 2019. But CymaBay pressed on, culminating in today’s deal with Gilead.

“Now that seladelpar has achieved priority review with the FDA, we are excited that Gilead, with its long-standing commitment to patients with liver disease, can apply its regulatory and commercial expertise to bring seladelpar as quickly as possible to people with PBC,” CymaBay CEO Sujal Shah said in a statement.

The deal has been approved by members of each company’s board and is set to close in the first quarter. CymaBay will become a wholly owned subsidiary of Gilead at close. Gilead is paying $32.50 per share in cash, a 27% premium to CymaBay's closing price as of Feb. 9.

CymaBay's shares climbed 24% in premarket trading Monday to $32 apiece, compared to $25.69 at close Friday. 

William Blair analysts said the Gilead deal validates the clinical performance and potential of seladelpar. 

"The acquisition by Gilead represents a poetic closure to the CymaBay story," the firm wrote, noting the company's difficult decision to cut the MASH indication after adverse events cropped up. "We commend management’s resilience and persistence that ultimately led to seladelpar demonstrating the best-in-class clinical profile in PBC, and we expect the drug to benefit thousands of patients living with PBC as soon as later this year." 

William Blair had previously assumed an acquisition price of $2.9 billion, calling the Gilead offer fair. The firm assumes that no other bidder will emerge with a better offer, and the deal will close as planned.