California Governor Gerry Brown has vetoed legislation designed to regulate the use of biosimilar drugs in the state.

The bill – SB 598 - which has received strong bipartisan support in both the state Assembly and the Senate, would allow biosimilars to be substituted for biologic drugs once they were approved by the Food and Drug Administration (FDA). In his veto note, Gov Brown says: “this is a policy I strongly support.”

However, the bill’s second change to the state pharmacy law, requiring pharmacists to send notifications back to prescribers about which drug was dispensed, “on its face looks reasonable, [but] is for some reason highly controversial,” he goes on. “Doctors with whom I have spoken would welcome this information [but] CalPERS [the California Public Employees’ Retirement System] and other large purchasers warn that the requirement itself would cast doubt on the safety and desirability of more cost-effective alternatives to biologics.”

Also, he says, the FDA has not yet determined what standards will be required for biosimilars to meet the higher threshold for “interchangeability.”

“Given this fact, to require physician notification at this point strikes me as premature,” he writes.

The bill is opposed for its “burdensome notification provisions” by the Generic Pharmaceutical Association (GPhA) and groups representing retirees, insurers and pharmacies. GPhA also notes that the FDA commented recently that legislation such as SB 598 is unnecessary because the 2010 Affordable Care Act “expressly states that an interchangeable biological product may be substituted for the reference product without the intervention of the health care provider who prescribed the reference product.”

The bill is supported by big California-based biopharmaceutical firms such as Amgen and Genentech, and industry group the California Healthcare Institute, which expressed disappointment with Gov Brown’s veto.

SB 598 “would have established a responsible pathway for increased patient access to biologic medicines for life-threatening illnesses as soon as they were available,” says the Institute. Gov Brown has “failed to recognise that the FDA cannot affect whether physicians in California will be notified of the biologic medicines their patients receive at a pharmacy. Only state regulation can do that,” it adds.

And Dr John Maa, of the San Francisco Medical Society and the American College of Surgeons, warned that the veto “does not make the need for addressing patient access to biosimilars in the pharmacy setting go away. A legislative remedy will still be required.”