Gov. Jerry Brown vetoed a bill supported by Thousand Oaks-based Amgen and other biotechnology companies that would have made it more difficult for pharmacists to dispense so-called biosimilars, the biotech industry’s analogue to generic pharmaceuticals. Senate Bill 598, approved by both houses of the legislature, looked mostly like a procedural change to state’s pharmacy laws. If it passed, the bill would have allowed pharmacists to fill prescriptions with biosimilars that the U.S. Food and Drug Administration deems “interchangeable” with brand-name counterparts.