Earlier this year the FDA approved a first-of-its-kind drug: a biosimilar. This is an imitation form of a cell-derived, or biologic, medication.  Biosimilars could offer patients powerful results – at reduced prices.  But because these medications derive from living tissues, not a chemical formula, biosimilars and biologics are not identical. Nor do they necessarily give patients identical results.  So as pharmacists begin to consider which form of the medications to dispense, California must ensure that physicians know what their patients receive at the pharmacy.  This information allows them to monitor patients’ progress and guide their treatment.

Our state legislature passed such a measure in 2013.  But Governor Brown vetoed the bill, calling it “premature.”  Not anymore.  Biosimilars are here to stay.  The state assembly and senate have passed SB 671, a bill that now awaits Governor Brown’s signature. And it’s time for California to once and for all establish precautions that keep physicians informed.

After all, these cell-derived medications offer innovative, groundbreaking treatment for chronic conditions. But patients still approach their health care much as they always have.  That is, they still prefer treatment directed by a physician who knows them well.  So as more biosimilar medicines become available, most patients will want their doctor – not their pharmacist – deciding which medication is right for them.  At the very least, they’ll want their doctor to knowwhich medication they’re taking.

And well they should.

Each patient is unique, a fact that’s abundantly clear to me now in my fourth decade of practicing rheumatology.  Symptoms, medical histories, life circumstances, and responses to medications all vary from patient to patient.  My treatment decisions, including whether to prescribe a particular medication, encompass all these factors.

I frequently prescribe biologics because they have visibly transformed my patients’ quality of life.  When I first began practicing rheumatology in the 1980s, some patients came to my office in wheelchairs or on stretchers.  Many patients took the steroid prednisone, which caused significant side effects.

Biologics changed all that.  Roughly two thirds of my rheumatoid arthritis patients now take biologics, and I see far fewer patients show up for appointments in wheelchairs. I think specifically of two patients with dramatically improved quality of life. One, a homemaker in her early 60s, found that rheumatoid arthritis prevented her from keeping up her home and interfered with her day-to-day life.  Another rheumatoid arthritis patient, an attorney, encountered problems writing and typing.  With a treatment plan that included biologics, both patients now live normal lives in remission.

But determining the route to remission can be painstaking for physicians.  In addition to considering an array of patient details, physicians must consider the unique nature of medications.  I occasionally observe differences – in efficacy and side effects – between brand-name and generic, among generics of the same medication, and between different delivery methods, such as intravenous versus self-injection.

Magnifying these variations, biologics are uniquely sensitive.  More than simply a recipe of chemical ingredients, these medications derive from the cell lines of living organisms.  Production and storage environments must be standardized to protect the integrity of these medications. This complexity also means that even similar therapies, biosimilars, are inherently different, and those differences can have a meaningful impact on patients’ response.

Determining and monitoring a patient’s treatment, therefore, requires analysis, precision and accurate data.  So if a pharmacist substitutes a biosimilar for a prescribed biologic, the physician should know.  For me or any physician to treat a patient without fully understanding their medication regimen would be unwise, even dangerous.

Gov. Brown has a second chance to make a choice that could help protect thousands of patients throughout our state.  Let’s hope he opts to allow physicians to treat patients based onall the facts, including which medications they take.

Robin Dore, MD is a board-certified rheumatologist practicing in Tustin, CA.  She is a clinical professor of medicine at UCLA and a member of the Alliance for Patient Access.