First Biosimilar Approved For Use in United States
The U.S. Food and Drug Administration in March gave the go-ahead for the first biosimilar product to be sold in this country, filgrastim-sndz (Zarxio). It is now available for sale in the U.S.
The newly approved medicine is highly similar to filgrastim (Neupogen), which is used during breast cancer treatment to boost white blood cell counts that help people receiving chemotherapy from getting infections.
What Are Biosimilars?
Though both are meant to provide lower-cost versions of original brand-name medicines, biosimilars are not the same as generic medicines.
Generics are identical copies of traditional medicines, which are made from chemicals. Generics have the same active chemical ingredient as the brand-name product and the same dose and side effects. They are taken or given the same way, work similarly, and have the same intended use.
Biosimilars, on the other hand, mimic medicines that fall into a newer category called “biological drugs,” or biologics. Biologics are made from living cells, and for that reason they can not be copied exactly. The word “biosimilar” describes a medicine that is highly similar to, but not exactly the same as, the original biological medicine.
Biosimilars “have allowable differences because they are made from living organisms,” according to the FDA. But biosimilars “have no clinically meaningful differences in terms of safety, purity and potency” from the original medicine.
More biosimilars, including a version of the anti-HER2 medicine trastuzumab (Herceptin), are expected to be approved for use in the U.S. over the next few years as patents on original medicines expire. The hope is that introducing biosimilars will lower treatment costs.
The biosimilar version of Neupogen, filgrastim-sndz, is sold as Zarxio by Sandoz, a division of the pharmaceutical company Novartis.
“I think most oncologists will be comfortable with using the biosimilar product for their patients,” said Douglas Yee, MD, professor of medicine and pharmacology and director of the Masonic Cancer Center at the University of Minnesota. He expects that many hospital pharmacies and insurance companies will prefer the biosimilar because it likely will be cheaper than the original Neupogen.
Neupogen is used in breast cancer because its ability to boost white blood cell counts allows chemotherapy treatments to be given every two weeks instead of every three weeks. The more frequent schedule has been shown to improve the chance for survival, Dr. Yee said.
Are Biosimilars Safe?
Blood tests that are routinely done to check blood cell counts during chemotherapy should show whether the biosimilar is having the desired effect of boosting the body’s immune system, Dr. Yee said. If not, a switch could be made back to the other medicine.
Dr. Yee has more concerns about other biosimilar products in development, such as those for trastuzumab (Herceptin), a targeted therapy for HER2-positive breast cancer.
“There would be no immediate readout of whether [the biosimilar] is behaving the exact same way” as Herceptin would for any given person, Dr. Yee said.
“If a small clinical trial could show equivalency to the trade drug, this would enhance confidence in use of a biosimilar Herceptin for treatment of women whose survival depends on the drug,” he said.
What You Should Know
Michael R. Cohen, RPh, MS, ScD, DPS, FASHP, president of the Institute for Safe Medication Practices, a patient safety organization based in suburban Philadelphia, said people should understand a “biosimilar is not exactly the same” as the reference medicine, though it is meant to work the same way. It must meet the same standards of safety and effectiveness to pass the FDA’s review process.
Generic medicines are given the same chemical name as the brand-name product they replace. But Dr. Cohen’s group has asked the FDA to require companies to identify themselves in the name so that they can be easily traced to the company that made them. This is why Sandoz’s Zarxio has the name filgrastim-sndz rather than simply filgrastim.
“If a patient happens to have a reaction to a drug, you want to know where the drug originated,” Dr. Cohen said.
Though biosimilars are expected to cost less than the original medicine, the savings won’t be as big as they are with many generics, he said. Some generics cost a fraction of their name-brand counterpart.
“I think these drugs will be more in the range of 15 to 20 percent less expensive than the original,” Dr. Cohen said.
LBBC will continue to report on this new class of medicines as information becomes available. Learn more from the FDA about biosimilars here.