The Outlook is Hopeful that Biosimilars will Mimic Effectiveness of Original Cancer Drugs for Less Money

BIOSIMILARS ARE LIKE GENERIC DRUGS except much more complex, and their anticipated entrance into standard cancer care is generating a lot of excitement — and questions.

Biosimilars are different from generic versions of brand-name drugs because they are biological treatments, made from living organisms. That means that, while biosimilar drugs are non-identical, being made from different cellular material than the drugs they mirror, they are nevertheless designed to have the same effects as the original drugs within the body, and similar safety profiles.

That’s a tough trick to pull off, but numerous pharmaceutical companies seem to be succeeding. Zarxio (filgrastim-sndz) is a copy of Neupogen (filgrastim), which helps patients avoid infection after chemotherapy; one of four biosimilars approved so far in America, it’s the only one specific to cancer treatment. But many additional biosimilars designed to treat cancer are in late stages of clinical trials, or under review by the U.S. Food and Drug Administration. Among others, these drugs would mimic Herceptin (trastuzumab) for the treatment of HER2-positive breast cancer.

So just how similar are these drugs to the originals? Before being approved by the FDA, biosimilars must be proven, in clinical trials, to act nearly identically to the original drugs they mimic. However, suppose a brand-name drug is approved to treat five different cancer types. Its biosimilar need only be tested and proven to show similar effectiveness and safety in one of those subtypes before getting the green light from the FDA. Does this represent enough investigation?

Opinions on that may vary on a case-by-case basis, depending on the complexity of each biosimilar. But so far, many American doctors and scientists believe the level of evidence needed to approve a biosimilar is sufficient, and that patients will eventually become as comfortable using these biologic twins as they are using generic drugs today.

It will be important that doctors choose biosimilars when possible, rather than prescribing brand-name versions of drugs, if biosimilars are to succeed in one of their main intended purposes — to lower the price of cancer drugs across the board. Because biosimilars are expected to cost less than brand-name drugs, it’s anticipated that they will drive all prices down through market competition. Perhaps future policy from third-party payers can help with that transformation by more strongly encouraging (or requiring) the use of biosimilars in cases where they exist.

Hopefully, as this new trend unfolds, both doctors and patients will find good reason to reach a high comfort level with the use of biosimilars. If that happens, we may see the prices of cancer drugs drop enough so that they become more accessible to a wider population of the people who need them.

DEBU TRIPATHY, MDEditor-in-ChiefProfessor of MedicineChair, Department of Breast Medical OncologyThe University of Texas MD Anderson Cancer Center