The American College of Rheumatology (ACR) has publicly released a policy statement expressing concerns about the recent FDA approval of a biosimilar version of the cancer drug filgrastim. It conveyed these reservations in a January meeting with FDA officials before the approval, and has now posted the statement on its website.
"It is uncertain whether patients will respond to these drugs the same way they would to an original biologic, because biologics are very sensitive to manufacturing changes." said ACR President E. William St.Clair MD in a press release sent today. "Even minor differences in a biosimilar’s molecular structure, purity or other chemical properties could change the way a patient responds to the drug.”
The specific issues are similar to those raised recently in a statement by the
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American Autoimmune Related Diseases Association (AARDA). They are:
Interchangeability: AARDA called for establishment of policies to assure that biosimilars and reference (original) drugs are similar enough to be substituted for each other. ACR calls for "rigorous clinical trials" to address the "tremendous" complexity in assuring that they are similar enough so that patients and phyicians can be confident in using them.
Safeguards against switching: Saying that experience outside the US raises concerns about adverse reactions from substituting a biosimilar for a reference drug, the ACR "believes there are too many unknowns about biosimilars to presume that repeated switching will be a safe practice."
Limiting biosimilar prescribing to physicians: ACR calls for safeguards that prevent insurers from forcing patients to switch from a reference drug to a biosimilar. If legislation permits a pharmacist to substitute a biosimilar, the ACR recommends requiring prior notification to both patient and physician to encourage monitoring for adverse events.
Naming: Like AARDA, ACR calls for naming conventions that avoid confusion between reference and biosimilar drugs.
Post-marketing surveillance: ACR calls for individual adverse event tracking for all biosimilars.
A member of the ACR will also speak before the FDA Arthritis Advisory Committee scheduled to meet next week to consider an application for a biosimilar for infliximab, designed to treat rheumatoid arthritis, Crohn's disease and plaque psoriasis.