The FDA Invitation that Patient Advocates are Awaiting

March 26, 2018

Open dialogue is an important part of the drug approval process.

Physicians, patients and advocates want transparent discussion about new therapies — their benefits, their risks, their impact and their accessibility.  The conversation is especially important for complex drugs, such as biologics and biosimilars.  Accordingly, in 2016, Food and Drug Administration regulators stated their intention to hold an advisory committee meeting each time they consider approval of the first biosimilar in a class of drugs.

But in 2018 the question is, will they?

A biosimilar may soon be available for a biologic that strengthens cancer patients’ immune systems after they undergo chemotherapy.  The drug is known as “pegfilgrastim.”

So far, however, the FDA has made no indication that it plans to hold an advisory committee meeting to discuss the biosimilar.

The Many Faces of Filgrastim

Uncertainty around whether an advisory committee will occur underscores potential confusion about what makes for a “first-in-class” biosimilar.  As it happens, biological drugs to boost chemo patients’ immune systems come in several forms:

  • Filgrastim.  The originator biologic drug is administered daily for up to 14 days after a patient’s chemotherapy treatment.
  • Pegfilgrastim.   A longer-acting biologic; a single dose treats patients for 14 days following their chemotherapy treatment.
  • Biosimilar filgrastims. Follow-ons to the original filgrastim biologic, these drugs are designed to offer comparable benefits at lower prices.
  • Biosimilar pegfilgrastims. These will be follow-ons to pegfilgrastim, designed to provide similar long-acting benefits but at lower prices.

The first biosimilar to filgrastim received an advisory committee meeting in 2015.  Which begs the question: Is biosimilar pegfilgrastim just another biosimilar of filgrastim?

Or do patients, physicians and advocates deserve a chance to weigh in on this new drug?

Continued Transparency

Pegfilgrastim uses the same protein as the original filgrastim, but in an altered form.  This is how manufacturers achieve the drug’s long-acting effects.

Moreover, the proprietary process used to create pegfilgrastim is very different from the process that produces original filgrastim – and very complex.  Several manufacturers have attempted a pegfilgrastim biosimilar only to have their applications denied by the FDA.  And two manufacturers submitted but then withdrew applications for approval to the European Medicines Agency.

In short, pegfilgrastim requires a unique manufacturing process and elicits a unique response.  Its pharmacokinetics – how it works in the body – are its own.  Thus, biosimilars of pegfilgrastim will be distinct from biosimilars of filgrastim.  They’ll have their own nuances and their own benefits.

One might even conclude that they, like other first-in-class biosimilars, should have their own advisory committee meeting.

When it comes to drugs as awe-inspiring and complex as biologics and biosimilars, patients and physicians are understandably eager to explore important issues and ask questions of regulators.  FDA communication has led them to expect an advisory committee meeting for the first biosimilar in each class of drugs.

Now they wait to see if the FDA will give them that opportunity.

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