From Buproion to Biosimilars

  • by: |
  • 10/10/2012
According to an article in BioWorld Today:

The FDA’s decision last week that an approved generic bupropion wasn’t comparable to GlaxoSmithKline plc’s antidepressant Wellbutrin XL 300 mg (bupropion) raises questions about the hurdles biosimilar developers may face along the new regulatory path.

Those challenges likely would be exacerbated when developing biosimilars to drugs such as antidepressants, which fall into a narrow therapeutic index, according to Pitts. In April 2010, the Pharmaceutical Science and Clinical Pharmacology Advisory Committee voted unanimously, with one abstention, that critical dose drugs constitute a distinct group and that the FDA should develop a formal list of those drugs, he pointed out. In an 11-2 vote, the committee also concluded that existing bioequivalence standards were not sufficient for drugs in the narrow therapeutic index group.

“The issue with biosimilars is interchangeability,” Pitts told BioWorld Today. Differences between small-molecule drugs like Wellbutrin and biosimilars are iteratively more complicated than they are with generics because they involve not just the chemical composition of the product but also the manufacturing process.

“When it comes to biosimilars, you’re talking about molecules that are between 5,000 and 20,000 atoms,” he added. “The question is whether a 5,000-atom biosimilar is less difficult than a 20,000-atom biosimilar. Of course it is.”

Thus, biosimilars developers must prepare to contend with “many, many more ways to cut safety and efficacy” data, Pitts added.

The Budeprion/Wellbutrin decision indicated the FDA now realizes that issues of similarity exist even with small molecules, Pitts said. “With biosimilars, it’s going it’s going to be a billion times more complicated,” he cautioned.

Still, the fact that the FDA is feeling its way along the biosimilars regulatory pathway and potentially revisiting its general approach to extrapolation should give biosimilars developers pause, Pitts suggested.

“Ten years from now, when the FDA has more experience dealing with this, [the pathway] will be more predictable,” he said. “But now, every biosimilar that comes before the FDA for review is going to be a de novo experience. It’s going to be a very difficult, very risky and very problematic process. From a business standpoint, you have to ask yourself: Is this a worthwhile proposition?”

Tough questions with no easy answers.

The complete Bioworld Today article can be found here (bottom right, page one).


Center for Medicine in the Public Interest is a nonprofit, non-partisan organization promoting innovative solutions that advance medical progress, reduce health disparities, extend life and make health care more affordable, preventive and patient-centered. CMPI also provides the public, policymakers and the media a reliable source of independent scientific analysis on issues ranging from personalized medicine, food and drug safety, health care reform and comparative effectiveness.

Blog Roll

Alliance for Patient Access Alternative Health Practice
Better Health
Biotech Blog
CA Medicine man
Cafe Pharma
Campaign for Modern Medicines
Carlat Psychiatry Blog
Clinical Psychology and Psychiatry: A Closer Look
Conservative's Forum
Club For Growth
Diabetes Mine
Disruptive Women
Doctors For Patient Care
Dr. Gov
Drug Channels
DTC Perspectives
Envisioning 2.0
FDA Law Blog
Fierce Pharma
Fresh Air Fund
Furious Seasons
Gel Health News
Hands Off My Health
Health Business Blog
Health Care BS
Health Care for All
Healthy Skepticism
Hooked: Ethics, Medicine, and Pharma
Hugh Hewitt
In the Pipeline
In Vivo
Internet Drug News
Jaz'd Healthcare
Jaz'd Pharmaceutical Industry
Jim Edwards' NRx
Kaus Files
Laffer Health Care Report
Little Green Footballs
Med Buzz
Media Research Center
More than Medicine
National Review
Neuroethics & Law
Nurses For Reform
Nurses For Reform Blog
Opinion Journal
Orange Book
Peter Rost
Pharm Aid
Pharma Blog Review
Pharma Blogsphere
Pharma Marketing Blog
Pharmacology Corner
Pharmaceutical Business Review
Piper Report
Prescription for a Cure
Public Plan Facts
Real Clear Politics
Shark Report
Shearlings Got Plowed
Taking Back America
Terra Sigillata
The Cycle
The Catalyst
The Lonely Conservative
Town Hall
Washington Monthly
World of DTC Marketing
WSJ Health Blog