Manufacturers trying to prove the similarity of their biosimilars must consider that regulations and reference medicines differ in different markets says Pfizer.
Biosimilars are expected to be worth more than $45bn a year, or 10 per cent of the total global biologics market, by 2024 according to Carol Kirchhoff, director of Pfizer's biomanufacturing sciences group.
She told attendees at the American Association of Pharmaceutical Scientists (AAPS) that while biosimilars are an opportunity, developing such medicines is a complex regulatory challenge, particularly because approval pathways in key future markets are still being introduced.
"Emerging markets are going to be key for biosimilars. India has just put their guideline out earlier this year , Brazil brought there's out in 2010, Mexico has theirs in draft, Chile has theirs out as well but Russia and China don't have a biosimilar pathway today. So how are we going enter those markets?"
One approach - Kirchhoff continued - is that taken for some 'biosimilars' on the market that have been approved using regulatory pathways designed for innovator drugs, citing products sold in Egypt, Iran and Columbia as examples.
And - even in regions where approval pathways are already established - Europe and Japan being the obvious examples - ongoing reviews may mean that these processes change.
"EMA put theirs out first in 2006 and they are under review...and the rest of world guidances may change" Kirchhoff said, adding that "the rest of the world is looking at what the EMA has done, what they are doing with their revision...so we do expect that man of the rest of world countries may revise their guidelines."
Regional variations in reference products' presentations and formulations around the world should also be considered by biosimilars developers according to Kirchhoff, citing Pfizer's own product Genotrpin as an example.
"Genotropin is out there as a powder for solution for injection, as vial for or a dual chamber cartridge. There are four strengths available with anywhere from two to four having been marketed across Europe.
"The biosimilar Omnitrope, made by Sandoz, has a powder for solution for injection and two strengths."
She also cited the EU's recent suggestion that it would consider allowing developers to use reference products sourced outside the region as an interesting development.