A US Food and Drug Administration (FDA) advisory committee voted 14 to one in favour of Pfizer’s anaemia drug Retacrit last week, paving the way for the first biosimilar of Amgen’s Epogen (epoetin alfa) to be available in the US.
“The Committee’s recommendation reinforces the potential value of biosimilars in expanding access to additional high-quality treatment options for the patients in the US who need them,” Diem Nguyen, global president of Pfizer Essential Health said in a statement.
If approved, Retacrit will become the sixth biosimilar in the US and the second for Pfizer which saw regulatory success for Inflectra, its version of J&J’s Remicade (infliximab), in February last year. The other US biosimilars, in order of approval, are: Sandoz’s Zarxio (March 2015), Sandoz’s Erelzi (August 2016), Amgen’s Amjevita (September 2016), and Samsung Bioepis’ Renflexis (April 2017).
Second submission
Retacrit has been available in Europe since 2008 but was first submitted to the FDA in January 2015 by Hospira. But in October that year the Agency sent a complete response letter (CRL) to Hospira’s new owner Pfizer demanding more evidence to support approval of the biosimilar.
And according to the Oncologic Drugs Advisory Committee’s briefing document, the FDA had concerns around clinical pharmacology, efficacy and immunogenicity, as well as with the manufacturing process.
The Agency requested minor adjustment in the “drug product (DP) manufacturing process content target to more closely match epoetin protein content of the reference product,” and the “addition of commercial product specifications for selected quality attributes and tightening of several proposed specifications,” both of which were addressed by Pfizer with additional data and sensitivity analyses.
The briefing document also revealed details about the manufacture of Pfizer’s Retacrit, ahead of a potential US approval:
“The engineered Chinese hamster ovary (CHO) cell line used to manufacture the Epoetin Hospira Drug Substance (DS) is the same as that used to produce the EU Retacrit DS. The DS manufacturing process for EU Retacrit was transferred to a larger scale manufacturing facility in the US and was validated to support the Epoetin Hospira program.
“The cell culture, harvest and purification steps used to manufacture the Epoetin Hospira DS are the same as those for EU Retacrit with minor modifications to enable production at a larger scale.”