March 9, 2015 | By Márcio Barra
Last Friday, the FDA issued the first approval in the U.S. of a biosimilar – Zarxio, made by Sandoz, the generics division of Novartis. The drug is a biosimilar of Amgen´s chemotherapy recovery agent Neupogen (Filgastrim, for the treatment of neutropenia), originally released in 1991.
This approval comes as a hit to Amgen´s, seeing as the company´s portfolio largely of biologicals to support cancer patients. Last year sales of Neupogen amounted to $1.2 billion. Future pressure is also incoming, as Sandoz is currently pursuing FDA approval of two more biosimilars of Amgen drugs: Neulasta (pegfilgrastim), also for the treatment of neutropenia, and Enbrel (etarnecept), for the treatment of rheumatoid arthritis. Hospira, recently acquired by Pfizer, is also seeking approval of a biosimilar of Amgen´s Epogen (human erythropoietin), for the treatment of anemia.
Biosimilars serve a similar purpose as generic drugs, but with some key differences and more stringent requirements, owing to the differences in replicating large molecules compared to smaller molecules. Seeing as biologic drugs are produced from living organisms, the production processes are quite sensitive to changes in the manufacturing processes, and thus is it very hard to create an exact replica of the original molecule. Biosimilars must be shown that they have no clinically meaningful differences in regards to safety and effectiveness from the reference product.
While biosimilars are expected to be cheaper than the original biologic, the reality is that the price discounts seen in Europe point towards a small price difference than what is seen with generics. In Europe, where several biosimilars have already been approved (Zarxio has been approved in Europe since 2009 with the slightly different name Zarzio) biosimilars have typically sold at a 20% to 30% discount to the original drug. In the US, a single injection of Neupogen can cost from between $315 to $500 for a single injection. It remains to be seen what will be the price of Zarxio.
Zarxio´s tardiness to be approved in the US is due to in part no regulatory pathway existed to bring copies of biologic drugs to market up until the signing of the Biologics Price Competition and Innovation Act of 2009. The act created an abbreviated licensure pathway for similars which have been shown to be “biosimilar” to or “interchangeable with an FDA-licensed biological product. This pathway allows sponsors and the regulator to rely on certain existing scientific knowledge about the safety and effectiveness of the original biologic, and enables a biosimilar to be licensed based on less than a full complement of product-specific preclinical and clinical data. In this case, Zarxio was approved with the use of animal study data, human pharmacokinetic, pharmacodynamics and clinical immunogenicity data. During the evaluation process, 20 lots of Zarxio were compared with 6 lots of Sandoz unfinished drug, and 10 to 15 lots of Neupogen.
Zarxio was approved by the FDA as a non-interchangeable biosimilar. Under the Biologics Price Competition and Innovation Act, a biosimilar drug that has approved as an interchangeable” may be substituted for the reference product without the intervention of the health care provider who prescribed the reference product.