The future of biosimilars in the United States is yet to be determined. The Food and Drug Administration (FDA) has not settled on a regulatory pathway for approval (expected by the end of 2011) and a recent research report shows that physicians want to see extensive studies before they will prescribe biosimilars for their patients.

Since the beginning of the biosimilar debate, critics have questioned their safety and have said that extensive clinical trials must be conducted to ensure that even the slightest changes in manufacturing will not impact the drugs efficacy or safety. They often cite the complex nature of biopharmaceuticals and their sensitivity during manufacturing. A recently published research report by Decision Resources found that physicians agree with critics particularly in the area of indication extrapolation. Indication extrapolation is the principal that if a biosimilar has been approved for one indication and performs similarly to the original product that the biosimilar should therefore be approved for all the same indications as the original product. For example, Enbrel has been approved for five indications, including rheumatoid arthritis and psoriatic arthritis and indication extrapolation would allow an Enbrel biosimilar approved for rheumatoid arthritis to subsequently be automatically approved for the other four indications. Normally, to receive those approvals for additional indications, Enbrel would have to undergo clinical studies for each indication. This is a step that could be avoided by biosimilars if the principal of indication extrapolation is accepted. However, based on this research report, physicians, primarily in the area of rheumatology, nephrology, and gastroenterology, expressed that they would not be comfortable using indication extrapolation as a basis for approving additional indications. The FDA has stated similar concerns and implied that they would require detailed data for each indication.

If the FDA does decide to require clinical trials in several indications it would drive the cost of biosimilar approval up significantly, possibly to the point where only the largest companies with the highest revenue streams would be able to shoulder the costs and compete in the biosimilar space. It takes an estimated 100 million dollars and five or more years to bring a biosimilar to market and these costs would ensure there would only be a few large drug companies that could reach a global market.

The high cost of approval threatens the promise of biosimilars, which is to reduce costs compared to the original drug. The Obama administration has strongly supported biosimilars as a way to reduce the overall cost of healthcare and improve access for all Americans. Supporters of biosimilars argue that biosimilars can provide a significant cost savings over existing biopharmaceuticals. For example, Omnitrope, a biosimilar human growth hormone that was approved in Europe in 2006, is offered at a 25% price reduction. Biosimilar companies also have the advantage of improved technologies including production systems that are more advanced, more cost effective, and more defined than systems being used when the innovator products were approved.

In Europe, 14 biosimilars have already been approved. There are an estimated 40 biosimilars in development, but if these products hope to compete with the original products in the United States, they will need to find a way to keep their costs down despite additional clinical trials and will need to find a way to inspire confidence in physicians who will prescribe these drugs.