BIOSIMILARS GENERIC DRUGS

Biosimilars Generic Drugs

Biosimilars Generic Drugs

Introduction

O "Biosimilars," or generic versions of biological drugs, are possible -- and are coming -- but scientific considerations must dictate the extent and kind of testing that is required, and the criteria for approval by regulators. O The drug described in the source article is less a generic version of a biological than it is a new and distinct drug -- because it is undergoing safety and efficacy testing instead of the merely the pharmacokinetics testing that usually is considered sufficient for a generic version of a small-molecule drug. O The testing of this product illustrates why "follow-on drug" might be a more apt description than "biosimilar" or "biogeneric." O Regulators (and the company that makes the follow-on drug in the source article) seem to be adopting a conservative approach -- performing the amount of testing that is necessary, even if it is far more than is usually required for a conventional generic version of a small-molecule drug.

Discussion

Since 1984, the marketing of generic versions of "small molecule" drugs such as antibiotics and medicines to control blood pressure, cholesterol and pain has been governed by the Drug Price Competition and Patent Term Restoration Act, commonly known as the Hatch-Waxman Act. By allowing approval of generic products through an abbreviated and less costly route than for innovator drugs, this legislation has given rise to a robust and important generic drug industry. It has balanced the need to preserve industry's incentive to innovate with the benefits of competition. When Hatch-Waxman was conceived, biopharmaceuticals were new; now they are both common and expensive, accounting for some 13 per cent of U.S. drug expenditures.

In order to extend the benefits of Hatch-Waxman, members of athe U.S. Congress plan to introduce legislation designed to speed up the process by which generic versions of biopharmaceuticals can be marketed. Supporters of these efforts want to replicate with biopharmaceuticals the kinds of savings that consumers have enjoyed with traditional medicines. They believe that generic versions of biotech drugs should be approved for the market rapidly after patents expire, with a minimum of testing. The advent of biogenerics would be a positive development -- as long as the politicians (and regulators and drug developers) don't forget that the issue has critical scientific, as well as political, components.

Not all classes of drugs are equal, and not all efforts to produce generics in order to drive down prices will be safe for patients. There are important differences between most biopharmaceuticals and the traditional, small-molecule drugs that control pain, blood pressure and high cholesterol. Because most conventional medicines can be manufactured with easily replicable chemical processes which lead to a largely reproducible drug formulation, the clinical trial data that supported approval of the original version can be relied upon for the generic versions.

The latter need only demonstrate "bioequivalence" -- similar blood levels and biological effects -- to the original version by means of simple tests. Biopharmaceuticals, which are proteins, are larger and have far more ...