Non-innovator biological products (NIBPs) or 'biocopies' are available in several countries at lower prices than biosimilars. These drugs, sometimes so-called 'biosimilars', may not meet all of the quality criteria expected of clinically equivalent products. NIBPs can exhibit major differences in physicochemical and pharmacological properties compared with their reference biological but may be presented to prescribers based on clinical trial data and claimed clinical equivalence. Tenecteplase (TNK-tpA) is a recombinant derivative of tissue plasminogen activator, used as a third-generation thrombolytic agent for treatment of acute myocardial infarction. A TNK-tPA presented as biosimilar to the originator (Metalyse®, Boehringer Ingelheim; TNKase®, Roche/Genentech) is now available for use in India (Elaxim®, Gennova Pharmaceuticals). Elaxim® is not approved in Europe or the USA but has been proposed in several countries as a replacement for the originator. Based on available literature, we discuss why this biocopy cannot be considered biosimilar to the originator tenecteplase. We describe clear differences in physicochemical and pharmacological properties. For example, the biocopy demonstrates clot lysis activity that is substantially lower than the originator and contains high concentrations of foreign proteins that confer potential for immunological reactions. Clinical data on the biocopy are limited; randomized trials to demonstrate the absence of difference in efficacy and safety between the biocopy and originator have not been conducted. This example demonstrates that confirmation of similarity, by close examination of pharmaceutical quality attributes, and preclinical and clinical data, is mandatory before presenting to prescribers a biological product as clinically equivalent.
