Pharmacologic reperfusion therapy with indigenous tenecteplase in 15,222 patients with ST elevation myocardial infarction - the Indian Registry

Biosimilarity. Do not confuse biosimilar and biocopy. Example of tenecteplase

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.

Evaluation of the tolerability and effectiveness of Tenecteplase in patients with ST-Segment-Elevation Myocardial Infarction in a Secondary Hospital in Malaysia: A Retrospective Case Series

Background

In Malaysia, knowledge regarding the clinical efficacy of tenecteplase (TNK), a fibrin-specific tissue-plasminogen activator, is limited.

Objectives

To evaluate the effectiveness and tolerability of TNK in patients with ST-segment-elevation myocardial infarction in a secondary referral Malaysian hospital.

Methods

This was a single-center retrospective case series based on the medical records of patients with ST-segment-elevation myocardial infarction admitted to the cardiac care unit between January 2016 and May 2019. Data regarding the mortality status and date of death were collected from the database of the National Registration Department of Malaysia.

Results

Data for 30 patients with ST-segment-elevation myocardial infarction, who received weight-adjusted doses of TNK, were analyzed. The patients’ mean (SD) age was 62 (14) years, and 77% were men. The median time to treatment was 265 minutes (interquartile range = 228–660 minutes), and the clinical success rate of thrombolysis was 79%. The overall all-cause in-hospital mortality rate was 33%. The 1-year survival rates were higher in patients achieving a time to treatment ≤360 minutes (P = 0.03), with a trend toward greater survival in this group at 30 days. Similarly, a trend toward lower in-hospital all-cause mortality was observed in this group (21% vs 50%; P = 0.12). Only 1 patient (3%), who had a HAS-BLED score based on hypertension, abnormal liver/renal function, stroke history, bleeding history or predisposition, labile international normalized ratio, old age, drug/alcohol use of 5, developed major bleeding that required blood transfusion. No cases of ischemic stroke, nonmajor bleeding, in-hospital reinfarction, or TNK-induced allergic reaction were identified.

Conclusions

We hypothesized that the mortality-related outcomes of TNK in patients with ST-segment-elevation myocardial infarction were influenced by TTT, with TTT ≤360 minutes indicating a better prognosis than TTT >360 minutes. TNK-induced bleeding-related complications were minimal in low-risk patients. Further local studies are needed to compare TNK's profile with that of streptokinase, which is a common agent currently used in clinical practice in Malaysian public hospitals. (Curr Ther Res Clin Exp. 2021; 82:XXX–XXX)

Comparison of clot lysis activity and biochemical properties of originator tenecteplase (Metalyse(®)) with those of an alleged biosimilar

The bioengineered tissue plasminogen activator tenecteplase is an important treatment modality of acute myocardial infarction recommended by international guidelines. Following introduction of originator tenecteplase (brand names Metalyse^® and TNKase^®), a “biosimilar” tenecteplase became available for commercial use in India under the brand name Elaxim^® in the absence of Indian biosimilar guidelines which came into force from September 15th, 2012. Based on a report of biochemical and fibrinolytical differences between Metalyse and Elaxim, we have systematically compared them in a range of routine quality testing assays. As compared to Metalyse, Elaxim exhibited less clot lysis activity and contained less of the two-chain form of tenecteplase. Even upon full in vitro conversion to the two-chain form Elaxim exhibited less clot lysis activity. This was linked to differences in sialic acid content and glycosylation pattern with Elaxim exhibiting less bi- and more tetra-antennary glycosylation, leading to a different charge heterogeneity profile. Regarding purity, Elaxim contained more tenecteplase aggregates and, in contrast to Metalyse, considerable amounts of Chinese hamster ovary cell protein. Taken together these data demonstrate that Metalyse and Elaxim differ considerably in clot lysis activity and biochemical properties. These data question whether Elaxim indeed can be considered a “biosimilar” of Metalyse, i.e., whether and to which extent the clinical efficacy and safety properties of Metalyse can be extrapolated to Elaxim in the absence of comparative clinical data.