Institute for Cardiology and Cardiovascular Surgery
Calle 17 y A
Vedado
Havana, Cuba
Tel: +53 7 8307250
Fax: +53 7 8344435
E-mail address: dircardio{at}infomed.sld.cu
Institute for Cardiology and Cardiovascular Surgery
Calle 17 y A
Vedado
Havana, Cuba
Tel: +53 7 8307250
Fax: +53 7 8344435
Center for Biological Research
Clinical Trials Division
Havana, Cuba
In the study of Hermentin et al.,1 a significant discrepancy between claimed and measured streptokinase (SK) activity of various tested products was found in addition to other physicochemical differences. However, it is difficult to interpret the results as they analysed only one sample of most products, and in some cases even from only one batch. The authors also raise the matter of the relationship between their data and clinical performance, but this kind of statement should be backed up by evidence from clinical trials and pharmacovigilance studies.
In this respect, we wish to report that there is enough clinical experience with one of the recombinant SKs mentioned in the paper (Heberkinasa). First, coronary patency (TIMI 2 and 3) was achieved in 14/20 (70%) acute myocardial infarction (AMI) patients after intracoronary administration of this product. Then clinical studies were performed in AMI patients treated with intravenous 1.5x106 IU of recombinant SK. A randomized trial in 224 patients2 compared it to the same reference product used by Hermentin et al.1 (natural SK: streptase). Similar results were obtained with respect to coronary patency, changes in haemostasis, and safety profile. Additionally, anti-SK antibody titres and their anti-SK neutralizing activities in serum were not only comparable between both groups, but also crossreacting, which shows that the small differences in structure do not seem to have clinical or immunological repercussions.3 A national extension study in 2923 AMI patients from 52 hospitals throughout Cuba evaluated Heberkinasa in clinical practice.4 A 28.3% relative and 4% absolute lethality reduction was found when compared with a survey made before recombinant SK treatment was introduced. Intracraneal haemorrhage was only reported in nine (0.3%) patients. Further use of this treatment in the country has been monitored by a pharmacovigilance system, where a similar post-marketing safety profile to those suggested in clinical trials was observed (manuscript in preparation). At present its pre-hospital use in Cuba is being extended as a national program to improve survival through a shorter symptom-needle period. A recent study with this recombinant SK in an albumin-free formulation suggested that its intravenous administration is a safe and appropriate therapy to get early (90 min) coronary patency in patients with AMI.5 The product has been successfully used in other applications of thrombolysis such as heart valve prosthesis thrombosis.6 Therefore, we can conclude that this product is clinically useful, which contrasts from what could be inferred from the report of Hermentin et al.1
References
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