Pharmacovigilance of biosimilars - Why is it different from generics and innovator biologics?

Biosimilars are being marketed in India since 2000. Like biologics, biosimilars have a large size, complex structure, and complicated manufacturing process, and they are produced in a living organism. It requires specialized delivery devices for administration and needs tighter temperature control to prevent degradation. As biosimilar development follows abbreviated pathway, adverse events (AEs) previously unknown during a clinical trial may be detected postmarketing. In India, the awareness on pharmacovigilance has increased significantly after implementation of the pharmacovigilance guidance in January 2018. However, biologics require tighter monitoring to ensure their safety and efficacy. This review article discusses the importance of pharmacovigilance for biosimilars, how it is different from generics, and provides recommendations to sensitize clinicians and researchers about the requirement of a different approach to improve pharmacovigilance for biosimilars. Pharmacovigilance for biosimilars is as important as it is for innovator biologics and more important than that for generics.

Haemoglobinuria is associated with chronic kidney disease and its progression in patients with sickle cell anaemia

To evaluate the association between haemoglobinuria and chronic kidney disease (CKD) in sickle cell anaemia (SCA), we analysed 356 adult haemoglobin SS or Sβ(o) thalassaemia patients from the University of Illinois at Chicago (UIC) and 439 from the multi-centre Walk-Treatment of Pulmonary Hypertension and Sickle Cell Disease with Sildenafil Therapy (Walk-PHaSST) cohort. CKD was classified according to National Kidney Foundation Kidney Disease Outcomes Quality Initiatives guidelines. Haemoglobinuria, defined as positive haem on urine dipstick with absent red blood cells on microscopy, was confirmed by enzyme-linked immunosorbent assay in a subset of patients. The prevalence of CKD was 58% in the UIC cohort and 54% in the Walk-PHaSST cohort, and haemoglobinuria was observed in 36% and 20% of the patients, respectively. Pathway analysis in both cohorts indicated an independent association of lactate dehydrogenase with haemoglobinuria and, in turn, independent associations of haemoglobinuria and age with CKD (P < 0·0001). After a median of 32 months of follow-up in the UIC cohort, haemoglobinuria was associated with progression of CKD [halving of estimated glomerular filtration rate or requirement for dialysis; Hazard ratio (HR) 13·9, 95% confidence interval (CI) 1·7-113·2, P = 0·0012] and increasing albuminuria (HR 3·1, 95% CI: 1·3-7·7; logrank P = 0·0035). In conclusion haemoglobinuria is common in SCA and is associated with CKD, consistent with a role for intravascular haemolysis in the pathogenesis of renal dysfunction in SCA.

Standard clinical practice underestimates the role and significance of erythropoietin deficiency in sickle cell disease

In sickle cell disease (SCD), vigorous reticulocytosis is required to partially compensate for chronic hemolytic anaemia. Consequently, early renal damage, insufficient to cause azotemia but sufficient to cause erythropoietin deficiency and chronic relative reticulocytopenia (chRR), could have severe clinical consequences. chRR was defined as reticulocytes <250×10(9) /l despite haemoglobin <9 g/dl on ≥ two occasions ≥4 weeks apart. The influence of multiple variables including chRR on time from first clinic visit to death was evaluated in 306 SCD patients. In univariate analyses, fetal haemoglobin, indices of renal damage (serum creatinine, proteinuria), chRR and age, were associated with rate of death. In multivariate analysis, only age and chRR (Hazard ratio 3·6, 95% CI 2·049-6·327, P<0·0001) were significant, underlining that chRR could be an early and important clinical consequence of renal damage. Even in chRR patients with normal serum creatinine levels, low haemoglobin and low reticulocyte counts were associated with low erythropoietin levels. In the general population, evaluation of erythropoietin levels is prompted by the combination of anaemia and abnormal serum creatinine. In SCD patients, this standard approach can miss a substantial risk factor for early death. chRR could be a practical and important criterion for diagnosis of erythropoietin deficiency in SCD.