Biosimilar Denosumab in Osteoporotic Patients Attending a Tertiary Care Hospital of Eastern India: A Real-world Comparative Retrospective Observational Study

Denosumab, a monoclonal antibody directed against RANK-Ligand, inhibits the formation, function, and survival of osteoclasts, leading to the inhibition of bone resorption, resulting in increased bone mass and prevention of fractures. Despite the availability of biosimilar denosumab in India for more than 5 years, Real-world Evidence (RWE) on the control of disease severity, tolerability, and safety of these biosimilars is lacking.

This analysis is intended to compare the in-clinic effectiveness and safety of the Indian drug authority-approved denosumab biosimilar (Intas-Pharma) with the innovator denosumab.

Data of osteoporotic patients receiving either innovator denosumab or biosimilar denosumab (60mg SC every 6 months) for 2 years in routine clinical practice as per patient choice were evaluated. Effectiveness was measured based on the change in Lumbar spine (LS-TS) and Total Hip T scores (HIP-TS). Student t-test was carried out to evaluate intragroup change in T-scores at both sites and compare inter-group T-scores at baseline, as well as after 2 years of denosumab treatment at both sites. Adverse events reported in both groups were noted.

A total of 49 osteoporotic patients receiving denosumab (n=28 biosimilar denosumab, n=21 innovator denosumab) were evaluated. All patients received concomitant vitamin D and calcium throughout the study duration.

The mean LS-TS values for the innovator and biosimilar groups at baseline were -3.85±0.20 and -3.82±0.21, respectively, while the mean HIP-TS values for the innovator and biosimilar group at baseline were -3.60±0.22 and -3.57±0.21, respectively. Both groups were comparable at baseline, and there was no significant difference between the two groups in terms of T scores at both sites. After 2 years of denosumab treatment, mean LS-TS values for the innovator and biosimilar groups reached -2.82±0.26 and -2.74±0.25, respectively, while the mean HIP-TS values for the innovator and biosimilar group were recorded to be -2.41±0.27 and -2.40±0.24, respectively. When post-treatment T scores were compared, there was no significant difference between the two groups at any of the sites.

When an intra-group change in T scores from baseline over 2 years was evaluated, both innovator and biosimilar denosumab groups were observed to have significant improvement (p<0.0001) in mean LS-TS as well as HIP-TS values. No severe adverse effects were noted in any group, and the safety profile of both groups was comparable.

Biosimilar denosumab was found to be as effective as innovator denosumab in increasing bone mineral density at the lumbar spine as well as total hip among osteoporotic patients attending Indian rheumatology clinics.