Evaluation of Biologic Efficacy and Cost per NNT in Moderate-to-Severe Psoriasis: Indian Analysis

Introduction

A recent study has identified ixekizumab and ustekinumab as the most cost-effective biologic treatments for achieving Psoriasis Area and Severity Index (PASI)100 and PASI90 responses in patients with moderate-to-severe plaque psoriasis (PsO). This analysis utilized a cost per number needed to treat (NNT) approach, shedding light on the financial implications of these therapies.

Study Overview

Published in August 2025 in the Indian Journal of Dermatology, Venereology and Leprology, the study emphasizes how the cost per NNT data can aid procurement agencies and dermatologists in estimating treatment costs for patients both in the short and long term.

Impact of Plaque Psoriasis

Plaque psoriasis, the most prevalent form of psoriasis, affects approximately 80% of patients and significantly diminishes quality of life (QoL). The advent of biologics has revolutionized the treatment of moderate-to-severe PsO, with new agents providing quick clearance of skin lesions and achieving high PASI 75, 90, and 100 responses. They also lead to significant improvements in the Dermatology Life Quality Index (DLQI) compared to traditional therapies. However, the high cost of biologics poses a significant challenge for Indian dermatologists when prescribing these treatments. A cost-efficacy comparison tool could enhance clinical decision-making.

Methodology

The study aimed to evaluate the relative efficacy and costs of biologic therapies approved or available in India for moderate-to-severe PsO. The analysis employed cost per NNT, derived from a network meta-analysis (NMA), a validated method that integrates both direct and indirect evidence to compare various drugs and generate comparative efficacy estimates.

Biologics Evaluated

The study assessed several biologics, including IL-17A inhibitors (ixekizumab and secukinumab), TNF inhibitors (adalimumab, etanercept, and infliximab), and the anti-IL-12/23 agent (ustekinumab). The analysis focused on multiple time points: 12 weeks (induction therapy), 24 weeks, 52 weeks (1 year), and 104 weeks (2 years) after therapy initiation.

Dosing and Cost Calculation

Dosing schedules for each biologic were based on approved guidelines. The cost of biologics was determined by calculating the number of doses needed up to each time point, multiplied by the maximum retail price (MRP) of the drug in India as of September 2024. The NNT indicates how many patients must be treated with a biologic to achieve one additional PASI90 or PASI100 response compared with a placebo.

NNT Calculation

The NNT was calculated using the formula:
NNT = 1 / (probability of response with biologic − probability of response with placebo).
The cost per NNT was derived by multiplying the NNT of each drug by the corresponding treatment cost.

Key Findings

The study revealed several critical findings:

Cost of Biologics per NNT for PASI100 Response

Ixekizumab exhibited the lowest NNT based on MRP for achieving PASI100 at all assessed time points, followed closely by ustekinumab. The cost advantage of ixekizumab over ustekinumab was noted to be 14% at 12 weeks, 24.4% at 24 weeks, 12% at 1 year, and 3.7% at 2 years. Over the entire 2-year period, ixekizumab maintained a cumulative cost per NNT advantage of 9% over ustekinumab. Etanercept presented the highest cost per NNT across all time points.

Cost of Biologics per NNT for PASI90 Response

Ustekinumab demonstrated the lowest cost per NNT for PASI90 responses across all time points, with ixekizumab following. Notably, etanercept consistently recorded the highest cost per NNT.

Considerations

It is important to note that the study did not evaluate data for patients weighing 100 kg or more. Additionally, administration costs were excluded, particularly pertinent for infliximab due to its intravenous delivery. Fluctuations in biologic prices influenced by market dynamics, brand pricing, and the availability of biosimilars may affect overall cost estimates.

Conclusion

The findings from this analysis provide valuable insights for dermatologists and procurement agencies in India, enhancing understanding of the cost-effectiveness of biologic treatments for moderate-to-severe psoriasis and aiding in informed clinical decision-making.

Reference

Sardana K, Neema S, Sapra D, Jagadeesan S, Muddebihal A, KB Rakesh, et al. A comparison of anti-IL-17A, anti-TNF, and anti-IL-12/23 biologics for moderate-to-severe plaque psoriasis in India, based on cost per NNT and its effect on the therapeutic landscape and outcome. Indian J Dermatol Venereol Leprol. doi: 10.25259/IJDVL_311_2025.

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