Biosimilars in India: What Prescribers Should Know Before Substituting
Biosimilars now account for a meaningful share of India’s biologics market, with more than a hundred approved for domestic and export use, spanning oncology, diabetes, and autoimmune disease treatment. Yet the single most important fact for a prescriber to know is one that surprises many: India has no formal legal concept of interchangeability for biosimilars, and no framework requiring or even permitting automatic substitution the way generic drugs are substituted at the pharmacy counter.
A Biosimilar Is Not a Generic
Unlike a small-molecule generic, which is chemically identical to its reference drug and can be verified through straightforward bioequivalence testing, a biosimilar is a large, structurally complex protein manufactured in living cells. Because biological molecules are sensitive to even small manufacturing variations, a biosimilar can never be proven chemically identical to its reference biologic, only highly similar with no clinically meaningful difference in safety or efficacy.
This distinction is why biosimilar approval in India, governed jointly by CDSCO, the Department of Biotechnology, and the Review Committee on Genetic Manipulation, requires a dedicated comparability exercise covering quality, non-clinical, and clinical data, rather than the simpler bioequivalence pathway used for chemical generics.
Why Substitution Decisions Fall Entirely on the Prescriber
India’s biosimilar guidelines, first issued in 2012 and revised in 2016, are silent on interchangeability and automatic substitution. There is no legal framework requiring prescribers, pharmacists, or hospitals to treat an approved biosimilar as automatically substitutable for its reference product, unlike jurisdictions that have introduced formal interchangeability designations for specific biosimilars.
In practice, this means every decision to switch a patient from a reference biologic to a biosimilar, or between different biosimilars of the same reference product, rests on individual clinical judgement, informed by institutional formulary listings, cost considerations, and the prescriber’s own assessment of the available comparability data, rather than any regulatory presumption of interchangeability.
What the 2025 Draft Guidelines Change
CDSCO’s 2025 Draft Guidelines on Similar Biologics mark a notable shift toward global harmonisation with the frameworks used by the US FDA, the European Medicines Agency, and the UK’s MHRA. The revised approach places greater weight on analytical and pharmacokinetic comparability data and moves away from mandating large clinical efficacy trials in every case, aligning with international practice that treats a strong analytical and PK/PD comparability package as sufficient evidence when it convincingly rules out clinically meaningful differences.
The draft also refines expectations around immunogenicity assessment for higher-risk biologic classes such as monoclonal antibodies, and clarifies extrapolation rules that determine whether a biosimilar approved for one indication of the reference product can be extended to other indications based on shared mechanism of action rather than requiring separate trials for each.
What This Means for Prescribing Practice
Because there is no automatic substitution framework, a prescriber switching a stable patient from a reference biologic to a biosimilar, or between biosimilars, should treat it as a distinct clinical decision requiring its own informed consent discussion, not an administrative or pharmacy-level swap. This is particularly relevant for patients on long-term biologic therapy for conditions like rheumatoid arthritis, inflammatory bowel disease, or certain cancers, where treatment continuity and immunogenicity risk are genuine clinical considerations.
Prescribers evaluating a new biosimilar should check that its approval was based on a full comparability dossier against the same reference product being replaced, since India permits biosimilars to be developed against reference products sourced from multiple regulatory jurisdictions, which can complicate direct comparison between two biosimilars of the same molecule that were each compared to a different reference product.
Conclusion
Biosimilars offer genuine cost advantages in India’s biologics market, but the absence of a legal interchangeability framework means the clinical responsibility for every substitution decision sits squarely with the prescriber. Staying current with CDSCO’s evolving 2025 guidelines, and documenting the clinical basis for any switch, remains the safest practice until India eventually develops a formal interchangeability designation of its own.
Researched Resources
1. BioRationality: The Revised Indian Biosimilar Guidelines Finally Bring Rationality
2. The Biosimilar Market in India: Regulatory Landscape
3. How to Obtain CDSCO Approval for Biosimilars in India (2026 Guide)
4. India’s biosimilar reform and the global shift away from routine efficacy trials
Disclaimer: This article is for general informational and educational purposes and reflects CDSCO’s biosimilar regulatory framework as understood at the time of writing; the 2025 draft guidelines remain subject to change before finalisation. It is not clinical or regulatory advice, and prescribers should consult current CDSCO notifications and institutional formulary guidance before making a biosimilar substitution decision.
Vivek Chaudhary is a Technical Content Developer specializing in healthcare, health technology, and digital healthcare business solutions. He creates research-driven, SEO-focused content for doctors, clinics, hospitals, healthcare professionals, and patients, covering topics such as healthcare technology, patient engagement, clinic management, digital communication, and online visibility.
