ICH Q5E: Comparability of Biotechnological/Biological Products

ICH Q5E provides the scientific framework for assessing whether a biotechnological or biological product remains highly similar before and after a manufacturing process change. For biologics, where “the process is the product,” even minor changes can alter critical quality attributes. The guideline sets out a comparability exercise—a structured, risk-based evaluation to show that a change has no adverse impact on quality, safety, or efficacy.

When successful, comparability can allow implementation of the change without repeating extensive non-clinical or clinical studies, relying instead on a robust quality comparison supported by targeted studies when needed.

Primarily applies to post-approval changes, but principles also apply during development if a manufacturing change occurs before licensure.
Core Principle

Comparability is determined from the totality of the evidence—a comprehensive, science-based evaluation integrating analytical, stability, and, where necessary, non-clinical or clinical data.

The Comparability Exercise

1. Analytical Foundation – Head-to-head testing of pre- and post-change material using:

• Physicochemical tests – Identity, purity, and primary/higher-order structure.

• Biological activity – a relevant potency bioassay (validated or suitably qualified, depending on stage)

• Impurity profiles – Product-related (aggregates, fragments, charge variants) and process-related (host cell proteins, DNA).

2. Comparative stability studies should be conducted under intended and, if appropriate, accelerated conditions.

3. Risk-Based Decision Framework

• The extent of additional data required falls on a continuum, guided by the degree and nature of observed differences.

4. Role of Risk Assessment – The scope of testing depends on the change’s potential impact on product quality (e.g., changing a host cell line is high risk).

Comparability vs. Biosimilarity

• Comparability (Q5E) – Same manufacturer, same product, post-change.

• Biosimilarity – Different manufacturer, new product, compared to reference.
  While scientific tools overlap, regulatory pathways, data requirements, and goals differ.

Comparability is a regulatory expectation for lifecycle management of the same product, not a separate approval pathway like biosimilarity.