Impurezas no mutagénicas

Do you need to qualify a non-mutagenic impurity above the ICH Q3A or Q3B qualification threshold?

When a non-mutagenic, or non-genotoxic impurity (NGI), exceeds the relevant qualification threshold, additional evidence may be needed to demonstrate that exposure at the observed level is toxicologically acceptable. We can assess the available evidence and product context to help determine the most appropriate route to qualification.

Could your impurity be qualified using existing evidence?

Before progressing to more complex assessments, existing information may provide a route to qualification. For example, an impurity may be a significant metabolite of the API or sufficiently comparable to the API to support a toxicological justification. We can evaluate the available evidence, including exposure and safety considerations, to determine whether it can support qualification.

Do you need a scientifically justified read-across assessment?

Where direct toxicological data are limited, read-across may provide an appropriate route to qualification. We can identify potential surrogate compounds and assess their structural, biological and toxicological relevance to determine whether they can support your impurity assessment. We will provide a clear expert justification for analogue selection and its use within the wider weight of evidence.

Could computational approaches or New Approach Methodologies (NAMs) strengthen your assessment?

Where existing evidence does not provide a clear answer, computational approaches can provide additional information on relevant toxicity endpoints. We can interpret in silico evidence alongside exposure, experimental data and other available information to strengthen a proportionate, evidence-based qualification strategy.

Do you need to bring the evidence together into a clear weight-of-evidence (WoE) justification?

Individual pieces of evidence need to be interpreted in the context of the impurity, exposure and overall safety profile. We can bring the available evidence together into a transparent WoE assessment, identifying any remaining gaps and providing a clear scientific rationale to support your qualification decision.

Is your residual solvent not covered by ICH Q3C?

Not every solvent used in pharmaceutical development or manufacture has an established permitted daily exposure (PDE) in ICH Q3C. Where no recognised limit is available, we can assess the available toxicological evidence and determine the most appropriate approach for establishing a scientifically justified exposure limit.

Do you need to establish a PDE for your residual solvent?

Where sufficient toxicological data are available, we can identify the critical effects and appropriate point of departure and use these to derive a PDE for your solvent. This provides a clear toxicological basis for assessing whether the proposed level of exposure is acceptable.

What if there is not enough data to derive a solvent-specific PDE?

Limited data do not necessarily mean the assessment has to stop. Where appropriate, we can identify suitable surrogate compounds and use read-across to determine whether existing toxicological evidence can support an acceptable exposure level for your solvent.

Do you need help applying the derived limit within your risk assessment?

We can help interpret the outcome of the toxicological assessment, explain the basis for the proposed limit and support how it is applied within your wider risk assessment and regulatory justification.

Do you need to assess the risk of elemental impurities in your drug product?

Elemental impurities can enter a drug product from multiple sources, including raw materials, excipients, manufacturing equipment and container closure systems. We can help you identify relevant sources, assess their potential contribution and evaluate the overall risk in line with ICH Q3D.

Are you unsure whether the level of an elemental impurity is acceptable?

We can evaluate estimated or measured exposure against the relevant permitted daily exposure (PDE), taking account of the route of administration and contributions from different components of the drug product. This can help determine which elemental impurities require further consideration and whether additional controls may be needed.

Do you need to determine whether additional controls are required?

Not every identified source of an elemental impurity requires additional control. We can interpret the available data and overall risk assessment to help determine whether existing controls are sufficient or whether further monitoring, specification or other measures should be considered.

Do you need support developing and justifying an elemental impurity control strategy?

Where additional controls are appropriate, we can help develop a proportionate control strategy based on the identified sources, estimated or measured exposure and existing manufacturing controls. We can bring the evidence together into a clear scientific justification for the proposed approach, supporting your wider risk assessment and regulatory documentation.

Do you need to derive or assess a health-based exposure limit (HBEL)?

Where an appropriate exposure limit is not already available, we can review the toxicological evidence and help derive or assess values such as occupational exposure limits (OELs) or other HBELs, depending on the intended use and exposure scenario.

Are you unsure whether the selected point of departure and calculation approach are appropriate?

The choice of point of departure can have a significant influence on the resulting limit. We can review the critical toxicological effects, study selection, adjustment factors and calculation approach to determine whether the proposed derivation is scientifically appropriate and proportionate.

Do you need a clear scientific and regulatory justification for the selected limit?

A defensible HBEL requires more than a final numerical value. We can bring together the relevant toxicological evidence, explain the basis for key decisions and provide a transparent rationale for the selected limit to support internal review and regulatory documentation.

Do you need support responding to comments or finalising your assessment?

Questions can arise as an assessment moves through internal, customer or regulatory review. We can help address scientific comments, revise the assessment where appropriate and ensure the final report clearly explains the evidence, assumptions and rationale behind the resulting exposure limit.

Do you need to understand carcinogenicity risk earlier in development?

Carcinogenicity risk may need to be considered before the full non-clinical package is available. Early assessment gives you a clearer view of what is already known, what is uncertain and what evidence may be needed as the programme progresses. We review available in vitro data, computational toxicology predictions and relevant literature to provide an early scientific view on potential carcinogenicity concerns and the next steps to consider.

Has an unexpected or borderline finding raised a carcinogenicity question?

Not every finding that raises concern will indicate a meaningful carcinogenic risk. Borderline, unexpected or difficult-to-interpret results need to be assessed quickly so they do not delay decisions or drive unnecessary follow-up work. We review the finding in context, assess whether it is biologically meaningful and explain what weight it should carry in the wider carcinogenicity assessment.

Could your API’s target or off-target activity plausibly contribute to cancer risk?

Carcinogenicity risk may be linked to the primary biological target, secondary pharmacology or other biological activity. These signals need to be interpreted in the context of target function, pathway relevance, cancer biology and available supporting evidence. We review target-related evidence, off-target activity, computational predictions and relevant literature to assess whether a plausible carcinogenic mode of action is supported and how this evidence contributes to the wider assessment.

Do your genotoxicity or other study findings need explaining in a human-relevant context?

Genotoxicity, repeat-dose toxicity, histopathology, hormonal activity or immune modulation findings can raise questions about carcinogenic potential. These findings are not always straightforward to interpret, particularly when their relevance to humans is uncertain. We assess whether the findings support a potential carcinogenic mechanism, how they fit with the wider evidence package and whether further clarification is needed, so the significance of the finding is understood rather than treated in isolation.

Do you need to justify your carcinogenicity testing strategy with a clear weight-of-evidence rationale?

Under ICH S1B(R1), a weight-of-evidence approach can support decisions on whether further carcinogenicity testing, including a 2-year rat carcinogenicity study, is scientifically justified. This requires a clear explanation of what the evidence shows, how uncertainty has been handled and why the conclusion is appropriate. We bring together biological, toxicological, computational, and literature-based evidence into a structured carcinogenicity weight-of-evidence narrative, with an expert rationale that explains the conclusion, confidence in the evidence, human relevance, and recommended next steps.