Question About Accelerated Stability Study

The Question posed on LinkedIn:

My question is: Does stability data generated on the drug product cover the stability requirement for this test article with elevated impurity level, or does this test article have to be tested for stability separately? Pl note that the impurity level, although at an elevated level, is still within the established specification for the drug product

My reply was this:

Hi Vich.

If the drugs is within release spec, an ‘elevated’ impurity level could be considered a worse case condition for the study but it is still in spec. If the stability testing passes, you’d be able to show with impurities at the upper level, the product’s efficacy and physical properties remain unaffected at least until product expiry.

ICH Q1A should prove useful: https://www.ema.europa.eu/en/documents/scientific-guideline/ich-q-1-r2-stability-testing-new-drug-substances-products-step-5_en.pdf