Stability Testing of Generics: FDA publishes Q&A Document

In June 2013, the FDA published a "Guidance for Industry" entitled "ANDAs: Stability Testing of Drug Substances and Products" which describes the requirements on stability data needed in a marketing authorisation application for generic drugs (see our GMP News from 1st August 2013).
With regard to this Guidance, the FDA has recently published a Question & Answer document that should clarify outstanding issues. The document is entitled "Guidance for Industry; ANDAs: Stability Testing of Drug Substances and Products"; Questions and Answers" and tackles the questions which were sent to the FDA with the consulting period between September 2012 and June 2013.

Answers are provided to the questions regarding the stability of generics with regard to the following aspects:

• General requirements on stability data
• Stability data in the Drug Master File
• Stability and packaging: various dosage forms
• Amendments to pending ANDA applications

In the following, you can see the position of the FDA regarding certain stability issues illustrated by some examples:

• Question: When do intermediate stability studies need to be initiated in the event of failure at accelerated condition?
  Answer: We recommend starting intermediate stability, accelerated, and long-term studies at the same time so the data are available at the time of submission, if needed.
• Question: During the review cycle, will the application need to be updated with 12 months of long-term data?
  Answer: Yes. FDA will grant a proposed expiry period of two times the available long-term data at the time of approval, i.e. up to 24 months. This approach is due to the ICH Guideline Q1E "Evaluation of Stability Data" and the decision tree contained in Appendix A.
• Question: Is it acceptable to submit the stability data of only two pilot scale batches of the finished product of a simple dosage form?
  Answer: No. The requirements of the stability Guidance have to be fulfilled for all dosage forms.
• Question: When a patent is due to shortly expire and there are no approved ANDAs, can we file with 3 months stability data with a commitment to supply 6 months data when available?
  Answer: No. ICH stability guidances should be followed. 6 months of accelerated data are recommended at the time of filing the ANDA.

This Q&A document  itself has a "Draft Guidance" status. Comments regarding the document should be submitted to the eRulemaking programme.