Are stability data from three current good manufacturing practice (CGMP) batches required to be filed in the DMF to support the API retest date? Also, how many months of long-term and accelerated data are required for pilot scale batches?

Yes. Per ICH Q1A(R2) data from formal stability studies should be provided
on at least three primary batches and the batches should be manufactured to a
minimum of pilot scale10 for the drug substance to be filed in the DMF. These
batches should be made under CGMPs. The FDA stability guidance
recommends 6 months of accelerated data and 6 months of long-term data for
the pilot scale batches to be submitted for a full scientific review of the DMF.
Additional long-term data for all three batches, as the data becomes available
through the proposed retest period, should be submitted as an amendment.