Bioequivalence and Bioavailability Forum

Hi Ben,

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❝ This is what came to my mind.

THX for the second opinion.

❝ ❝ Problematic in the Japanese population is the (age-dependent) high percentage of achlorohydric subjects. […]

❝ Oh, this is interesting. I was not aware of this phenomenon. Do you have a reference …

Mentioned at various conferences. Even by speakers of the Japanese agency. I’m a little bit stressed at the moment – maybe I can dig out some handouts. I’m sure you find sumfink im Zwischennetz.
This story is the reason why the Japanese agency does not accept BCS-based biowaivers. They think that the concept with three (sometimes four) pH-values is not suitable for them.
I was surprised when I heard for the first time that the ICH will come up with a guideline. Japan is a founding member of the ICH… In the meantime the GL is final.
Of course you find:

1.2. Scope
BCS-based biowaivers may be used to substantiate in vivo bioequivalence. Examples include comparison between products used during clinical development through commercialization, post-approval changes, and applications for generic drug products in accordance with regional regulations.

(my emphasis)

End of the story.

❝ … and/or an explanation why this is the case?

Genetics, Helicobacter pylori?

Morihara M, Aoyagi N, Kaniwa N, Kojima S, Ogata H. Assessment of Gastric Acidity of Japanese Subjects over the Last 15 Years. Biol. Pharm. Bull. 2001; 24(3): 313—5. doi:10.1248/bpb.24.313. Open access.

»[…] bioavailability and bioequivalence studies should be performed taking into consideration the effects of gastric acidity on in vivo performance of drug products.«