Regulatory Open Forum

​​Hi there,

Is anyone able to assist in advising the typical/standard regulatory pathway to register a new route of administration/new dosage form (via PK bridge) of a company's own product in the US (also known as a line extension)? There are very standard regulatory pathways in most territories around the world, but I am struggling when it comes to the US.

Would this be submitted via the 505(b)(1) route or 505(b)(2)? The data package would bridge to the original approved product (so an abridged data set), but is this eligible for the 505(b)(2) route if the referenced data is all owned by the same company (505(b)(2) guidance refers to referencing data not owned by the applicant).

To further complicate matters, what if the original product was approved itself via a 505(b)(2) application? For example:

- Company X submits a 505(b)(2) application to register Product A. The 505(b)(2) uses RLD 1 (of Company Y). The NDA is approved.
- Company X now wishes to register Product B, a new dosage form/new route of admin of Product A. Product B is scientifically bridged to Product A through PK data.

Would Company X:
a) submit a 505(b)(1) NDA to register Product B, because the safety and efficacy data being referenced is their own (Product A)? Can a 505(b)(1) NDA comprise only a PK bridge (i.e. not two adequate and well-controlled efficacy studies)?

OR
2) submit a 505(b)(2) NDA to register Product B, referencing Product A as their RLD, despite this being a reference to their own data?

Furthermore, in the case of option (2), because Product A was itself registered via 505(b)(2) against RLD 1 (of Company Y), would this then mean that the 505(b)(2) NDA to register Product B, is really circling around to also reference the RLD of Product A, i.e. RLD of Product B is RLD 1 of Company Y, because that was the RLD of Product A, and Product B is bridged to Product A?

Any advice would be greatly appreciated. Many thanks in advance.