AstraZeneca, Mylan and others want more from FDA in generic patch guidance

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Several companies in the generic topical patch space have chimed in on a May draft guidance from the FDA that was meant to make data on those patches’ adhesion properties easier to use. And they feel the administration fell short.

Four companies stood in the face of the guidance: Mylan, Perrigo, Astrazeneca and Apotex, the Regulatory Affairs Professionals Society (RAPS) reported. They each had specific improvements in mind to the way the FDA would regulate generic results and requirements for patch adhesion.

Back in the original guidance, the FDA sought to clarify the expectations for patches that stick to the skin to ensure that the correct dosing was achieved. It said at the time, “It is expected that the entire surface of a TDS should remain consistently and uniformly adhered to the skin throughout the duration of wear under the conditions of use included in the product label.”

While RAPS wrote that the companies “appreciate” the FDA’s approach, each contested various parts of the evaluation method. Mylan, for instance, noted that the FDA’s consistent margin of adhesiveness for all drugs was too restrictive when it came to drugs of a certain reference score. It would put a patch at a distinct disadvantage in proving noninferiority due to the raised bar.

Perrigo’s was more straightforward: The company took issue with the FDA guidance on photographs to document adhesion. Perrigo said photographs would contain too many variables and would be of inferior quantitative value. They called it an “unnecessary and excessive burden.”

And AstraZeneca was concerned with where these regulations would be applicable down the road, as new transdermal systems come into place, like iontophoresis, microneedles, poration or ablation, among others. Finally, Apotex hoped everyone would be held to the same standards, including those whose studies were conducted before the guidance was released.

Overall, the companies want further details from the FDA as it strives to make these products more user-friendly. As Perrigo recommended, the FDA should “add language to clarify that adhesion assessment studies may be run in a clinical setting and where feasible allow subjects to freely conduct daily activities and to simulate real-world conditions.”

- here's the RAPS report
- and the May FDA guidance

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