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# Purdue Wants Restrictions on Butrans Follow-ons
- URL: https://www.fdaweb.com/purdue-wants-restrictions-on-butrans-follow-ons/
- Published: 2016-10-18T12:00:00.000Z
- Updated: 2026-09-14T21:40:36.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5137100

Purdue Pharma is petitioning FDA to ensure that applications for approval of follow-on products citing its Butrans (buprenorphine) transdermal system as the reference-listed drug are supported by pharmacokinetic data establishing equivalent buprenorphine exposure over the entire seven-day dosing interval. “Absent such data,” the [petition](https://www.regulations.gov/contentStreamer?documentId=FDA-2016-P-3313-0001&attachmentNumber=1&disposition=attachment&contentType=pdf&ref=fdaweb.com) says, “there would be no basis for the agency to rely upon its previous findings of safety and efficacy for Butrans and, correspondingly, no basis to conclude that a follow-on product would provide the same clinical effect as Butrans.” Butrans is indicated for managing pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate.

Specifically, the petition asks that FDA for any 505(j) or 505(b) application:

- apply bioequivalence criteria for partial area under the curve during each of the last three days of the seven-day dosing interval to ensure similar systemic exposure to buprenorphine and hence similar clinical response between the test and reference formulations;
- assess adhesion in accordance with a 6/2016 draft guidance on assessing adhesion with transdermal delivery systems and topical patches for ANDAs and the recently revised 10/2016 draft bioequivalence guidance for buprenorphine transdermal system for seven-day transdermal administration; and
- carefully evaluate irritation and sensitization potential in accordance with the applicable draft bioequivalence guidance.

The petition also asks that FDA refuse to approve any ANDA submitted under section 505(j) or any other new drug product seeking approval by means of demonstrating bioequivalence that references Butrans unless and until the products meet the criteria specified by Purdue.