Dive Brief:

• FDA has finalized its guidance on 510(k) submissions for metal expandable biliary stents after reviewing feedback from Boston Scientific and Cook Medical.

• The final guidance hews closely to the draft released for consultation last year, despite device companies calling for a variety of changes to the text.

• FDA opted against making many of the suggested changes, resulting in guidance that differs from what industry proposed.

Dive Insight:

FDA created the guidance to provide advice to developers of metal expandable stents for use in the palliative care of patients with malignant strictures in the biliary tree. The guidance details the tests stent developers should perform before seeking clearance via the 510(k) pathway.

Responding to the 2018 draft, Cook, which sells the Zilver biliary stent, identified several changes it wanted FDA to make. Cook asked FDA to rewrite an entire background section, delete a statement that metal expandable biliary stents cannot use the Special 510(k) Program, and expand the scope to cover the use of devices outside of palliative contexts. FDA didn't make any of those changes.

Those three examples are some of the many of Cook's suggestions that didn't make it into the FDA final text. For example, Cook called FDA’s recommendation that biocompatibility tests use chronic toxicity and implantation as endpoints “excessive.” Nonetheless, the recommendation appears in the final guidance. 

FDA was more amenable to other changes Cook proposed. Cook called for the deletion of a statement about the value of additional biocompatibility testing in certain circumstances, arguing that "it is not possible to know if there are 'differences in formulation, processing, sterilization, or device surface properties' between the Subject Device and the Predicate Device owned by another Sponsor." FDA removed the statement from the final guidance.  

Boston Scientific made fewer suggested changes than Cook and FDA adopted more of its suggestions into the final text. Many of the changes made in response to feedback from Boston Scientific were small and technical, such as the clarification that companies can use media other than a 37 °C saline bath to thermally equilibrate test samples.

The final guidance supersedes a text adopted in 1998, giving developers of metal expandable biliary stents a more up-to-date set of recommendations to guide their 510(k) submissions.