Another Win for HCT/P Manufacturers: Court Vacates and Remands FDA’s AXIOFILL Determination

On September 21, 2026, the U.S. District Court for the Northern District of Georgia handed the regenerative medicine industry a significant win, vacating two key FDA determinations regarding MiMedx Group, Inc.’s wound-care product AXIOFILL. The decision, MiMedx Group, Inc. v. FDA, No. 1:24-cv-01287 (N.D. Ga. Sept. 21, 2026), addresses foundational questions about how FDA evaluates whether a human cell, tissue, and cellular and tissue-based product (HCT/P) is “minimally manipulated,” and whether the Agency can classify a product as a biological product when it has treated materially similar products as medical devices. Especially because FDA recently lost a similar case before a different district court, Vitti Labs, LLC v. FDA, No. 25-cv-011 (W.D. Mo. Mar. 18, 2026), motion to alter or amend judgment denied (Aug. 28, 2026), the ruling carries potentially broad implications for manufacturers of HCT/Ps, particularly those derived from placental tissue, as it would constrain FDA’s analytical framework and demand consistency in the Agency’s biologic vs. device classification decisions.

AXIOFILL is a dry powder made from extracellular matrix (ECM) isolated from donated human placental tissue, processed through soaking, rinsing, cutting, and grinding, and applied to wounds as a structural scaffold to support new cell growth. MiMedx submitted first a pre-request for designation (RFD) and then a formal RFD requesting classification of AXIOFILL as a “361 HCT/P” (a human cell/tissue product subject to less stringent regulatory requirements). Under FDA regulations, an HCT/P qualifies for the lighter-touch 361 HCT/P pathway only if it meets four criteria, including that it is “minimally manipulated” and intended for “homologous use.” See 21 C.F.R. § 1271.10. Importantly, 361 HCT/Ps are exempt from FDA’s premarket review requirements, and instead are regulated solely under section 361 of the Public Health Service Act and FDA’s 21 C.F.R. Part 1271 regulations.

FDA found that AXIOFILL failed the minimal manipulation criterion because its manufacturing process altered the placental disc’s original ability to function as a selective barrier between fetal and maternal circulatory systems, and separately, in a footnote, suggested AXIOFILL also did “not appear to meet” the homologous use criterion.  After receiving FDA’s initial pre-RFD response, MiMedx submitted its RFD which challenged FDA’s conclusion that AXIOFILL was not minimally manipulated, asserting that FDA focused on the “wrong unit of analysis” by evaluating the whole placental disk instead of considering whether the placental disk tissue ECM was minimally manipulated; and by looking only to the placental disc’s “selective barrier” function in the donor, rather than its “ECM function for structural support” relevant to its use in a recipient.  FDA held its course and in response to the RFD concluded that AXIOFILL failed the minimal manipulation criterion.  FDA further concluded AXIOFILL was a “biological product” because it is comprised of ECM proteins intended to treat injured skin through chemical action, rather than a device (which must not work through chemical action in the body).

MiMedx filed suit under the Administrative Procedure Act (APA) on March 25, 2024, arguing that FDA’s classification decision was arbitrary and capricious and contrary to law. It was undisputed that AXIOFILL is an HCT/P; the dispute was whether it should be classified as a 361 HCT/P, a biological product, or a medical device. In addition to challenging FDA’s “minimal manipulation” determination, MiMedx argued FDA’s biological-product classification was arbitrary because FDA had classified numerous similar ECM scaffold wound products as medical devices despite comparable composition and function.

Applying the Kisor v. Wilkie framework for reviewing an agency’s interpretation of its own regulations, the court held that the “minimal manipulation” analysis must start with the original, unprocessed placental disc tissue rather than the post-processed ECM, rejecting MiMedx’s argument that the isolated ECM was the correct unit of analysis. However, the court found FDA misapplied the “relevant characteristics” prong: it held that the regulation requires assessing whether original tissue characteristics “relevant . . . to the tissue’s utility for reconstruction, repair, or replacement” in the recipient —not solely its function in the donor, such as the placental barrier function—were preserved, and vacated and remanded FDA’s minimal-manipulation determination on that basis. In doing so, the court agreed with the Vitti Labs court that FDA cannot look only to whether a “relevant characteristic” of the donor tissue alone was altered (in that case, the umbilical cord’s function as a conduit for blood flow between a mother and fetus; and on which issue the court also vacated and remanded an FDA RFD decision).

On the homologous-use footnote, the court held that FDA’s brief, four-sentence footnote observation did not constitute “final agency action” reviewable under the APA, since it neither marked the consummation of the Agency’s decision-making nor determined legal rights, so that issue was not before the court.

On the device-versus-biologic question, the court found FDA classified AXIOFILL differently from materially similar ECM scaffold products that had been classified as medical devices, without providing a reasoned explanation or record evidence justifying the disparate treatment, rendering that determination arbitrary and capricious.

Therefore, the court vacated and remanded both FDA’s determination that AXIOFILL is not minimally manipulated and its determination that AXIOFILL is a biological product rather than a device, directing FDA to reconsider both issues consistent with the order.

If left undisturbed, the MiMedx decision marks a meaningful check on FDA’s discretion in classifying HCT/Ps. By requiring the Agency to evaluate “relevant characteristics” in terms of a tissue’s utility in the recipient rather than its original function in the donor, and by requiring FDA to explain its seemingly inconsistent treatment of materially similar ECM scaffold products, the court has significantly altered the analytical framework the Agency may use going forward. On remand, FDA must revisit both its minimal-manipulation finding and its biological-product classification in light of these constraints. (And while not required by the court, it is also possible that on remand FDA will attempt to formally apply the “homologous use” prong as a different avenue to finding AXIOFILL not to be a 361 HCT/P—something FDA did not do the first time around, but in its briefing telegraphed it may want to on the second try).

FDA has not yet indicated whether it will appeal this decision; it has two months from the decision to decide. FDA also has about a month left to decide whether to appeal the Missouri court’s similar Vitti Labs decision.

The upshot of these decisions is that they could herald a real expansion for products that fall under the 361 HCT/P framework, as FDA could no longer rely on a relatively narrow understanding of a “relevant characteristic” of tissues’ function in the donor to find they are more than “minimally manipulated” in a resulting HCT/P.  Similarly, MiMedx could mark greater scrutiny of FDA’s device-versus-biologic classifications more broadly.  HPM is closely monitoring any appeal and/or remand proceedings for these cases, and advising HCT/P manufacturers on the impact of the current state of the litigation on their products.  We can support companies who have received similar adverse classification decisions to develop strategies for potentially challenging those earlier outcomes.