This Week at FDA: Agency starts diagnostics reform rulemaking, top Aduhelm-linked official retiring

Updated 7 March 2023 to clarify what products FDA's guidance on potency assays for monoclonal antibodies applies to.
 
Welcome to another installment of This Week at FDA, your weekly source for updates – big and small – on FDA, drug and medical device regulation, and what we’re reading from around the web. This week, we learned that the agency is indeed moving forward with rulemaking to get diagnostics reform, a top official involved in the Aduhelm approval story is leaving, and more.
 
This week Bioworld reported that Elizabeth Hillebrenner, associate director for scientific and regulatory programs at FDA’s Center for Devices and Radiological Health (CDRH), said the agency is moving forward with the rulemaking process to ensure it can regulate laboratory-developed tests (LDT). Robert Califf, FDA commissioner has noted several times lately that the agency is hopeful that Congress will pass the Verifying Accurate Leading-Edge IVCT Development (VALID) Act, which failed last year. In the meantime, Hillebrenner told attendees at the American Clinical Laboratory Association annual meeting that FDA is moving forward with trying to produce a rule to regulate LDTs if all else fails.
 
According to the FDA, Billy Dunn, director of the FDA’s office of neuroscience, is retiring. The neuroscientist joined the agency in 2005 and became known for his involvement in the FDA’s decision to overrule the recommendation of its advisory committee to approve Biogen’s Alzheimer’s drug Aduhelm. Back in 2019, Dunn had an off-the-book meeting with Biogen’s head scientist that raised concerns about a potential conflict of interest.
 
Pfizer and GlaxoSmithKline’s respiratory syncytial virus (RSV) vaccines got the thumbs up from an FDA advisory committee this week. However, it may take several months before the agency decides on the matter. If approved, they would be the first vaccines for RSV on the US market.
 
On Thursday, twelve Democratic state attorneys general (AG) announced they are suing the FDA to force the agency to loosen restrictions on the distribution of mifepristone, which is used in medication abortions. The drug has been at the center of the reproductive health debate after the Supreme Court overturned Roe v. Wade. The AGs are accusing the FDA of singling out the drug and imposing particularly burdensome limitations on its distribution.
 
Drugs & Biologics
 
Fierce Pharma reported that Merck ended its last Keytruda trial to treat prostate cancer. The company launched an aggressive campaign in 2019 but now reports the drug didn’t add any survival benefit for metastatic castration-resistant prostate cancer (mCRPC) patients who hadn’t received prior chemotherapy. The PD-1 inhibitor also did not help ward off cancer progression.
 
An FDA advisory panel says it will review Merck and AstraZeneca’s application for the expanded use of their drug Lynparza to treat an advanced form of prostate cancer. The Oncologic Drugs Advisory Committee, or ODAC, will review the application on 28 April.
 
Sarepta won’t face an FDA advisory committee in its mission to get the first gene therapy approved for Duchenne muscular dystrophy. After a mid-cycle review of SRP-9001 with the agency, the company answered questions about chemistry, manufacturing, and controls, and regulators said they do not plan to hold an advisory committee. A decision on the therapy is due by May 29.
 
FDA described how CDER is advancing rare disease drug development through the Accelerating Rare Disease Cures (ARC) program in a web post published in conjunction with Rare Disease Day, 28 February.
 
The agency also announced  the release of draft guidance  on developing potency assays for monoclonal antibodies and other therapeutic proteins targeting viral pathogens. The guidance updates a previous version issued in 2021 to state the recommendations are applicable to antibodies and other therapeutic proteins outside the context of the public health emergency not just SARS-CoV-2.
 
Medtech
 
This week FDA announced it has already enrolled four devices into its Total Product Lifecycle Advisory Program (TAP) pilot, which was created under the latest Medical Device User Fee Amendments (MDUFA V) deal. The advisory program was a major point of contention during negotiations between the FDA and industry; the sides ultimately agreed to a pilot program to test it before committing to a full program.
 
Abbott and FDA have sent letters to healthcare providers warning them that its Trifecta family of bioprosthetic aortic valves may begin deteriorating within the first five years of implantation. If they deteriorate it could require patients to get an earlier-than-expected replacement and in some cases, if left unaddressed it could lead to deaths.
 
FDA rejected a bid from Elon Musk’s brain chip company Neuralink to begin human trials. According to Reuters, the agency raised dozens of issues that the company first has to address including safety concerns about the device’s lithium battery, the potential for the implant’s wires to migrate to other areas of the brain, and questions over whether and how the device can be removed without damaging brain tissue.