FDA meeting gives window into gene therapy field's angst

Yahoo

06-06-2025

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Anyone looking for evidence of genetic medicine's enormous promise need only read of KJ Muldoon. The 10-month-old infant headed home from a Philadelphia hospital this week, dressed in a celebratory cap and gown, after his life-threatening disease was successfully treated with a bespoke CRISPR therapy.
While baby KJ is not cured, the treatment has stabilized his disease, a rare liver condition known as CSP1 deficiency, to such extent he's able to resume eating a normal diet. Doctors, who hurriedly designed and constructed KJ's custom therapy in a matter of months, have backed off supportive medications and hope he'll no longer need a liver transplant.
'Each year, 10 million babies are born with one of about 10,000 known rare genetic diseases, many of which are, in principle, now treatable with genetic medicines,' David Liu, a pioneering CRISPR scientist whose laboratory helped in KJ's treatment, said at a meeting hosted by the Food and Drug Administration Thursday.
'The opportunity created by this perfect storm moment in scientific, medical, regulatory and manufacturing innovation is to provide on-demand genetic treatments like KJ's at scale.'
Yet Liu and 22 other gene therapy experts and advocates who attended Thursday's roundtable didn't travel to the regulator's headquarters in White Oak, Maryland to extol the field's advances. By and large, they came to warn of a crisis.
There are now dozens of approved cell and gene therapies in the U.S., some of which offer near-curative potential for serious diseases like spinal muscular atrophy, sickle cell disease and acute lymphoblastic leukemia. However, the sector that's produced these therapies is struggling.
Investors have soured on genetic medicine as developers struggle to prove they can profitably sell the complex and often hugely expensive treatments. Biotechnology companies are cutting research, laying off staff and, in some cases, shutting down. Large pharmaceutical firms are no longer willing to bet billions of dollars they can surmount the regulatory and reimbursement hurdles that stand in the way of many of these therapies. And academic labs, still bursting with promising new ideas for technologies like CRISPR, now fear their projects will wither on the vine.
'We estimate that over 100 rare disease gene therapy products that had reached clinical stage have been discontinued since 2023 — not because of treatment failure, but because of the risk of market failure,' said Terence Flotte, dean of the University of Massachusetts' T.H. Chan School of Medicine and president of the American Society of Cell and Gene Therapy.
'The scientific advances that we have witnessed are just nothing short of spectacular. It's not hyperbole,' said Crystal Mackall, a professor at Stanford University and founding director of the cancer cell therapy center there. 'Despite this unconditional scientific success, the field is really struggling to deliver these therapies to all patients who can benefit.'
Their warnings found a receptive audience in FDA leadership. Commissioner Martin Makary and top official Vinay Prasad, who leads the office that oversees cell and gene therapies, were sympathetic to experts' arguments and pledged to help.
'We are going to continue the successes of the FDA in facilitating the regulatory process for these conditions and these products,' said Makary. 'We're also going to try to improve by creating more efficiencies.'
Prasad, who in the past has criticized the FDA's accelerated approval of a gene therapy for Duchenne muscular dystrophy, showed support for flexible trial designs and endpoints when appropriate for the disease or treatment.
He also noted the agency accepts that cell and gene therapies don't always comes with transformative potential. 'We understand that progress is not always made in a single leap,' he added. 'We will consider incremental steps forward, because those add up.'
The assembled experts came with lists of possible solutions. Carl June, a famed immunologist and cell therapy researcher at the University of Pennsylvania, called for the U.S. to borrow from the two-tier regulatory system used in China, which allows for medical institutions to more rapidly start first-in-human trials under the supervision of local review boards.
Don Kohn, a University of California, Los Angeles scientist who has developed gene therapies, asked the FDA to reduce the requirements for 'comparability' testing when companies transition production from academic to commercial settings.
Others emphasized the importance of regulatory awards, like the priority review vouchers granted by the FDA to developers of certain therapies, who often sell them for needed capital. And many called for the agency to share more feedback and lessons learned from the applications they receive from industry.
Behind all of their suggestions was a consistent concern: If regulators don't help solve the field's problems, the U.S. risks losing its leadership in developing the kinds of treatments that can cure diseases.
'If we don't adapt, the next generation of treatments will emerge abroad,' said June. 'The future of medicine with cell and gene therapy is at stake.'
Their message seemed to be heard by Makary and Prasad, who noted that many of the issues raised are on their radar at FDA. Prasad, for instance, noted that they hope to redact and make available more internal documents to aid developers' understanding of what the FDA is looking for.
'This is not a horse and pony show to say we did this,' added Makary. 'This is an honest listening session.'
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