gene therapy

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Top FDA official overrules staff to approve gene therapy that failed trial

clinical data, clinical trials, duchenne muscular dystrophy, elevidys, fda, fda approval, gene therapy, Peter Marks, sarepta, Science / /

Internal conflict —

Peter Marks overruled three teams and two top directors.

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Dr. Peter Marks, Director of the Center for Biologics Evaluation and Research within the Food and Drug Administration on March 18, 2021 in Washington, DC.

Enlarge / Dr. Peter Marks, Director of the Center for Biologics Evaluation and Research within the Food and Drug Administration on March 18, 2021 in Washington, DC.

The Food and Drug Administration (FDA) on Thursday announced expanded approval for a gene therapy to treat Duchenne muscular dystrophy (DMD)—despite the fact that it failed a Phase III clinical trial last year and that the approval came over the objections of three of FDA’s own expert review teams and two of its directors.

In fact, the decision to expand the approval of the therapy—called Elevidys (delandistrogene moxeparvovec-rokl)—appears to have been decided almost entirely by Peter Marks, Director of the FDA’s Center for Biologics Evaluation and Research.

Elevidys initially gained an FDA approval last year, also over objections from staff. The therapy intravenously delivers a transgene that codes for select portions of a protein called dystrophin in healthy muscle cells; the protein is mutated in patients with DMD. Last year’s initial approval occurred under an accelerated approval process and was only for use in DMD patients ages 4 and 5 who are able to walk. In the actions Thursday, the FDA granted a traditional approval for the therapy and opened access to DMD patients of all ages, regardless of ambulatory status.

“Today’s approval broadens the spectrum of patients with Duchenne muscular dystrophy eligible for this therapy, helping to address the ongoing, urgent treatment need for patients with this devastating and life-threatening disease,” Marks said in the announcement Thursday. “We remain steadfast in our commitment to help advance safe and effective treatments for patients who desperately need them.”

Criticism

The move, which follows a string of controversies in recent years of the FDA issuing questionable approvals over the assessments of advisors and its own staff, has quickly drawn criticism from agency watchers.

In a blog post Friday, a notable pharmaceutical industry expert and commentator, Derek Lowe, admonished the approval. Lowe expressed concern that the agency seems to be tilting toward emotional rhetoric and the will of patient advocates over scientific and medical evidence.

“It appears that all you need is a friend high up in the agency and your clinical failures just aren’t an issue any more,” he wrote. “Review committees aren’t convinced? Statisticians don’t buy your arguments? Who cares! Peter Marks is here to deliver hot, steaming takeout containers full of Hope. … And while I realize that this may make me sound like a heartless SOB, I think this is a huge mistake that we will be paying for for a long time.”

In a comment to Stat News, former FDA chief scientist Luciana Borio echoed concerns about how decisions like this will affect the agency in the longer term.

“I don’t know what to say. Peter Marks makes a mockery of scientific reasoning and approval standards that have served patients well over decades,” said Borio, who has also opposed earlier controversial approvals. “This type of action also promotes the growing mistrust in scientific institutions like the FDA.”

Internal dissent

In a series of review documents and memos released by the FDA, the divide between Marks and agency staff is abundantly clear. A review by FDA statisticians concluded that the collective clinical trial results “do not suggest there is substantial evidence to support the effectiveness of [Elevidys] for the expanded indication to all DMD patients and do not support the conversion of accelerated to traditional approval.”

A joint review from the agency’s Clinical and Clinical Pharmacology teams likewise concluded that the “totality of the data does not provide substantial evidence of effectiveness of Elevidys for treatment of ambulatory DMD patients of any age” and that the results “argue against” expanding access.

In a memo, Lola Fashoyin-Aje, Director of the Office of Clinical Evaluation in the Office of Therapeutic Products (OTP), and Dr. Nicole Verdun, Super Office Director of the OTP, concluded that the clinical results “cast significant uncertainty regarding the benefits of treatment of DMD with Elevidys.” The two directors found the primary clinical trial endpoint results were “not statistically significant” and smaller analyses looking at secondary endpoints of specific patient measures—such as the time it takes patients to rise from the floor or walk 10 meters—were “inconclusive,” in some cases “conflicting,” and overall illustrated the “unreliability of exploratory analyses to support regulatory decision-making.”

In a memo of his own, Marks agreed that primary endpoint result of the trial—based on scores on a standardized assessment of motor function in patients—did not show a statistically significant benefit. But he argued that the secondary endpoints were convincing enough for him. Marks wrote:

Specifically, although acknowledging that the Applicant’s randomized study of Elevidys failed to meet its statistical primary endpoint … I find that the observations regarding the secondary endpoints and exploratory endpoints are compelling and, combined with other data provided in the efficacy supplement and the original [Biologics License Application], meet the substantial evidence of effectiveness standard …

If Marks had not overruled the agency’s reviewers and directors, Fashoyin-Aje wrote that she would have recommended the therapy’s maker, Sarepta, conduct “an additional adequate and well-controlled study of Elevidys in the subgroup(s) of patients for which [Sarepta] believes the effects of Elevidys to be most promising.” However, Marks’ decision to approve renders the possibility of such a trial “highly infeasible to explore in a post-approval setting,” she wrote.

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IV infusion enables editing of the cystic fibrosis gene in lung stem cells

Biology, CRISPR, Cystic Fibrosis, gene editing, gene therapy, Genetics, medicine, Science / /

Right gene in the right place —

Approach relies on lipid capsules like those in the mRNA vaccines.

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Abstract drawing of a pair of human hands using scissors to cut a DNA strand, with a number of human organs in the background.

The development of gene editing tools, which enable the specific targeting and correction of mutations, hold the promise of allowing us to correct those mutations that cause genetic diseases. However, the technology has been around for a while now—two researchers were critical to its development in 2020—and there have been only a few cases where gene editing has been used to target diseases.

One of the reasons for that is the challenge of targeting specific cells in a living organism. Many genetic diseases affect only a specific cell type, such as red blood cells in sickle-cell anemia, or specific tissue. Ideally, to limit potential side effects, we’d like to ensure that enough of the editing takes place in the affected tissue to have an impact, while minimizing editing elsewhere to limit side effects. But our ability to do so has been limited. Plus, a lot of the cells affected by genetic diseases are mature and have stopped dividing. So, we either need to repeat the gene editing treatments indefinitely or find a way to target the stem cell population that produces the mature cells.

On Thursday, a US-based research team said that they’ve done gene editing experiments that targeted a high-profile genetic disease: cystic fibrosis. Their technique largely targets the tissue most affected by the disease (the lung), and occurs in the stem cell populations that produce mature lung cells, ensuring that the effect is stable.

Getting specific

The foundation of the new work is the technology that gets the mRNAs of the COVID-19 mRNA vaccines inside cells. The nucleic acids of an mRNA are large molecules with a lot of charged pieces, which makes it difficult for them to cross a membrane to get inside of a cell. To overcome that problem, the researchers package the mRNA inside a bubble of lipids, which can then fuse with cell membranes, dumping the mRNA inside the cell.

This process, as the researchers note, has two very large advantages: We know it works, and we know it’s safe. “More than a billion doses of lipid nanoparticle–mRNA COVID-19 vaccines have been administered intramuscularly worldwide,” they write, “demonstrating high safety and efficacy sustained through repeatable dosing.” (As an aside, it’s interesting to contrast the research community’s view of the mRNA vaccines to the conspiracies that circulate widely among the public.)

There’s one big factor that doesn’t matter for vaccine delivery but does matter for gene editing: They’re not especially fussy about what cells they target for delivery. So, if you want to target something like blood stem cells, then you need to alter the lipid particles in some way to get them to preferentially target the cells of your choice.

There are a lot of ideas on how to do this, but the team behind this new work found a relatively simple one: changing the amount of positively charged lipids on the particle. In 2020, they published a paper in which they describe the development of selective organ targeting (SORT) lipid nanoparticles. By default, many of the lipid particles end up in the liver. But, as the fraction of positively charged lipids increases, the targeting shifts to the spleen and then to the lung.

So, presumably, because they know they can target the lung, they decided to use SORT particles to send a gene editing system specific to cystic fibrosis, which primarily affects that tissue and is caused by mutations in a single gene. While it’s relatively easy to get things into the lung, it’s tough to get them to lung cells, given all the mucus, cilia, and immune cells that are meant to take care of foreign items in the lung.

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More children gain hearing as gene therapy for profound deafness advances

gene therapy, health, profound deafness, Science / /

Success —

The therapy treats a rare type of deafness, but experts hope it’s a “jumping point.”

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Opal Sandy (center), who was born completely deaf because of a rare genetic condition, can now hear unaided for the first time after receiving gene therapy at 11-months-old. She is shown with her mother, father, and sister at their home in Eynsham, Oxfordshire, on May 7, 2024.

Enlarge / Opal Sandy (center), who was born completely deaf because of a rare genetic condition, can now hear unaided for the first time after receiving gene therapy at 11-months-old. She is shown with her mother, father, and sister at their home in Eynsham, Oxfordshire, on May 7, 2024.

There are few things more heartwarming than videos of children with deafness gaining the ability to hear, showing them happily turning their heads at the sound of their parents’ voices and joyfully bobbing to newly discovered music. Thanks to recent advances in gene therapy, more kids are getting those sweet and triumphant moments—with no hearing aids or cochlear implants needed.

At the annual conference of the American Society for Gene & Cell Therapy held in Baltimore this week, researchers showed many of those videos to their audiences of experts. On Wednesday, Larry Lustig, an otolaryngologist at Columbia University, presented clinical trial data of two children with profound deafness—the most severe type of deafness—who are now able to hear at normal levels after receiving an experimental gene therapy. One of the children was 11 months old at the time of the treatment, marking her as the youngest child in the world to date to receive gene therapy for genetic deafness.

On Thursday, Yilai Shu, an otolaryngologist at Fudan University in Shanghai, provided a one-year progress report on six children who were treated in the first in-human trial of gene therapy for genetic therapy. Five of the six had their hearing restored.

That trial, like the one Lustig presented, involved treating just one ear in all of the children—a safety precaution for such early trials. But Shu and colleagues have already moved on to both ears, or bilateral treatment. After presenting a progress report on the first trial, Shu presented unpublished early data on five additional patients who participated in the first in-human trial of bilateral treatment. All had bilateral hearing restoration and speech perception improvement.

“The opportunity of providing the full complexity and spectrum of sound in children born with profound genetic deafness is a phenomenon I did not expect to see in my lifetime,” Lustig said in a statement.

Jumping point

Shu and Lustig’s trials are separate but the treatments are, in broad strokes, similar. Both are aimed at restoring hearing loss caused by mutations in the OTOF gene the codes for the protein otoferlin. Normally, otoferlin is a critical protein for transmitting sound signals to the brain, specifically playing a key role in synaptic transmission between the ear’s inner hair cells and the auditory nerve. Using gutted adeno-associated viruses as vectors for gene delivery, the therapies provide the inner ear with a functional version of the OTOF gene. Once in the ear, the gene can be translated into functional otoferlin, restoring auditory signaling.

In the trial Lustig presented, the two patients saw a gradual improvement of hearing as otoferlin protein built up after treatment. For the 11-month-old, normal levels of hearing were restored within 24 weeks of treatment. For the second patient, a 4-year-old, improvements were detected at a six-week assessment. In the trial Shu presented, children began seeing hearing improvements at three- and four-week assessments. The children will continue to be followed into the future, which holds some uncertainties. It’s unclear if they will, at some point in their lives, need additional treatments to sustain their hearing. In mice, at least, the treatment lasts for the duration of the animals’ lives—but they only live for a few years.

“We expect this to last a long time,” Lustig said Wednesday. But “we don’t know what’s going to happen and we don’t know whether we can do a second dose. But, probably, I would guess, at some point that would have to be done.”

For now, the treatment is considered low-hanging fruit for the burgeoning field of gene therapy since it targets a severe condition caused by recessive mutations in a single gene. Otoferlin mutations lead to a very specific type of deafness called auditory neuropathy, in which the ear fails to send signals to the brain but works perfectly fine otherwise. This is an ultra-rare form of deafness affecting 1–8 percent of people with deafness globally. Only about 30 to 50 people in the US are born with this type of deafness each year.

However, Lustig calls it a “jumping point.” Now that researchers have shown that this gene therapy can work, “This is going to really spark, we hope, the development of gene therapy for more common types of deafness,” he said.

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Lifesaving gene therapy for kids is world’s priciest drug at $4.25M

drug pricing, fda, gene therapy, health, metachromatic leukodystrophy, Orchard, rare genetic conditions, Science / /

promising but pricey —

It’s unclear if government and private insurance plans can cover the costs.

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A mother with her twin 6-year-old boys who have metachromatic leukodystrophy, a genetic disease that leaves them unable to move. Photo taken on September 3, 2004.

Enlarge / A mother with her twin 6-year-old boys who have metachromatic leukodystrophy, a genetic disease that leaves them unable to move. Photo taken on September 3, 2004.

In a medical triumph, US Food and Drug Administration on Monday approved a gene therapy that appears to trounce a rare, tragic disease that progressively steals children’s ability to talk, move, and think, leading to a vegetative state and death. For those who begin to slip away in infancy, many die by age 5. But, with the new therapy, 37 children in an initial trial were all still alive at age 6. Most could still talk, walk on their own, and perform normally on IQ tests, which was unseen in untreated children. Some of the earliest children treated have now been followed for up to 12 years—and they continue to do well.

But, the triumph turned bittersweet today, Wednesday, as the company behind the therapy, Lenmeldy, set the price for the US market at $4.25 million, making it the most expensive drug in the world. The price is $310,000 higher than what experts calculated to be the maximum fair price for the lifesaving drug; the nonprofit Institute for Clinical and Economic Review, or ICER, gave a range last October of between $2.29 million to $3.94 million.

The price raises questions about whether state, federal, and private health insurance plans will be able to shoulder the costs. “Unless states have allocated appropriately for it, and looked at the drug pipeline, they may not be prepared for what could be significant cost spikes,” Edwin Park, a research professor at the McCourt School of Public Health at Georgetown University, told CNN.

It’s also unclear whether the drug can reach the children who need it in time. Lenmeldy must be given before symptoms develop or early on in symptom development in children. However, diagnosis of the rare genetic condition can be slow, and many children treated so far were identified because older siblings, now too old for treatment, developed the condition first.

Devastating disease

Stat, for instance, spoke with the mother of an 8-year-old with the condition, who can no longer talk or move, has frequent seizures, and requires a feeding tube and 28 different medications. Meanwhile, her 3-year-old brother, who has the same genetic mutation, is a typical toddler—he was able to get the new treatment when he was six months old. To get it, the family flew him to Milan, Italy, where Lenmeldy was first developed. It was approved for use in Europe in 2021.

The condition Lenmeldy treats is called metachromatic leukodystrophy (MLD), which occurs in about 40 children in the US each year. MLD is caused by a mutation in the gene that codes for the enzyme arylsulfatase A (ARSA). Without this enzyme, the body can’t break down sulfatides, a fatty substance that then builds up to toxic levels in the brain and peripheral nervous system. Sulfatides are essential components of myelin, the fatty insulation on nerve cells critical for quick transmission of electrical impulses. But, too much sulfatides leads to a loss of myelin, which gradually destroys myelin producing cells and leads to nervous system damage.

Lenmeldy prevents that damage by giving the body a working copy of the ARSA gene. In a one-time infusion, patients are given a dose of their own blood stem cells that have been genetically engineered to contain a functional ARSA gene. Patients undergo chemotherapy to clear out their own stem cells from bone marrow so the genetically modified cells can replace them. The engineered stem cells then produce myeloid cells that travel around the body in the blood, producing ARSA enzyme that can halt progression of MLD.

It’s unknown how long the therapy lasts, but it’s clearly buying children time and giving them hope for a full, normal life.

“MLD is a devastating disease that profoundly affects the quality of life of patients and their families,” Nicole Verdun, director of the FDA’s Office of Therapeutic Products, said in a statement. “Advancements in treatment options offer hope for improved outcomes and the potential to positively influence the trajectory of disease progression.”

It “has the potential to stop or slow the progression of this devastating childhood disease with a single treatment, particularly when administered prior to the onset of symptoms,” Bobby Gaspar, CEO of Lenmeldy’s maker, Orchard Therapeutics, said in a statement Wednesday. “We are committed to enabling broad, expedient, and sustainable access to this important therapy for eligible patients with early-onset MLD in the US.”

The company is working on expanding newborn screening to include tests for MLD, to try to find children early, Orchard reported. Still, with such a rare condition, it’s unclear if the pricey drug will be a moneymaker for the company. Stat notes that Orchard has previously abandoned four therapies for other rare genetic conditions because of the difficulty in meeting regulatory standards for essentially custom therapies and questions about whether health plans will pay the steep, multimillion-dollar prices. In April of last year, Belgium, Ireland, and the Netherlands walked away from price negotiations with the company, saying they couldn’t come to an agreement on this “extremely expensive therapy.”

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