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pulmonology

Inside Pediatrics, Pulmonology

Children’s of Alabama Muscular Dystrophy Care Center Offers Life-Saving Treatment for Rare, Fatal Disease

MDA_WEB

Brad Troxler, M.D., director of the Muscular Dystrophy Care Center (MDA) at Children’s of Alabama, chats with a patient. The MDA Care Center is the only MDA clinic in Alabama and one of only a few in the region.

The Muscular Dystrophy Care Center (MDA) at Children’s of Alabama sees about 280 patients a year with a wide variety of neuromuscular conditions. They require multidisciplinary care from neuromuscular specialists, neurologists, pulmonologists, genetic counselors and cardiologists, among others. They also need respiratory, physical and occupational therapies, nutritional counseling and social work support.

One of the most devastating conditions the clinic sees is spinal muscular atrophy (SMA), a rare autosomal recessive genetic disorder that is the leading cause genetic cause of death in infants. It is characterized by degeneration and loss of lower motor neurons, leading to muscle atrophy. Infants with the most serious form of the disease, Type 0, can be diagnosed prenatally and typically die before 6 months, while those with Type 1 begin showing symptoms around 6 months, require ventilation and typically die before age 2. Other types of SMA may not manifest until childhood or even adulthood and are less severe, although all of those affected experience some neuromuscular effects.

Until recently, SMA was primarily treated with supportive care. Today, however, there are two groundbreaking treatments and Children’s is the only MDA clinic in the state, and one of only few in the region, to offer both: nusinersen (Spinraza), approved for children and adults, which is administered in several doses the first year and annually after that; and onasemnogene abeparvovec-xioi (Zolgensma), a single-dose treatment approved for use in children with SMA Type 1 under age 2.

Both are gene therapies designed to address genetic mutations in the SMN1 and/or SMN2 genes, which make the protein required to control muscle movement. Both are also extremely expensive, with the first 10 years of treatment with Spinraza estimated at $4 million and a single dose of Zolgensma costing $2.1 million, making it the most expensive drug ever marketed.[1]

The cost could be worth it, though, given the benefits of the drugs. “Clinical trials showed huge improvement,” said Brad Troxler, M.D., who MDA Care Center director. Indeed, after four years, infants treated with Spinraza before they turned 6 weeks were still achieving and maintaining motor milestones such as walking and sitting without assistance, things SMA babies would not normally be able to do.[2]

Participants in the Zolgensma trials were demonstrating similar results, with all children who received the drug still alive at 2 years and none requiring ventilation.[3]

Don’t call the treatments cures, however, says Troxler. “‘Cure’ is a hard word to define,” he said. While improved, patients still don’t have normal neuromuscular function after receiving the drug, with some muscle weakness remaining and an increased risk of scoliosis and other issues related to the disease. “But if we give it early enough, they are able to walk and talk and eat so it’s pretty close to a cure,” he said.

The earlier the drugs are administered, the greater the benefit. “Time is neurons,” said Shelley Coskery, MSN, CRNP-AC, MDA Care Center coordinator. However, Alabama is one of the few states that doesn’t screen newborns for SMA, which could delay treatment until symptoms appear. “We’re working on it,” Coskery said. “We need to start treating these patients before they develop symptoms and then, hopefully, we will see fewer and fewer affected with the disease.”

Becoming one of the first centers to offer SMA treatments, she said, “puts us at the forefront of the gene replacement movement.” Indeed, the center is also beginning clinical trials for genetic therapies for children with Duchenne, one of the most common neuromuscular diseases.

The ability to provide such effective treatments to children who otherwise would have died before age 2 “is very profound,” Troxler said. “You can see the difference it makes on individual families in a really powerful way. Conversations historically been about how ‘this is a terrible disease that will likely end in your child’s death.’” Now, Troxler said, the conversation has changed to, “‘Your child has a horrible disease, but we have some therapies that are going to change what this looks like.’ It’s completely different.”

“There is a lot of excitement throughout the SMA community,” Coskery said. “We are very grateful when the parents send emails of the child standing and achieving milestones we didn’t think they would.”


[1] Thomas K. his New Treatment Could Save the Lives of Babies. But It Costs $2.1 Million. The New York Times. May 24, 2019.

[2] Biogen Announces New Data Further Establishing SPINRAZA® (nusinersen) as a Foundation of Care in Spinal Muscular Atrophy for a Broad Range of Patients. Available at: http://investors.biogen.com/news-releases/news-release-details/biogen-announces-new-data-further-establishing-spinrazar

[3] New Data Shows Long-Term Benefits of Zolgensma in SMA Patients. Available at: https://www.biospace.com/article/in-wake-of-data-manipulation-scandal-avexis-releases-long-term-efficacy-of-zolgensma-at-conference/

Inside Pediatrics, Pulmonology

Using Pharmacogenetics to Help Identify Patients with Cystic Fibrosis Most Likely to Respond to Targeted Therapies

Pharmacogenetics_WEB

Children’s of Alabama and the University of Alabama at Birmingham (UAB) are on a mission to determine how patients use Cystic Fibrosis Transmembrane Conductance Regulator modulators at the cellular level.

The discovery of the genetic mutation responsible for cystic fibrosis (CF) and the subsequent development of drugs that target this mutation, called Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators, together with improved supportive treatments, has revolutionized the management of the disease. Today, the median life expectancy of someone with CF has increased from age 10 in 1962 to 47, with many patients living into their 50s or 60s. With the newer drugs, many expect those with CF will be able to live a normal lifespan.

However, studies of the four currently available CFTR modulator therapies, three of which are combination drugs, find that between 20 and 25 percent of patients who should respond based on their disease’s genetic fingerprint don’t.1,2 Given that the drugs can cost up to $300,000 a year, it is important to find biomarkers to identify which drug will be most effective for which patient.3 Currently, the only option is a rectal biopsy followed by complicated testing or nasal brushing, neither of which are approved by the U.S. Food and Drug Administration, accepted by insurance or widely used.

Children’s of Alabama pulmonologist Jennifer S. Guimbellot, M.D., Ph.D., together with Steven M. Rowe M.D., who directs the Gregory Fleming James Cystic Fibrosis Research Center at the University of Alabama at Birmingham (UAB), and  Edward P. Acosta, Pharm.D.,  who directs UAB’s Division of Clinical Pharmacology, are on a mission to change that.  Their research focuses on how patients use CFTR modulators at the cellular level.

Until fairly recently, Guimbellot said,We didn’t have the tools to measure levels in the tissue.” Now they can use a simple, minimally invasive test Guimbellot helped develop. The assay measures concentrations of CFTR modulators in plasma and nasal epithelial cells, which, like epithelial cells in the lungs, are the drug’s site of action. Obtaining the cells is simple and inexpensive, requiring only a nasal brush, and can be done repeatedly to monitor drug levels.

After obtaining cells from patients, Guimbellot said, her team found that while plasma concentrations seem to correlate with the drug response, concentrations in tissue differ from those in plasma.

The question is why.

The answer may be related to pharmacogenomics, or the genetic variation in the way individuals metabolize drugs. Thanks to the epithelial tissue assays, she said, “our lab found that there may be substantial differences in the levels of modulators and also of metabolism proteins in people with CF.” Thus, once the drug is delivered to the cell, the effect may differ between patients. For instance, one person may be a fast metabolizer and clear the drug quickly; while the other may be a slow metabolizer and the drug accumulates in the tissue.

The protein known to metabolize CFTR modulators, CYP3A4, is primarily active in the liver. But in about 20 percent of people, it may also be produced in other tissues. While Guimbellot’s team has not found CYP3A4 in the epithelial cells from CF patients they’ve examined, they have found substantial levels of mRNA from the almost identical CYP3A7 protein and its cousin, CYP3A5. “So we hypothesize the CFTR modulator drugs are substantially metabolized by those proteins since it’s so similar to CYP3A4, and that this could affect how well patients respond to the drug.” They also found wide variation in the expression levels of both, which could contribute to the amount of available modulator at the target site.

“By understanding how genetic variation may influence the expression of these proteins and how that might affect the amount of drug available to do its job in the target tissue we can then relate the findings back to whether or not a patient can be expected to respond well to it or not,” she said.

Which is the next step in their research.

The team’s work is currently funded by the Cystic Fibrosis Foundation.


[1] National Institutes of Health. Cystic Fibrosis. 2019; https://report.nih.gov/nihfactsheets/ViewFactSheet.aspx?csid=36&key=C.

[2] Cystic Fibrosis News Today. Cystic Fibrosis Statistics. 2019; https://cysticfibrosisnewstoday.com/cystic-fibrosis-statistics/. Accessed June 19, 2019.

[3] Starner CI. How much is too much? Prime Therapeutics. May 31, 2019. Available at: https://www.primetherapeutics.com/en/news/prime-insights/2019-insights/Story_Cystic_Fibrosis_Treatments.html.