From the category archives:

Drug discovery

ADHD long term drug safety rare adverse events FDA approval Kenneth Mandl Florence BourgeoisYou’d think drugs meant to be taken by children for years would be studied in children for a long time to measure their long-term safety.

You’d think drugs for a condition affecting millions of children would be tested in many, many children to catch any rare side effects.

You’d think all this would happen before the Food and Drug Administration, an agency known for its strict criteria, approved them for marketing.

But if a new PLoS ONE paper by Boston Children’s Hospital’s Florence Bourgeois, MD, MPH, and Kenneth Mandl, MD, MPH, is any indication, you’d be wrong.

In it, the pair reports that the FDA approved 20 attention deficit hyperactivity disorder (ADHD) drugs over the last 60 years without what would be considered sufficient long-term safety and rare adverse event data.

Their findings, they say, point to larger issues in how the FDA’s approval process addresses the long-term safety of drugs intended for chronic use in children. Full story »

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Bioengineered blood vessels

A bioengineered network of blood vessels

Juan Melero-Martin, PhD, runs a cell biology and bioengineering lab in the department of Cardiac Surgery at Boston Children’s Hospital. In May, he received an Early Career Investigator Award from Bayer HealthCare, part of the prestigious Bayer Hemophilia Award.

In 1982, insulin became the first FDA-approved protein drug created through recombinant DNA technology. It was made by inserting the human insulin gene into a bacterial cell’s DNA, multiplying the bacteria and capturing and purifying the human insulin in bioreactors. Full story »

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A cocktail of approaches is most likely to successfully preserve muscle.

Rather than a single drug, cocktail of approaches is most likely to successfully preserve muscle.

It’s been 28 years since a missing dystrophin protein was found to be the cause of Duchenne muscular dystrophy (DMD), a disease affecting mostly boys in which muscle progressively deteriorates. Dystrophin helps maintain the structure of muscle cells; without it, muscles weaken and suffer progressive damage, forcing boys into wheelchairs and onto respirators.

Today, a variety of approaches that attempt to either restore dystrophin or compensate for its loss are in the therapeutic pipeline.

“We’re at the point where lots of things are going into clinical trials,” says Louis Kunkel, PhD, who is credited with identifying dystrophin in 1987. “I call it the decade of therapy.” Full story »

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heart chip BarthIt was the variability that intrigued pediatric cardiologist William Pu, MD, about his patient with heart failure. The boy suffered from a rare genetic mitochondrial disorder called Barth syndrome. While he ultimately needed a heart transplant, his heart function seemed to vary day-to-day, consistent with reports in the medical literature.

“Often patients present in infancy with severe heart failure, then in childhood it gets much better, and in the teen years, much worse,” says Pu, of the Cardiology Research Center at Boston Children’s Hospital. “This reversibility suggests that this is a disease we should really be able to fix.”

Though it needs much more testing, a potential fix may now be in sight for Barth syndrome, which has no specific treatment and also causes skeletal muscle weakness and low white-blood-cell counts. It’s taken the work of multiple labs collaborating across institutional lines. Full story »

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De-risking drug development for orphan diseasePerhaps counter-intuitively, rare diseases can present attractive business opportunities for pharmaceutical companies. As discussed previously on Vector, they generally offer:

1) a population of patients with a high, unmet need, greatly lowering the bar to FDA approval

2) a closely networked disease community, greatly lowering the bar to creating disease registries and mounting clinical trials

3) well-studied disease pathways.

Recoiling from expensive failures of would-be blockbuster drugs, companies like Pfizer, Novartis, GlaxoSmithKline, Sanofi, Shire and Roche are embracing rare diseases, despite their small market sizes, because of their much clearer path to clinic. But in the current risk-averse industry environment, some projects are stalling. Industry may need more incentive to jump in—and Cydan Development is basing its business model on providing it. Full story »

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Ear-engraved styleThis post is adapted from a commentary in this week’s edition of Science by Jeffrey R. Holt, PhD, and Gwenaelle S. G. Géléoc, PhD, of the Department of Otolaryngology and F.M. Kirby Neurobiology Center at Boston Children’s Hospital.

Hearing loss affects more than 300 million people worldwide, making it the most common sensory disorder. While there are no cures, recent efforts to develop biological treatments for hearing loss provide reason for cautious optimism. Three strategies—gene therapy, stem cells and drugs—have shown encouraging results in animal models, poising them for translation into potential therapies for humans.

Hearing loss can arise from many different causes, so it is unlikely that a single “magic bullet” will be developed to treat all forms of deafness. Rather, each individual cause may require a tailored and specific treatment strategy. Full story »

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Bone marrow on a chip organs on chips Wyss Institute Donald Ingber

Microscopic view of the engineered bone with an opening exposing the internal trabecular bony network, overlaid with colored images of blood cells and a supportive vascular network that fill the open spaces in the bone marrow-on-a-chip. (James Weaver, Harvard's Wyss Institute)

We’ve had a lung on a chip, and a gut on a chip. Now researchers at the Wyss Institute for Biologically Inspired Engineering have added another tissue to their list of “organs-on-chips”— devices that mimic in vitro tissues’ in vivo structure and function for pharmaceutical discovery and testing. In a paper published in Nature Methods, a team led by Donald Ingber, MD, PhD, (a member of Boston Children’s Hospital’s Vascular Biology Program and founding director of the Wyss), announced that they have developed “bone marrow-on-a-chip.”

The sheer complexity of the new device sets it apart from the Wyss’s previous organs, reflecting the greater natural complexity of bone marrow. Full story »

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Neural stem cells Lou Gehrig's disease amyotrophic lateral sclerosis ALSUntil recently, most scientific knowledge about amyotrophic lateral sclerosis (ALS), better known as Lou Gehrig’s disease, came from mouse studies. But new research is taking this incurable neurodegenerative condition to the dish, tapping induced pluripotent stem cells (iPS cells)—made from ALS patients’ skin cells—to create motor neurons. These motor neurons are being used not just to model how ALS works at the cellular level but also to screen potential drugs.

This work, taking place at the Harvard Stem Cell Institute (HSCI) in collaboration with Boston Children’s Hospital and Massachusetts General Hospital (MGH), has now paved the way for a clinical trial of a drug that might never otherwise have been thought of. Full story »

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In this screengrab from a Nature video, a siRNA, cradled by an argonaute protein, binds to a messenger RNA. (Watch the full video at: https://www.youtube.com/watch?v=cK-OGB1_ELE)

In this screen grab from a Nature video, a siRNA, cradled by an argonaute protein, binds to a messenger RNA. (More at www.youtube.com/watch?v=cK-OGB1_ELE)

RNA interference (RNAi) is a therapeutic technology that blocks gene expression with either small interfering RNAs (siRNA) or microRNAs (miRNA). RNAi’s discovery was considered transformative enough to earn the 2006 Nobel Prize for Physiology or Medicine, but from the start the challenge of delivering RNA-silencing therapeutics to the right tissues has hobbled efforts to use RNAi to treat patients.

Citing this challenge, the pharmaceutical giant Novartis is the latest major company to withdraw from RNAi research, following Merck and Roche. Forbes was prompted to write:

…for certain diseases where an RNAi therapeutant can be more readily introduced, such as the eye, or ‘privileged compartments’ such as the liver, RNAi still has potential. But given that these therapies would be expensive due to the high cost-of-goods involved in synthesizing these agents, they would have to be targeted to diseases where the cost of therapy would be justified by the beneficial medical effects. … to say that RNAi therapy will rival monoclonal antibodies in terms of revenue potential—well, that’s a bit of a stretch.

Barry Greene, COO of Alnylam Pharmaceuticals, a biotech that’s championed RNAi, countered in Fierce Drug Delivery: “Novartis pulling out is an exemplar of Big Pharma not being able to innovate, and historically they have never been able to innovate.” Full story »

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Daniel Kohane of Boston Children's Hospital is developing drug delivery technologies that rely on nanoparticles and the spectrum of light.Getting drugs where they need to be, and at the right time, can be more challenging than you think. Tumors, for example, tend to have blood vessels that are tighter and twistier than normal ones, making it hard for drugs to penetrate them. Despite decades of research on antibodies, peptides and other guidance methods, drug makers struggle to target drugs to specific tissues or cell types.

And even once a drug arrives at the right place, the ability to fine-tune the dose so that the drug is released at the right time and in the right amount remains an elusive goal.

What’s needed is some kind of trigger, a stimulus that a clinician can turn on and off to guide when a drug is available and where it goes to make sure it does its job with the fewest side effects.

Daniel Kohane, MD, PhD, a critical care specialist and director of the Laboratory for Biomaterials and Drug Delivery at Boston Children’s Hospital, thinks he’s hit upon a promising trigger, one that’s all around us: light. Full story »

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