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Miriam Bornhorst

Miriam Bornhorst, M.D., receives DOD New Investigator Award

Miriam Bornhorst

Miriam Bornhorst, M.D., clinical director of the Gilbert Neurofibromatosis Institute at Children’s National Hospital, received the Department of Defense’s Neurofibromatosis Research Program New Investigator Award.

This award, which is funded by the U.S. Department of Defense, has granted $450,000 in funds which Dr. Bornhorst hopes to use towards a study for patients with Neurofibromatosis Type 1 (NF1).

“There is very little known about metabolism in NF1, but we know that abnormalities in metabolism can not only affect a person’s overall health, but may also influence how tumors develop and grow,” Dr. Bornhorst explained.

Patients with NF1 can have defining clinical features related to growth and energy metabolism, such as short stature, low weight and decreased bone mineral density, findings that are more prominent in patients with high plexiform neurofibroma (a nerve sheath tumor) burden. The mechanism for this metabolic phenotype and its association with plexiform neurofibromas is not currently understood.

Preliminary data and the work of others suggest that the MAPK pathway may play a role in metabolism and Mek-inhibitor (MEKi) treatment, which decreases activity of the MAPK pathway and promotes weight gain in patients with NF1. Dr. Bornhorst’s study will be the first to explore global metabolism in NF1, determine which metabolic pathways are most active in plexiform neurofibromas and define how metabolomic signatures change during MEKi treatment.

“These findings will improve management and may lead to novel treatment options for patients with NF1,” she said. “It is my hope that the grant funding received for my study will not only allow me to generate data that will answer questions about metabolism in NF1, but foster interest in this topic so there are more opportunities for researchers in the future.”

The NFRP was initiated in 1996 to provide support for research of exceptional scientific merit that promotes the understanding, diagnosis, and treatment of neurofibromatosis (NF) including NF type 1 (NF1) and type 2 (NF2) and schwannomatosis. Since it was first offered, 346 new Investigator Award applications have been received and only 79 have been recommended for funding – with Children’s National receiving one in the latest grant cycle. The Gilbert Family Neurofibromatosis Institute at Children’s National is one of the world’s largest programs and the longest standing program in the United States.

Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the Department of Defense.

Maddox and family

Family love and the right care for neurofibromatosis type 1 give Maddox a fresh start

Maddox and family

Maddox and his family in early 2020.

13-year-old Maddox Gibson is learning to cook. He says he wants to be a chef and wants to make meals for people who need it most — the homeless and the hungry.

It makes sense that he’s eager to help people who need it. As a young child growing up in a group home in his native country of China, he knows firsthand how important that support can be. In 2017 at age 10, he found his own endless supply of love and support when he met and was adopted by the Gibson family.

Zhen Chao, now called Maddox, was born in China with a genetic condition called neurofibromatosis type 1 that can cause painful or disfiguring tumors called plexiform neurofibromas. Zhen Chao had two on his head when he arrived — on his scalp and on his left optic nerve — which had been largely untreated for most of his life in China. On top of that, his right leg had been fractured and not fixed properly years before, causing him pain and weakness that left him wheelchair bound.

Adoptive mom Lindsey, a registered nurse, knew he would need special care to meet all the unique challenges he faced, and she’d done her homework — he needed the expertise of Miriam Bornhorst, M.D.,  and the Gilbert Family Neurofibromatosis Institute at Children’s National Hospital to help him thrive in his new life in the U.S. Since shortly after he came to the U.S., Lindsey has been driving Maddox the 6-plus hours from their home in North Carolina to Washington, D.C., regularly, to get care for all of his health challenges.

Maddox’s optic neurofibroma was too large when he arrived at Children’s National for a simple surgical removal. Due to her role as the lead investigator on a cutting edge clinical trial for the orphan drug selumetinib — a so-called MEK inhibitor that has shown early promise at reducing the cell growth of tumors like plexiform neurofibromas, Dr. Bornhorst enrolled Maddox in a compassionate use program for the drug, an opportunity that is not widely available. The drug was initially developed for something completely different — treatment of melanoma and non-small cell lung cancer in adults–but has been adapted through its FDA orphan drug designation for pediatric clinical trials in NF1. In the time since Maddox started taking it, it was approved for use in NF1 patients by the FDA.

The trial drug did its job — in late 2019, Maddox’s tumor had shrunk enough that chief neurosurgeon Robert Keating, M.D., and plastic surgeon Michael Boyajian, M.D., were able to successfully remove it. Follow-up procedures led by that team have also worked to repair the tissue that was impacted by the optic neurofibroma.

In addition to treatment of his neurofibromas, Maddox and his mom are able to see every service they need during one stay in D.C. The Neurofibromatosis Institute works closely across specialties, so his corrective surgery for his leg from Children’s chief of orthopaedics, Matthew Oetgen, M.D., MBA, in September 2019. He was assessed and prescribed physical therapy early in the process and even before surgery, so now he’s stronger than ever and walking. Learning difficulties, including autism and ADHD are common in NF1 patients, and so the NF Institute’s neuropsychology team has evaluated him and worked with the family to find resources and strategies near home that will support him. It should be noted, those learning difficulties only became apparent after Maddox taught himself English from scratch in only two years’ time with the help of his school’s ESOL program.

This kind of full spectrum care, from clinical assessment to surgical treatment and psychological supports, is crucial to the lives of patients with neurofibromatosis type 1 and is only available at a pediatric specialty care institution like Children’s National. The hospital has gathered some of the preeminent researchers, surgeons, and physicians within the NF Institute to make sure that the care families will travel hundreds of miles to receive is the best possible, using the latest evidence-based treatments for every challenge they face.

Though his care and follow-ups will continue at Children’s National Hospital and his condition may pose  new challenges in the future, for now, Maddox is able to focus on exploring new things and doing what he loves — playing outdoors with his family, learning to cook and building with Legos.

Dr. Bornhorst talks with her patient Maddox Gibson,

A melanoma drug shows promise for NF1 plexiforms

Dr. Bornhorst talks with her patient Maddox Gibson,

Dr. Bornhorst talks with her patient Maddox Gibson, who is part of the compassionate use trial of selumentinib for which she serves as site principal investigator.

A class of drugs originally approved for stopping tumor growth in adult cancers including melanoma and small cell lung cancer may be the key to treating plexiform neurofibromas in neurofibromatosis type 1 (NF1), too. If effective, doctors will finally have a treatment to offer for children with complicated plexiform neurofibromas that can’t be removed via surgery.

These drugs, including selumentinib, work by inhibiting the activity of the mitogen-activated protein kinase enzymes MEK1 and MEK2. The enzymes have a direct impact on the activity of the cellular signaling pathway MAPK/ERK, which can be overactive some cancers.

Ongoing pre-clinical studies made possible by national and international neurofibromatosis research collaborations demonstrated that this same pathway is overactive in children with NF1 who have plexiform neurofibromas. The compelling findings from these studies set the stage for clinical trials to test the safety and efficacy of selumetinib and other MEK inhibitors as a therapy for pediatric NF1 patients with inoperable plexiform neurofibromas.

At Children’s National, these studies are run by clinicians such as Miriam Bornhorst, M.D., clinical director of the Gilbert Family Neurofibromatosis Institute and AeRang Kim, M.D., Ph.D. Children’s is one of only four sites in the United States to participate in a National Institutes of Health-led clinical trial to study the use of selumetinib in NF1. Dr. Kim is the site principal investigator and Dr. Bornhorst serves as co-principal investigator on phase 2 of the trial.

“Any time we find a medication that works with NF1, we’re excited, especially because for so many years, we didn’t have any of these options for these families,” Dr. Bornhorst says. “We’re offering something these families have never had before – a treatment that may stop growth and maybe even keep these tumors from returning. It means we’re doing more than managing symptoms – we’re really treating them.”

NF1 affects a relatively small number of people, particularly children. However, researchers and clinicians who are dedicated to the condition have banded together via collaborations and consortia to fuel research and development of new therapies across multiple institutions in the U.S. and abroad.

“Patients come to see me who’ve been at our clinic for years and I’ll talk about MEK inhibitors, and they are just shocked to hear there may be a new option,” Dr. Bornhorst says.

The NIH trial continues to collect data at four U.S. centers, with the ultimate goal of submitting the results for FDA review. Additional data is also collected from patients who didn’t qualify for the trial but who received the drug for compassionate use, an effort led by Dr. Bornhorst. The information collected from that compassionate use trial also helps investigators make the case to broaden the eligibility criteria for future trials.

“The medications are showing that they work,” Dr. Bornhorst notes. “Now we need to determine how to identify the patients who we know will need these therapies.”

To meet that need, other studies, led by both Dr. Bornhorst and Dr. Kim, seek radiographic and blood biomarkers that will identify children with NF1 who are more likely to develop plexiform neurofibromas, and whose plexiforms may progress to something malignant.