Running Against Erythropoietic Protoporphyria: Emily Pearson’s Journey

Emily Pearson was only 8 years old when she began experiencing painful reactions after spending a few minutes in the sun. Her hands and feet would feel as if they were in a hot oven poked with pins and needles, causing her significant distress and discomfort for days at a time. Despite these severe symptoms, no one knew why she was affected in this way.

Over the next decade, Pearson’s parents sought medical advice to identify the cause of her reactions. Sunblock was ineffective, prompting her to wear protective clothing and minimize her time outdoors. Family vacations in Minnesota became unusually challenging, as any extended sun exposure led to painful consequences for her hands, feet, and face.

At 17, Pearson received a diagnosis of erythropoietic protoporphyria (EPP) from a doctor at the Mayo Clinic in Rochester, Minnesota. This rare skin disorder makes a person essentially allergic to the sun. Although this diagnosis brought some relief, Pearson had to contend with the reality of limited treatment options for her condition.

Running provided a form of solace for Pearson. After 12 years of competitive swimming, she transitioned to running half-marathons when she finished high school. To avoid triggering painful reactions, she ran either in layers or during sunrise and sunset. Despite the difficulties, running brought her immense joy.

While Pearson dreamed of participating in marathons, she assumed her condition made it unattainable. During college, any outdoor activity without protective gear would result in severe pain. Everyday tasks like grocery shopping or filling up the car became mental and emotional burdens due to the precautions required.

In 2025, Pearson volunteered at Sun Escape—a camp for children with EPP and similar conditions—where she learned about a clinical trial for bitopertin, a drug offering potential relief. Intrigued, she researched further, though skeptical of its efficacy.

Dr. Sioban Keel, a porphyria expert at the University of Washington involved in the trial, explained that bitopertin targets protoporphyrin IX—a molecule activated by sunlight in the skin. People with EPP have genetic mutations leading to excess protoporphyrin IX, causing painful reactions. Taken as a daily pill, bitopertin reduces these levels, thus enhancing sunlight tolerance.

Participating in the trial’s second phase, Pearson began bitopertin treatment in July 2025. She regularly traveled to Boston for medical evaluations. Within weeks, her sunlight tolerance improved significantly. Keel noted similar success stories among other trial participants.

Clinical trial data published by Disc Medicine in April showed substantial reductions in protoporphyrin-IX levels among EPP patients and improved sunlight tolerance with no significant safety concerns. Bitopertin is now in Phase 3 with 183 patients enrolled, and data expected in late 2026.

Pearson remains on bitopertin through an open-label extension of the trial. Her improved tolerance enabled her to run her first marathon in October 2025. Proudly, she wore ordinary athletic attire throughout the race, enjoying the experience free of the usual anxiety associated with sun exposure.

Her success encouraged Pearson to further test her limits. She trained for a subsequent marathon held in June and then spent a sun-filled week at her family’s cabin without adverse reactions. While minor reactions occasionally occur after extended outdoor activity, they are far less severe, marking a remarkable increase in her tolerance.

Looking ahead, Pearson intends to take things easy in the coming months, but she plans to participate in another marathon in June 2027. She also hopes to try a triathlon, blending her passion for running and swimming. With newfound independence from her previous anxiety around sun exposure, the future appears promising.

“I’m living worry-free, unlike before,” Pearson said. “I am much happier and more energetic. My life has transformed dramatically.”