Story summary
Emily Pearson, now 27 and living in Minneapolis, has suffered from erythropoietic protoporphyria (EPP) since the age of 8, experiencing severe pain when exposed to sunlight. Just minutes outdoors caused her hands and feet to hurt intensely, similar to being poked with pins and needles or placed in a hot oven. After years of searching for answers, she was diagnosed at Mayo Clinic in Rochester, Minnesota, at 17.
A recent clinical trial involving the drug bitopertin has shown promise, significantly reducing protoporphyrin-IX levels and improving sunlight tolerance for EPP patients like Pearson. Currently, bitopertin is in Phase 3 trials with 183 participants, with expected results by the end of 2026's fourth quarter. For Pearson, whose condition has severely limited her daily activities and vacations, the trial offers hope for a better quality of life.
Written for “Light Sensitivity Treatment” on 2026-10-04,
grounded in this article and the 0 other(s) covering the same event.
Emily Pearson was 8 years old when the attacks started.
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attacks → start → ?
Just minutes in the sun would leave her hands and feet hurting.
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minutes → leave → hands
Her extremities "felt like they were in a hot oven" while being poked "with pins and needles."
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they → feel → pins
A short while outdoors could leave her in pain for days.
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while → leave → days
Worst of all, no one knew why.
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one → know → all
Over the next decade, Pearson's parents tried to identify the cause of her reactions.
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parents → try → reactions
Sunblock didn't help.
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Sunblock → help → ?
She started wearing protective clothing and staying indoors as much as possible.
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She → start → clothing
Vacations at her family's Minnesota cabin became an endurance test.
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Vacations → become → cabin
If she slipped up and found herself in the sun for too long, her hands, feet and face paid the price.
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hands → slip → price
I would never wish that pain upon anyone, because it's so horrible," said Pearson, who lives in Minneapolis.
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who → wish → Minneapolis
When she was 17, a doctor at the Mayo Clinic in Rochester, Minnesota, made the diagnosis of erythropoietic protoporphyria, a rare skin disorder that means a person is essentially allergic to the sun.
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person → make → sun
Having an answer was a relief, Pearson said — but it also meant she had to grapple with not being able to do much about her condition.
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she → have → condition
Pearson had been a competitive swimmer for 12 years, then transitioned into running half-marathons out of high school.
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Pearson → transition → school
She had to either layer up or run in the dark, at sunrise or at sunset, to avoid having a reaction.
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She → have → reaction
But the difficulties were worth the joy it brought her, she said.
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she → bring → her
Pearson dreamed of running a marathon, but believed her condition made that impossible.
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that → dream → marathon
Throughout college, braving the sun for a few hours of fun without protective gear would leave her "in severe pain" later.
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braving → brave → pain
"Going to the grocery store, going to get gas, going for any kind of car ride or working outside, you constantly have to think about what you're doing and how it's going to affect your health, and dealing with those consequences after," Pearson, now 25, said.
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Pearson → go → consequences
It was a big mental load, and it was never-ending.
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it → end → ?
In 2025, Pearson volunteered at Sun Escape, a weekend camp for kids with EPP and similar conditions.
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Pearson → volunteer → EPP
There, she learned about a clinical trial for a drug called bitopertin.
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she → learn → drug
She was intrigued and searched for more information.
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She → intrigue → information
"I was very wary of it, like, 'Does it really work?
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it → work → it
I know it works for other people, but will it work for me?'"
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it → know → me
Pearson remembered.
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Pearson → remember → ?
"I can't believe I'm hearing this"
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I → believe → this
Bitopertin works by targeting protoporphyrin IX, a naturally occurring molecule in the skin that is activated when people are exposed to sunlight, said Dr. Sioban Keel, a porphyria expert at the University of Washington who is involved in the clinical trial.
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who → work → trial
In patients with EPP and similar conditions, mutations mean the body creates too much protoporphyrin IX, resulting in painful reactions.
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body → mean → reactions
Bitopertin, taken as a once-daily pill, lowers the amount of protoporphyrin IX in those patients, Keel explained.
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Keel → take → patients
Clinical trials in the U.S. have four phases, as defined by the U.S. Food and Drug Administration.
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trials → have → Administration
The first stage involves a small group of participants and determines if a drug is safe and sets its dosage.
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drug → involve → dosage
In the second phase, up to several hundred people are studied for months or years.
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people → study → months
This is the stage that determines how effective a drug is, as well as what side effects it may have.
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it → determine → effects
The third and fourth stages expand that to an even larger population for longer periods.
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stages → expand → periods
After the process is complete, the FDA reviews the data and decides whether or not to approve the medication for use in the general public.
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FDA → review → public
As a participant in the trial's second stage, Pearson began taking bitopertin regularly in July 2025.
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Pearson → begin → July
She had regular appointments with physicians in Boston to follow her progress.
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She → have → progress
Within weeks, she began to do "really, really well," and her tolerance to the sun started to increase.
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tolerance → begin → sun
Keel, who did not treat Pearson, said she's heard similar stories from other patients involved in the trial.
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she → treat → trial
…and 24 more, not listed.
The Aporia
