How A 60-Year-Old Drug Developer Built A $4.4 Billion Biotech Treating ‘Butterfly Skin Disease’

Longtime drug developer Suma Krishnan was 51 when she cofounded Krystal Biotech. Now the company has one gene therapy on the market and more in the works.

By Amy Feldman, Forbes Staff


Longtime drug developer Suma Krishnan was in her late-40s when she had the idea for a topical gene therapy to treat a rare and terrible skin disorder in which the skin becomes as fragile as butterfly wings. In 2016, at 51, after a few months of modeling the idea and starting the process of patenting it, she and her husband Krish Krishnan, with whom she’d worked in biotech for more than a decade, cofounded Krystal Biotech.

Focusing on a rare disease, with just thousands of patients in the U.S., was unusual. So, too, was shunning venture capital in favor of self-funding a biotech startup, with some $5 million they’d made mainly from previous biotech companies. But perhaps the biggest bet was the science, taking a completely new approach to a problem with a gene therapy delivered as a gel that would potentially pay off big if it succeeded, but also stood a high chance of failure. “I had to work with the regulators because they had never seen this,” Krishnan told Forbes. “It was completely new.”

Just 18 months after launching the Pittsburgh-based company, the Krishnans took it public on the Nasdaq stock exchange. Today, Krystal has a market cap of $4.4 billion with one FDA-approved therapy, Vyjuvek, for that “butterfly skin disease,”called dystrophic epidermolysis bullosa, on the market, and other gene therapies, including for cystic fibrosis and lung cancer, in various stages of clinical development. All rely on the modified herpes simplex virus, but they have different delivery mechanisms. The company’s revenue reached $291 million for 2024, up more than five-fold from $51 million in 2023. Net income surged eightfold to $89 million from $11 million in the same period.

The Krishnans have a combined 12% stake in the business. Suma, the company’s president of research and development, is worth some $300 million by Forbes estimates, almost entirely from her stake in the business and sales of stock over the years. Krystal’s stock has been volatile: It’s up more than 1,300% since the IPO, but has fallen nearly 25% over the past year.

“You have to be brave and bold to do this,” Krishnan says. “I was never afraid of risk-taking. I never felt like I needed a stable job.”

Krishnan is one of the 200 entrepreneurs and leaders on this year’s Forbes’ 50 Over 50 list. These women—who this year also include actress Halle Berry, on the list for her menopause-related startup; social mission-oriented investor Freada Kapor Klein; and Maria Shriver, who founded the Women’s Alzheimer’s Movement toward the end of her first term as first lady of California—are all generating outsized professional impact in their sixth, seventh or eighth decades.

Suma Krishnan, who is now 60, grew up in Bombay where her parents struggled to raise three kids. As the middle child and a girl, Krishnan says, her mother, who married at 18, began looking for arranged marriages for her as soon as she finished college. She refused. “I always defied it and fought it,” she says. “I was a tough one for them. I broke all the rules.”

She came to the U.S. for graduate school, getting a master’s degree in organic chemistry at Villanova University. (While there, she met Krish Krishnan, who was getting his MBA at Wharton and lived nearby.) After that, she worked as a drug developer, starting at Janssen Pharmaceuticals. At New River Pharmaceuticals, she led the discovery, development and approval of Vyvanse, a blockbuster drug to treat ADHD. After European drugmaker Shire (acquired by Takeda for $62 billion in 2018) bought New River for $2.6 billion in 2007, she worked on rare diseases. Then, at Intrexon (now known as Precigen), she focused on gene therapy treatments as its head of therapeutics. She holds more than 70 patents for a variety of drugs. “For 25, 30 years, this is all that I did,” she says. “I am familiar with all kinds of rare diseases and where the unmet need is.”

“I was never afraid of risk-taking. I never felt like I needed a stable job.”

Krystal Biotech cofounder Suma Krishnan

She had an idea for a gene therapy for butterfly skin patients that could be delivered as a gel directly onto the affected skin using a modified version of the herpes simplex virus to deliver the treatment. The drug works by delivering a healthy copy of the gene that encodes a type of collagen to the skin cells, enabling healing to occur. Some 25,000 people in the United States have epidermolysis bullosa, but only around 3,000 of them have the dystrophic form of it, which is severe and for which Krystal’s treatment is used.

Brett Kopelan, executive director of Debra, a nonprofit for those affected by the disease, and whose daughter, now 17, was born with a severe form of it, calls it “the worst f—-ing disease you’ve never heard of.” Kids with it often live with constant pain and need to be bandaged on much of their bodies; they’re also susceptible to numerous other ailments, including a form of skin cancer. “My goal is to make this a chronic, livable disease like type 2 diabetes,” says Kopelan, whose daughter uses Krystal’s treatment, among others. “We’re getting really close to that, and we have Suma and Krish to thank.”

When she had the idea that became Vyjuvek, there were no treatments on the market. While she was at Intrexon, that company had been working with another biotech, Fibrocell (which has since been purchased by Castle Creek), on a hospital-based therapy. “I saw the pain and suffering,” Krishnan says. “These kids are born with missing skin from birth and it gets worse over time. They say, ‘Nobody cares about us.’”

She took the idea to her husband Krish, who had been the chief operating officer at New River and Intrexon and with whom she had worked for well over a decade. They decided to develop the drug—this time on their own. Biotech was booming and lab space was impossible to find in San Francisco. Instead, they searched the country for locations, settling up in a vacant lab space in Pittsburgh, a city known more for robotics startups than biotech but where they could hire grad students from Carnegie Mellon, at first flying back and forth from their home in northern California. They shunned VC funding, raising a small amount from friends and family and telling them bluntly to think of their investment as philanthropy. “We figured if it didn’t work out, we’d shut it down,” Krishnan says.

In 2017, they took the company public, raising $45 million, thanks to Krish Krishnan’s network taking previous companies through their IPOs. “It was a Mickey Mouse IPO,” he says, noting that it allowed an investor from Fidelity who’d backed his previous companies to become a shareholder.


Source: https://www.forbes.com/sites/amyfeldman/2025/07/31/the-butterfly-skin-disease-centimillionaire/