4D Molecular Therapeutics: Delivering Gene Therapy Cures
Company founded: 2013
Founders: UC Berkeley Professor David Schaffer, David Kirn (UC Berkeley, Bachelor of Arts, 1985, Physiology & Physical Anthropology), Melissa Kotterman (UC Berkeley, Ph.D., 2013, Chemical and Biomolecular Engineering), Theresa Janke
David Schaffer is a UC Berkeley professor of chemical and biomolecular engineering, bioengineering, and molecular and cell biology. He is an inventor on more than fifty patents and a serial entrepreneur, having cofounded eight companies as of 2024.1
According to Schaffer, the old joke in the field of gene therapy is that there are only three problems with gene therapy: delivery, delivery, delivery. That inspired him and cofounder David Kirn to spin out 4D Molecular Therapeutics (4DMT) in 2013, based on directed evolution technology used in Schaffer’s lab to solve the problem of gene therapy delivery. 4DMT licensed the patent rights from the university and built a proprietary Therapeutic Vector Evolution platform to develop adeno-associated viruses (AAV) vectors and related gene therapies. The startup initially targeted cures for blinding diseases ranging from inherited defects like retinitis pigmentosa to degenerative illnesses of old age, such as macular degeneration.
Schaffer met Kirn during an event at QB3, a University of California hub for innovation and entrepreneurship in the life sciences. Getting to know each other, they determined they had a lot in common. Kirn, a biotechnology entrepreneur and physician-scientist, had already cofounded a number of startups as well as consulted on clinical development programs. “Working with David has been fruitful,” Schaffer said. “I’ve been able to come up-to-speed on the business side of developing startups along with working with him on clinical trials.”2
4DMT began operating in the QB3 Garage incubator. The company’s first hire was Melissa Kotterman, who had prior experience with Schaffer as a graduate student in his lab where she worked on the gene therapy technology that the university licensed to 4DMT.3 In 2019, Kotterman said, “I think it is very rare for a graduate student to have a direct opportunity, so quickly out of graduate school, to see their research really be translated, able to help patients in a really, really, rapid way.”4 Now a serial entrepreneur and investor, Kotterman advises new founders in the QB3 mentoring program.
In a 2019 interview, Schaffer discussed how he manages both his lab and multiple startups: “My lab is always going to be my priority, but that said, being able to work with companies has really benefited the lab in a couple of ways. It has taught me about the next steps of drug development, and that has helped the way that I shape the research in our lab. And it has also really motivated the people in the lab—I can say that something a graduate student created a few years ago is in a human clinical trial.”5 In December 2020, 4DMT raised $193 million in its initial public offering that valued the company at about $500 million. As of 2024, 4DMT has grown into a clinical-stage biopharma company developing therapies that unlock the full potential of genetic therapy to treat a range of diseases.
When asked what advice he has for up-and-coming young entrepreneurial scientists, Schaffer said: “It’s important to learn across fields. You need to figure out how to ‘speak’ both science and business. You can consider a multi-disciplinary approach, which could mean taking classes outside your major or doing research across fields. UC Berkeley recognizes the need for such training and now offers simultaneous degree programs that allow students to study both science and business, but nothing can replace the hands-on experience of starting a new company.”6
1In addition to 4D Molecular Therapeutics, other companies that Schaffer cofounded include Axent Biosciences, Ignite Immunotherapy (acquired by Pfizer), Rewrite Therapeutics (acquired by Intellia), and Valitor.
2Marge D’Wylde, “The College of Chemistry and the Startup Culture,” Catalyst Magazine (Spring/Summer 2019), 15, https://escholarship.org/uc/item/6t84c4sd.
3In 2024, Melissa Kotterman joined Dave Schaffer’s most recent startup as the company’s CEO.
4, 5, 6D’Wylde, “The College of Chemistry and the Startup Culture,” 15.
Published in Startup Campus: How UC Berkeley Became an Unexpected Leader in Entrepreneurship and Startups, August 2025
