Vaccines for COVID-19 were the first time that mRNA technology was used to address a worldwide health challenge. The Penn Medicine scientists behind that technology were awarded the 2023 Nobel Prize in Physiology or Medicine. Next come all the rest of the potential new treatments made possible by their discoveries.
Starting in the late 1990s, working together at Penn Medicine, Katalin Karikó and Drew Weissman discovered how to safely use messenger RNA (mRNA) as a whole new type of vaccine or therapy for diseases. When the COVID-19 pandemic hit in 2020, these discoveries made Pfizer/BioNTech and Moderna’s new vaccines possible—saving millions of lives.
But curbing the pandemic was only the beginning of the potential for this Nobel Prize-winning technology.
These biomedical innovations from Penn Medicine in using mRNA represent a multiuse tool, not just a treatment for a single disease. The technology’s potential is virtually unlimited; if researchers know the sequence of a particular protein they want to create or replace, it should be possible to target a specific disease. Through the Penn Institute for RNA Innovation led by Weissman, who is the Roberts Family Professor of Vaccine Research in Penn’s Perelman School of Medicine, researchers are working to ensure this limitless potential meets the world’s most challenging and important needs.
Infectious diseases and beyond
Just consider some of the many projects Weissman’s lab is partnering in: “We’re working on malaria with people across the U.S. and in Africa,” Weissman says. “We’re working on leptospirosis with people in Southeast Asia. We’re working on vaccines for peanut allergies. We’re working on vaccines for autoimmunity. And all of this is through collaboration.”
Clinical trials are underway for the new malaria vaccine, as well as for a Penn-developed mRNA vaccine for genital herpes and one that aims to protect against all varieties of coronaviruses. Trials should begin soon for vaccines for norovirus and the bacterium C. difficile.
Single-injection gene therapies for sickle cell and heart disease
The Weissman lab is working to deploy mRNA technology as an accessible gene therapy for sickle cell anemia, a devastating and painful genetic disease that affects about 20 million people around the world. About 300,000 babies are born each year with the condition, mainly in sub-Saharan Africa. Weissman’s team has developed technology to efficiently deliver modified mRNA to bone marrow stem cells, instructing red blood cells to produce normal hemoglobin instead of the malformed “sickle” version that causes the illness.
Conventional gene therapies are complex and expensive treatments, but the mRNA gene therapy could be a simple, one-time intravenous injection to cure the disease. Such a treatment would have applications to many other congenital gene defects in blood and stem cells.
In another new program, Penn Medicine researchers have found a way to target the muscle cells of the heart. This gene therapy method developed by Weissman’s team, together with Vlad Muzykantov, the Founders Professor in Nanoparticle Research, could potentially repair the heart or increase blood flow to the heart, noninvasively, after a heart attack or to correct a genetic deficiency in the heart. “That is important because heart disease is the number one killer in the U.S. and in the world,” Weissman says. “Drugs for heart disease aren’t specific for the heart. And when you’re trying to treat a myocardial infarction or cardiomyopathy or other genetic deficiencies in the heart, it’s very difficult, because you can’t deliver to the heart.”
Weissman’s team also is partnering on programs for neurodevelopmental diseases and for neurodegenerative diseases, to replace genes or deliver therapeutic proteins that will treat and potentially cure these diseases.
“The potential is unbelievable,” Weissman says. “We haven’t thought of everything that can be done.”
Global access to lifesaving mRNA therapies
Crucially, mRNA technology is simple enough that it should be possible to make these future treatments for sickle cell and other diseases available around the world, at low cost, even in places with few resources. And this is a priority for Weissman and for Penn. “It’s just an IV injection,” Weissman explains. “You can do that anywhere. You don’t need fancy equipment, a fancy medical center. You give somebody an IV injection, and you’re done.”
To date, Weissman has partnered in building 18 mRNA-capable Good Manufacturing Practice (GMP) sites across the world, a type of specialized production facility that can make drugs and vaccines for human use. All of these sites are beginning with manufacturing vaccines in low- and middle-income countries, Weissman says, but all are interested in developing therapeutics and gene therapies. “I think, in the next few years, we’re going to see more and more of these GMP sites and research infrastructure sites across the world developing new and novel treatments.”
Collaboration is key for the global reach of Penn Medicine’s mRNA research, something at the heart of new lab space that is home to Weissman’s team, allowing them to partner with colleagues across teams.
“It would be impossible for the members of my lab to have to learn and set up new model systems for every disease we wanted to follow,” Weissman says. “We find the best people in the world and ask them, ‘Do you want to collaborate on making this vaccine or therapeutic?’ And to me, that’s the most important thing that makes research work, and that allows research to move forward.”
