Hospital Marks Anniversary of First Personalized CRISPR Therapy

- The patient, KJ Muldoon, was born with a rare metabolic disease called severe carbamoyl phosphate synthetase 1 (CPS1) deficiency. This condition, which affects about 1 in 1.3 million newborns, prevented his body from breaking down protein, leading to toxic ammonia buildup. - A team of physician-scientists, including Dr. Rebecca Ahrens-Nicklas and Dr. Kiran Musunuru from CHOP and Penn Medicine, led the development of the personalized therapy. Their work represents a blend of direct patient care and intensive laboratory research, showcasing career paths that bridge medicine and scientific discovery. - The bespoke treatment was developed and administered in just six months, a remarkably fast timeline for a personalized gene therapy. This rapid development was a collaborative effort involving academic researchers and industry partners who manufactured the components for the therapy. - The therapy utilized a base editor, a newer form of CRISPR technology, delivered to the liver via lipid nanoparticles to correct the specific mutation in the *CPS1* gene. This approach highlights the work of biochemists and molecular biologists in designing and engineering the therapeutic molecules. - One year after receiving his first of three infusions in February 2025, KJ is reportedly thriving, able to eat more protein, and hitting developmental milestones like walking and talking. - Prior to this personalized therapy, the only FDA-approved CRISPR-based treatments were for more common genetic diseases like sickle cell disease and beta thalassemia, which use a more standardized approach. - The success of this single-patient therapy has prompted discussions about creating new regulatory pathways for approving highly personalized medical treatments for other rare diseases. - The team and patient's family have advocated on Capitol Hill for increased funding and policies to expand access to similar personalized gene therapies for other children with rare diseases.