Tisagenlecleucel (Kymriah): First FDA-Approved CAR-T Cell Therapy

The concept of engineering a patient's own immune cells to recognize and destroy cancer had been explored in various forms since the 1980s, but the chimeric antigen receptor approach moved the field into clinical relevance. Carl June's laboratory at the University of Pennsylvania spent years refining lentiviral transduction of T cells to express a receptor that coupled extracellular antibody-derived antigen binding to intracellular CD3-zeta and 4-1BB costimulatory signaling. Early results in chronic lymphocytic leukemia and in pediatric acute lymphoblastic leukemia were striking enough to attract Novartis as a commercial partner, and by the mid-2010s the therapy was entering multicenter trials.

Tisagenlecleucel, the CD19-targeting CAR-T product developed under that collaboration, received FDA approval on August 30, 2017, for B-cell ALL that was refractory or had relapsed at least twice, in patients up to age 25. The ELIANA trial, a single-arm global study led by Stephan Grupp at the Children's Hospital of Philadelphia, provided the primary evidence. Among the 75 infused patients evaluable for response, 81% achieved overall remission within three months. The population was heavily pretreated: participants had received a median of three prior lines of therapy, and more than 60% had previously undergone stem cell transplantation.

Manufacturing was not incidental to the approval; it was part of what made the therapy novel as a regulatory category. Patient T cells were collected by apheresis, shipped to a central manufacturing facility, transduced with the lentiviral vector, expanded in culture, and returned as a frozen infusion product. The entire process took three to four weeks. The FDA created a new designation, RMAT (Regenerative Medicine Advanced Therapy), to expedite review of such products. Cytokine release syndrome, caused by rapid immune activation after infusion, affected 77% of patients in ELIANA, with 48% experiencing severe CRS requiring intensive intervention.

Tocilizumab, an IL-6 receptor antagonist, was approved that same day, August 30, 2017, as the first FDA-approved treatment for severe CAR-T-induced cytokine release syndrome. That approval was based on a retrospective analysis of 45 adult and pediatric patients treated for severe CRS, building on earlier data from the University of Pennsylvania team showing that tocilizumab could reverse severe CRS without abrogating the antitumor response. Neurotoxicity, now termed immune effector cell-associated neurotoxicity syndrome, was separately characterized as a distinct complication with its own management algorithm.

A second CAR-T product, axicabtagene ciloleucel (Yescarta), developed by Kite Pharma, was approved weeks later for diffuse large B-cell lymphoma in adults, confirming that tisagenlecleucel's approval had opened a new product class. By 2023, six CAR-T therapies had received FDA approval across B-cell lymphomas, ALL, myeloma, and follicular lymphoma. Access, driven by cost (the initial list price of tisagenlecleucel was $475,000 for a single infusion), manufacturing capacity, and the need for specialized centers, remained the central challenge in broadening these approvals into population-level benefit.