Abstract
Introduction: Chimeric Antigen Receptor (CAR) T-cell therapy targeting CD19 has demonstrated high efficacy in relapsed/refractory (R/R) B-cell malignancies. However, its implementation in low- and middle-income countries (LMICs), particularly in Latin America, remains limited due to logistical, access and manufacturing barriers. This study presents interim results of a pioneering academic Phase I point-of-care CD19-directed CAR-T cell trial, conducted entirely within a Brazilian academic institution.
Objective: To evaluate the safety, manufacturing feasibility, and preliminary efficacy of autologous CD19 CAR-T therapy in patients with R/R B-cell malignancies.
Methods: This single-center, prospective Phase I trial evaluated autologous CAR-T cell therapy manufactured onsite using the CliniMACS Prodigy system (Miltenyi Biotec). Patient-derived T cells were transduced with a lentiviral vector encoding an anti-CD19 scFv, a CD8 hinge, the transmembrane domain of TNFRSF19, and intracellular signaling regions from 4-1BB and CD3ζ. The manufacturing process spanned 12 days, during which cells were expanded and maintained under GMP-compliant conditions. Patients were assigned to one of three cohorts based on disease type and age: cohort 1 (pediatric ALL), cohort 2 (adult ALL), and cohort 3 (adult NHL or CLL). A standard 3+3 dose-escalation design was used, with CAR+ cell doses ranging from 5×10⁵, 1×10⁶ and 2×10⁶ cells/kg, following lymphodepletion with fludarabine (25 mg/m²/day for 3 days) and cyclophosphamide (60 mg/kg on day –1).
Results: Eighteen patients were screened; seven were excluded due to lack of active disease (n=4), active infection (n=1), protocol-ineligible comorbidity (n=1), or pending treatment (n=1). Eleven patients received CAR-T infusion. Median age was 42 years (range: 9–69), and 72.7% were male. All patients were from Latin America and came from different regions of Brazil (North, Northeast and Southeast). Diagnoses included ALL (n=4), CLL (n=2), and NHL (n=5). Median number of prior therapies was 4 (range: 2–10); all patients had ECOG 0–1. Six patients (54.5%) had High CAR-HEMATOTOX (≥2) scores. Manufacturing success was 100%, with a median vein-to-vein time of 22.3±7.9 days. Fresh products were infused in 36% and cryopreserved in 63%.
Cytokine release syndrome (CRS) occurred in 90% (Grade 3: 9%) and immune effector cell-associated neurotoxicity syndrome (ICANS) in 45% (Grade 3–4: 27%); all events were reversible. Infections occurred in 72%, with CMV reactivation and bacterial pneumonia each observed in 36%. RBC and PLT transfusions were required in 90.9% of patients, with 54.5% requiring support beyond day +30. 0. High CAR-HEMATOTOX (≥2) was not associated with increased transfusion needs.Overall response rate (ORR) was 81% (95% CI: 48.2–97.7), including 72% complete responses (CR) (95% CI: 39.0–93.9). At a median follow-up of 11 months, 7 of 11 infused patients were alive and progression-free (4 ALL, 1 CLL, 2 NHL). Two patients with NHL died: one from early disease progression (day +115) and one from Acinetobacter baumannii sepsis (day +10), which precluded response assessment. Among non-CR patients, one with NHL relapsed after initial CR (1 year post-infusion) and one with CLL progressed after partial response but is alive on day +164. PFS was 71% (95% CI: 35.0–89.9), OS was 80% (95% CI: 42.4–94.8), and median OS was not reached.
Peak CAR-T expansion by flow cytometry occurred between days 10–14 in NHL (mean CAR+ in CD3+: 34.4%), days 7–10 in ALL (mean CAR+ in CD3+: 61.9%), and day 21 in CLL (mean CAR+ in CD3+: 19.1%). CAR-T cells remained detectable up to day +360. Central memory T cells predominated during peak expansion (means: 70%, 68%, 71%, and 63.7% on days 7, 10, 14, and 21), followed by effector memory T cells (means: 23.1%, 21.4%, 19.6%, and 14.1%, respectively).
Conclusion: Point-of-care, academic CD19 CAR-T cell manufacturing in Brazil is feasible, safe, and demonstrates promising early efficacy in patients with R/R B-cell malignancies. Toxicity was manageable, and the approach shows potential for broader implementation in Latin America. These results underscore the key role of industry-academic institutions partnerships in expanding access to cellular therapies in resource-limited settings. This initiative was supported by the Brazilian Ministry of Health, highlighting the importance of public investment in fostering innovation and equity in access to advanced therapies in LMICs.
