GD2-CART01 for Relapsed or Refractory High-Risk Neuroblastoma.

BACKGROUND: Immunotherapy with chimeric antigen receptor (CAR)-expressing T cells that target the disialoganglioside GD2 expressed on tumor cells may be a therapeutic option for patients with high-risk neuroblastoma. METHODS: In an academic, phase 1-2 clinical trial, we enrolled patients (1 to 25 years of age) with relapsed or refractory, high-risk neuroblastoma in order to test autologous, third-generation GD2-CAR T cells expressing the inducible caspase 9 suicide gene (GD2-CART01). RESULTS: A total of 27 children with heavily pretreated neuroblastoma (12 with refractory disease, 14 with relapsed disease, and 1 with a complete response at the end of first-line therapy) were enrolled and received GD2-CART01. No failure to generate GD2-CART01 was observed. Three dose levels were tested (3-, 6-, and 10×106 CAR-positive T cells per kilogram of body weight) in the phase 1 portion of the trial, and no dose-limiting toxic effects were recorded; the recommended dose for the phase 2 portion of the trial was 10×106 CAR-positive T cells per kilogram. Cytokine release syndrome occurred in 20 of 27 patients (74%) and was mild in 19 of 20 (95%). In 1 patient, the suicide gene was activated, with rapid elimination of GD2-CART01. GD2-targeted CAR T cells expanded in vivo and were detectable in peripheral blood in 26 of 27 patients up to 30 months after infusion (median persistence, 3 months; range, 1 to 30). Seventeen children had a response to the treatment (overall response, 63%); 9 patients had a complete response, and 8 had a partial response. Among the patients who received the recommended dose, the 3-year overall survival and event-free survival were 60% and 36%, respectively. CONCLUSIONS: The use of GD2-CART01 was feasible and safe in treating high-risk neuroblastoma. Treatment-related toxic effects developed, and the activation of the suicide gene controlled side effects. GD2-CART01 may have a sustained antitumor effect. (Funded by the Italian Medicines Agency and others; ClinicalTrials.gov number, NCT03373097.).

Allogeneic, donor-derived, second-generation, CD19-directed CAR-T cells for the treatment of pediatric relapsed/refractory BCP-ALL.

Autologous CD19-directed chimeric antigen receptor (CAR)-T cells have shown unprecedented efficacy in children with relapsed/refractory B-cell precursor acute lymphoblastic leukemia (BCP-ALL). However, patients either relapsing after allogeneic hematopoietic stem cell transplantation (allo-HSCT) or displaying profound lymphopenia and/or rapidly progressing disease often cannot access autologous products. These hurdles may be overcome by allogeneic, donor-derived CAR-T cells. We tested donor-derived T cells transduced with a second-generation (4.1BB) CD19-directed CAR for treatment of patients with BCP-ALL in a hospital-exemption setting. Two constructs were tested: a retroviral construct incorporating the suicide gene inducible caspase-9 (CD19-CAR-Retro_ALLO) first and then a lentiviral construct and an automated, Prodigy-based manufacturing process (CD19-CAR-Lenti_ALLO). Thirteen children/young adults received ALLO-CAR-T cells between March 2021 and October 2022. Doses ranged between 1.0 × 106 and 3.0 × 106 CAR-T cells per kg. The toxicity profile was comparable with that of autologous CAR-T cells, characterized mainly by cytopenia, cytokine release syndrome (maximum grade 1), and grade 2 immune-effector cell-associated neurotoxicity syndrome. One case of acute graft-versus-host disease (GVHD) occurred and was rapidly controlled with steroids and ruxolitinib. None of the other patients, including 3 given ALLO-CAR-T cells from an HLA-haploidentical donor, experienced GVHD. Two patients received ALLO-CAR-T cells before HSCT and showed a significant expansion of CAR-T cells without any sign of GVHD. All patients obtained complete remission (CR) with absence of minimal residual disease in the bone marrow. With a median follow-up of 12 months (range, 5-21), 8 of 13 patients maintained CR. Allogeneic anti-CD19 CAR-T cells can effectively treat highly refractory BCP-ALL relapsing after allo-HSCT without showing increased toxicity as compared with autologous CAR-T cells.

Allogeneic chimeric antigen receptor T cells for children with relapsed/refractory B-cell precursor acute lymphoblastic leukemia.

Chimeric antigen receptor (CAR) T-cell therapy has emerged as a breakthrough cancer therapy over the past decade. Remarkable outcomes in B-cell lymphoproliferative disorders and multiple myeloma have been reported in both pivotal trials and real-word studies. Traditionally, the use of a patient's own (autologous) T cells to manufacture CAR products has been the standard practice. Nevertheless, this approach has some drawbacks, including manufacturing delays, dependence on the functional fitness of the patient's T cells, which can be compromised by both the disease and prior therapies, and contamination of the product with blasts. A promising alternative is offered by the development of allogeneic CAR-cell products. This approach has the potential to yield more efficient drug products and enables the use of effector cells with negligible alloreactive potential and a significant CAR-independent antitumor activity through their innate receptors (i.e., natural killer cells, γδ T cells and cytokine induced killer cells). In addition, recent advances in genome editing tools offer the potential to overcome the primary challenges associated with allogeneic CAR T-cell products, namely graft-versus-host disease and host allo-rejection, generating universal, off-the-shelf products. In this review, we summarize the current pre-clinical and clinical approaches based on allogeneic CAR T cells, as well as on alternative effector cells, which represent exciting opportunities for multivalent approaches and optimized antitumor activity.

Mucosal-associated invariant T cells are functionally impaired in pediatric and young adult patients following allogeneic hematopoietic stem cell transplantation and their recovery correlates with clinical outcomes.

Mucosal-associated invariant T (MAIT) cells are innate-like T-cells implicated in the response to fungal and bacterial infections. Their contribution to restoring T-cell immunity and influencing hematopoietic stem cell transplant (HSCT) outcomes remains poorly understood. We retrospectively studied MAIT-cell recovery in 145 consecutive children and young adults with hematological malignancies undergoing allo-HSCT, between April/2019 and May/2022, from unrelated matched donor (MUD, n=52), with standard graft-versus-host-disease (GvHD) prophylaxis, or HLA-haploidentical (Haplo, n=93) donor after in vitro αßT/CD19-cell depletion, without post-HSCT pharmacological prophylaxis. With a median follow-up of 33 months (12-49), overall survival (OS), disease-free survival (DFS) and non-relapse mortality (NRM) were 79.5%, 72% and 7%, respectively; GvHD-free, Relapse-free Survival (GRFS) was 63%, while cumulative incidence of relapse was 23%. While WWT-cells reconstituted 1-2 years post-HSCT, MAIT-cells showed delayed recovery and prolonged functional impairment, characterized by expression of activation (CD25, CD38), exhaustion (PD1, TIM3) and senescence (CD57) markers, and suboptimal ex vivo response. OS, DFS and NRM were not affected by MAIT-cells. Interestingly, higher MAIT-cells at day+30 correlated with higher incidence of grade II-IV acute GvHD (19% vs 7%, p=0.06). Furthermore, a greater MAIT-cell count tended to be associated with a higher incidence of chronic GvHD (17% vs 6%, p=0.07) resulting in lower GRFS (55% vs 73%, p=0.05). Higher MAIT-cells also correlated with greater cytomegalovirus (CMV) reactivation and lower late blood stream infections (BSI) (44% vs 24%, p=0.02 and 9% vs 18%, p=0.08, respectively). Future studies are needed to confirm the impact of early MAIT-cell recovery on cGvHD, CMV reactivation and late BSI.

Human leukocyte antigen evolutionary divergence influences outcomes of paediatric patients and young adults affected by malignant disorders given allogeneic haematopoietic stem cell transplantation from unrelated donors.

High genetic heterogeneity in the human leukocyte antigen (HLA) increases the likelihood of efficient immune response to pathogens and tumours. As measure of HLA diversity, HLA evolutionary divergence (HED) has been shown to predict the response of tumours to immunotherapy and haematopoietic stem cell transplantation (HSCT) in adults. We retrospectively investigated the association of HED with outcomes of 153 paediatric/young adults patients, treated for malignant disorders with HSCT from 9-10/10 HLA-matched unrelated donors. HED was calculated as pairwise genetic distance between alleles in patient HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1, using the locus median to stratify patients with 'high' or 'low' HED. Patients with high HED-B and -DRB1 showed significantly improved disease-free survival (DFS), especially when combined (70.8% vs 53.7% p = 0.008). High HED-B + -DRB1 was also associated with improved overall survival (OS) (82.1 vs 66.4% p = 0.014), and concomitant reduction of non-relapse-mortality (5.1% vs 21.1% p = 0.006). The impact on OS and DFS of combined HED-B + -DRB1 was confirmed in multivariate analysis [hazard ratio (HR) 0.39, p = 0.009; and HR 0.45, p = 0.007 respectively]. Only high HED scores for HLA-DPB1 were associated, in univariate analysis, with reduced incidence of relapse (15.9% vs 31.1%, p = 0.03). These results support HED as prognostic marker in allogeneic HSCT and, if confirmed in larger cohorts, would allow its use to inform clinical risk and potentially influence clinical practice.

Brentuximab vedotin in combination with bendamustine in pediatric patients or young adults with relapsed or refractory Hodgkin lymphoma.

Although children and young adults with Hodgkin's lymphoma usually have a favorable prognosis, patients with primary refractory disease and some subsets of relapsed patients still have a dismal outcome. Brentuximab vedotin (BV) in combination with bendamustine may represent a suitable salvage therapy; data on 32 patients aged less than 25 years were retrospectively analyzed. Patients received up to six cycles of treatment of BV 1.8 mg/kg on day 1 and bendamustine 90-120 mg/m2 on days 2 and 3. At the end of treatment, the overall response rate was 81%. The 3-year overall and progression-free survivals are 78.1% and 67%, respectively.

Antifungal Effect of All-trans Retinoic Acid against Aspergillus fumigatus In Vitro and in a Pulmonary Aspergillosis In Vivo Model.

Aspergillus fumigatus is the most common opportunistic fungal pathogen and causes invasive pulmonary aspergillosis (IPA), with high mortality among immunosuppressed patients. The fungistatic activity of all-trans retinoic acid (ATRA) has been recently described in vitro We evaluated the efficacy of ATRA in vivo and its potential synergistic interaction with other antifungal drugs. A rat model of IPA and in vitro experiments were performed to assess the efficacy of ATRA against Aspergillus in association with classical antifungal drugs and in silico studies used to clarify its mechanism of action. ATRA (0.5 and 1 mM) displayed a strong fungistatic activity in Aspergillus cultures, while at lower concentrations, synergistically potentiated fungistatic efficacy of subinhibitory concentration of amphotericin B (AmB) and posaconazole (POS). ATRA also enhanced macrophagic phagocytosis of conidia. In a rat model of IPA, ATRA reduced mortality similarly to posaconazole. Fungistatic efficacy of ATRA alone and synergistically with other antifungal drugs was documented in vitro, likely by inhibiting fungal heat shock protein 90 (Hsp90) expression and Hsp90-related genes. ATRA treatment reduced mortality in a model of IPA in vivo Those findings suggest ATRA as a suitable fungistatic agent that can also reduce dosage and adverse reactions of classical antifungal drugs and add to the development of new therapeutic strategies against IPA and systemic fungal infections.

CD28.OX40 co-stimulatory combination is associated with long in vivo persistence and high activity of CAR.CD30 T-cells.

The prognosis of many patients with chemotherapy-refractory or multiply relapsed CD30+ non-Hodgkin Lymphoma (NHL) or Hodgkin lymphoma (HL) still remains poor, and novel therapeutic approaches are warranted to address this unmet clinical need. In light of this consideration, we designed and pre-clinically validated a Chimeric Antigen Receptor (CAR) construct characterized by a novel anti-CD30 single-chain variable-fragment cassette, linked to CD3ζ by the signaling domains of two costimulatory molecules, namely either CD28.4-1BB or CD28.OX40. We found that CAR.CD30 T-cells exhibit remarkable cytolytic activity in vitro against HL and NHL cell lines, with sustained proliferation and pro-inflammatory cytokine production, even after multiple and sequential lymphoma cell challenges. CAR.CD30 T-cells also demonstrated anti-lymphoma activity in two in vivo xenograft immune-deficient mouse models of metastatic HL and NHL. We observed that administration of CAR.CD30 T-cells, incorporating the CD28.OX40 costimulatory domains and manufactured in the presence of IL7 and IL15, were associated with the best overall survival in the treated mice, along with the establishment of a long-term immunological memory, able to protect mice from further tumor re-challenge. Our data indicate that, in the context of in vivo systemic metastatic xenograft mouse models, the costimulatory machinery of CD28.OX40 is crucial for improving persistence, in vivo expansion and proliferation of CAR.CD30 T-cells upon tumor encounter. CD28.OX40 costimulatory combination is ultimately responsible for the antitumor efficacy of the approach, paving the way to translate this therapeutic strategy in patients with CD30+ HL and NHL.

Unrelated donor vs HLA-haploidentical α/ß T-cell- and B-cell-depleted HSCT in children with acute leukemia.

Traditionally, hematopoietic stem cell transplantation (HSCT) from both HLA-matched related and unrelated donors (UD) has been used for treating children with acute leukemia (AL) in need of an allograft. Recently, HLA-haploidentical HSCT after αß T-cell/B-cell depletion (αßhaplo-HSCT) was shown to be effective in single-center studies. Here, we report the first multicenter retrospective analysis of 127 matched UD (MUD), 118 mismatched UD (MMUD), and 98 αßhaplo-HSCT recipients, transplanted between 2010 and 2015, in 13 Italian centers. All these AL children were transplanted in morphological remission after a myeloablative conditioning regimen. Graft failure occurred in 2% each of UD-HSCT and αßhaplo-HSCT groups. In MUD vs MMUD-HSCT recipients, the cumulative incidence of grade II to IV and grade III to IV acute graft-versus-host disease (GVHD) was 35% vs 44% and 6% vs 18%, respectively, compared with 16% and 0% in αßhaplo-HSCT recipients (P < .001). Children treated with αßhaplo-HSCT also had a significantly lower incidence of overall and extensive chronic GVHD (P < .01). Eight (6%) MUD, 32 (28%) MMUD, and 9 (9%) αßhaplo-HSCT patients died of transplant-related complications. With a median follow-up of 3.3 years, the 5-year probability of leukemia-free survival in the 3 groups was 67%, 55%, and 62%, respectively. In the 3 groups, chronic GVHD-free/relapse-free (GRFS) probability of survival was 61%, 34%, and 58%, respectively (P < .001). When compared with patients given MMUD-HSCT, αßhaplo-HSCT recipients had a lower cumulative incidence of nonrelapse mortality and a better GRFS (P < .001). These data indicate that αßhaplo-HSCT is a suitable therapeutic option for children with AL in need of transplantation, especially when an allele-matched UD is not available.

Congenital Rhabdomyosarcoma: a different clinical presentation in two cases.

BACKGROUND: Rhabdomyosarcoma (RMS), one of the most common soft tissue sarcomas of childhood, is very rare in the neonatal period (0.4-2% of cases). In order to gain a deeper understanding of this disease at such age, patient and tumor features, as well as treatment modality and outcome need to be reported. CASE PRESENTATION: We describe two cases with congenital RMS treated at Bambino Gesù Children's Hospital between 2000 and 2016. They represent only 2.24% of all RMS patients diagnosed during that period in our Institution; this data is in agreement with the incidence reported in the literature. They reflect the two different clinical forms in which the disease may manifest itself. One patient, with the alveolar subtype (positive for specific PAX3-FOXO1 fusion transcript) and disseminated disease, had a fatal outcome with central nervous system (CNS) progression despite conventional and high dose chemotherapy. The other child, with the localized embryonal subtype, was treated successfully with conservative surgery and conventional chemotherapy, including prolonged maintenance therapy. He is disease free at 7 years of follow-up. CONCLUSIONS: RMS can also be diagnosed during the neonatal period. Given the young age, disease management is often challenging, and especially for the alveolar subtype, the outcome is dismal despite intensified multimodality therapy. In fact, it characteristically manifests with multiple subcutaneous nodules and progression most commonly occurs in the CNS (Rodriguez-Galindo et al., Cancer 92(6):1613-20, 2001). In this context, CNS prophylaxis could play a role in preventing leptomeningeal dissemination, and molecular studies can allow a deeper tumor characterization, treatment stratification and identification of new potential therapeutic targets.

Growth hormone excess in children with neurofibromatosis type-1 and optic glioma.

In children with neurofibromatosis type 1 (NF1) and optic pathways glioma (OPG), growth hormone (GH) excess has been rarely reported and mainly associated to central precocious puberty. The aim of our study is to evaluate the prevalence of GH excess, the association with central precocious puberty, the relation with tumor site and the evolution over time in a large cohort of children with NF1 and OPG. Sixty-four NF1 children with OPG were evaluated. Patients with stature and/or height velocity >2 SD for age were studied for GH secretion. Seven out of 64 children (10.9%) with NF1 and optic pathways glioma showed GH excess, isolated in 5 cases and associated to central precocious puberty in 2. All the children with GH excess had a tumor involving the chiasma. Children with GH excess underwent medical treatment with lanreotide and a minimum clinical/biochemical follow up of 2 years is reported. The present study demonstrates that GH excess should be considered as a relative frequent endocrine manifestation in NF1 patients, similarly to central precocious puberty. Therefore, these patients should undergo frequent accurate auxologic evaluations. On the other hand, an increase in height velocity in children with NF1, even despite normal ophthalmological exams, can suggest the presence of OPG and therefore represents an indication to perform brain MRI.

An Inducible Caspase-9 Suicide Gene to Improve the Safety of Therapy Using Human Induced Pluripotent Stem Cells.

Human induced pluripotent stem cells (hiPSC) hold promise for regenerative therapies, though there are several safety concerns including the risk of oncogenic transformation or unwanted adverse effects associated with hiPSC or their differentiated progeny. Introduction of the inducible caspase-9 (iC9) suicide gene, which is activated by a specific chemical inducer of dimerization (CID), is one of the most appealing safety strategies for cell therapies and is currently being tested in multicenter clinical trials. Here, we show that the iC9 suicide gene with a human EF1α promoter can be introduced into hiPSC by lentiviral transduction. The transduced hiPSC maintain their pluripotency, including their capacity for unlimited self-renewal and the potential to differentiate into three germ layer tissues. Transduced hiPSC are eliminated within 24 hours of exposure to pharmacological levels of CID in vitro, with induction of apoptosis in 94-99% of the cells. Importantly, the iC9 suicide gene can eradicate tumors derived from hiPSC in vivo. In conclusion, we have developed a direct and efficient hiPSC killing system that provides a necessary safety mechanism for therapies using hiPSC. We believe that our iC9 suicide gene will be of value in clinical applications of hiPSC-based therapy.

Mesenchymal Stromal Cells for Linked Delivery of Oncolytic and Apoptotic Adenoviruses to Non-small-cell Lung Cancers.

Oncolytic adenoviruses (OAdV) represent a promising strategy for cancer therapy. Despite their activity in preclinical models, to date the clinical efficacy remains confined to minor responses after intratumor injection. To overcome these limitations, we developed an alternative approach using the combination of the OAdv ICOVIR15 with a replication incompetent adenoviral vector carrying the suicide gene of inducible Caspase 9 (Ad.iC9), both of which are delivered by mesenchymal stromal cells (MSCs). We hypothesized that coinfection with ICOVIR15 and Ad.iC9 would allow MSCs to replicate both vectors and deliver two distinct types of antitumor therapy to the tumor, amplifying the cytotoxic effects of the two viruses, in a non-small-cell lung cancer (NSCLC) model. We showed that MSCs can replicate and release both vectors, enabling significant transduction of the iC9 gene in tumor cells. In the in vivo model using human NSCLC xenografts, MSCs homed to lung tumors where they released both viruses. The activation of iC9 by the chemical inducer of dimerization (CID) significantly enhanced the antitumor activity of the ICOVIR15, increasing the tumor control and translating into improved overall survival of tumor-bearing mice. These data support the use of this innovative approach for the treatment of NSCLC.

Myeloid Sarcoma Presenting as Low Back Pain in the Pediatric Emergency Department.

BACKGROUND: Low back pain is a common symptom in the pediatric population; approximately half of all children present with at least one episode of low back pain. The majority of cases are due to nonspecific causes such as musculoskeletal trauma with spontaneous regression. On some occasions, however, life-threatening diseases have to be considered. CASE REPORT: A 15-year-old girl presented to the Pediatric Emergency Department for a history of continuous 2-day duration of low back pain and transient paresthesia of the right gluteal area. Low back pain was diagnosed and nonsteroidal anti-inflammatory treatment combined with rest were prescribed. After 7 days, worsening of the clinical conditions was observed with bilateral gluteus paresthesia. A corset was recommended, and magnetic resonance imaging (MRI) and rheumatological evaluation were prescribed on an outpatient basis. After 5 days she was hospitalized due to urinary incontinence and persistence of pain. Blood tests revealed neutrophil leukocytosis associated with mild anemia, thrombocytopenia, hyperuricemia, and increased lactate dehydrogenase. MRI examination of the spine demonstrated a mass involving the sacral canal and the presacral region, extending through the sacral foramina, along the nerve roots. Similar tissue was found at multiple levels in the spine and in the right orbit. Bone marrow aspiration and biopsy highlighted the presence of myeloid blasts and myeloid dysplasia, consequently, myeloid sarcoma was diagnosed. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Our case demonstrates the importance of prompt identification of diagnostic "red flags" in childhood low back pain, indicating the need for diagnostic investigations such as MRI and blood tests.

Response of recurrent BRAFV600E mutated ganglioglioma to Vemurafenib as single agent.

BACKGROUND: Ganglioglioma (GG) and pilocytic astrocytoma (PA) represent the most frequent low-grade gliomas (LGG) occurring in paediatric age. LGGs not amenable of complete resection (CR) represent a challenging subgroup where traditional treatments often fail. Activation of the MAP Kinase (MAPK) pathway caused by the BRAFV600E mutation or the KIAA1549-BRAF fusion has been reported in pediatric GG and PA, respectively. CASE PRESENTATION: We report on a case of BRAFV600E mutated cervicomedullary GG treated with standard chemotherapy and surgery. After multiple relapse, BRAF status was analyzed by immunohistochemistry and sequencing showing a BRAFV600E mutation. Treatment with Vemurafenib as single agent was started. For the first time, a radiological and clinical response was obtained after 3 months of treatment and sustained after 6 months. CONCLUSION: Our experience underline the importance of understanding the driver molecular alterations of LGG and suggests a role for Vemurafenib in the treatment of pediatric GG not amenable of complete surgical resection.

Large cell anaplastic medulloblastoma metastatic to the scalp: tumor and derived stem-like cells features.

BACKGROUND: Extraneural metastases (ENM) rarely occur in medulloblastoma (MBL) patients and only few cases of subcutaneous localizations have been described. ENM indicate an aggressive disease associated with a worse prognosis. The characterization of metastatic tumours might be useful to understand their pathogenesis and to identify the most appropriate therapeutic strategies. CASE PRESENTATION: We present the case of a child with Large Cell Anaplastic (LC/A) MBL, who developed multiple subcutaneous metastases in the scalp area after a ventriculo-peritoneal shunting procedure. The disease rapidly progressed and the child died despite chemotherapy and primary tumour surgical debulking.We molecularly classified the tumour as a group 3 MBL; in addition, we derived stem-like cells (SLC) from a metastatic lesion. Primary tumour, metastases and SLC were further analysed, particularly focusing on features linked to the cutaneous dissemination. Indeed, molecules involved in angiogenesis, cell invasion and epidermal growth factor signalling resulted highly expressed. CONCLUSIONS: The present report describes a very rare case of subcutaneous metastatic MBL. The tumour, metastases and SLC have been clinically, pathologically and molecularly characterized. Our case is an example of multidisciplinary approach aiming to characterize MBL aggressive behaviour.

Autologous CD19- targeting CAR T cells in refractory juvenile dermatomyositis.

OBJECTIVES: To report safety and efficacy of CD19-targeting CAR T cells in a child with refractory juvenile dermatomyositis (JDM). PATIENTS AND METHODS: We describe the case of a 12-year-old Caucasian boy with severe, chronically active JDM, refractory to multiple immunosuppressive treatment lines, including B-cell depletion with rituximab. The patient received a single infusion of fresh, autologous, second-generation anti-CD19 CAR T-cell product (lentiviral vector) manufactured on the Prodigy device (1x106 CAR T cells/kg), after lymphodepletion with cyclophosphamide (1000 mg/m2 over 2 days) and fludarabine (90 mg/m2 over 3 days). Immunosuppressive and glucocorticoid treatment were withdrawn before leukapheresis and CAR T-cell infusion. RESULTS: Before anti-CD19 CAR T-cell therapy, the patient had persistent severe skin and muscular disease activity. CAR T cells expanded significantly (peak at day 7, 32.69 cells/µL). Complete B-cell depletion was documented on day 5 in blood and at week 2 in bone marrow. The patient presented fever as part of mild cytokine release syndrome (G1), transient anemia (G2) and neutropenia (G4). Neither infection nor neurotoxicity were observed. Laboratory tests, MRI imaging, Physician's Global Assessment of disease activity (PGA), Childhood Myositis Assessment Scale (CMAS) and Cutaneous Assessment Tool for myositis (CAT) were performed at baseline and follow-up to assess treatment response, showing remarkable progressive improvement that persists over time, even after B-cell recovery. CONCLUSIONS: This JDM patient with severe chronic disease, refractory to multiple treatments, achieved sustained B-cell depletion and ongoing immunosuppressive drug-free clinical and radiological improvement eight months after a single infusion of anti-CD19 CAR T cells.