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A pesar de ser una enfermedad rara, el cáncer es la primera causa de mortalidad por enfermedad durante la edad pediátrica en los países desarrollados. En este momento, la irrupción de nuevos tratamientos como la inmunoterapia constituye un nuevo paradigma clínico y regulatorio. Uno de estos tipos de inmunoterapia es la inmunoterapia celular. En particular, los medicamentos de terapia avanzada con receptores antigénicos quiméricos en los linfocitos T (CAR-T), y en concreto las células CAR-T19, han supuesto un nuevo escenario en el abordaje de los tumores hematológicos, como la leucemia aguda linfoblástica y los linfomas de células tipo B. La aprobación por las autoridades regulatorias de tisagenlecleucel y axicabtagene ciloleucel, ha impulsado la puesta en marcha del Plan Nacional de Terapias Avanzadas-Medicamentos CAR-T en España, evidenciándose no solo la conveniencia de identificar los centros más adecuados para su administración, sino la necesidad de que estos sufran una profunda transformación para que su actividad asistencial se extienda en algunos casos a la capacidad de fabricación propia de este tipo de terapias. Los hospitales especializados en hematooncología pediátrica tienen por tanto el reto de evolucionar hacia un modelo asistencial que integre la inmunoterapia celular, dotándose de capacidad propia para gestionar todos los aspectos relativos al uso, fabricación y administración de estos nuevos tratamientos.

Graft-versus-host disease (GVHD) is the main complication after allogeneic hematopoietic stem cell transplantation. We previously unveiled a correlation between proportions of C-C motif chemokine receptor 7 (CCR7)+T cells in the apheresis and the risk of developing GVHD. We wanted to evaluate in vivo whether apheresis with low proportion of CCR7+cells or treatment with an anti-human CCR7 monoclonal antibody (mAb) were suitable strategies to prevent or treat acute GVHD in preclinical xenogeneic models. Therapeutic anti-CCR7 mAb was the most effective strategy in both prophylactic and therapeutic settings where antibody drastically reduced in vivo lymphoid organ infiltration of donor CCR7+T cells, extended lifespan and solved clinical signs. The antibody neutralized in vitro migration of naïve and central memory T cells toward CCR7 ligands and depleted target CCR7+subsets through complement activation. Both mechanisms of action spared CCR7−subsets, including effector memory and effector memory CD45RA+ T cells which may mediate graft versus leukemia effect and immunity against infections. Accordingly, the numbers of donor CCR7+T cells in the apheresis were not associated to cytomegalovirus reactivation or the recurrence of the underlying disease. These findings provide a promising new strategy to prevent and treat acute GVHD, a condition where new specific, safety and effective treatment is needed.

Relapsed/refractory T-cell acute lymphoblastic leukemia (T-ALL) has a dismal outcome, and no effective targeted immunotherapies for T-ALL exist. The extension of chimeric antigen receptor (CAR) T cells (CARTs) to T-ALL remains challenging because the shared expression of target antigens between CARTs and T-ALL blasts leads to CART fratricide. CD1a is exclusively expressed in cortical T-ALL (coT-ALL), a major subset of T-ALL, and retained at relapse. This article reports that the expression of CD1a is mainly restricted to developing cortical thymocytes, and neither CD34+ progenitors nor T cells express CD1a during ontogeny, confining the risk of on-target/off-tumor toxicity. We thus developed and preclinically validated a CD1a-specific CAR with robust and specific cytotoxicity in vitro and antileukemic activity in vivo in xenograft models of coT-ALL, using both cell lines and coT-ALL patient–derived primary blasts. CD1a-CARTs are fratricide resistant, persist long term in vivo (retaining antileukemic activity in re-challenge experiments), and respond to viral antigens. Our data support the therapeutic and safe use of fratricide-resistant CD1a-CARTs for relapsed/refractory coT-ALL.

Relapsed/refractory T-cell acute lymphoblastic leukemia (T-ALL) has a dismal outcome, and no effective targeted immunotherapies for T-ALL exist. The extension of chimeric antigen receptor (CAR) T cells (CARTs) to T-ALL remains challenging because the shared expression of target antigens between CARTs and T-ALL blasts leads to CART fratricide. CD1a is exclusively expressed in cortical T-ALL (coT-ALL), a major subset of T-ALL, and retained at relapse. This article reports that the expression of CD1a is mainly restricted to developing cortical thymocytes, and neither CD34+progenitors nor T cells express CD1a during ontogeny, confining the risk of on-target/off-tumor toxicity. We thus developed and preclinically validated a CD1a-specific CAR with robust and specific cytotoxicity in vitro and antileukemic activity in vivo in xenograft models of coT-ALL, using both cell lines and coT-ALL patient–derived primary blasts. CD1a-CARTs are fratricide resistant, persist long term in vivo (retaining antileukemic activity in re-challenge experiments), and respond to viral antigens. Our data support the therapeutic and safe use of fratricide-resistant CD1a-CARTs for relapsed/refractory coT-ALL.