Incidence of CD19-negative relapse after CD19-targeted immunotherapy in R/R BCP acute lymphoblastic leukemia: a review

How I treat postimmunotherapy relapsed B-ALL

ABSTRACT

Despite significant advancements in single-antigen targeted therapies for B-cell acute lymphoblastic leukemia (B-ALL), nonresponse and relapse persist as major challenges. Antigen escape after blinatumomab or CD19-directed chimeric antigen receptor (CAR) T cells (CD19-CAR), as CD19-negative B-ALL or lineage switch (LS) to acute myeloid leukemia, present diagnostic and treatment complexities. Given the poor outcomes for patients experiencing a postinfusion relapse, particularly those with loss of the target antigen, a strategic approach to diagnosis and treatment is imperative. In this discussion, we outline a systematic approach to managing postimmunotherapy events, categorized by CD19-positive relapse, CD19-negative relapse, and LS. We explore treatment modalities including CD19-CAR reinfusions, humanized CAR constructs, combinatorial strategies, and alternative antigen-targeted therapies, such as blinatumomab and inotuzumab. Challenges in diagnosis, particularly with antigen-escape, are addressed, highlighting the role of next-generation sequencing and multiparameter flow cytometry for myeloid marker monitoring.

Fratricide-resistant CD7-CAR T cells in T-ALL

T cell acute lymphoblastic leukemia (T-ALL) is difficult to treat when it relapses after therapy or is chemoresistant; the prognosis of patients with relapsed or refractory T-ALL is generally poor. We report a case series of 17 such patients who received autologous chimeric antigen receptor (CAR) T cells expressing an anti-CD7 CAR and an anti-CD7 protein expression blocker (PEBL), which prevented CAR T cell fratricide. Despite high leukemic burden and low CAR T cell dosing, 16 of the 17 patients attained minimal residual disease-negative complete remission within 1 month. The remaining patient had CD7- T-ALL cells before infusion, which persisted after infusion. Toxicities were mild: cytokine release syndrome grade 1 in ten patients and grade 2 in three patients; immune effector cell-associated neurotoxicity syndrome grade 1 in two patients. Eleven patients remained relapse-free (median follow-up, 15 months), including all nine patients who received an allotransplant. The first patient is in remission 55 months after infusion without further chemotherapy or transplantation; circulating CAR T cells were detectable for 2 years. T cells regenerating after lymphodepletion lacked CD7 expression, were polyclonal and responded to SARS-CoV-2 vaccination; CD7+ immune cells reemerged concomitantly with CAR T cell disappearance. In conclusion, autologous anti-CD7 PEBL-CAR T cells have powerful antileukemic activity and are potentially an effective option for the treatment of T-ALL.

Frontline treatment of adults with newly diagnosed B-cell acute lymphoblastic leukaemia

In the past decade, there has been considerable progress in the treatment of adults with newly diagnosed B-cell acute lymphoblastic leukaemia. This evolution is the product of a more profound understanding of acute lymphoblastic leukaemia biology, innovations in measurable residual disease quantification that led to precise disease-risk stratification, adoption of contemporary paediatric-inspired regimens, inclusion of tyrosine kinase inhibitors in the treatment of Philadelphia chromosome-positive acute lymphoblastic leukaemia, and the introduction of immunotherapy in the frontline setting. Nevertheless, outcomes of acute lymphoblastic leukaemia in adults are inferior compared with those of children, with excessive rates of treatment failure, and therapy-related morbidity and mortality. Simultaneously, transplant consolidation has continued to be used frequently for high-risk adults with acute lymphoblastic leukaemia in first complete remission. Considering the rapid pace of evolution in acute lymphoblastic leukaemia management, novel trial designs are warranted to accelerate advancements and streamline approaches. Here, we summarise progress in the treatment of adults with newly diagnosed acute lymphoblastic leukaemia, which adds to previously published guidelines by focusing specifically on first-line decisions for B-cell acute lymphoblastic leukaemia and how to best personalise treatment. This Viewpoint also includes experiences with regimens and testing approaches currently available not only in Europe, but also on multiple continents with different practices and resources.

Bispecific T-cell engagers in childhood B-acute lymphoblastic leukemia

Immunotherapy has revolutionized treatment for a wide variety of cancers yet its use has been relatively limited in childhood malignancies. With the introduction of bispecific T-cell engagers (BiTE®) and chimeric antigen T-cell receptor technologies, previously refractory patients have attained remission, including molecularly negative states of disease, thus providing the possibility of long-term cure. Blinatumomab is a widely available CD3-CD19 BiTE that has dramatically changed the landscape of therapy for some children with precursor-B acute lymphoblastic leukemias (B-ALL) and lymphoblastic lymphomas. Challenges remain with using BiTE in a broader population although the appeal of now-confirmed reduced toxicity and deeper molecular remissions suggests that this approach will be an essential part of future treatment of childhood B-ALL. Herein, we review some of the pertinent literature covering clinical trials with blinatumomab and address future approaches and combination trials including BiTE.

GMP-manufactured CRISPR/Cas9 technology as an advantageous tool to support cancer immunotherapy

BACKGROUND

CRISPR/Cas9 system to treat human-related diseases has achieved significant results and, even if its potential application in cancer research is improving, the application of this approach in clinical practice is still a nascent technology.

MAIN BODY

CRISPR/Cas9 technology is not yet used as a single therapy to treat tumors but it can be combined with traditional treatment strategies to provide personalized gene therapy for patients. The combination with chemotherapy, radiation and immunotherapy has been proven to be a powerful means of screening, identifying, validating and correcting tumor targets. Recently, CRISPR/Cas9 technology and CAR T-cell therapies have been integrated to open novel opportunities for the production of more efficient CAR T-cells for all patients. GMP-compatible equipment and reagents are already available for several clinical-grade systems at present, creating the basis and framework for the accelerated development of novel treatment methods.

CONCLUSION

Here we will provide a comprehensive collection of the actual GMP-grade CRISPR/Cas9-mediated approaches used to support cancer therapy highlighting how this technology is opening new opportunities for treating tumors.