The treatment landscape for hematologic malignancies has changed since the recent approval of highly effective CAR-T. Chimeric antigen receptor T-cell therapy (CAR-T) is a type of immunotherapy in which a patient’s T cells are collected and genetically engineered to improve their ability to recognize and kill cancer cells. However, several issues are still unsolved and represent the challenges for the coming years. The lack of initial responses and early relapse are some hurdles to be tackled. Moreover, new strategies are needed to increase the safety profile or shorten the manufacturing process during CAR-T cells therapy production. Finally, the clinical experience with CAR-T cells for solid tumors has been less encouraging, and development in this setting is desirable.
Name |
General Description |
Therapeutic Indications |
---|---|---|
Tisagenlecleucel |
Immunocellular therapy containing tisagenlecleucel, autologous T cells genetically modified ex vivo using a lentiviral vector encoding an anti-CD19 chimeric antigen receptor. |
Pediatric and young adult patients up to and including 25 years of age with B-cell acute lymphoblastic leukemia that is refractory, in relapse post-transplant, or in second or later relapse. Adult patients with R/R diffuse large B-cell lymphoma after two or more lines of systemic therapy. |
Axicabtageneciloleucel |
A CD19-directed genetically modified autologous T-cell immunotherapy. T cells are genetically modified ex vivo by retroviral transduction to express a chimeric antigen receptor comprising a murine anti-CD19 single-chain variable fragment linked to the CD28 co-stimulatory domain and CD3-zeta signaling domain. |
After two or more lines of systemic therapy, adult patients with R/R diffuse large B-cell lymphoma and primary mediastinal large B-cell lymphoma. |
Lisocabtagenemaraleucel |
Anti-CD19 single-chain variable fragment (scFv) targeting domain for antigen specificity, a transmembrane domain, a 4-1BB costimulatory domain hypothesized to increase T-cell proliferation and persistence, and a CD3-zeta T-cell activation domain. |
After two or more lines of systemic therapy, adult patients with R/R large B-cell lymphoma, including diffuse large B-cell lymphoma, not otherwise specified, high-grade B-cell lymphoma, primary mediastinal large B-cell lymphoma, and follicular lymphoma grade 3B. |
Brexucabtageneautoleucel |
Autologous peripheral blood T-lymphocytes (PBTL) that have been transduced with a retroviral vector expressing a chimeric antigen receptor (CAR) consisting of an anti-CD19 single-chain variable fragment (scFv) coupled to the zeta chain of the T-cell receptor (TCR)/CD3 complex (CD3 zeta) and the costimulatory signaling domain CD28. |
Treatment of adult patients with R/R mantle cell lymphoma. |
Idecabtagenevicleucel |
Anti B-Cell maturation antigen (BCMA) scFv fused to the CD137 (4-1BB) co-stimulatory and CD3ζ signaling domains. |
Adult patients with R/R multiple myeloma after four or more prior lines of therapy, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody. |
Ciltacabtageneautoleucel |
BCMA-targeted T-cell therapies are directed against two BCMA epitopes (VH1 and VH2) to confer improved affinity for BCMA-expressing cells. |
Not authorized. Trials ongoing in R/R multiple myeloma to both immunomodulatory agents and proteasome inhibitors, or with at least three prior lines of therapy and previously exposed to anti-CD38 monoclonal antibody. |
Several studies are underway to combine CAR-T with cytokine administration, checkpoint blockade, oncolytic viruses, radiation, and vaccines [44]. In addition, investigators have explored the use of T cells to deliver viruses into tumors directly. For example, combining CAR-T infusion with the local delivery of an oncolytic adenovirus encoding RANTES and IL-15 in preclinical models has improved homing to and the persistence of CAR-T cells at tumor sites [44].
The composition of immune cells in the tumor microenvironment is an essential element for the heterogeneity of tumors, and creates interesting yet challenging complexities when investigating dynamic interactions between cancer and immune cells [45]. Tumor transcriptomics data are informative; however, they do not immediately indicate immune cell compositions, which require computational inference. The computational algorithms are based on two categories: deconvolution approaches and gene signature [46]. Deconvolution methods define the problem as mathematical equations that model the gene expression of a tissue sample as the weighted sum of the expression profiles from the cells in the population mix. Gene signature-based approaches utilize a list of cell-type-specific gene sets. These two complementary categories of algorithms have demonstrated variable performance advantages in estimating specific immune cell types in different tumors [47]. The algorithms could help the user gain more comprehensive and robust results with CAR-T cells.
Since the first CAR-T cells therapies gained FDA approval in 2017, the one-time treatments have led to unprecedented response rates in patients with R/R lymphoid malignancies, with remarkable price tags of about $373,000 for a single infusion.
In the late 1980s, the Italian hospitals developed a calculating tariff method based on diagnosis-related groups (DRG)[48]. The DRGs have also been applied in North America [49]. DRGs are awarded by a “grouper” program based on International Classification of Diseases diagnoses, physical characteristics (gender, age), procedures, the presence of complications or comorbidities, and discharge status. By the DRG identified and the length of hospital stay, the region pays the cost of hospitalization. DRGs include all the actions necessary to treat and diagnose the patient for each treatment because patients within each category are clinically similar and are expected to employ the same level of hospital resources (fixed price).
According to DRG, CAR-T cells therapy in Italy is remunerated at $59,806 in most authorized centers. However, the actual repayment of the DRG does not correspond to the cost of the CAR-T cells procedure and, in general, of a transplant procedure [68]. Furthermore, the price does not account for manufacturing the product, managing potential long-term complications, or managing other therapy lines after relapse. The DRG model finds complex applications in this scenario, and maybe a novel model should be explicitly applied for cell therapies. For example, activity-based costing (ABC) is a tool developed to improve efficiency and control cost. The procedure is based on the concept that the production of a product or the performance of a service spends activities that consume resources [50] [51]. ABC endeavors to assign costs to each of these activities, and resources so that total costs can be better understood and administrated. Finally, the pharmaceutic company introduced an outcome-based pricing model: if the treatment does not work, no one pays for it. That proposal is exciting with many problems, the least of which is that the definition of “not working” is unclear [48].
CAR-T cells therapy has shown unprecedented results in patients without curative options. Future work focusing on target identification, toxicity management, and manufacturing time shortening will broaden this exciting therapy’s clinical applicability and sustainability, with more prolonged remissions without additional treatment.