Chimeric antigen receptor T-cell therapy: a promising treatment modality for relapsed/refractory mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a distinct histological type of B-cell lymphoma with a poor prognosis. Several agents, such as proteasome inhibitors, immunomodulatory drugs, and inhibitors of B cell lymphoma-2 and Bruton's tyrosine kinase have shown efficacy for relapsed or refractory (r/r) MCL but often have short-term responses. Chimeric antigen receptor (CAR) T-cell therapy has emerged as a novel treatment modality for r/r non-Hodgkin's lymphoma. However, long-term safety and tolerability associated with CAR T-cell therapy are not defined well, especially in MCL. In this report, we described a 70-year-old patient with r/r MCL with 48-month duration of follow-up who achieved long-term remission after CAR T-cell therapy. CAR T-cell-related toxicities were also mild and tolerated well even in this elderly patient. This report suggested that CAR T-cell therapy is a promising treatment modality for patients with MCL, who are generally elderly and have comorbid conditions.

CD19/CD22 chimeric antigen receptor T-cell therapy for refractory acute B-cell lymphoblastic leukemia with FLT3-ITD mutations.

Treatment of acute lymphoblastic leukemia (ALL) is still a challenge despite years of researching, especially for those of poor prognosis. Zhang and his team recently proved that FLT3 gene mutation was identified in ~5% of ALL and the mutation spectrum is different from AML. Recently, chimeric antigen receptor T cells (CART) therapy presents great efficacy in treating refractory leukemia. We report a case of a refractory ALL patient with FLT3-ITD mutations and unfavorable karyotypes, who failed to respond to chemotherapy and small molecule tyrosine kinase inhibitors, successfully treated by CART therapy. FLT3-ITD mutations were downregulated dramatically into 14.1% positive 3 days after the infusion and remained negative until now. MRD has stayed to be negative from the 10th day. This case suggests that CART-cell therapy might be effective in treating FLT3-ITD positive refractory ALL, implying the possibility to overcome the traditional prognosis scoring system for leukemia and providing a new chance for other leukemia patients with inferior prognosis factors.

Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Predicting the Adverse Effects of Chimeric Antigen Receptor T Cell Therapy in Patients with Non-Hodgkin Lymphoma.

CD19-targeting chimeric antigen receptor (CAR)-T cell therapy has shown great efficacy in patients with relapsed/refractory non-Hodgkin lymphoma (NHL) but has been associated with serious adverse effects, such as cytokine release syndrome (CRS). It has been speculated that NHL baseline disease burden might affect clinical outcome and CRS, but this has not been explored in detail in any previous study. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG), as measured by fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET-CT), are quantitative indicators of baseline tumor burden. Using FDG PET-CT, we calculated baseline and post-CAR-T cell therapy MTV and TLG in 19 patients with NHL. The median MTV was 72 cm3 (range, .02 to 1137.7 cm3), and the median TLG was 555.9 (range, .011 to 8990.3). After a median follow-up of 5 months (range, 1 to 12 months), the best overall response rate was 79.0%. The baseline MTV and TLG did not differ significantly between patients with response and those without response (P = .62 and .95, respectively). On Cox regression analysis, baseline MTV and TLG were not significantly associated with overall survival (P = .67 and .45, respectively). Patients with mild and moderate CRS (grade 0 to 2) had significantly lower MTV and TLG than those with severe CRS (grade 3 to 4) (P = .008 for MTV comparison, P = .011 for TLG comparison). Using FDG PET-CT, we also demonstrated that CAR-T cell therapy in patients with NHL was associated with pseudoprogression and local immune activation. Our data indicate that patients with higher baseline disease burden have more severe CRS, and that CAR-T cell therapy is associated with lymphoma pseudoprogression and local immune activation.

A retrospective comparison of allogenic and autologous chimeric antigen receptor T cell therapy targeting CD19 in patients with relapsed/refractory acute lymphoblastic leukemia.

The source of CAR T cells can be autologous (autoCAR) or allogeneic (alloCAR). The latter is seen in patients with a history of allogeneic hematopoietic stem cell transplantation, and can be either donor-derived (DD-alloCAR) or recipient-derived (RD-alloCAR). While autoCAR is activated by CAR only, alloCAR receives activation signals from both T-cell receptor (TCR) and CAR. As a result, the biological differences could impact clinical outcomes. We retrospectively reviewed 31 patients: 17 received autoCAR, 11 received RD-alloCAR, and 3 received DD-alloCAR. After a median follow-up of 9 months, CR rate was 88.2% (95% CI 63.6-98.5%) in autoCAR and 100% (95% CI 71.5-100%) in RD-alloCAR. The median peak expansion in the autoCAR was significantly higher than the RD-alloCAR group (p = 0.007). RD-alloCAR group had significantly less patients with severe CRS (Grade ≥ 3) than the autoCAR group (p = 0.049). Acute graft-versus-host disease (GVHD) occurred in 2 (18.2%) of RD-alloCAR patients and 1 (33.3%) of DD-alloCAR patients. Univariate subgroup analysis of alloCAR group showed the presence of cGVHD at the time of T-cell collection was significantly associated with less than 6-month relapses (p = 0.022). RD-alloCAR patients with or without cGVHD at PBMC collection did not differ regarding the peak CAR T-cell expansion, CRS grades and OS.