Search

Background CAR-T targeting CD19 has been a success in treating B-cell acute lymphoblastic leukemia (B-ALL). However, relapse rate is high and the long term survival in pateints is not satisfactory, which is partly due to the limited expansion and persistence of the conventionally-manufactured CAR-T cells. In addition, long manufacturing time and high cost of CAR-T product further limit the wider applications of CAR-T therapy. To solve these issues, we have developed a new manufacturing platform, FasT CAR-T, which shorten the manufacturing time to one day as compared to the conventional CAR-T manufacturing time of 9-14 days, which is critical for patients with rapidly progressing disease. More importantly, CD19-directed FasT CAR-T has been shown to have superior expansion capability, younger and less exhausted phenotype, and higher potency in eliminating B-ALL both in vitro and in vivo. Based on the preclinical study, we initiated a multi-center clinical study to determine the safety, feasibility and efficacy of CD19-FasT CAR-T in treating patients with CD19+ relapsed/refractory B-ALL. Methods CD19-directed CAR-T was manufactured using the FasT CAR-T platform. Peripheral blood (PB) mononuclear cells were obtained by leukapheresis and T cells were separated. CD19-FasT CAR-T manufacturing were all successful. Conventional CAR-T (C-CAR-T) from healthy donor were also made in parallel for comparison in preclinical study. From Dec. 2018 to July 2019, 10 adult CD19+ R/R ALL patients were recruited and all patients received fludarabine and cyclophosphamide as pre-conditioning followed by a single CAR-T infusion 48-72 hours later. Doses used in this study were: 3 DL1 (5 x 104 CAR+ T/kg), 4 DL2 (1 x 105 CAR+ T/kg), and 3 DL3 (1.5 x 105 CAR+ T/kg). The endpoints of the study were clinical toxicity, feasibility, PK of CAR-T and efficacy. Results: In comparison to conventional CAR-T cells, CD19-FasT CAR-T cells had several key features (Table 1). 1) More robust expansion. Upon antigen stimulation, the FasT CAR-T proliferated 5-30 times stronger than that of C-CAR-T. 2) Higher percentage of CD62L+CD45RO- (Tscm) and CD62L+CD45+ (Tcm) population in FasT CAR-T. 3) Lower expression of PD-1+, LAG3+ and Tim3+ in FasT CAR-T. 4). More potent in eliminating Raji tumor in an in vivo xenograft mouse model. 5) More efficient migration to bone marrow which is likely due to the higher expression of CXCR4 on the FasT CAR-T cells. The trial was conducted during Dec. 2018 to July 2019. The pre-treatment bone marrow (BM) blasts were < 5% in 5 cases, 5%-50% in 3 cases, and >50% in 2 cases (Table 2). All 10 patients achieved complete remission (CR) 4 weeks after FasT CAR-T infusion, and 9 were with negative minimal residual disease (MRD-). CAR-T cells proliferation and persistence in peripheral blood (PB) were monitored by qPCR and flow cytometry. CAR-T cells peaked at Day 10 (range Day 8-13) after infusion. The median persistence period of CAR-T in PB was 56 days ((range 28-212 days) after infusion, and the longest persistence is 7 months and still being monitored at the last follow-up. The median peak of CAR copy number is 90,446/mg DNA (range 4,670-247,507/mg DNA) (Figure). The major adverse event was cytokine release syndrome (CRS) which was observed in 9 patients, including 1 patient with grade IV in DL3 group, 3 grade III, 4 grade II and 1 grade I. The clinical manifestation of CRS mainly included fever and hypotension. The median time to the development of CRS was 5 days (2-10 days), and the peak body temperature was at Day 7 (Day 5- 11) and fever lasted for an average of 5 days (3-8 days). Serum IL-6 level increased and peaked on Day 7 post-infusion, which coincided with fever but slightly preceded the CAR-T expansion peak. Three patients experienced CAR-related encephalopathy syndrome (CRES) after CAR-T infusion, in which 1 was grade III CRES. All patients who developed CRS or CRES recovered after intervention. Conclusion FasT CAR-T have superior expansion capacity with younger and less exhausted phenotype, and more potent cytotoxicity against B-ALL. This first-in-human clinical study in China showed CD19-directed FasT CAR-T therapy is highly effective in treating R/R B-ALL with manageable toxicity. The safety, efficacy and potential long-term clinical benefit of FasT CAR-T therapy will be further evaluated in large multi-center trial. (http://www.chictr.org.cn/listbycreater.aspx:ChiCTR1900023212) Disclosures No relevant conflicts of interest to declare.

Backgroud T-cell lymphoblastic lymphoma (T-LBL) is a highly aggressive lymphoma with very poor clinical outcomes which has not standard treatment. This study evaluated the efficacy and safety of tandem autologous hematopoietic stem cell transplantation (auto-HSCT) treatment for adult T-LBL and assessed the factors that affect survival. Methods 160 newly diagnosed adult T-LBL patients were divided into three groups: chemotherapy group (68 patients), single auto-HSCT group (46 patients), and tandem auto-HSCT group (46 patients). The primary outcome measure was failure-free survival. The intermediate primary outcomes were progression/relapse rate and overall survival. Factors influencing toxicity related to tandem auto-HSCT treatment and prognosis for the patients were analyzed as well. Results The 3-year progression/relapse rate of the tandem auto-HSCT group was significantly lower than that of the single auto-HSCT group and chemotherapy group (19.6% vs 45.7% and 70.6%, p < 0.05). The 3-year PFS rate and OS rate of the tandem auto-HSCT group (68.3% and 72.5%, respectively) were significantly higher than those of the single auto-HSCT group (41.5% and 55.4%, respectively, p < 0.05) and the chemotherapy group (23.3% and 43.3%, respectively, p < 0.05). In the tandem auto-HSCT group, age and disease status after the first transplant had an influence on the OS and PFS. Multivariate analysis identified disease status after the first transplant as the only independent prognostic factor for outcome in T-LBL. Conclusions Tandem auto-HSCT improves long-term survival of adult T-LBL patients. Disease status after the first transplant was an independent prognostic indicator for those patients. Disclosures No relevant conflicts of interest to declare.

Life-threatening complications, such as severe bleeding and/or differentiation syndrome at admission and/or along with induction treatment, among high-risk patients with acute promyelocytic leukemia (APL) are a worldwide puzzle towards the cure of the disease. Taking the rationale that high WBC count, at least in part, may cause cytokine storm related symptoms, we designed this refined regimen with low dose mitoxantrone and ATRA plus arsenic trioxide to determine the safety and efficiency of this WBC reduction, prevention of differentiation syndrome, and supportive care centered approach. In total there were 50 patients with high risk APL (WBC>10x109) from 2003-2017 were enrolled with a medium follow-up of 39 months (15-72 months). Our treatment strategy and detailed protocol are: 1) WBC reduction: it started with ATRA (25mg/m2/day) and arsenic trioxide (0.15mg/kg/day) based double induction. The advantage of decreased dose of ATRA can help to lower the happening of leukocytosis which will trigger the cytokine releasing related syndrome. Low dose mitoxantrone (3mg/m2) was added from day 2-5 plus hydroxyurea (1.5g, p.o. q6h) started from day 1. The criteria for withdrawal hydroxyurea is once both of the following standard are met: i) the WBC count has continuously decreased for three days after reached the peak value; ii) WBC < 10x109/L. 2) Prevention of Differentiation Syndrome (DS): Dexamethasone (5mg/day) was added once the diagnosis was confirmed at day 1. The criteria to taper dexamethasone are the same as to stop hydroxyurea. We require to withdraw dexamethasone within one week once start the taper process. In general, our goal is to prevent the occurrence of both leukopenia and leukocytosis and maintain the WBC count between 2-20x109. 3) Supportive care: We maintain the PLT count between 20-30x109 and fibrinogen >1.5g/L which helped to decrease the occurrence of myelo-suppression, DS and severe bleeding. 4) CNS Prophylaxis: The Intrathecal injection was given after the CR was achieved. Unless there was evidence of CNS infiltration, we gave intrathecal injection after correcting the coagulation abnormality. The consolidation began at four weeks after the end of induction. It contained four weeks of an on and off schedule of arsenic trioxide (0.15mg/kg/day), in total four cycles, and two weeks of an on and off schedule of ATRA (25mg/m2/day), in total seven cycles. A total of eight intrathecal injections were given on the first and last day of arsenic trioxide. Two death was observed through our strategy during the induction. All patients reached hCR by the end of induction. Relapse occurred in four out of 50 patients, and there was no treatment-related mortality. All the relapsed patients entered CR again after using the same protocol. Grade 3-4 adverse events were observed among 12% of all the cases. Three-year probability of overall survival (pOS) was found to be 92%. Our strategy focus of reducing WBC count sheds new light on maximally eliminating early mortality of high-risk APL patients. Disclosures No relevant conflicts of interest to declare.

The treatment options for patients with acute myeloid leukemia (AML) under inferior performance status (i.e. senior patients, MDS transformed AML, and patients with proven invasive fungal disease) are limited. The conventional "3+7" (idarubicin plus cytarabine) induction for those patients can be either too toxic, which leads to higher mortality rate, or requires prolonged recovery time thus raise medical cost. And the delay of consolidation may compromise outcome thus cause early relapse in such patients. Giving the rationale from the designing art of CPX-351, the prolonged IV time requirement for cytarabine, as well as mini-transplantation for AML treatment, at least in part, reflects the philosophy of a longer exposure to the chemo agent can be a more effective treatment approach for leukemia. On the other hand, the D-CAG protocol, which indicated an encouraging result for elderly patients with AML, indicated effectiveness of the strategy with reduced intensity. However, the cyto-toxic effect of decitabine with standard dose (20mg/m2) could still lead to severe treatment adverse events (AEs) thus raise the need of optimization of D-CAG regimen for patients with inferior PS. When considering the low dose hypo-methylation agent (HMA) can trigger the innate immunity response, the unique effect of homoharringtonine, as well as the effectiveness of CAG, we designed this DHCAG protocol following the principle of "longer exposure, lower intensity preceded by priming" and observed an unexpected excellent outcome with high CR rate, low induction failure and treatment mortality, as well as a higher cost effective value for patients with AML, when compared to "3+7" protocol, whom under inferior PS. From March 2016 - January 2018, we initiated this pilot study and investigated the safety and efficiency of this DHCAG protocol in patients with AML under poor PS. We enrolled 25 patients and administer the regimen as followings: i) G-CSF: 5μg/kg used when WBC 1*10^9/L then increase the dosage of homoharringtonine to 2mg/m2); iv) Cytarabine:10mg/m2 q12h at day 1-14 subcutaneous injection (if WBC >20*10^9/L then increase to 100mg/m2 by 24h CIV, or 50mg/m2 q12h by subcutaneous injection). The primary end point was complete hematologic remission, defined as a bone marrow blast cells ≤5%, Neutrophils in peripheral blood ≥1.0X109 /L, hemoglobin≥90g/L, and platelets ≥100X109/L and no any evidence of extramedullary leukemic infiltration; Secondary end points included numbers of adverse events, length of hospital stay, medical costs, and quality of life as measured with the use of the Functional Assessment of Cancer Therapy - General (FACT-G) questionnaire. Among the 25 patients in the study, 23 completed the induction therapy. And 21/25 patients had a hematologic complete remission after a median time of 19 days. Once complete remission had occurred, all 21 patients received post-remission treatment for another 5 cycles of DHCAG. Median follow-up was 14 months (range, 8 to 19) by June 2018. Interestingly, regardless of grade 3-4 myelo-suppression occurred all of our patients during induction, eight patients did not experienced grade 3-4 myelo-suppression during the following cycles. The median hospital stay is 22 days. The median of total medical costs for induction was $9,815 (range, $5,053 to $16,336) vs $14,705 for "3+7" induction protocol (history control. Data unpublished). Patients resumed their usual lifestyle during post-remission therapy, and their quality of life was rated as nearly normal on the FACT-G questionnaire. At the time of the last follow-up, seven patients had had a hematologic relapse. The results of our pilot study, in which we tested a priming based, low dose and longer exposure in 25 patients with AML under poor PS, showed that the treatment was safe, effective, and economical. A prospective multicenter, randomized trial comparing DHCAG with IA is now under way in China. Disclosures No relevant conflicts of interest to declare.