CD133 Directed CART Cells For Advanced Malignancies: Basic And Clinical Study

Hepatocellular carcinoma(HCC)is the second most common cause of cancer-related death globally.Although the incidence of HCC has reduced in some areas with the increased use of vaccines against viral hepatitis B(HBV),the global incidence and mortality rates of HCC continue to increase,resulting in at least 600,000 deaths annually.Because the symptoms and physical characteristics of HCC cannot be easily detected,curative treatment is not possible at the time of diagnosis for>80% of patients.Thus,the treatment of HCC remains a major healthcare challenge globally,and thus additional treatment options for advanced HCC are clearly needed.Chimeric antigen receptor(CAR)-T cells are genetically altered T cells comprised of a single variable chain fragment(sc Fv),a spacer domain,a transmembrane domain and intracellular domain.CART cells are able to identify tumor surface antigens independent of the MHCexpression,which is likely to be beneficial in preventing immune evasion.In hematologic malignancies including lymphomas,multiple myeloma and ALL,CART cell therapy has shown promising activity,particularly those targeting CD19.Given the clinical benefit demonstrated in refractory ALL patients,CART cell therapy was recently approved by the USA for this indication.The encouraging data in hematologic malignancies have engendered enthusiasm in solid tumors where there has been some preliminary evidence of activity,albeit not as robust as hematologic malignancies.There are now preliminary efficacy data for CART cell therapy in colon cancer,neuroblastoma,non-small-cell lung cancer and sarcoma.Methods: Part I: Firstly,we verified the specific anti-tumor effect of CART cells targeting CD133 on CD133 positive tumor cells in vitro,and we also carried out phase I clinical trials of CART-133 cells in the treatment of malignant solid tumors to determine the safety and efficacy of CART-133 cells.23 patients with advanced and CD133+ tumors [14 HCC,7 pancreatic carcinomas and 2 colorectal carcinomas] received CART-133 cell infusion.The initially enrolled 8 patients with HCC were treated by a CART-133 cell dose escalation test(0.05-2×106/kg).The higher CARcopy numbers and its reverse relationship with the count of CD133+ cells in peripheral blood led to the determination of an acceptable cell dose is 0.5-2×106/kg and reinfusion cycle in all patients.This trial is registered with Clinical Trials.gov,number NCT02541370.Part II: Patients with histologically confirmed and measurable advanced HCC and adequate hematologic,hepatic,and renal functions received CART-133 cell infusions.The primary endpoints were safety in phase I and progression-free survival(PFS)and overall survival(OS)in phase II.Other endpoints included biomarkers for CART-133 T cell therapy.Result: Part I: Of 23 patients,three achieved partial remission,and fourteen achieved stable disease.The 3-month disease control rate was 65.2%,and the median PFS was 5 months.Especially in patients who achieved stable disease after the first cell-infusion,repeated cell-infusions seemed to provide a longer period of disease stability.Notably,21 out of 23 patients had no detectable novel lesions during this term.The reverse relationship between CD133+ cell number in PB and the infused CAR-gene was robustly established.Analysis of biopsied tissues by immunohistochemistry showed CD133+ cells were eliminated after CART-133 infusions.The primary toxicity is a decrease in hemoglobin/platelet(? grade 3)and self-recovered within 1 week,grade 3 hyperbilirubinemia was observed in three patients who had obstruction of the biliary tract accompanied by a high bilirubin background.Part II: Between June 1,2015,and September 1,2017,this study enrolled 21 patients who subsequently received CART-133 T cells across phases I and II.The median OS was 12 months(95% CI,9.3-15.3 months)and the median PFS was 6.8 months(95% CI,4.3-8.4 months).Of 21 evaluable patients,1 had a partial response,14 had stable disease for 2 to 16.3 months,and 6 progressed after Tcell infusion.The most common high-grade adverse event weas hyperbilirubinemia.Outcome was correlated with the baseline levels of vascular endothelial growth factor(VEGF),soluble VEGF receptor 2(s VEGFR2),stromal cell-derived factor(SDF)-1 and EPC counts.Changes in EPC counts,VEGF,SDF-1,s VEGFR2 and interferon(IFN)-g after cell infusion were associated with survival.Conclusion: This trial showed the feasibility,controllable toxicities,and partly effective activity of CART-133 transfer for the treatment of late-stage HCC or other gastrointestinal metastasis malignancies patients.We identified early changes in circulating molecules as potential biomarkers of response to CART-133 cells.The predictive value of these proangiogenic and inflammatory factors as potential biomarkers of CART-133 cell therapy in HCC will be explored in prospective trials...