Optimization of universal allogeneic CAR-T cells combining CRISPR and transposon-based technologies for treatment of acute myeloid leukemia

Despite the potential of CAR-T therapies for hematological malignancies, their efficacy in patients with relapse and refractory Acute Myeloid Leukemia has been limited. The aim of our study has been to develop and manufacture a CAR-T cell product that addresses some of the current limitations. We initially compared the phenotype of T cells from AML patients and healthy young and elderly controls. This analysis showed that T cells from AML patients displayed a predominantly effector phenotype, with increased expression of activation (CD69 and HLA-DR) and exhaustion markers (PD1 and LAG3), in contrast to the enriched memory phenotype observed in healthy donors. This differentiated and more exhausted phenotype was also observed, and corroborated by transcriptomic analyses, in CAR-T cells from AML patients engineered with an optimized CAR construct targeting CD33, resulting in a decreased in vivo antitumoral efficacy evaluated in xenograft AML models. To overcome some of these limitations we have combined CRISPR-based genome editing technologies with virus-free gene-transfer strategies using Sleeping Beauty transposons, to generate CAR-T cells depleted of HLA-I and TCR complexes (HLA-IKO/TCRKO CAR-T cells) for allogeneic approaches. Our optimized protocol allows one-step generation of edited CAR-T cells that show a similar phenotypic profile to non-edited CAR-T cells, with equivalent in vitro and in vivo antitumoral efficacy. Moreover, genomic analysis of edited CAR-T cells revealed a safe integration profile of the vector, with no preferences for specific genomic regions, with highly specific editing of the HLA-I and TCR, without significant off-target sites. Finally, the production of edited CAR-T cells at a larger scale allowed the generation and selection of enough HLA-IKO/TCRKO CAR-T cells that would be compatible with clinical applications. In summary, our results demonstrate that CAR-T cells from AML patients, although functional, present phenotypic and functional features that could compromise their antitumoral efficacy, compared to CAR-T cells from healthy donors. The combination of CRISPR technologies with transposon-based delivery strategies allows the generation of HLA-IKO/TCRKO CAR-T cells, compatible with allogeneic approaches, that would represent a promising option for AML treatment.

Treatment of steroid-refractory chronic graft-versus-host disease with imatinib: Real-life experience of the Spanish group of hematopoietic transplantation (GETH)

Treatment of steroid-refractory chronic graft-versus-host disease (cGVHD) is a challenge. Here, we describe a retrospective analysis of 66 patients with steroid-refractory cGVHD treated with imatinib (starting dose of 100 mg in 70% of patients; maximum dose of 100-200 mg in 74%). Most patients had multi-organ involvement (≥2 organs, 83%), with the most affected being skin (85%), oral mucosa (55%), eyes (42%), and lungs (33%). The overall response rate was 41% (21 partial and three complete responses). The organ with the best response rate was the skin (46%), followed by gastrointestinal tract (43%), liver (41%), the oral mucosa (36%), eyes (29%), and lungs (18%). Imatinib led to steroid tapering in 17/38 patients. Twenty-five (38%) patients experienced imatinib-related adverse events, comprising extra-hematologic toxicity (n = 24, 36%) and hematologic toxicity (n = 6, 9%). No cases of grade 4-5 toxicity were reported. The main causes of imatinib discontinuation were treatment failure (52%) and toxicity (9%). After a median follow-up of 41 months, the 3-year overall survival was 81%, with no difference between imatinib responders and non-responders. These real-life results show that imatinib is safe and has moderate efficacy in patients with heavily pre-treated cutaneous sclerotic cGVHD; however, activity against lung cGVHD is very limited.

Efficacy of the Combination of Immunoadsorption and Rituximab for Treatment in a Case of Severe Focal and Segmental Glomerulosclerosis Recurrence after Renal Transplantation

Background/Aims: We present a case of a male patient with severe recurrence of focal and segmental glomerulosclerosis (FSGS) after transplant. Methods: Before the transplant he was treated with plasma exchange. Massive proteinuria was detected post-transplantation and plasma exchanges were performed without response. We administered 5 doses of Rituximab (375 mg/m2) and partial remission was achieved. Proteinuria relapse occurred 1 year post-transplant, so Immunoadsorption (IA) was started instead of plasma exchange with reduction of proteinuria. Later, 2 new episodes of proteinuria relapse were detected and treated by increasing the number of IA sessions and administering new cycles of Rituximab. After achieving partial remission, IA was reduced to one session every 7–10 days as maintenance therapy. Results: Despite the fact of the severe recurrence, renal function and proteinuria remain stable over 8 years after the transplantation was performed. Conclusion: Combination of maintenance IA and cycles of Rituximab is an effective treatment for aggressive forms of FSGS recurrence after renal transplantation.

Phase I trial of gemcitabine (GEM) infused at fixed-dose rate (FDR) with high-dose docetaxel/melphalan/carboplatin (GEM-DMC) and autologous stem-cell transplant (ASCT)

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Background: More active ASCT regimens are needed. We combined GEM, which inhibits DNA damage repair, with the potent DMC regimen (BBMT 11:297–306,2005). GEM infusions at FDR of 10 mg/m2/min, targeting steady-state concentrations (Css) <20 μM, which in vitro do not saturate its intracellular activation to GEM-triphosphate (GEM-TP), result in greater activity but more myelotoxicity than its usual short infusions. Methods: Pts with advanced, refractory tumors and normal organ function were eligible. Study endpoints: to define the maximum tolerated duration (MTD) of GEM at FDR with ASCT, dose-limiting toxicity (DLT) and regimen-related toxicity (RRT) of GEM-DMC, and pharmacokinetics (PK) of high-dose GEM and docetaxel. Daily GEM FDR infusions (d-5 to d-2) were extended in sequential cohorts (total length: 9 to 20 hr), followed on d-5 by docetaxel (350 mg/m2), on d-4 to d-2 by melphalan (50 mg/m2/d) and carboplatin (333 mg/m2/d), and ASCT on d0. Results: 52 pts accrued (breast ca [N=31], Ewing's [5], germ-cell [4], lymphoma [4], Hodgkin's [3], sarcoma [5]), median age 40 (6–66), 3 median prior chemo regimens and 3 organs involved. GEM MTD: 5 hr/d x 4 (total 20 hr, 12 g/m2). Neutrophils engrafted on d+8 (6–10) and platelets on d+11 (8–33). There were 3 non-RRT deaths (1 aspiration, 2 catheter-related sepsis). At the MTD (N=25), enteritis (20% G3) was DLT; all other RRT were = G3 and reversible (28% stomatitis, 8% ileus, 8% rash). The response rate was 97% (60% complete). At median follow-up of 18 (7–27) months, 58% EFS (median 22 mo) and 85% OS rates (median not reached). All pts had GEM Css <20 μM. The infusion length correlated linearly with the AUC of GEM (r2= 0.65, p<10-5) but not with its clearance (r2=0.03) or t1/2 (r2= 0.02). GEM AUC was associated with G3 RRT (p<10-3). The AUCs of GEM and GEM-TP (/106 mononuclear cells) correlated on d-5 (r2=0.5, p=0.01), but not on d-2 (r2= 0.05) due to late GEM-TP accumulation. Docetaxel had 3–4 fold higher AUC and peak levels and similar clearance compared to its standard-dose population PK. Conclusions: GEM-DMC, markedly extending GEM infusions at FDR, is tolerable and highly active, without saturating the activation of GEM to GEM-TP. High-dose GEM and docetaxel show adequate linear PK.

No significant financial relationships to disclose.

Autologous stem-cell transplantation in diffuse large B-cell non-Hodgkin's lymphoma not achieving complete response after induction chemotherapy: the GEL/TAMO experience

BACKGROUND

Here we evaluate the results of high-dose chemotherapy and autologous stem-cell transplantation (HDC/ASCT) in 114 patients included in the GEL/TAMO registry between January 1990 and December 1999 with diffuse large B-cell lymphoma who failed to achieve complete remission (CR) with front-line conventional chemotherapy.

PATIENTS AND METHODS

Sixty-eight per cent had a partial response (PR) and 32% failed to respond to front-line therapy. At transplant, 35% were chemoresistant and 29% had two to three adjusted International Prognostic Index (a-IPI) risk factors.

RESULTS

After HDC/ASCT, 57 (54%) of 105 patients evaluable for response achieved a CR, 16 (15%) a PR and 32 (30%) failed. Nine patients were not assessed for response because of early death due to toxicity. With a median follow-up of 29 months for alive patients, the survival at 5 years is 43%, with a disease-free survival for complete responders of 63%. The lethal toxicity was 8%. Multivariate analysis revealed a-IPI and chemoresistance to be predicting factors.

CONCLUSIONS

Our results show that one-third of patients who do not obtain a CR to front-line chemotherapy may be cured of their disease with HDC/ASCT. However, most chemoresistant patients pretransplant failed this therapy. For this population, as well as for those who presented with adverse factors of the a-IPI, pretransplant novel therapeutic modalities need to be tested.

High-dose chemotherapy and autologous stem cell transplantation in peripheral T-cell lymphoma: the GEL-TAMO experience

BACKGROUND

T-cell immunophenotype constitutes an unfavorable prognostic factor in aggressive non-Hodgkin's lymphomas. High-dose chemotherapy with autologous stem-cell rescue (HDC/ASCT) is the best salvage therapy for patients with aggressive B-cell lymphomas. However, results with this therapy in peripheral T-cell lymphoma (PTCL) are not well defined.

PATIENTS AND METHODS

From January 1990 to December 1999, 115 patients with PTCL underwent HDC/ASCT inside the Grupo Español de Linfomas/Trasplante Autólogo de Médula Osea (GEL-TAMO) registry. At diagnosis the median age was 41 years and 60% of patients presented with two or three risk factors from the adjusted International Prognostic Index (a-IPI). Thirty-two per cent of patients were transplanted in first complete response (CR), 62% in chemosensitive disease and 5% in refractory disease.

RESULTS

Eighty-six per cent of the patients attained a CR and 5% a partial response (PR). With a median follow-up of 37 months (range 1-133), overall survival (OS), time-to-treatment failure (TTF) and disease-free survival (DFS) at 5 years was 56%, 51% and 60%, respectively; for the 37 patients transplanted in first CR, OS and DFS at 5 years were 80% and 79%, respectively. Lactase dehydrogenase (LDH), a-IPI and disease status pre-transplant were associated with outcome.

CONCLUSIONS

More than half of patients with chemosensitive disease who were transplanted are expected to be alive at 5 years. We confirm the utility of the pre-transplant IPI system in predicting outcome. Salvage treatment results with HDC/ASCT in PTCL are similar to those found in corresponding aggressive B-cell lymphomas.

Are myeloma patients with renal failure candidates for autologous stem cell transplantation?

INTRODUCTION

Renal function is one of the most important prognostic factors in multiple myeloma (MM). Patients with renal failure are generally excluded from high dose therapy even though they display a poor prognosis with conventional chemotherapy schemes. The aim of this study was to analyze the outcome of MM patients with renal insufficiency undergoing autologous stem cell transplantation (ASCT), including the evaluation of the quality of PB stem cell collections, kinetics of engraftment, transplant-related mortality, response to high dose chemotherapy and survival.

MATERIALS AND METHODS

From a total of 566 valuable patients included in the MM Spanish ASCT registry, three groups of patients were defined: group BA, patients with abnormal renal function at diagnosis but normal at transplant (73 cases); group BB, patients with abnormal function both at diagnosis and at transplant (14 cases); and group AA (control group, 479 cases), patients who constantly had normal renal function.

RESULTS AND CONCLUSION

Patients from groups BA and BB presented with a significantly higher number of adverse prognostic factors, reflecting that we were dealing with high tumor MM cases, as compared with patients from group AA. The number of mononuclear cells, CD34+ cells and CFU-GM cells collected in patients with non-reversible renal insufficiency was similar to those harvested in MM patients with normal renal function. Moreover, neutrophil and platelet engraftments were identical in patients with and without renal failure (days +11 and +12, respectively). By contrast, transplant-related mortality (TRM) was significantly higher in group BB patients (29%) than in groups BA (4.1%) and AA (3.3%). In multivariate analysis only three variables showed independent influence on TRM: poor performance status (ECOG 3), hemoglobin <9.5 g/dl and serum creatinine > or =5 mg/dl. The response to high dose therapy was independent of renal function. Interestingly, 43% of patients from group BB showed an improvement in renal function (creatinine < 2 mg/dl) after transplant. The three-year overall survival from transplantation was 56, 49 and 61% for the BB, BA and AA groups, respectively, with a statistically significant difference favoring group AA (P<0.01). PFS did not differ significantly between the three groups of patients. In multivariate analysis the only unfavorable independent prognostic factors for overall survival were poor performance status either at diagnosis or at transplant, high beta(2)-microglobulin levels, and no response to transplant. According to these results, ASCT is an attractive alternative for MM patients with renal insufficiency, and it should not constitute a criterion for exclusion from transplant unless patients display poor performance status and very high creatinine levels (>5 mg/dl).

BEAM chemotherapy followed by autologous stem cell support in lymphoma patients: analysis of efficacy, toxicity and prognostic factors

In the present paper, we evaluate tolerability, outcome and prognostic factors in patients with poor prognosis non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD) when uniformly treated with BCNU, etoposide, cytarabine and melphalan (BEAM) and autologous stem cell transplant (ASCT). On hundred and forty-eight patients with NHL (n = 112) or HD (n = 36) received BEAM followed by infusion of bone marrow (n = 55), peripheral blood stem cells (n = 79) or both (n = 14). Twenty-eight patients had low-grade lymphoma (LGL), 68 intermediate- and 16 high-grade lymphoma (IGL). Within the NHL group, 21 patients were in 2nd or subsequent complete remission (CR) at transplant, 34 had sensitive disease and 11 resistant disease; 46 patients were transplanted in 1st CR due to the presence of > or = 2 adverse prognostic features at diagnosis or to a slow CR. Of the HD patients at transplant 17 had active disease, 16 were in > or = 2 CR and three in 1st CR. The overall percentage of toxic deaths was 5.4%, while in the group of patients transplanted with PBSC it was only 1.3%. NHL patients: 78% were in CR following ASCT, including 25 out of 45 patients (56%) who were transplanted with active disease. Only two of the 11 patients transplanted with resistant disease achieved CR. Incidence of overall survival (OS) and disease-free survival (DFS) at 3 years was 65 and 75%, respectively. As far as histology was concerned, OS was significantly better for patients with LGL in comparison with IGL (88 vs 56%) (P = 0.002). DFS was significantly higher for patients transplanted in first CR or first partial remission (PR) than it was for those transplanted in a later CR or PR (86 vs 53%) (P = 0.02). Multivariate analysis for OS showed that histology, bulky disease, poor performance status at transplant and achievement of CR were independent prognostic factors. In addition, a high number of infused MNC was associated with poor DFS. HD patients: 30 (83%) were in CR after transplantation, with 25 maintaining CR at the end of the study. Only one of the four patients transplanted with resistant disease reached CR. Incidence of OS and DFS at 3 years was 78 and 81%. DFS was similar for patients transplanted with early or late relapse (95 and 93%). With multivariate analysis, the only independent variable for OS was CR after transplant. In conclusion, the present results demonstrate the efficacy and low toxicity of the BEAM regimen in high-risk lymphoma patients with sensitive disease. Other strategies should be investigated for patients with refractory lymphoma.