Inclusion of an IgG1-Fc spacer abrogates efficacy of CD19 CAR T cells in a xenograft mouse model.

Cancer therapy with T cells expressing chimeric antigen receptors (CARs) has produced remarkable clinical responses in recent trials, but also severe side effects. Whereas most protocols use permanently reprogrammed T cells, we have developed a platform for transient CAR expression by mRNA electroporation. This approach may be useful for safe clinical testing of novel receptors, or when a temporary treatment period is desirable. Herein, we investigated therapy with transiently redirected T cells in vitro and in a xenograft mouse model. We constructed a series of CD19-specific CARs with different spacers and co-stimulatory domains (CD28, OX40 or CD28-OX40). The CAR constructs all conferred T cells with potent CD19-specific activity in vitro. Unexpectedly, the constructs incorporating a commonly used IgG1-CH2CH3 spacer showed lack of anti-leukemia activity in vivo and induced severe, partly CD19-independent toxicity. By contrast, identical CAR constructs without the CH2-domain eradicated leukemia in vivo, without notable toxicity. Follow-up studies demonstrated that the CH2CH3-spacer bound soluble mouse Fcγ-receptor I and mediated off-target T-cell activation towards murine macrophages. Our findings highlight the importance of non-signalling CAR elements and of in vivo studies. Finally, the results show that transiently redirected T cells control leukemia in mice and support the rationale for developing an mRNA-CAR platform.

Ultra-short course sirolimus contributes to effective GVHD prophylaxis after reduced-intensity allogeneic hematopoietic cell transplantation.

Reduced-intensity conditioning (RIC) allo-SCT is a potentially curative treatment approach for patients with relapsed Hodgkin's or non-Hodgkin's lymphoma. In the present study, 37 patients underwent RIC allo-SCT after induction treatment with EPOCH-F(R) using a novel form of dual-agent immunosuppression for GVHD prophylaxis with CsA and sirolimus. With a median follow-up of 28 months among survivors, the probability for OS at 3 and 5 years was 56%. Treatment-related mortality was 16% at day +100 and 30% after 1 year of transplant. Acute GVHD grades II-IV developed in 38% of patients, suggesting that the regimen consisting of CsA and an ultra-short course of sirolimus is effective in the prevention of acute GVHD.

The mild inflammatory response in febrile neutropenic lymphoma patients with low risk of complications is more pronounced in patients receiving tobramycin once daily compared with three times daily.

We evaluated inflammatory markers in febrile neutropenic lymphoma patients undergoing high-dose chemotherapy with autologous stem cell support. Based on MASCC scores, our patients had a low risk of serious complications and a perspective of a benign initial clinical course of the febrile neutropenia. We also studied the impact of tobramycin given once versus three times daily on these immune markers. Sixty-one patients participating in a Norwegian multicentre prospective randomized clinical trial, comparing tobramycin once daily versus three times daily, given with penicillin G to febrile neutropenic patients, constituted a clinically homogenous group. Four patients had bacteraemia, all isolates being Gram-positive. Thirty-two patients received tobramycin once daily, and 29 patients received tobramycin three times daily. Blood samples were taken at the onset of febrile neutropenia and 1-2 days later. All samples were frozen at -70 °C and analysed at the end of the clinical trial for C-reactive protein (CRP), procalcitonin (PCT), complement activation products, mannose-binding lectin (MBL) and 17 cytokines. We found a mild proinflammatory response in this series of patients. CRP was non-specifically elevated. Ten patients with decreased MBL levels showed the same mild clinical and proinflammatory response. Patients receiving tobramycin once daily showed a more pronounced proinflammatory response compared with patients receiving tobramycin three times daily. Overall, febrile neutropenic cancer patients with a benign clinical course show a mild proinflammatory immune response.

Priming with r-metHuSCF and filgrastim or chemotherapy and filgrastim in patients with malignant lymphomas: a randomized phase II pilot study of mobilization and engraftment.

SCF has been shown to synergize with G-CSF to mobilize CD34(+) PBPCs. In this study we report results from this combination after a phase II trial of 32 patients with malignant lymphoma randomized to receive recombinant methionyl human SCF (ancestim, r-metHuSCF) in combination with recombinant methionyl human G-CSF (filgrastim, r-metHuG-CSF) (experimental arm A) or routine chemotherapy plus filgrastim (conventional arm B). The primary objective was to evaluate the side effects and toxicity during priming and mobilization. The secondary objectives were efficacy by the level of blood-circulating PBPCs, the number of harvest days and the time to three-lineage engraftment after autografting. First, during priming 5 patients had 8 serious events, 4 in each arm. A summary of all adverse events revealed 30 (94%) patients suffering from 132 events of all grading. Second, neutropenia and thrombocytopenia was documented in arm B. Third, 9/14 (64%) patients in arm A reached the target of 5 million CD34(+) cells/kg body weight (bw) compared with 13/15 (87%) in arm B. The results represent the first randomized trial of growth factor plus chemotherapy priming and indicate that a formal phase III trial very unlikely may challenge chemotherapy plus r-metHuG-CSF priming in candidates for high-dose therapy.

mRNA transfection of DC in the immature or mature state: comparable in vitro priming of Th and cytotoxic T lymphocytes against DC electroporated with tumor cell line-derived mRNA.

BACKGROUND: The use of mRNA in vaccine studies has generally been through loading or transfection of immature DC followed by a maturation step. A recent study has suggested that this strategy may result in inferior priming of cytotoxic T lymphocytes (CTL). Furthermore the study did not address any possible effects on the priming of CD4(+) T-cell responses. METHODS: We compared mRNA transfection of mature DC with that of immature DC, using as a read-out their capacity to prime autologous T cells during one cycle of in vitro stimulation. In this model system we used mRNA from the tumor cell line Jurkat E6. DC transfected at either the immature stage (day 5) or mature stage (day 7) displayed a similar phenotype. RESULTS: Interestingly, no major differences in their ability to prime CD4 and CD8 T-cell responses were observed. As in vitro priming to some extent may reflect the capacity of these DC to prime T cells in vivo after vaccination, these studies support the use of mRNA-transfected mature DC in clinical protocols. DISCUSSION: Transfection of DC at the end of the maturation process represents a logistical improvement in the GMP production of mRNA-transfected DC for clinical protocols.

Phase I/II trial of melanoma therapy with dendritic cells transfected with autologous tumor-mRNA.

We have developed an individualized melanoma vaccine based on transfection of autologous dendritic cells (DCs) with autologous tumor-mRNA. Dendritic cells loaded with complete tumor-mRNA may generate an immune response against a broad repertoire of antigens, including unique patient-specific antigens. The purpose of the present phase I/II trial was to evaluate the feasibility and safety of the vaccine, and the ability of the DCs to elicit T-cell responses in melanoma patients. Further, we compared intradermal (i.d.) and intranodal (i.n.) vaccine administration. Twenty-two patients with advanced malignant melanoma were included, each receiving four weekly vaccines. Monocyte-derived DCs were transfected with tumor-mRNA by electroporation, matured and cryopreserved. We obtained successful vaccine production for all patients elected. No serious adverse effects were observed. A vaccine-specific immune response was demonstrated in 9/19 patients evaluable by T-cell assays (T-cell proliferation/interferon-gamma ELISPOT) and in 8/18 patients evaluable by delayed-type hypersensitivity (DTH) reaction. The response was demonstrated in 7/10 patients vaccinated intradermally and in 3/12 patients vaccinated intranodally. We conclude that immuno-gene-therapy with the described DC-vaccine is feasible and safe, and that the vaccine can elicit in vivo T-cell responses against antigens encoded by the transfected tumor-mRNA. The response rates do not suggest an advantage in applying i.n. vaccination.

Growth factor receptors in hematopoietic stem cells: EPH family expression in CD34+ and CD133+ cell populations from mobilized peripheral blood.

Cell-surface antigen expression of hematopoietic stem cells has a crucial role in characterizing cell subpopulation with distinct functional properties. The Eph receptors are the largest receptor tyrosine kinase family being involved in processes like vascular remodelling during development and physiological and pathological angiogenesis. Some Eph/Ephrin members are expressed in hematopoietic cells. The ability to isolate purified cell populations co-expressing CD34 and CD133 antigens as most commonly used markers for identification of hematopoietic progenitors has provided the opportunity to identify their surface-receptor profile. As positively expressed CD34 and CD133 cells take place not only in hematopoietic but also in endothelial differentiation, we aimed to define the Eph/Ephrin characteristic of these cells and relate these findings to new therapy strategies. Positive selections of CD34 and CD133 cells from PBPC in lymphoma patients were performed using magnetic beads and AutoMACS (Miltenyi Biotec) device. The purity of isolated cells was tested by flow cytometry. Immunocytochemistry was used to assess the Eph/Ephrin expression profile of positively selected samples. Our study revealed that all samples (10 from CD34+ and 8 from CD133+ cells) expressed one or more of Eph/Ephrin antigens in different proportions. All CD34+ cell samples, and 6 of 8 in the CD133+ cell fraction were strongly immunoreactive for EphA2. EphB2 was strongly expressed in all CD133+ cases, but 50% of the CD34 positive group lacked or weakly expressed this receptor. EphB4 was negative in 9 of 10 CD34+ cases and in all CD133+ cells. Thus, we have shown the surface marker profile of positively selected CD34 and CD133 cells in leukapheresis samples from lymphoma patients with regard to Eph/Ephrin receptors and discussed their biological clinical potential.

Immunotherapy with allotumour mRNA-transfected dendritic cells in androgen-resistant prostate cancer patients.

Here, we present results from a clinical trial employing a new vaccination method using dendritic cells (DCs) transfected with mRNA from allogeneic prostate cancer cell lines (DU145, LNCaP and PC-3). In all, 20 patients were enrolled and 19 have completed vaccination. Each patient received at least four weekly injections with 2 x 10(7) transfected DCs either intranodally or intradermally. Safety and feasibility of vaccination were determined. Immune responses were measured as delayed-type hypersensitivity and by in vitro immunoassays including ELISPOT and T-cell proliferation in pre- and postvaccination peripheral blood samples. Serum prostate-specific antigen (PSA) levels and bone scans were monitored. No toxicity or serious adverse events related to vaccinations were observed. A total of 12 patients developed a specific immune response to tumour mRNA-transfected DCs. In total, 13 patients showed a decrease in log slope PSA. This effect was strengthened by booster vaccinations. Clinical outcome was significantly related to immune responses (n = 19, P = 0.002, r = 0.68). Vaccination with mRNA-transfected DCs is safe and results in cellular immune responses specific for antigens encoded by mRNA derived from the prostate cancer cell lines. The observation that in some patients vaccination affected the PSA level suggests that this approach may become useful as a treatment modality for prostate cancer patients.

Development of a clinical grade procedure for generation of mRNA transfected dendritic cells from purified frozen CD34(+) blood progenitor cells.

Enriched CD34(+) peripheral blood progenitor cells (PBPC) are frequently used as stem cell support in cancer patients following high dose therapy. Since precursor dendritic cells (DCs) originate from haematopoietic progenitor cells, purified CD34(+) cells might also serve as starting cells for ex- vivo production of DC. In the present study we developed a clinical grade procedure for ex- vivo production of DC derived from enriched CD34(+) cells. Different concentrations of CD34(+) cells were grown in gas-permeable Teflon bags with different serum-free and serum-containing media supplemented with GM-CSF, IL-4, TNF-alpha, SCF, Flt-3L and INF-alpha. Serum-free CellGroSCGM medium for 7 days followed by CellGroDC medium in 7 days gave the same results as serum-containing medium. After incubation the cultured cells containing immature DCs were concentrated and transfected with tumour mRNA from human prostate cancer cell lines employing a highly efficient electroporation procedure. Thawed transfected DCs were able to elicit primary T-cell responses in vitro against antigens encoded by the prostate cancer mRNA as shown by ELISPOT assay using mock-transfected DCs as control. Our results show that frozen enriched CD34(+) cells can be an alternative and efficient source for production of DCs for therapeutic purpose.

Treatment of Burkitt's/Burkitt-like lymphoma in adolescents and adults: a 20-year experience from the Norwegian Radium Hospital with the use of three successive regimens.

BACKGROUND: Burkitt's/Burkitt-like lymphoma (BL/BLL) are highly aggressive lymphomas mainly affecting children and young adults. We report the results in adolescent and adult patients with the use of three successive regimens. PATIENTS AND METHODS: Forty-nine patients aged 15-70 years admitted to the Norwegian Radium Hospital in the period 1982-2001 with a diagnosis of BL/BLL on histological review and who were given chemotherapy with curative intent are included in this analysis. Up to 1987 patients were given doxorubicin-based chemotherapy supplemented with intravenous and intrathecal methotrexate (MmCHOP). From 1987 to 1994, patients who obtained complete remission upon this regimen were consolidated with high-dose therapy with stem-cell support (MmCHOP + HDT). In 1995 we introduced as frontline therapy the German Berlin-Frankfurt-Munster (BFM) regimen. RESULTS: By intention to treat analyses, the progression-free survival rates for patients who received MmCHOP (n=13), MmCHOP + HDT (n=17) or BFM therapy (n=19) are 30.8%, 70.6% and 73.7%, respectively. In the groups of patients who received either the BFM regimen or MmCHOP + HDT, all patients who obtained complete remission upon induction therapy are continuously disease free. There was no treatment-related death. CONCLUSIONS: BL/BLL in adolescents and adults can successfully be treated with 5-day blocks of intensified chemotherapy such as the BFM regimen or CHOP/methotrexate-based chemotherapy consolidated with high-dose therapy. Using the BFM regimen, continuous remissions are obtained without additional myeloablative chemotherapy.

Infused CD34 cell dose, but not tumour cell content of peripheral blood progenitor cell grafts, predicts clinical outcome in patients with diffuse large B-cell lymphoma and follicular lymphoma grade 3 treated with high-dose therapy.

Previously, we have shown that patients with diffuse large B-cell lymphoma (DLBCL) transplanted with contaminated bone marrow (BM) generally have a poor outcome. Whether this is also the case when peripheral blood progenitor cell (PBPC) grafts are used is not known. Forty-three patients with chemosensitive DLBCL or follicular lymphoma grade 3 (FLgr3) were treated with high-dose therapy (HDT) and autologous stem cell support. Nine patients received purged grafts. Quantitative real-time polymerase chain reaction (QRT-PCR) for either the BCL2/IgH translocation or allele specific oligonucleotide (ASO) QRT-PCR for the immunoglobulin heavy chain (IgH) complementarity-determining region 3 were used. Nine of 25 (36%) PBPC grafts contained tumour cells as tested by QRT-PCR, including two grafts purged by CD34(+) cell enrichment combined with B-cell depletion. The level of contamination of the PBPC/CD34(+) cells ranged from 0 to 8.28%. No relationship could be shown between the total number of tumour cells infused and relapse. Patients receiving PCR-positive or PCR-negative PBPC grafts had similar progression-free survival (PFS) (P = 0.49). However, a significant difference was seen in PFS and overall survival (OS) for the patients given >/=6.1 x 10(6) CD34(+) cells/kg compared with those given <6.1 x 10(6) CD34(+) cells/kg (P = 0.01 and P < 0.05 respectively).

A protocol for generation of clinical grade mRNA-transfected monocyte-derived dendritic cells for cancer vaccines.

With the aim of producing large quantities of mRNA-transfected monocyte-derived dendritic cells (DCs) to be used as cancer vaccines, a new clinical grade procedure has been developed. Peripheral blood mononuclear cells (PBMCs) obtained by leukapheresis were enriched for monocytes by immunomagnetic depletion of CD19+ B cells and CD2+ T cells employing the ISOLEX 300i device. After 5 days of culture of enriched monocytes in gas permeable Teflon bags, using serum-free medium supplemented with granulocyte/macrophage-colony stimulating factor and interleukin-4 (IL-4), immature DCs were generated. Following transfection with mRNA from three human prostate cancer cell lines (DU145, LNCaP and PC-3), employing a newly developed square wave electroporation procedure, the immature DCs were immediately transferred to Teflon bags and matured for 48 h, using serum-free medium supplemented with IL-1alpha, IL-6, tumour necrosis factor-alpha and PGE2. The electroporation procedure efficiently transferred mRNA into the DCs with minor effect on the viability of the cells. The generated matured transfected DCs show high expression of the antigens CD83, CD80, CD86 and human leucocyte antigen-DR. Freezing and thawing of the transfected matured DCs had minor effect on cell viability and the phenotype. From 4 x 109 PBMCs, about 1 x 108 transfected matured DCs are produced. The thawed transfected DCs were able to elicit primary T-cell responses in vitro against antigens encoded by the prostate cancer mRNA as shown by enzyme-linked immunospot assay using mock-transfected DCs as control. Based on these results, clinical trials in cancer patients have been initiated.

Detection of isolated tumor cells in bone marrow is an independent prognostic factor in breast cancer.

PURPOSE: This study was performed to disclose the clinical impact of isolated tumor cell (ITC) detection in bone marrow (BM) in breast cancer. PATIENTS AND METHODS: BM aspirates were collected from 817 patients at primary surgery. Tumor cells in BM were detected by immunocytochemistry using anticytokeratin antibodies (AE1/AE3). Analyses of the primary tumor included histologic grading, vascular invasion, and immunohistochemical detection of c-erbB-2, cathepsin D, p53, and estrogen receptor (ER)/progesterone receptor (PgR) expression. These analyses were compared with clinical outcome. The median follow-up was 49 months. RESULTS: ITC were detected in 13.2% of the patients. The detection rate rose with increasing tumor size (P =.011) and lymph node involvement (P <.001). Systemic relapse and death from breast cancer occurred in 31.7% and 26.9% of the BM-positive patients versus 13.7% and 10.9% of BM-negative patients, respectively (P <.001). Analyzing node-positive and node-negative patients separately, ITC positivity was associated with poor prognosis in the node-positive group and in node-negative patients not receiving adjuvant therapy (T1N0). In multivariate analysis, ITC in BM was an independent prognostic factor together with node, tumor, and ER/PgR status, histologic grade, and vascular invasion. In separate analysis of the T1N0 patients, histologic grade was independently associated with both distant disease-free survival (DDFS) and breast cancer-specific survival (BCSS), ITC detection was associated with BCSS, and vascular invasion was associated with DDFS. CONCLUSION: ITC in BM is an independent predictor of DDFS and BCSS. An unfavorable prognosis was observed for node-positive patients and for node-negative patients not receiving systemic therapy. A combination of several independent prognostic factors can classify subgroups of patients into excellent and high-risk prognosis groups.

A survey of therapeutic hemapheresis in Norway year 2000.

In a survey of therapeutic hemapheresis in Norway, we sent a questionnaire to all regional and central hospitals, asking about hemapheresis activities, patients, indications, and adverse events. All units responded to the questionnaire: 17 dialysis units, 7 blood units, and 2 specialized units for stem cell apheresis. In total, they performed 2141 procedures that is 5.0 stem cell collections and 42.5 therapeutic apheresis procedures per 100,000 inhabitants. The most frequent indications were Guillain-Barré syndrome, hypercholesterolemia, and myasthenia gravis. Adverse effects were frequent, but mild. Dialysis units performed a majority of the procedures, leading to an extensive use of filtration techniques.

Detection of isolated tumor cells in bone marrow in early-stage breast carcinoma patients: comparison with preoperative clinical parameters and primary tumor characteristics.

UNLABELLED: PURPOSE/EXPERIMENTAL DESIGN: The importance of detection of disseminated isolated tumor cells (ITCs) in bone marrow (BM) is still not settled. BM aspirates from 920 patients with primary breast cancer were analyzed for tumor cells by standardized direct immunocytochemical analysis (ICC) of 2 x 10(6) mononuclear cells (MNCs) using anticytokeratin monoclonal antibody (AE1/AE3). Samples (637) were analyzed by negative immunomagnetic enrichment (IMS) followed by ICC (10 x 10(6) MNCs). Analyses of the primary tumor specimens have been performed, including histomorphology, tumor-node-metastasis (TNM) staging, grading, and immunohistochemical analyses. RESULTS: Of the patients with infiltrating carcinoma, 63% were node negative (N0) and 33%, node positive (N+). The results show the presence of tumor cells in 13.4% of the evaluable patients after direct ICC analysis. The presence of tumor cells correlated to the nodal- and tumor stage, showing BM positivity in 9.9% of the N0 cases and 20.6% in the N+ group (P < 0.0005), 11.2% of the stage T(1) were positive, and 15.0% and 22.6% were positive in the T(2) and T(3/4) groups, respectively (P = 0.013). No correlation between detection of ITC and detection of p53 and cathepsin D expression was found. Vascular invasion and c-erbB2 expression were associated with ITCs in BM (P = 0.045 and P = 0.024, respectively). Node-negative patients with estrogen receptor (ER)+ and/or progesterone receptor (PgR)+ tumors had lower frequency of ITCs than ER-/PgR- (P = 0.004). The use of negative IMS increased the frequency of positive BM by 63% (P < 0.0005). CONCLUSIONS: The direct ICC detection of ITCs in BM correlated with primary tumor stage, nodal stage, vascular invasion, c-erbB2 expression, and ER/PgR status. Analysis of larger BM samples by negative IMS resulted in increased number of ITC-positive patients.

Effects of dose-intensive chemotherapy and radiotherapy on serum n-terminal proatrial natriuretic peptide in high-risk breast cancer patients.

By using N-terminal proatrial natriuretic peptide (proANP) in serum as a marker of cardiac function, we compared the cardiac side effects of two intensive adjuvant treatment regimens for breast cancer. Patients received either 9 cycles of FEC (5-fluorouracil, epirubicin and cyclophosphamide) where the doses of epirubicin and cyclophosphamide were escalated according to the leucocyte nadir (n = 49, FEC-group) or three cycles of FEC followed by high-dose chemotherapy with alkylating agents (n = 56, CTCb-group) given with the support of peripheral blood stem cells support. Both groups received adjuvant radiotherapy. Serial measurements of proANP were performed up to three years after treatment. Mean proANP values in the FEC-group was on average 19% higher than in the CTCb-group (p = 0.002). The proANP levels showed a significant association with the cumulative dose of epirubicin (p < 0.001) but not with cyclophosphamide (p = 0.151) and 5-FU (p = 0.160). The pharmacokinetics of epirubicin was studied at the first and third chemotherapy course. The proANP levels after treatment were significantly related to the AUC (p = 0.034) and Cmax(p = 0.037) of epirubicin. Left-sided chest irradiation was associated with on average 12% higher proANP values than right-sided (p = 0.031). We conclude that dose-escalated FEC causes a stronger increase in proANP than 3 FEC followed by high-dose CTCb-treatment. Increase of proANP levels might represent an early sign of cardiotoxicity secondary to chemotherapy and radiation treatment. Long-time follow-up is necessary to determine the clinical significance of these findings.