ALBERT

Description: Purpose Vincristine (VCR) is frequently used for the treatment of pediatric cancer. However, it can lead to dose-limiting vincristine-induced peripheral neuropathy (VIPN). This study aimed to investigate if prolonging the duration of VCR administration (1-hour infusions instead of push injections) reduces VIPN in children with cancer during the first year of treatment. Methods The VINCA trial is an international multicenter randomized controlled trial. Participants were randomized to receive all VCR administrations through push injections or 1-hour infusions. Dose of VCR was 1.5-2 mg/m2 with a maximum of 2 mg. VIPN measurements were performed at baseline and 1-3 times during treatment, depending on the number of VCR administrations and the total treatment time, using 4 items of the common toxicity criteria of adverse events (CTCAE version 4.03): constipation, peripheral sensory neuropathy, peripheral motor neuropathy and neuralgia. Individual item scores range from zero (no complaints) to five (death). The primary outcome of this trial was total sum CTCAE score during first year of treatment. For the current analysis, patients treated for acute lymphoblastic leukemia (ALL) or Hodgkin's lymphoma were included. All included patients were analyzed according to the intention-to-treat principle. Besides VIPN measurements, data on all relevant co-medication during treatment were collected, including data of concurrent azole therapy (as azole treatment is known to interact with VCR treatment). Descriptive data were analyzed using either chi-square tests or t-tests. Longitudinal data were analyzed using repeated measures mixed model analysis for continuous outcomes (total CTCAE sum score) and generalized estimating equations for dichotomous outcomes (having VIPN yes or no, with VIPN defined as a CTCAE score of ≥ 2 on any of the 4 CTCAE items). Patients were considered to have been treated with concurrent azole therapy when azoles were used during the week before or following VCR administration and if ≥ 50% of VCR administrations between two succeeding measurements were given with concurrent azole therapy. Results were corrected for concurrent azole therapy, cumulative VCR dose, disease, age, gender, ethnicity and time since diagnosis. Results In total 90 children (n=45 one hour infusions group, n=45 push injections group) participated in the study, 58 (64%) with ALL and 18 (20%) with HL. Participants in the two randomization groups did not significantly differ regarding gender, age, ethnicity, diagnosis, or cumulative VCR dose. Overall results showed no effect of randomization on total CTCAE score (β=0.07, 95% confidence interval (CI) -0.42-0.56, p=0.78). However, concurrent azole treatment appeared to be an effect modifier in this analysis and therefore results are reported separately for measurements with (n=24) and without concurrent azole therapy (n=226). Among patients who received concurrent azole therapy, total CTCAE sum score was significantly higher in the push group compared to the 1-hour group (β=1.95, 95% CI 0.49-3.41, p=0.01), while among those without concurrent azole therapy, these CTCAE sum scores did not differ between the two randomization groups (β=-0.17, 95% CI: -0.67-0.34, p=0.52). The risk of developing VIPN (no/yes) did not significantly differ between both randomization groups, irrespective whether concurrent azole treatment was given or not (with azole: OR (95% CI)=4.92 (0.60-40.37), p=0.14; without azole: OR (95% CI)=0.97 (0.51-1.82, p=0.92). Conclusions Overall, administration method of VCR given as push injection or 1-hour infusion did not seem to affect the risk of developing VIPN in children treated for ALL or HL when using the current dosing regimen. However, when concurrent azole treatment is given, total CTCAE scores are significantly lower in children in the 1-hour infusion group compared to the push injection group, demonstrating less VIPN. These results indicate that for children treated with VCR and concurrent azole therapy for the prevention or treatment of fungal infections, administration of VCR by 1-hour infusions instead of push injections is recommended. Figure Disclosures Kaspers: Helsinn Healthcare: Consultancy; Boehringer Ingelheim Pharma: Other: Member of a DSMC. van der Sluis:medac: Consultancy; jazz farmaceuticals: Consultancy.

Description: Human cardiac stem cells isolated from atrial appendages based on aldehyde dehydrogenase activity (CASCs) can be expanded in vitro and differentiate into mature cardiomyocytes. In this study, we assess whether Wnt activation stimulates human CASC proliferation, whereas Wnt inhibition induces cardiac maturation. CASCs were cultured as described before. Conventional PCR confirmed the presence of the Frizzled receptors. Small-molecule inhibitors (IWP2, C59, XAV939, and IWR1-endo) and activator (CHIR99021) of the Wnt/β -catenin signaling pathway were applied, and the effect on β-catenin and target genes for proliferation and differentiation was assessed by Western blot and RT-qPCR. CASCs express multiple early cardiac differentiation markers and are committed toward myocardial differentiation. They express several Frizzled receptors, suggesting a role for Wnt signaling in clonogenicity, proliferation, and differentiation. Wnt activation increases total and active β-catenin levels. However, this does not affect CASC proliferation or clonogenicity. Wnt inhibition upregulated early cardiac markers but could not induce mature myocardial differentiation. When CASCs are committed toward myocardial differentiation, the Wnt pathway is active and can be modulated. However, despite its role in cardiogenesis and myocardial differentiation of pluripotent stem-cell populations, our data indicate that Wnt signaling has limited effects on CASC clonogenicity, proliferation, and differentiation.

Description: Abstract 4102 Donor leucocyte infusion (DLI) after alloHSCT can induce strong graft-versus-leukemia (GvL) effects, inspiring investigators to examine this approach for solid tumors resistant to conventional therapies (Grivas et al. Curr Clin Pharmacol. 2011). However, DLI produces graft-versus-host disease (GvHD). Recipient-type leucocyte infusion (RLI) is currently being explored clinically as a means to induce GvL without risk of GvHD (clinicaltrials.gov; Rubio et al. Blood 2003; De Somer et al. Haematologica. 2011). High-risk neuroblastoma carries a bleak prognosis despite aggressive treatment with chemo-, radiotherapy and autologous HSCT. Clinical observations in such patients suggest that alloHSCT may produce a graft-vs-neuroblastoma effect (Kanold et al. Bone Marrow Transplantation. 2008). In mice, alloHSCT delays local neuroblastoma growth, and adoptive transfer of tumor-pulsed donor dendritic cells and donor leucocytes enhances this effect (Ash et al. Cancer Immunol Immunother. 2009, Br J Cancer 2010). In this study, we show that not only DLI by itself, but also RLI enhances the local anti-neuroblastoma effect of alloHSCT in mice. MHC-mismatched [C57BL/6 (H-2Kb) → A/J (H-2Kk)] bone marrow chimeras were given a subcutaneous inoculation with 1 × 106 Neuro2A cells (A/J neuroblastoma) on day 14 post HSCT. On day 21, we performed adoptive transfer of 10 × 106 donor splenocytes (DLI), 50 × 106 recipient splencoytes (RLI) and/or 1 × 106 recipient-type MACS-isolated DX5+ NK cells. We measured tumor volume twice weekly using a caliper (volume = width2 × length × 0,4). Validation of this model showed progressive tumor growth and mortality as a result of metastasis. Peripheral blood chimerism and tumor infiltrating lymphocytes were studied using flow cytometry. AlloHSCT chimeras developed mixed donor T cell chimerism by day 21 and full donor chimerism by day 76 post HSCT. DLI induced a conversion to full donor T cell chimerism and RLI induced a complete loss of donor T cells chimerism, both within 1 week. AlloHSCT chimeras showed reduced local growth of subcutaneous neuroblastoma tumors relative to synHSCT chimeras. This delay in tumor growth was enhanced not only by DLI, but also by RLI; DLI provoked lethal GvHD whereas mice treated with RLI remained healthy. Within tumor-infiltrating lymphocytes, T and NK cell chimerism mirrored the systemic chimerism changes seen after RLI and DLI, associated with an increased intratumoral CD8/CD4 ratio, CD8+ T-cell IFN-γ-expression and NK-cell Granzyme B-expression. This indicates a close relation between lymphohematopoietic alloreactivity and the anti-tumor effect, and suggests that the anti-tumor mechanism of DLI and RLI involves not only CD8+ T cells but also cytotoxic NK cells. The baseline antitumor effect seen in alloHSCT chimeras was also accompanied by increased Granzyme B expression by intratumoral NK-cells, supporting a role for NK cells also in this baseline antitumor effect. In vivo Neuro2A-inoculation experiments in (poly(I:C)-treated) C57BL/6, TCR−/− C57BL/6 and A/J mice, and in vitro NK cytotoxicity experiments showed that 1° donor T cells critically resist Neuro2A cells, 2° donor NK cells exhibit spontaneous cytotoxic reactivity to Neuro2A that is enhanced by NK activation, but also that 3° syngeneic NK cells may acquire reactivity to Neuro2A cells provided they are activated. Interestingly, when RLI was given, the intratumoral NK-cell frequency declined markedly, and adoptive transfer of additional NK cells obtained from naïve A/J mice enhanced the local antitumor effect of RLI. This supports the hypothesis that, in addition to donor NK cells, also syngeneic NK cells can play a critical role in mediating a growth-limiting effect on local neuroblastoma. Along this line, we observed that also in synHSCT mice, which showed a reduced local neuroblastoma growth relative to naïve mice, the intratumoral NK cells showed increased FasL-expression. These are the first experimental data showing that RLI after alloHSCT may induce immune-mediated anti-neuroblastoma effects, and that NK cells, in particular syngeneic NK cells, may play a critical role herein. Our data support the exploration of post alloHSCT adoptive cell therapy with recipient-type T and NK cells to produce enhanced immune antitumor effects for high-risk neuroblastoma, and potentially for other solid tumors that are unresponsive to traditional therapies, without the risk of GvHD. Disclosures: No relevant conflicts of interest to declare.