ALBERT

Description: Background Ponatinib is a third-generation tyrosine kinase inhibitor (TKI) indicated for adult patients with resistant or intolerant chronic phase (CP), accelerated phase, or blast phase chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), or those with the T315I mutation. In Belgium, ponatinib has been commercially available since March 2016. The goal of this registry was to collect efficacy and safety data in CML and Ph+ ALL patients and to evaluate ponatinib in routine clinical practice in Belgium. Methods This ongoing, prospective, multi-center registry includes patients ≥18 years of age with CML or Ph+ ALL, who have initiated ponatinib treatment. Demographic, efficacy and safety data were collected for patients enrolled from March 2016 (day 0) onwards. Results up to study month 24 are presented. Data were analyzed by descriptive statistics. Ethics Committee approval was obtained and all patients provided informed consent. Results At time of data analysis, 34 patients (21 CP-CML and 13 Ph+ ALL) were enrolled. The median age of CP-CML and Ph+ ALL patients was 57 and 55 years, respectively. Patients were heavily pretreated: 90% of CML and 92% of Ph+ ALL patients had received ≥2 prior TKIs. Several patients had one or more risk factors for TKI cardiovascular toxicity: hypertension (10), history of cardiovascular disease (11), smoker (10), hypercholesterolemia (5), and diabetes (4). Median follow-up was 539 days for CML and 135 days for Ph+ ALL patients. The reasons for starting ponatinib therapy were related to refractoriness to previous TKIs (36%), progression (18%), presence of the T315I mutation (18%) or intolerance (29%). Eighty percent (8/10) of the patients who started ponatinib due to intolerance to previous TKIs had received ≥3 prior TKIs. At entry, 17 of the 34 patients (50%) had a confirmed BCR-ABL mutation. Of these 17, 10 (59%; 5 CML and 5 Ph+ ALL) had the T315I mutation. Starting doses of ponatinib in CML patients were 45 mg (76%), 30 mg (10%) and 15 mg (14%) once daily. Starting doses in Ph+ ALL patients were 45 mg (85%), 30 mg (8%) and 15 mg (8%). At latest follow up, the median treatment duration for the 21 CML patients was 531 days (range 15 - 2483) and for the 13 Ph+ ALL patients it was 123 days (range 13 - 1945). Best response was a major molecular response (MMR), which was obtained in 71% of CML patients and 38% of Ph+ ALL patients. The median time-to-best response was 175 days in CML and 35 days in Ph+ ALL patients. In the 10 patients (7 CML and 3 Ph+ ALL) who started ponatinib because of intolerance to several previous TKIs, 80% achieved MMR. The median time to achieve best response in these patients was 192 days for CML and 31 days for Ph+ ALL patients. Treatment-related adverse events (AEs) were reported in 20 patients (59%); the most common were rash (26%), dry skin (9%) and constipation (9%). Three patients reported ≥1 treatment-related serious AE (SAE): thrombocytopenia (n=1), cholecystitis (n=1) and hepatocellular injury (n=1). Three serious cardiovascular events were observed in 1 patient, who had a history of congenital cardiomyopathy and aortic prosthesis. They were scored as not related to ponatinib. Dose reductions or interruptions occurred in 33 cases (20 in CML and 13 in Ph+ ALL patients), with the following reasons most frequently mentioned: AEs (76%), to prevent AEs (18%) and other (6%). Dose increases occurred in 12 cases (10 in CML and 2 in Ph+ ALL patients), for the following reasons: good tolerance of treatment (58%), no or low response (33%) or other (8%). At time of analysis, 19 patients (9 CML and 10 Ph+ ALL) had discontinued treatment, of which 32% due to AEs, 5% due to an SAE, 21% due to planned allogeneic transplant, 16% due to disease progression and 26% due to other reasons. [Note: Percentages may not total 100 due to rounding] Conclusion Real-world evidence from this Belgian registry shows that ponatinib has a favorable efficacy and safety profile in, and supports its use in CML and Ph+ ALL patients who are resistant or intolerant to previous therapies or those with the T315I mutation. Deep molecular responses were obtained in the majority of patients. No new safety signals emerged with ponatinib treatment than those previously reported. Funding: Incyte Biosciences Benelux BV Disclosures Devos: Takeda: Consultancy; Novartis: Consultancy; Celgene: Consultancy. Theunissen:Incyte: Honoraria. Van Eygen:Janssen: Consultancy, Research Funding; Roche: Research Funding; Amgen: Research Funding. Kuipers:Incyte Biosciences Benelux BV: Employment.

Description: Background Iclusig (ponatinib) is a third-generation tyrosine kinase inhibitor (TKI) indicated for adult patients with chronic, accelerated or blast phase CML resistant or intolerant to nilotinib or dasatinib or with Ph+ ALL resistant or intolerant to dasatinib or for patients with the T315I mutation. Long-term efficacy and safety of ponatinib have been demonstrated in clinical trials, but real-world data are still limited. Here, we report the data on ponatinib use in CML and Ph+ ALL patients in routine clinical practice collected over 3 years in Belgium. Methods This ongoing prospective registry (NCT03678454) is conducted in Belgium and includes patients ≥18 years of age eligible for ponatinib treatment per product label. Data on demographics, medical history, disease characteristics, treatment patterns, treatment outcomes and safety were collected for patients enrolled from 1 March 2016 (ponatinib reimbursement in Belgium) onwards. Median follow-up was 15 and 4.5 months for CML and Ph+ ALL patients, respectively. All analyses were descriptive. The study received Ethics Committee approval and patients' consents were collected as per Helsinki Declaration. Results In total, 50 patients (33 CML and 17 Ph+ ALL) were enrolled from 20 hospitals. The median age of CML and Ph+ ALL patients was 58 and 56 years, respectively. 91% of CML and 94% of Ph+ ALL patients had received ≥2, and 54% of CML and 29% of Ph+ ALL patients had received ≥ 3 prior TKIs. Potential risk factors for TKI cardiovascular toxicity were observed: hypertension (17 patients), history of cardiovascular disease (19), smoking (13), hypercholesterolemia (6), hyperlipidemia (5) and diabetes (8). The reasons for starting ponatinib were: intolerance to previous TKIs (20, 40%), refractoriness to previous TKIs (14, 28%), disease progression (8, 16%) or T315I mutation (8, 16%). At entry, 22 patients (44%; 11 CML and 11 Ph+ ALL) had a confirmed BCR-ABL mutation. Of these, 12 (55%; 6 CML and 6 Ph+ ALL) had the T315I mutation. Starting doses of ponatinib in CML patients were: 45 mg (70%), 30 mg (12%) and 15 mg (15%) once daily. One patient with CML started with 15 mg every 2 days. Starting doses in Ph+ ALL patients were: 45 mg (76%), 30 mg (12%) and 15 mg (12%). The median treatment duration was 380 days (range 15-2777) for CML patients and 123 days (range 13-2114) for Ph+ ALL patients, which included recently enrolled patients. Major molecular response (MMR) was achieved as best response in 19 (58%) CML patients and 7 (41%) Ph+ ALL patients; while 2 (6%) of CML and 3 (18%) of Ph+ ALL patients achieved complete cytogenetic response (CCyR) as best response. Of patients who started ponatinib due to intolerance to previous TKIs, 9 CML (64%) and 4 Ph+ ALL (67%) achieved MMR. There were 57 cases (38 in CML and 19 in Ph+ ALL) of dose reduction or interruption, due to AEs (74%), to prevent AEs (25%) and other reason (2%). There were 24 cases (19 in CML and 5 in Ph+ ALL) of dose increase: due to good tolerance of treatment (54%) and absent or low response (46%). At time of analysis, 29 patients (15 CML and 14 Ph+ ALL) had discontinued treatment, for the following reasons: AEs (34%), planned allogeneic transplantation (21%), disease progression (14%), intolerance (3%) and other reasons (28%). Treatment-related adverse events (AEs) were reported in 34 patients (68%); the most common were rash (26%) and dry skin (10%). Six (12%) patients reported ≥1 treatment-related serious AE (SAE): thrombocytopenia (2), palpitations (1), hypertension (1), pneumonia (1), coeliac artery stenosis (1), cholecystitis (1) and hyponatremia (1). One patient, with a history of congenital cardiomyopathy and aortic prosthesis, reported 3 serious cardiovascular events; these were considered as not related to ponatinib by the investigator. Conclusion Results from this real-world Belgian registry support the use of ponatinib in CML and Ph+ ALL patients who are resistant or intolerant to previous TKIs or have the T315I mutation. Most CML and a large proportion of Ph+ ALL patients obtained deep molecular responses. No new safety signals emerged with ponatinib treatment. The obtained results were in line with those of the PACE clinical trial, with the frequency of cardiovascular events apparently lower, possibly due to selection or improved monitoring of patients, or possible under-reporting vs clinical trial. Longer follow-up will be done to assess the long-term clinical efficiency in this real-life population. Disclosures André: Celgene: Other: Travel grants, Research Funding; Chugai: Research Funding; Takeda Millenium: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers-Squibb: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel grants; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Other: Travel grants, Research Funding; Amgen: Other: Travel grants, Research Funding; Johnson & Johnson: Research Funding. Bailly:Incyte Biosciences: Other: Local PI of the Study. De Becker:Celgene: Other: ad hoc member of advisory board; Pfizer: Other: ad hoc member of advisory board; Sanofi Pasteur: Other: ad hoc member of advisory board; Incyte: Other: ad hoc member of advisory board. Deeren:Alexion, Amgen, Janssen, Roche, Sunesis, Takeda, Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bekaert:Incyte Biosciences: Employment. Beck:Incyte Biosciences: Employment. Selleslag:INCYTE: Consultancy, Other: Travel Expenses.

Description: Abstract 16 Immunization using tumor antigen-loaded dendritic cells (DC) holds promise for the adjuvant treatment of cancer to control residual disease. In a phase I/II trial, we investigated the effect of autologous DC vaccination in 17 patients with acute myeloid leukemia (AML) in remission but at high risk of full relapse. Wilms’ tumor 1 protein (WT1), a nearly universal tumor antigen, was chosen as an immunotherapeutic target because of its established role in leukemogenesis and superior immunogenic characteristics. Two out of 3 patients, who were in partial remission with morphologically demonstrable disease after chemotherapy, were brought into complete remission following 4 biweekly intradermal injections of WT1 mRNA-electroporated DC. In those 2 patients as well as in 7 other patients who were in complete remission but who had molecularly demonstrable residual disease, there was a return to normal of the AML-associated WT1 mRNA tumor marker following DC vaccination, compatible with clinical and molecular response in 9/17 patients. In 3 patients, the WT1 mRNA tumor marker returned to pathological values following normalization after initial DC vaccination and additional injections of DC were needed to bring back the tumor marker to normal. Of the 9 responders, 3 have relapsed and 2 have died. Of the 8 non-responders, 7 have relapsed and 7 have died. Of the 2 patients in partial remission who were brought into complete remission by the DC vaccination, 1 has relapsed and has died. Median overall survival was 52.0 months in responders as compared to 6.0 months in non-responders (P=0.0007). Median relapse-free survival was 47.0 months in responders and 3.0 months in non-responders (P smaller than 0.0001). Immunomonitoring performed on the first 10 patients, showed a significant increase in WT1-specific interferon-gamma+ CD8+ T cells and signs of general immune stimulation, such as a significant increase of plasma levels of interleukin 2 and of HLA-DR+ CD4+ T-cells. Clinical responses were correlated with elevated levels of activated natural killer cells post-vaccination. Long-term clinical responses, lasting for at least 3 years, were significantly correlated with an increase in polyepitope WT1-specific tetramer+ CD8+ T-cell frequencies. There was no significant change post-vaccination in WT1 antibody levels or of regulatory T lymphocytes. In conclusion, DC-based immunotherapy elicits both innate and adaptive cellular immune responses correlated with clinical benefit. WT1 mRNA-loaded DC emerge as a feasible and effective strategy to control residual disease in AML, in particular as a post-remission treatment to prevent full relapse. Disclosures: Berneman: Argos Therapeutics: Patents & Royalties. Van Tendeloo:Argos Therapeutics: Patents & Royalties.

Description: Tumor recurrence and lack of tumor control are major problems in cancer treatment. In order to control malignant disease, we performed phase I/II dendritic cell (DC) vaccination studies in an adjuvant setting in 30 patients with acute myeloid leukemia (AML) and in 36 patients with solid tumors. Following chemotherapy, the patients underwent leukapheresis; CD14+ monocytes were isolated, cultured into clinical-grade mature DC, electroporated with mRNA encoding the Wilms' tumor protein WT1 and injected intradermally (Van Tendeloo et al. PNAS 2010;107:13824-9). No major DC-related systemic toxicity was observed. DC vaccination as a post-remission treatment was evaluated in 30 AML patients following chemotherapy; 27 patients were in complete remission (CR) but at very high risk of relapse and 3 in partial remission (PR). WT1 mRNA levels in blood and marrow were followed as a measure of residual disease. Clinical and molecular response, as determined by normalization of WT1 transcript levels in blood and/or marrow, occurred in 8/23 patients who had increased levels of that marker at the start of DC vaccination. Of these 8 responding patients, 5 are still in complete and molecular remission, all of them now more than 5 years after diagnosis and most probably cured; 1 of those 5 patients was in PR following chemotherapy and was brought into complete and molecular remission by the DC vaccination only. There was a possible effect of DC vaccination in 6 additional patients: 3 with stable disease, some of it late; and 3 at high risk of relapse but without increased WT1 mRNA levels before DC vaccination: 1 patient with erythroleukemia and 2 patients with initial leucocytosis 〉20,000/µL have remained in CR, now at respectively 57, 52 and 45 months post-diagnosis. Overall 8/30 patients have not relapsed yet, with a median follow-up from diagnosis and start of DC vaccination of respectively 70 months (range 45 - 92 months) and 63 months (range 39-90 months). Delayed type hypersensitivity (DTH) testing showed immunoreactivity to the DC vaccine in all patients tested. WT1 epitope tetramer+ CD8+ T-cells were evaluated in 13 HLA-A2+ patients: an increase following DC vaccination in tetramer+ T-cells for at least 2/4 epitopes tested was only observed in patients with long-standing CR. Ten patients with unresectable, epithelial-type malignant pleural mesothelioma and non-progressive disease after platinum/pemetrexed-based chemotherapy received DC vaccination. Evaluation of response according to RECIST criteria showed 7 patients with stable disease and 3 with progressive disease. DTH testing showed vaccine-elicited immunity in 9/10 patients. Median overall survival (OS) from start of chemotherapy was 32 months; this compares with an OS of 22 months reported in the literature for a similar subgroup of patients treated with chemotherapy only (Hillerdal et al. J Thorac Oncol 2008). Twenty-six patients with other advanced and pre-treated cancers also underwent DC vaccination (13 with breast cancer (12 with metastatic disease), 5 with glioblastoma multiforme (GBM), 1 with brain stem astrocytoma and 1 each with metastatic melanoma, Ewing sarcoma, esophageal, colon, pancreatic, renal cell and ovarian cancer). Significant DTH responses were recorded in all patients. At a median follow-up from start of DC vaccination of 23.3 months, 8/26 patients (31%) are still alive and median OS was 23.5 months. Evaluation of response showed 3 patients with PR (1 brain stem astrocytoma, 1 GBM and 1 breast cancer) and 1 patient with CR (1 GBM). In the breast cancer patient subgroup, 5/13 patients are still alive (38%) and median OS was 33.5 months after start of DC vaccination; this compares with OS data from the literature of 21.7 months after diagnosis (Kiely et al. J Clin Oncol 2011;29:456-63). In the GBM (n=5) patient subgroup, 1/5 patients is alive in CR 26 months and median OS was 14.7 months after start of DC vaccination; this compares with OS data from the literature of 14.6 months after diagnosis (Stupp et al. N Engl J Med 2005;352:987-96). In conclusion, WT1-targeted DC vaccination is feasible, safe and immunogenic in cancer patients. In AML, metastatic breast cancer and malignant glioma, there is evidence of objective response. In addition, OS data in solid tumors compare favorably with the best data reported so far for similar cohorts of patients, suggesting that adjuvant WT1/DC-based immunotherapy provides a clinical benefit to these patients. Disclosures Off Label Use: Dendritic cells as immunotherapy.

Description: Relapse remains a major problem in acute myeloid leukemia (AML) and has an important impact on survival, especially in the majority of older patients who cannot undergo allogeneic hematopoietic stem cell transplantation. In a phase II study, we investigated the impact on relapse of dendritic cell (DC) vaccination as a post-remission treatment in 29 AML patients; 26 patients were in complete remission and 3 in partial remission following chemotherapy. DC were derived from blood monocytes, electroporated with mRNA encoding the Wilms' tumor 1 protein (WT1) and administered via the intradermal route. Three different WT1 constructs were used to generate mRNA by in vitro transcription: 'construct 1' encoding full-length WT1, 'construct 2' with a Sig-DC-LAMP major histocompatibility complex (MHC) class II-skewing signal and a deletion of the WT1 nuclear localization signal and 'construct 3', a codon-optimized version of construct 2. WT1 mRNA levels in blood and marrow were followed as a measure of minimal residual disease. DC electroporated with mRNA derived from constructs 1, 2 and 3 were used to vaccinate respectively 13, 6 and 10 AML patients at very high risk of relapse. In those 3 groups, clinical and molecular response, as determined by normalization of WT1 transcript levels in blood and/or marrow, occurred in respectively 7/13, 1/4 and 0/6 patients who had increased levels of that marker at the start of DC vaccination. Of these 8 responding patients, 3 relapsed and died; the other 5 are still in complete remission, 4 of them now more than 5 years after diagnosis and most probably cured; 1 of those 4 patients was in partial remission following chemotherapy and was brought into complete and molecular remission by the DC vaccination only. All 15 patients who did not normalize WT1 mRNA levels following DC vaccination relapsed and/or died. There was a possible effect of DC vaccination in 6 additional patients: 3 with stable disease, some of it late; and 3 at high risk of relapse but without increased WT1 mRNA levels before DC vaccination: 1 patient with erythroleukemia and 2 patients with initial leucocytosis 〉 20,000/µL have remained in complete remission, now at respectively 46, 42 and 35 months post-diagnosis. Overall 8/29 patients have not relapsed yet, with a median follow-up from diagnosis and start of DC vaccination of respectively 60 months (range 35 - 84 months) and 53 months (range 27-78 months). Delayed type hypersensitivity (DTH) testing showed immunoreactivity to the DC vaccine components in all patients tested. There was also evidence of natural killer (NK) cell activation following DC vaccination. WT1 epitope tetramer+ CD8+ T-cells were evaluated in 13 HLA-A2+ patients: an increase following DC vaccination in tetramer+ T-cells for at least 2/4 epitopes tested was only observed in patients with long-standing complete remission. In conclusion, DC vaccination had a demonstrable antileukemic effect in 8/29 AML patients and a possible effect in another 6. Contrary to expectations, the WT1 constructs with MHC class II-skewing signal did not seem to have superior activity over the full-length WT1 construct without that signal. Vaccination with WT1 mRNA-transfected DC is emerging as a non-toxic strategy to prevent or delay relapse in AML. Disclosures: Off Label Use: Dendritic cell vaccination.

Description: The Wilms’ tumor protein WT1 is a target for immunotherapy in malignancies, such as acute myeloid leukemia (AML). Following our demonstration that dendritic cells (DC) can be efficiently transfected by messenger (m)RNA electroporation (Van Tendeloo VF et al. Blood2001;98:49–56) and that WT1 mRNA-electroporated DC stimulate WT1-specific T cells in vitro (Van Driessche A et al. Leukemia2005;19:1863–1871), we performed a phase I/II dose-escalation trial, in which patients with AML in remission but at high risk of relapse and without a direct sib allo-transplant option (9 patients) or with slowly progressive AML (1 patient) received intradermal injections of WT1 RNA-loaded DC. Following apheresis and CD14 immunomagnetic monocyte separation, DC were generated in 6-day cultures in clinical-grade medium supplemented with serum, granulocytemacrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4, matured with prostaglandin (PG)E2 and tumor necrosis factor (TNF)-alpha, harvested, electroporated with WT1 mRNA and used as vaccines. The patients received four biweekly DC vaccines and a delayed-type hypersensitivity (DTH) test was performed 2 weeks following the last vaccination. Patients were monitored for minimal residual disease (MRD) by analyzing WT1 RNA expression in peripheral blood by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) (Cilloni D et al. Leukemia2002;16:2115–2121 & Cilloni D et al. Haematologica2008;93:921–924). Before and after vaccination, peripheral blood was collected for immunomonitoring purposes. Feasibility, safety, immunogenicity and effect on MRD were investigated. There was successful DC generation and vaccine production in all 10 patients. No serious adverse events or toxicity were observed and vaccinations were well tolerated. A decrease in WT1 RNA expression was observed during the course of the vaccination in 4/7 patients who had an increased WT1 mRNA level in peripheral blood. Three of those patients are still in complete hematological remission. An in vivo vaccine-specific immune response was demonstrated in 10/10 patients by DTH. Ex vivo immunomonitoring analysis showed a significant increase in circulating activated HLA-DR+ CD4+ T cells and in IL-2 plasma levels following vaccination. Importantly, in vitro restimulation assays of peripheral blood mononuclear cells revealed a significant postvaccination increase in interferon (IFN)-gamma-producing WT1-specific CD8+ T cells (n= 8 evaluable patients), but not in cytokine-producing WT1-specific CD4+ T cells. There was no significant change in WT1-specific antibodies following vaccination. We conclude that vaccination of AML patients with WT1 RNA-loaded DC is feasible and safe. Furthermore, the DC elicit vaccine-specific and WT1-specific CD8+ T-cell responses. The correlation between reduction of circulating WT1 mRNA and the administration of the DC vaccines strongly suggests that this DC vaccine elicits an antileukemic activity.