Citations

2637 Background: Mutation-associated neoantigens (MANAs) constitute attractive antigens for the design of cancer vaccines. However, clinical implementation remains challenging because of the patient specific nature of MANAs, hereby requiring that a bespoke vaccine is designed for each subject. We developed a pipeline for the genomic characterization and the design of tailored vaccine using a modified vaccinia Ankara viral vector. Methods: Immunogenicity, safety and early clinical activity of personalized cancer vaccines are being assessed in two phase I trials, respectively in high grade serous OC and HPV-negative HNSCC. Patients (Pts) at high risk of relapse are enrolled in the study being in remission following surgical primary treatment. High risk is defined as stage IIIC or IVA for OC and stage III or IVA for HNSCC. A vaccine is manufactured for each patient. OC pts are treated at asymptomatic relapse based on radiological finding or elevation of CA-125 with the vaccine alone; HNSCC pts in complete remission after surgery and adjuvant therapy are randomized to receive the vaccine either at the end of locoregional treatment or in combination with standard of care at relapse. The vaccine was administered weekly for 6 weeks and a booster dose every three weeks over a year or until progression, whichever occurred first. Results: At the time of the data cut-off, a total of 8 pts were treated: 4 relapsing OC pts, 3 HNSCC pts in complete remission and 1 relapsing HNSCC pt. AE attributable to the vaccine were mainly grade 1 injection site reactions and fatigue. One OC pt displayed an objective response 6 weeks after initiation of vaccine and for 9 months with a normalization of CA-125 until death from an unrelated cause; 1 other OC pt remains on treatment with a stable radiological disease for 11 months. The 2 other OC progressed at the first evaluation on day 43. HNSCC pts treated in complete remission received respectively 20, 15 and 4 doses, and remain on treatment and disease free. One HNSCC patient received 9 doses of vaccine after relapse in conjunction with chemotherapy and anti-PD-1 therapy and remains on treatment with stable disease after 5 months. Immune monitoring demonstrates priming of a polyepitopic T cell response against class I and II antigens. Responses were observed regardless of HLA and without cross-reactivity to the germline protein. Adaptive response was associated with a shift of CD4 and CD8 T cells toward an effector phenotype and innate cellular immunity was activated with a strong maturation and activation of NK cells. Immune changes were stronger in pts with controlled disease versus progressors. Conclusions: Data demonstrate that TG4050 is safe, well tolerated and able to induce T cell responses whatever the HLA haplotype. Early signs of clinical activity were observed in OC pt. These data pave the way for further development and synergistic immunotherapeutic combinations. Clinical trial information: NCT04183166.

Abstract T is a farnesyltransferase inhibitor with clinical activity in elderly adults with newly diagnosed AML who are not candidates for TCC. For adults age ≥ 65 with poor-risk AML, T 600 mg BID for 21 out of 28–63 days induced complete remissions (CR) in 14%, median duration 7.3 mos, median survival 18.3 mos (Lancet JE, et al, Blood109:1387–1394,2007). In vitro, T+E exhibits synergistic anti-AML activity. In an attempt to increase CR rates in elderly AML pts, we conducted a Phase I trial of oral T+E, with escalation of both drugs and 14 vs. 21 days of T every 28–63 days (median 31 days, range 29–50). T+E resulted in a 25% CR rate (21/84 pts), duration 2 – 26+ mos, with best rates achieved with T dose ≥ 400 mg BID for 14 days (Karp JE, et al, Blood108:130a,2006). In the context of this trial, we have conducted longitudinal laboratory studies of changes in DNA damage and apoptosis in AML marrow blasts obtained from 84 patients prior to T+E (Day 0) and on Day 8 of T+E. Blasts were enriched by Ficoll density gradient separation and fixed in 70% ethanol. Persistent, unrepaired DNA damage was quantified by flow cytometry of cells stained with antibody to phosphorylated histone H2AX (γH2AX). Apoptosis was measured by flow cytometry of propidium iodide-stained cells with sub2n DNA content as observed in cell cycle distribution. To date, we have analyzed changes in in vivo γH2AX from 10 pts (4 CR, 6 stable disease or no response, SD/NR). CR pts had a 2-fold increase (range 1.91–2.22) in DNA damage induced by Day 8 of T+E relative to Day 0 values, while patients with SD/NR had no such increase (0–1.06) in DNA damage. Similarly, the apoptotic fraction of the cell cycle distributions of CR patients increase by 2-fold (range 1.2–5.3) for Day 8 marrow blasts. In contrast, changes in apoptosis were widely divergent for SD/NR patients (range 0.2–7.0). Taken together, these preliminary studies on AML marrow blasts obtained prior to and during T+E therapy suggest a possible linkage among induction of DNA damage, apoptotic response, and clinical outcome. Full analysis of all acquired specimens is ongoing.

726 Background: Primary tumor location is an important prognostic factor in mCRC. Efficacy differences with EGFR antibodies by tumor location show a predictive effect (Arnold et al. Ann Oncol 2017). Two first-line (1L) pivotal bev trials showed the prognostic value of sidedness (Loupakis et al. J Natl Cancer Inst 2015). In this exploratory study, further analysis of the predictive effect of bev is presented. Methods: Data from two randomized phase III studies (NO16966 [NCT00069095], AVF2107g [NCT00109070]) of bev+CT vs CT-alone as 1L treatment for mCRC were analyzed retrospectively. Patients (pts) with sidedness information available were included; pts from NO16966 (part 1) randomized to CT only were excluded. Sidedness was identified by case report forms. Results: Sidedness was determined in 1590 pts (27% Right and 73% Left) out of 2214 pts total (Table). In the pooled analysis, PFS improved with bev+CT compared to CT only in both right-sided (HR=0.75; 95% CI 0.61, 0.93) and left-sided (HR=0.76; 95% CI 0.67, 0.86) mCRC with similar magnitude of benefit in both sides. OS also improved with bev+CT in right-sided (HR=0.82; 95% CI 0.65, 1.03) and left-sided (HR=0.85; 95% CI 0.74, 0.98) pts. Conclusions: This exploratory subgroup analysis of two pivotal studies indicates that the effect of bev is independent of tumor location in mCRC patients. Survival outcomes. Clinical trial information: NCT00069095 and NCT00109070. [Table: see text]

Background The GGGGCC-repeat expansion in C9orf72 is the most frequent mutation found in patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Most of the studies on C9orf72 have relied on repeat-primed PCR (RP-PCR) methods for detection of the expansions. To investigate the inherent limitations of this technique, we compared methods and results of 14 laboratories. Methods The 14 laboratories genotyped DNA from 78 individuals (diagnosed with ALS or FTD) in a blinded fashion. Eleven laboratories used a combination of amplicon-length analysis and RP-PCR, whereas three laboratories used RP-PCR alone; Southern blotting techniques were used as a reference. Results Using PCR-based techniques, 5 of the 14 laboratories got results in full accordance with the Southern blotting results. Only 50 of the 78 DNA samples got the same genotype result in all 14 laboratories. There was a high degree of false positive and false negative results, and at least one sample could not be genotyped at all in 9 of the 14 laboratories. The mean sensitivity of a combination of amplicon-length analysis and RP-PCR was 95.0% (73.9–100%), and the mean specificity was 98.0% (87.5–100%). Overall, a sensitivity and specificity of more than 95% was observed in only seven laboratories. Conclusions Because of the wide range seen in genotyping results, we recommend using a combination of amplicon-length analysis and RP-PCR as a minimum in a research setting. We propose that Southern blotting techniques should be the gold standard, and be made obligatory in a clinical diagnostic setting.

Abstract One hundred and ninety patients with Clostridium difficile toxin-associated colitis (CTAC) or pseudomembranous colitis (PMC) were identified, from microbiology records, disease index and proctoscopy service records, and studied retrospectively. CTAC was associated with cephalosporin antibiotic administration in 70 per cent of the patients. CTAC developed postoperatively in 108 patients after all types of surgery with no preponderance for abdominal surgery. Identification of cytotoxin in stool samples was the primary diagnostic test in 81 per cent of patients but cytotoxin was isolated in 98 per cent of all patients. Pseudomembranes visible on proctoscopy established the diagnosis in 19 per cent of patients and were more commonly seen in severe colitis (71 per cent) than in mild colitis (23 per cent). CTAC responded similarly to oral vancomycin and metronidazole with a relapse rate of 20–23 per cent, respectively. With its association with cephalosporin administration, CTAC is likely to occur with increasing frequency in surgical practice. Oral metronidazole is an effective, cheap, alternative to vancomycin therapy.