The clinical efficacy of first-generation carcinoembryonic antigen (CEACAM5)-specific CAR T cells is limited by poor persistence and transient pre-conditioning-dependent respiratory toxicity.

The primary aim of this clinical trial was to determine the feasibility of delivering first-generation CAR T cell therapy to patients with advanced, CEACAM5+ malignancy. Secondary aims were to assess clinical efficacy, immune effector function and optimal dose of CAR T cells. Three cohorts of patients received increasing doses of CEACAM5+-specific CAR T cells after fludarabine pre-conditioning plus systemic IL2 support post T cell infusion. Patients in cohort 4 received increased intensity pre-conditioning (cyclophosphamide and fludarabine), systemic IL2 support and CAR T cells. No objective clinical responses were observed. CAR T cell engraftment in patients within cohort 4 was significantly higher. However, engraftment was short-lived with a rapid decline of systemic CAR T cells within 14 days. Patients in cohort 4 had transient, acute respiratory toxicity which, in combination with lack of prolonged CAR T cell persistence, resulted in the premature closure of the trial. Elevated levels of systemic IFNγ and IL-6 implied that the CEACAM5-specific T cells had undergone immune activation in vivo but only in patients receiving high-intensity pre-conditioning. Expression of CEACAM5 on lung epithelium may have resulted in this transient toxicity. Raised levels of serum cytokines including IL-6 in these patients implicate cytokine release as one of several potential factors exacerbating the observed respiratory toxicity. Whilst improved CAR designs and T cell production methods could improve the systemic persistence and activity, methods to control CAR T 'on-target, off-tissue' toxicity are required to enable a clinical impact of this approach in solid malignancies.

A Cancer Research UK First Time in Human Phase I Trial of IMA950 (Novel Multipeptide Therapeutic Vaccine) in Patients with Newly Diagnosed Glioblastoma.

PURPOSE: To perform a two-cohort, phase I safety and immunogenicity study of IMA950 in addition to standard chemoradiotherapy and adjuvant temozolomide in patients with newly diagnosed glioblastoma. IMA950 is a novel glioblastoma-specific therapeutic vaccine containing 11 tumor-associated peptides (TUMAP), identified on human leukocyte antigen (HLA) surface receptors in primary human glioblastoma tissue. EXPERIMENTAL DESIGN: Patients were HLA-A*02-positive and had undergone tumor resection. Vaccination comprised 11 intradermal injections with IMA950 plus granulocyte macrophage colony-stimulating factor (GM-CSF) over a 24-week period, beginning 7 to 14 days prior to initiation of chemoradiotherapy (Cohort 1) or 7 days after chemoradiotherapy (Cohort 2). Safety was assessed according to NCI CTCAE Version 4.0 and TUMAP-specific T-cell immune responses determined. Secondary observations included progression-free survival (PFS), pretreatment regulatory T cell (Treg) levels, and the effect of steroids on T-cell responses. RESULTS: Forty-five patients were recruited. Related adverse events included minor injection site reactions, rash, pruritus, fatigue, neutropenia and single cases of allergic reaction, anemia and anaphylaxis. Two patients experienced grade 3 dose-limiting toxicity of fatigue and anaphylaxis. Of 40 evaluable patients, 36 were TUMAP responders and 20 were multi-TUMAP responders, with no important differences between cohorts. No effect of pretreatment Treg levels on IMA950 immunogenicity was observed, and steroids did not affect TUMAP responses. PFS rates were 74% at 6 months and 31% at 9 months. CONCLUSIONS: IMA950 plus GM-CSF was well-tolerated with the primary immunogenicity endpoint of observing multi-TUMAP responses in at least 30% of patients exceeded. Further development of IMA950 is encouraged. Clin Cancer Res; 22(19); 4776-85. ©2016 AACRSee related commentary by Lowenstein and Castro, p. 4760.

A phase I trial of AT9283 (a selective inhibitor of aurora kinases) in children and adolescents with solid tumors: a Cancer Research UK study.

PURPOSE: A phase I trial of AT9283 (a multitargeted inhibitor of Aurora kinases A and B) was conducted in children and adolescents with solid tumors, to identify maximum-tolerated dose (MTD), safety, efficacy, pharmacokinetics, and pharmacodynamic (PD) activity. EXPERIMENTAL DESIGN: AT9283 was administered as a 72-hour continuous intravenous infusion every 3 weeks. A rolling-six design, explored six dose levels (7, 9, 11.5, 14.5, 18.5, and 23 mg/m(2)/d). Pharmacokinetic and PD assessments, included inhibition of phospho-histone 3 (pHH3) in paired skin punch biopsies. RESULTS: Thirty-three patients were evaluable for toxicity. There were six dose-limiting toxicities and the MTD was 18.5 mg/m(2)/d. Most common drug-related toxicities were hematologic (neutropenia, anemia, and thrombocytopenia in 36.4%, 18.2%, and 21.2% of patients), which were grade ≥3 in 30.3%, 6.1%, and 3% of patients. Nonhematologic toxicities included fatigue, infections, febrile neutropenia and ALT elevation. One patient with central nervous system-primitive neuroectodermal tumor (CNS-PNET) achieved a partial response after 16 cycles and 3 cases were stable for four or more cycles. Plasma concentrations were comparable with those in adults at the same dose level, clearance was similar although half-life was shorter (4.9 ± 1.5 hours, compared with 8.4 ± 3.7 hours in adults). Inhibition of Aurora kinase B was shown by reduction in pHH3 in 17 of 18 patients treated at ≥11.5 mg/m(2)/d. CONCLUSION: AT9283 was well tolerated in children and adolescents with solid tumors with manageable hematologic toxicity. Target inhibition was demonstrated. Disease stabilization was documented in intracranial and extracranial pediatric solid tumors and a phase II dose determined.

Carcinogenesis in MYH-associated polyposis follows a distinct genetic pathway.

Colorectal carcinomas develop according to particular genetic pathways, including the chromosomal instability (CIN+), microsatellite instability (MSI+) and MSI- CIN- routes. We have determined the genetic pathway in patients with MYH-associated polyposis (MAP), a syndrome of colorectal adenomas and cancer that results from defective base excision repair (BER). As in previous studies, MAP tumors showed a high frequency of G>T mutations in APC, in accordance with defective BER. We found that K-ras mutations were common in MAP tumors, all of the changes comprising conversion of the first guanine residue of codon 12 to thymidine (G12C, GGT>TGT). We found no BRAF mutations at the codon 599 hotspot or elsewhere in exon 14. Almost all of the MAP cancers were near-diploid (CIN-), and none was MSI+. A few p53 mutations were found, but these were not predominantly G>T changes. p53 overexpression was, however, frequent. No SMAD4 or TGFBIIR mutations were found. MAP tumors appear to follow a distinct genetic pathway, with some features of both the CIN and MSI pathways. BER deficiency is rarely accompanied by CIN or MSI. The spectrum of somatic mutations in MAP tumors reflects both selection and hypermutation to which certain guanine residues are particularly prone.

MSI-low, a real phenomenon which varies in frequency among cancer types.

This study assessed whether low-level microsatellite instability (MSI-L) is a phenomenon specific to colorectal cancers or is also present in other tumour types. Breast (grade III ductal and lobular), endometrial and ovarian carcinomas, as well as colorectal cancers, were analysed for MSI-L using eight microsatellite markers. The markers were selected from a panel that had previously been shown to be sensitive for the detection of MSI-L in colorectal cancers. It was found that MSI-L was present in 30 of 87 (35%) colorectal cancers, 2 of 59 (3%) grade III breast carcinomas, 1 of 35 (3%) lobular breast cancers, 16 of 50 (32%) endometrial cancers, and 9 of 34 (26%) ovarian cancers. These results suggest that MSI-L is a very rare occurrence in breast carcinomas, but does occur as a real phenomenon in colorectal, endometrial, and ovarian carcinomas, which are all part of the hereditary non-polyposis colon cancer (HNPCC) syndrome. PCR artefact was also found to masquerade as MSI-L; criteria for the assessment of MSI-L are suggested to eliminate this problem.

Germline mutations but not somatic changes at the MYH locus contribute to the pathogenesis of unselected colorectal cancers.

MYH-associated polyposis is a recently described, autosomal recessive condition comprising multiple colorectal adenomas and cancer. This disease is caused by germline mutations in the base excision repair (BER) gene MYH. Genes involved in the BER pathway are thus good candidates for involvement in the pathogenesis of sporadic tumors of the large bowel. We have screened a set of 75 sporadic colorectal cancers for mutations in MYH, MTH1, and OGG1. Allelic loss at MYH was also assessed. Selected samples were screened for mutations and allele loss at APC and mutations in p53, K-ras, and beta-catenin. A panel of 35 colorectal cancer cell lines was screened for MYH mRNA and protein expression. One of 75 cancers had bi-allelic germline mutations in MYH and on retrospective analysis of medical records this patient was found to have synchronous multiple small adenomas in addition to carcinoma. No somatic MYH mutations were found and mRNA and protein were expressed in all of our cell lines. There were no clearly pathogenic mutations in MTH1 or OGG1 in any tumor. Bi-allelic germline MYH mutations cause approximately 1 to 3% of unselected colorectal cancers, but appear always to be associated with multiple adenomas. Somatic inactivation of the DNA glycosylases involved in the BER pathway however does not appear to be involved in colorectal tumorigenesis.