IGNYTE-ESO: A master protocol to assess safety and activity of letetresgene autoleucel (lete-cel; GSK3377794) in HLA-A*02+ patients with synovial sarcoma or myxoid/round cell liposarcoma (Substudies 1 and 2)

TPS11582

Background: Letetresgene autoleucel (lete-cel; GSK3377794) is an autologous T-cell product using a genetically modified T-cell receptor to target cancer cells expressing the cancer testis antigen New-York esophageal squamous cell carcinoma 1 (NY-ESO-1). Lete-cel is currently being investigated alone and in combination in multiple tumor types [1,2]. NY-ESO-1 is expressed in 70‒80% of synovial sarcoma (SS) and 80‒90% of myxoid/round cell liposarcoma (MRCLS) tumors [3,4], suggesting these tumors may be prime lete-cel targets. This master protocol design (IGNYTE-ESO; NCT03967223) enables evaluation of multiple cell therapies in multiple tumor types and treatment stages in separate substudies, beginning with lete-cel in Substudies 1 and 2 for SS and MRCLS. Methods: Substudy 1 is a single-arm study assessing lete-cel in treatment-naïve patients (pts; ie, anthracycline therapy-naïve for metastatic disease) with advanced (metastatic/unresectable) NY-ESO-1+ SS or MRCLS as a first line of therapy (n=10 planned). Substudy 2 is a pivotal, single-arm study assessing lete-cel in pts with NY-ESO-1+ SS or MRCLS who progressed after anthracycline therapy (n=70 planned). Key eligibility criteria are age ≥10 y and NY-ESO-1 and HLA-A*02 positivity. Exclusion criteria include prior NY-ESO-1–specific/gene therapy, allogeneic stem cell transplant, and central nervous system metastases. Screened pts undergo leukapheresis for lete-cel manufacture, lymphodepletion, lete-cel infusion, and follow-up (FU). Long-term FU (15 y) may be done under a separate protocol. The Substudy 2 primary endpoint is overall response rate (ORR) per RECIST v1.1 assessed by central independent review. Substudy 1 is not testing any formal hypotheses; statistical analysis will be descriptive. Substudy 2 is comparing ORR with the historical control assuming at least 90% power with 0.025 one-sided type I error. Secondary endpoints include efficacy (time to/duration of response, disease control rate, progression-free survival), safety (adverse event [AE] frequency/severity, serious AEs, AEs of special interest), and pharmacokinetic (maximum transgene expansion [Cmax], time to Cmax, area under the time curve from zero to time t as data permit). Enrollment began in December 2019. References: 1. Reckamp KL, et al. Ann Oncol 2019;30(Suppl_5):v602–v660. 2. Rapoport A, et al. J Clin Oncol 2020 38:15_suppl, TPS8555. 3. D’Angelo SP, et al. Cancer Discov 2018;8(8):944–957. 4. D’Angelo SP, et al. J Clin Oncol 2018 36:15_suppl, 3005. Funding: GSK. Editorial support was provided by Eithne Maguire, PhD, of Fishawack Indicia, part of Fishawack Health, and funded by GSK. Previously presented at BSG 2021 (P914542). Clinical trial information: NCT03967223.

A phase 2 study of belinostat and SGI-110 (guadecitabine) for the treatment of unresectable and metastatic conventional chondrosarcoma

TPS11578

Background: Conventional chondrosarcoma (cCS) accounts for ̃25% of primary bone cancers and is the second most common primary bone tumor after osteosarcoma. Surgical resection is the primary treatment for localized disease. No FDA approved therapy exists for advanced disease and chemotherapy has marginal efficacy with ORR < 12%. IDH1/2 mutation is seen in 50% of cases. Epigenetic dysregulation is central to oncogenesis in both IDH1/2 mutant and wild-type CS. Pre-clinical studies from our group show that combination treatment with HDAC and DNMT inhibitors is significantly more effective at suppressing the growth of CS models in vitro and in vivo compared to either therapy alone. The combination regimen mediates anti-tumor effects on CS by induction of apoptosis, induction of tumor suppressor genes (eg. E-cadherin), the induction of interferon responsive genes (eg. IRF7, OASL, ISG15, DDX58) and reversal of global hypomethylated state. Based on these findings we have designed a phase 2 clinical trial with an HDAC inhibitor (belinostat) and a DNMT inhibitor (guadecitabine) in patients with advanced cCS. Methods: NCI # 10330 is a single-arm, multi-center, Simon 2-stage, phase 2 clinical trial evaluating belinostat and guadecitabine in patients with advanced cCS. Eligible patients will have biopsy proven cCS which is measurable by RECIST v1.1 and amenable to biopsy, ECOG PS ≤ 2, any number of prior treatments (including none). Patients will receive guadecitabine 45 mg/m2 SC followed by belinostat 1000 mg/m2 IV once daily on days 1-5 of a 28-day cycle. A safety lead-in and continuous toxicity monitoring rule will be applied. The primary endpoint will be ORR. Since chemotherapy is associated with an ORR of 8-12% and targeted agents have shown an ORR of 0% in cCS, we will consider an ORR of 8% as inactive while an ORR of 28% will suggest promising activity. A Simon 2-stage design is employed. The design calls for 26 patients. If ≥ 2 responses are observed among 13 patients in stage I, the study will proceed to full accrual. If ≥ 5 responses are seen among 26 patients, the study treatment is considered promising. This design has 85% power with α of 0.054 to test for a response rate of 8% vs 28%. Secondary objectives include safety, tolerability and PFS. All patients will undergo pre-treatment and on-treatment tumor biopsies. Paired tissue will be used for correlative analysis including: 1) whole exome sequencing/RNAseq to evaluate changes in gene expression in response to treatment, 2) multiplex IHC to interrogate the effect of combination therapy on tumor immune microenvironment and 3) a global DNA methylation assay to better understand the changes in epigenetic landscape in response to treatment. This study is open throughout the ETCTN (NCT04340843). Six of the planned 26 patients in the safety lead-in have been enrolled without DLT. Further accrual is on hold pending completion of the safety lead-in. Clinical trial information: 04340843.

A phase 2 study using ipilimumab, nivolumab, and trabectedin for previously untreated metastatic soft tissue sarcoma

11562

Background: Sarcoma cells are most immunogenic earlier in the disease course and before treatment when the immune system can recognize and destroy them. Hypothesis: Immune checkpoint inhibitors would be most effective when given to previously untreated patients with metastatic soft tissue sarcoma. Methods: Eligible patients for this Phase 2 study are previously untreated patients ≥ 18 years of age with unresectable or metastatic soft tissue sarcoma, with measurable disease by RECIST v1.1. Immune checkpoint inhibitors Ipilimumab (I) and Nivolumab (N) were given with Trabectedin (T), a marine derived alkaloid with defined doses of I (1 mg/kg i.v. q 12 weeks), N (3 mg/kg i.v. q 2 weeks), and T (1.2 mg/m2 i.v. q 3 weeks). Primary endpoints: (1) Objective response rate by RECIST v1.1 via CT scan or MRI, (2) Progression-free survival (PFS): from first day of treatment to disease progression or death due to any cause; otherwise, it is censored at the time of last follow-up, and (3) Overall survival: from first day of treatment to death due to any cause; otherwise, it is censored at the time of last follow-up. Results: There were eighty-two evaluable subjects, having completed the first cycle of I, N, and T and have had a CT or MRI scan at the 6-week follow-up period. Best Overall Response by RECIST v1.1 = 7 CR (2 surgical CR), 9 PR, 54 SD, and 12 PD. Disease control rate was 85.4%. The median PFS was >6.4 (range: 0-32) months; 6-month PFS rate: 57.3%. The median OS was >12.0 (0-38) months; 6-month OS rate: 78.8%. Safety analysis: The most common Grade 3 TRAEs include increased ALT (26), anemia (11), increased AST (9), and fatigue (8). Common Grade 4 TRAEs include thrombocytopenia (2), increased AST (2), increased ALT (2), and increased CPK (2). There was one Grade 5 TRAE of rhabdomyolysis (1). Conclusions: Taken together, these results suggest that first-line combinatorial therapy with I, N, and T are (1) synergistic, and (2) may be equal or superior to, and safer than, standard first line therapy for advanced/metastatic soft tissue sarcoma. Clinical trial information: NCT03138161.

A phase 2 study of talimogene laherparepvec, nivolumab, and trabectedin (TNT) in advanced sarcoma

11567

Background: Combination trabectidin (T) and nivolumab (N) has been shown to be a safe and effective therapy in soft tissue sarcoma (STS). Intratumoral injection of talimogene laherparepvec (TVEC) has a local oncolytic effect, and increases immune response via enhanced recruitment of antigen presenting cells, and thereby cytotoxic immune response. This study aims to determine if the addition of TVEC to combination trabectedin and nivolumab is effective and safe in advanced sarcoma. Methods: Eligible patients include patients ≥ 18 years of age with locally advanced unresectable or metastatic STS, measurable disease by RECIST v1.1, and at least one accessible tumor for TVEC intratumoral injection. N (3 mg/kg i.v. q 2 weeks), T (1.2 mg/m2 i.v. q 3 weeks) and TVEC (1x10e8 PFU/ml q 2 weeks depending on tumor size) were administered. A test dose of TVEC (1x10e6 PFU/ml) was initially given, followed three weeks later by full dose TVEC. Primary endpoint: Progression-free survival (PFS); Secondary endpoints: (1) Best overall response during treatment period, (2) PFS rate at 6 and 9 months, (3) Overall survival (OS) rate at 6, 9, and 12 months, (4) Incidence of conversion from unresectable to resectable tumor, and (5) Incidence of treatment-related adverse events. Interim. Results: There were 36 evaluable subjects under the Modified Intention-to-Treat (MITT) population, having completed the first cycle of TNT and a CT or MRI scan at the 6-week follow-up period. The most common histological subtypes include leiomyosarcoma (9), liposarcoma (5), spindle cell sarcoma (3), pleomorphic sarcoma (2), Ewing’s sarcoma (2), and other (5). Median number of prior lines of therapy was 4 (range 1-8). Best Overall Response by RECIST v1.1 = 3 PR, 27 SD, 5 PD. One patient, with previously unresectable disease was taken for resection and was found to have 100% necrosis on surgical pathology. Disease control rate (CR+PR+SD) was 86.1%. The median PFS was 5.5 (range: 1-18) months; 6-month PFS rate: 62.1%. Median PFS on therapy immediately preceding this trial was 2.0 months (range = 1-14 months). There were 47 evaluable subjects for OS analysis under the Intention-to-Treat (ITT) population having received at least one dose of T and N. The median OS was 9.0 (range 0-20) months; 6-month OS rate: 73%. Safety analysis: There were 47 evaluable subjects under the ITT population. 28% of these patients experienced ³1 SAE. The most common grade 3/4 TRAEs include anemia (12), increased ALT (8), fatigue (4), thrombocytopenia (4), neutropenia (4). There were no grade 3/4 TVEC injection site reactions. 22% of patients in the MITT cohort remain on study. Conclusions: These results suggest that combination therapy with TNT appears to be as effective as standard therapy, with no new safety signals seen. Furthermore, median PFS exceeded that of the immediately preceding lines of therapy in this heavily pre-treated cohort. As data matures, further data will be reported. Clinical trial information: NCT03886311.

Genomic alterations and associated pathway abnormalities in Ewing sarcoma

11532

Background: Ewing Sarcoma (ES) is an aggressive, translocation-associated, bone cancer associated with a poor prognosis in the recurrent or metastatic setting. ES is identified by the canonical balanced reciprocal chromosomal translocation involving EWSR1 and ETS transcription factors. Secondary somatic alterations in ES are rarely described and genomic alterations (GA) affecting various molecular pathways may work synergistically with ETS-FL1 translocations to promote oncogenesis. Alterations in fibroblast growth factor receptor 4 (FGFR4), a receptor tyrosine kinase protein that functions in cellular processes, have been observed to affect carcinogenesis. Moreover, the FGFR4-Gly388Arg (G388R) single nucleotide polymorphism (SNP) is found to increase the risk of cancer with mouse embryonic fibroblasts derived from knock-in strain of homologous Fgfr4 G385R mice exhibiting a transformed phenotype. We sought to further evaluate the frequency of FGFR4 G388R SNP in relation to other identifiable pathway alterations observed with Comprehensive Genomic Profiling (CGP). Methods: Next generation sequencing (NGS) analysis was obtained in the context of clinical care with clinical status, outcomes, and source acquisition (primary tumor, metastasis, or recurrence) unknown to Foundation Medicine. CGP, FoundationOne Heme, evaluated GAs including base substitutions, indels, amplifications, copy number alterations, gene fusions and rearrangements. 189 samples were assayed by hybrid-capture based CGP, including 406 DNA-sequenced genes in addition to 265 RNA-sequenced genes commonly reported to be rearranged in cancer, as previously described. Tumor mutational burden was assessed from a minimum 1.4 Mb sequenced DNA. Microsatellite instability (MSI) status was determined by a novel algorithm analyzing 114 specific loci. Results: The median age of evaluated patients was 20 (range 0-70) with the number of alterations averaging 7 per patient. Pathways noted to be altered in the presence of FGFR388R SNP occurred frequently with the following pathways most observed: MAPK (33%), WNT (32%), NOTCH1 (20%), HRR (19%), Histone/chromatin remodeling (18%). FGFR388R SNP was observed in more than half (51%) of evaluated samples. Most affected pathways irrespective of FGFR388R SNP status included: MAPK (n = 89), HRR (n = 75), and PIK3 (n = 64). All evaluated samples were TMB low ( < 10 mut/mb) and Microsatellite Stable. Conclusions: Secondary GAs affecting major pathways were observed in high frequency, often co-occurring with the FGFR4 G388R SNP. Secondary alteration of known oncogenic pathways may contribute to sarcoma formation in ES potentially informing further therapeutic strategies in the future.

Safety and activity of autologous T cells with enhanced NY-ESO-1–specific T-cell receptor (GSK3377794) in HLA-a*02+ previously-treated and -untreated patients with advanced metastatic/unresectable synovial sarcoma: A master protocol study design (IGNYTE-ESO)

TPS11571

Background: T cells modified to target NY-ESO-1 have shown encouraging activity in HLA-A*02+ patients with NY-ESO-1–positive synovial sarcoma. NY-ESO-1 is a cancer/testis antigen that is expressed across multiple tumor types and highly expressed in synovial sarcoma. NY-ESO-1 TCR T (GSK3377794) are autologous polyclonal T cells transduced by a self-inactivating lentiviral vector to express an affinity-enhanced TCR able to recognize NY-ESO-1 epitope in complex with HLA-A*02. Ongoing trials are evaluating GSK3377794 in multiple solid tumors and multiple myeloma. Methods: This study (NCT03967223) uses a Master Protocol design that allows investigation of GSK3377794 in multiple tumor types under the same protocol in separate substudies. The first two are single-arm substudies in patients with advanced metastatic or unresectable synovial sarcoma: treatment-naïve (1st line [1L], substudy 1; n = 10 planned) and progressing after anthracycline-based chemotherapy (2L+, substudy 2; n = 55 planned). Patients must be aged ≥10 years, have adequate organ function, ECOG performance status 0–1, measurable disease, and no central nervous system metastases. Excluded prior treatments include gene therapy with an integrating vector or NY-ESO-1–specific T cells, vaccine or targeting antibody, or allogeneic stem cell transplant. Patients will undergo leukapheresis and manufacture of GSK3377794; lymphodepletion then GSK3377794 infusion, followed by safety and disease assessments; and long-term follow-up for 15 years (under a separate protocol). The primary objective of substudy 2 is overall response rate per RECIST v1.1 by central independent review. Secondary objectives include time to response, duration of response, disease control rate, progression-free survival, overall survival, plus safety and tolerability. Exploratory objectives include assessment of the correlation of T-cell persistence with safety, clinical responses, and infused T-cell phenotype. Evaluation of quality of life and daily functioning of patients will also be assessed. Enrollment began in December 2019. These data are presented on behalf of the original authors with their permission. A similar presentation (P453) was presented at the SITC Annual Meeting, National Harbor, MD, USA, Nov 6–10, 2019. Funding: GlaxoSmithKline (208467) Clinical trial information: NCT03967223 .

A randomized phase II study of nivolumab monotherapy versus nivolumab combined with ipilimumab in advanced gastrointestinal stromal tumor (GIST)

11017

Background: Most GISTs are driven by mutations in KIT and PDGFRa and secondary mutations are felt to confer resistance to TKIs. In advanced/metastatic GIST, the benefit of second line TKIs and beyond is progressively less after imatinib failure. As such, novel non-TKI approaches are important to explore. Here we report interim analyses of safety and efficacy in advanced GIST patients treated with immunotherapy. Methods: Patients with advanced/metastatic GIST refractory to at least imatinib were enrolled on a randomized, parallel group, unblinded Phase 2 trial of either nivo (240 mg Q2wks) or nivo (240 mg Q2wks) with ipi (1mg/kg Q6wks) for up to 2 years. The primary endpoint was the objective response rate(ORR) of nivo alone or nivo + ipi by RECIST 1.1 criteria. Imaging was assessed by investigator and 3 independent radiologists. Patients were randomized 1:1 and were restaged every 8 weeks. With a sample size of 20 per group, an exact binomial test with a nominal 0.050 one-sided significance level will have 82% power to detect the difference between the null hypothesis response rate 1.5% and the alternative response rate of 15%. Secondary objectives are to ascertain the PFS, CBR, RR by Choi criteria and safety. Blood and biopsies are also being collected. Results: At cutoff, 29 patients (27 evaluable) with a median of 3 (1-7) lines of prior therapies have started on trial. In the nivo only arm, 7/15 pts had a best response of SD for a CBR of 46.7% with the median PFS being 8.57 wks. In the nivo + ipi arm, 1/12 patients had a PR and 2/12 have SD for a CBR of 25.0% (95% exact C.I. 5.5%-57.2%) with a median PFS of 9.1 wks. 8 patients have been on therapy for more than 6 months and two patients with a KIT Exon 17 mutation had radiographic disease shrinkage. Most AEs were grades 1-2 with fatigue (37%) being the most common. 4 Grade 3/4 AEs occurred in the nivo and ipi arm (hyperglycemia, weakness, diarrhea x 2) and 4 grade 3/4AEs occurred in the nivo arm (DKA, hyperglycemia, rash, fatigue). Pretreatment biopsies have been obtained in all patients and blood has been collected on all patients for correlative analysis. Conclusions: In a heavily pretreated GIST population, responses and disease control with both nivo and nivo + ipi were observed. To date, the drugs have been well tolerated and no new safety signals have been observed in this disease state. Clinical trial information: NCT02880020.

Secondary genomic alterations in Ewing sarcoma

11024

Background: Ewing sarcoma (ES) is the second most common bone cancer in children and young adults. The prognosis of recurrent or metastatic ES is poor, with a 5-year overall survival <30%. ES is characterized by translocations involving ETS transcription factors ( EWS– FLI and EWS– ERG translocations are the most common). Secondary somatic alterations in ES are infrequently described. Aberrations in fibroblast growth factor receptor 4 ( FGFR4), a receptor tyrosine kinase protein that plays an important role in cellular processes,have been shown to contribute to carcinogenesis in different types of cancer.More recently, the FGFR4-Gly388Arg (G388R) single nucleotide polymorphism (SNP), with the substitution of arginine instead of glycine in the transmembrane domain of the receptor, is found to significantly increase the risk of breast and prostate cancer. Mouse embryonic fibroblasts derived from knock-in strain of homologous FGFR4-G388R mice display a transformed phenotype, and TGFα-induced mammary carcinogenesis in this strain is significantly enhanced. The association between FGFR4 G338R SNP and ES has not been evaluated. We evaluated the frequency of FGFR4 G338R and whether comprehensive genomic profiling (CGP) might uncover additional, potentially targetable, genomic alterations (GA) in ES. Methods: Tissue from 253 patients with ES was assayed by hybrid-capture based CGP (FoundationOne Heme, next generation sequencing (NGS), analysis which includes both DNA sequencing of 406 genes and RNA sequencing of 265 genes), performed in the course of clinical care to evaluate GAs, including base substitutions, indels, amplifications, copy number alterations and gene fusions/rearrangements. Tumor mutational burden (TMB) was calculated from a minimum of 1.4 Mb sequenced DNA and reported as mutations/Mb. Microsatellite instability (MSI) status was determined by a novel algorithm analyzing 114 specific loci. Results: CGP identified several GAs in ES: TP53 (n= 50, 20%), MLL3 (n=15, 6%), MSH3 (n=14, 5%), ARID1A (n=11, 4%) and FGFR4 (n=3, 1%). FGFR4 G338R SNP was found in almost half of the patients (n=123, 49%). Conclusions: Secondary GAs in TP53, MLL3, MSH3, ARID1A and FGFR4 were found in more than one third of patients with ES (n=93, 37%). FGFR4 G388R SNP was detected in nearly half of patients, and may represent an alternative method of sarcomagenesis. Overall, the frequency of these GAs is significantly greater than previously reported. These GAs may inform the potential for targeted therapies.

Open label, non-randomized, multi-cohort pilot study of genetically engineered NY-ESO-1 specific NY-ESO-1c259t in HLA-A2+ patients with synovial sarcoma (NCT01343043)

3000

Background: NY-ESO-1 is expressed in ~70% of synovial sarcomas (SS). NY-ESO-1c259T cells recognizing an NY-ESO-1 derived peptide complexed with HLA-A*02 are being studied in SS. Methods: Eligible patients (pt) are HLA-A*02:01, 02:05 or 02:06, with unresectable, metastatic or recurrent SS expressing NY-ESO-1. Primary endpoint of ORR (CR+PR) is evaluated in high (≥ 50% tumor cells express 2+/3+) and low (≥ 1+ in ≥ 1% cells, not exceeding 2+/3+ in ≥ 50% cells) NY-ESO-1 expressers with different lymphodepleting regimens. Secondary endpoints are safety, DOR, PFS, OS, and gene-marked cell persistence. Lymphocytes are obtained by leukapheresis, isolated, activated, transduced to express NY-ESO-1c259T, and expanded. Target dose is 1–6 × 109cells. Disease is assessed at wk 4, 8 and 12 post-T-cell infusion, and then every 3 months. Results: 34 pt have been enrolled with 24 treated. 50% are male; median age is 30 yr (range 15 – 73). 12/15 pt in cohort 1 were treated. ORR was 50% (1 CR; 5 PR). Time to response was 6 wk (range 4-9) and median DOR 31 wk (range 13-72). Cohort 3 was closed due to only 1 PR out of 5 pt. Evaluation is ongoing in cohorts 2 (6 enrolled; 5 treated) and 4 (8 enrolled; 2 treated) as of 1/9/17. The most common AE are leukopenia (96%), nausea and pyrexia (88%), neutropenia (88%), lymphopenia (83%), anemia (79%), and thrombocytopenia (79%). 11 events of CRS were reported (3 G3; 1 G4), with no events of seizure, cerebral edema or fatal neurotoxicity; all resolved with supportive therapy. One fatal SAE (bone marrow failure) occurred in cohort 2; investigations have not identified a mechanism by which NY-ESO-1c259T may have caused this event. Conclusions: NY-ESO-1c259T has promising efficacy and acceptable safety. CRS is not associated with severe neurotoxicity and appears manageable with appropriate supportive care. Cohort 3 data indicate that Flu may be important for efficacy. Efficacy and safety data will be further evaluated and presented. Clinical trial information: NCT01343043. [Table: see text]

Phase I trials of PS-341 (bortezomib, B) in combination with topotecan (T) in advanced solid tumors: A potential pharmacokinetic (PK) interaction

3108

Background: Preclinical data has demonstrated that B when combined with camptothecins enhances apoptotic effects which may be independent of NF-κB status and dependent on the sequence of exposure to the proteasome inhibitor. Other data suggests PK interactions of B with some chemotherapeutic agents. It is hypothesized that B will act synergistically with T and enhance the apoptotic effects of T. Conflicting data exists regarding schedule dependent synergistic cytotoxicity of the combination. This study examined both sequences of administration and determined the PK of each sequence. Methods: A standard 3 + 3 schedule was used in both sequences (S). The dose of B was fixed with escalating doses of T. S1: B 1.3 mg/m2 on days 1, 4, 8, and 11. T 2 to 3.5 mg/m2 on days 1 and 8 was given 6 h before B. S2: B 1.3 mg/m2 on days 1, 4, 8, 11 followed by T 2 to 3 mg/m2 given 6 h after B. Cycle length was q28 days. PK sampling for both sequences was performed. Results: 54 pts (S1: 27, S2: 27) received a median of 2 cycles (range 1-7) of therapy. Pts were heavily pre-treated. For S1, the maximum tolerated dose (MTD) of B and T were 1.3 and 3 mg/m2 respectively. For S2, the MTD of B and T were 1.3 and 2.5 mg/m2 respectively. Dose-limiting toxicities (2 pt in each sequence) were gr 3 thrombocytopenia in S1, and gr 4 thrombocytopenia in S2. Stable disease was seen in 6/27 pts in S1, and 6/27 in S2. PK results for S2 show no significant difference between the day 1 and day 8 PKs. However, the mean AUC (454±150 mg/Lxhr) and Cmax (123±51 mg/L) at the MTD of 2.5 mg/m2 reached on this trial is similar to those reported with single agent doses of 4 mg/m2 given over 30 minutes weekly x 3. As a result, the estimated topotecan clearance (11.3±5 L/hr) when given following bortezomib is approximately one half of the reported clearance for the single agent. (Curtis et al, J Clin Pharmacol, 50:268, 2010). Conclusions: The tolerability and toxicity of both sequences was similar. MTD differs with S2 having a lower tolerated dose of T. PK results suggest a possible drug-drug interaction with decreased clearance of T with S2. PK results for S1 are pending. Supported by CCSG CA62505.

The prognostic significance of extra-intestinal tumor location for primary nonmetastatic gastrointestinal stromal tumors

2

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm of the GI tract. Tumor size, tumor location, and mitotic index are established factors that risk stratify recurrence and survival. Extra-intestinal GISTs are infrequently observed and our objective was to investigate the outcomes of patients with primary GISTs found outside the GI tract.

Methods: The Surveillance Epidemiology and End Results registry was used to identify patients with GIST treated with surgery between 1996 and 2008. Patients were evaluated by standard clinical and pathological indices including: age, primary tumor location (extra−intestinal vs. GI tract), tumor size, tumor grade, and extent of disease. Overall survival differences between primary site groups were assessed by Kaplan-Meier method. Univariate and stepwise multivariate Cox proportional hazards analyses were performed.

Results: Of the 2812 patients with surgically treated GIST, 2489 (88.5%) had a primary tumor location in the GI tract and 323 (11.5%) were located in extra-intestinal sites. Comparison of patients by primary tumor location demonstrated more locally advanced cancers with lymph node involvement (40.2% vs. 18.4%; p<.0001) and a higher occurrence of distant metastatic disease (22.3% vs. 16.6%; p<.0001) among the extra-intestinal GISTs. When comparing overall survival, patients with extra-intestinal GISTs had significantly worse 5 year survival (62% vs. 70%, respectively; p=0.002) than patients with primary tumors within the GI tract. Stepwise multivariate analysis showed that non-intestinal site was an independent predictor of poorer survival (HR 1.29, 95% CI [1.05-1.59], p=0.015).

Conclusions: Our data indicates that extra-intestinal location for primary non-metastatic GIST is an independent poor prognostic factor, with worse overall survival, compared to GISTs located within the GI tract. Risk stratification for prognosis should account for these rare GIST locations.

A study of radiotherapy modalities combined with continuous 5-FU infusion for locally advanced gastrointestinal malignancies

AIM

We describe the feasibility of combining infusional 5-fluorouracil (5-FU) with intraoperative radiation therapy (IORT).

METHODS

Patients with surgically resectable locally advanced gastrointestinal cancers were treated concurrently during surgery with IORT and a 72 h infusion of 5-FU. Patients without previous external beam radiation therapy (EBRT) were subsequently treated with EBRT (40-50Gy) concurrent with a 21-day continuous infusion of 5-FU. Pancreatic, gastric, duodenal, ampullary, recurrent colorectal, and recurrent anal cancer were included.

RESULTS

During IORT/5-FU, no chemotherapy-related grade III or IV hematologic or gastrointestinal toxicity was noted. Post-surgical recovery or wound healing was not affected. One of nine patients who received post-operative radiation required a treatment break. During follow-up, there were more complications in patients with pelvic tumours, especially those with previous radiation. Nine patients have had local and/or local regional recurrences, two of these in the IORT field.

CONCLUSIONS

Treatment with a combination of IORT and 5-FU followed by EBRT and 5-FU is feasible. However, long-term complications may be increased in previously irradiated recurrent pelvic tumours.

The IFN regulatory factor family participates in regulation of Fas ligand gene expression in T cells

TCR engagement leads to the transcriptional activation of cytokine genes and activation-induced cell death. Activated T cells undergo apoptosis upon expression and ligation of Fas ligand (FasL) to Fas/APO-1 (CD95) receptor. FasL expression is under the transcriptional regulation of multiple factors. The present study demonstrates that TCR-inducible FasL expression is also under the direct influence of the IFN regulatory factor (IRF) transcription factor family. Deletion and mutagenesis of a putative IRF-1 binding site in the FasL promoter results in deficient expression of FasL. EMSAs demonstrate specific FasL promoter binding by IRF-1 and IRF-2. Forced expression of either IRF-1 or IRF-2 leads to FasL promoter activation in T cells and FasL expression in heterologous cells. Finally, suppression of IRF-1 expression in T cells results in deficient TCR-induced FasL expression. These results confirm that the IRF family participates in the regulation of FasL gene expression.

Soft tissue masses of the chest wall and axilla: has metastatic melanoma been considered?

Isolated axillary and chest wall soft tissue masses are an uncommon presentation of metastatic cancer. The authors present three patients in whom malignant melanomas metastatic to these sites had been misdiagnosed, leading to inappropriate oncologic treatment planning in all three cases. The presumed diagnoses, even after fine-needle aspiration or trucut biopsies, were soft-tissue sarcoma (n = 2) and undifferentiated breast cancer (n = 1). The combination of taking a thorough history and performing proper immunohistochemical analysis of the biopsy material would have suggested the presence of malignant melanoma in all cases. As the disease appeared locoregionally limited in all patients, radical surgical resection with extended lymphadenectomy was performed without significant dysfunction of the upper extremity. One patient agreed to postoperative immunotherapy with interferon-alpha. Two patients are currently alive 17 and 14 months after operation. One patient was found to have systemic recurrence at 5 months, one experienced two isolated local recurrences in a prior operative site that were amenable to reresection and presently has no evidence of disease 12 months after resection, and one patient remains free of disease at 14 months. Clinical presentation, suggested diagnostic workup, and therapeutic implications are discussed to avoid misdiagnoses in this setting of possible clinical presentations of metastatic melanoma.

Unusual interactions between cleavage products of a cis-cleaving hammerhead ribozyme

We have synthesized and tested a cis-cleaving ribozyme designed to have thermodynamically stable stem-loop structures. This cis-ribozyme cleaves very efficiently in vitro, with a cleavage rate of about 0.5/min. Surprisingly, during the course of in vitro transcription and cleavage of our ribozyme, a product of unusual mobility accumulates and coincides with a sharp decline in the rate of formation of cleavage products. Analyses of this electrophoretic variant demonstrated that it is formed by interactions of the cleavage products. Despite the fact that the products and ribozyme transcript are of identical sequence, the cleavage products interact only with one another and not with the uncleaved precursor. This suggests a significant structural difference between the cleaved and uncleaved ribozyme transcripts. Testing of this cis-ribozyme in both yeast and mammalian cells shows no significant cleavage activity in vivo. We conclude that the structure of the ribozyme flanking sequences is important for optimizing the rate of ribozyme cleavage, but this enhanced rate does not necessarily correlate with enhanced in vivo function.