TARGET National: A U.K.-wide liquid-based molecular profiling program to enhance recruitment to early-phase trials

TPS3163

Background: Precision medicine programs have largely focused on tissue-based assays to screen patients for genomic variants amenable to experimental targeted therapies. Challenges faced in such studies include time taken to acquire archival biopsies and limitation in capturing tumor heterogeneity and clonal evolution. The TARGET study (Rothwell, Nature Medicine 2019) previously demonstrated feasibility of using ctDNA to match patients to early phase trials with the benefit of rapid turnaround of results. With an ever-increasing number of novel therapies in development targeting rare genomic alterations across different tumor types, ctDNA holds great promise in enhancing recruitment to studies with rapid and efficient comprehensive genomic profiling assays covering a broad range of variants. There is need to perform profiling at scale to identify rare alterations and to utilise networks for identification of suitable clinical trials across the country. ctDNA is not detectable in all patients (owing to differences across disease types/ burden), thus tissue analysis still plays an important role. Methods: TARGET National is an investigator-initiated multi-centre molecular profiling study. The primary endpoints are to establish a national framework to offer profiling from blood samples (or tissue if appropriate) for patients being considered for early phase clinical trials across the UK Experimental Cancer Medicine Centre (ECMC) Network, and to measure the number of patients receiving matched therapy (MT). Secondary endpoints include curating the genomic landscape of the early phase population in the UK, and outcomes for patients receiving MT versus unmatched. Enrolment began in July 2021 and >250 patients have been recruited across 9 ECMCs with plans to expand to 20 centres by Q3 2022. Planned enrolment is 6000 patients over 5 years. Patients must be ≥ 16 years old, provide written consent, have histologically confirmed advanced solid cancer, progressing disease and be considered fit enough to receive an experimental therapy. ctDNA is analysed with Foundation Medicine Liquid CDx with option for other providers. A multi-disciplinary national Molecular Tumor Board enables interpretation of genomic reports and identifies suitable clinical trials, supported by eTARGET; a bespoke clinical-genomic data capture solution including trial finding software. The study provides broad access to genomic profiling throughout the UK, increasing experience with ctDNA assays, and will improve opportunities for patients to participate in early phase research. The UK database will provide means for identification of rare genomic patient groups for new first-in-human studies, and the program provides a national infrastructure to collect additional samples for translational research and pre-clinical models to progress understanding of biological predictors of response and resistance. Clinical trial information: NCT04723316.

Imaging Modality and Frequency in Surveillance of Stage I Seminoma Testicular Cancer: Results From a Randomized, Phase III, Noninferiority Trial (TRISST)

PURPOSE

Survival in stage I seminoma is almost 100%. Computed tomography (CT) surveillance is an international standard of care, avoiding adjuvant therapy. In this young population, minimizing irradiation is vital. The Trial of Imaging and Surveillance in Seminoma Testis (TRISST) assessed whether magnetic resonance images (MRIs) or a reduced scan schedule could be used without an unacceptable increase in advanced relapses.

METHODS

A phase III, noninferiority, factorial trial. Eligible participants had undergone orchiectomy for stage I seminoma with no adjuvant therapy planned. Random assignment was to seven CTs (6, 12, 18, 24, 36, 48, and 60 months); seven MRIs (same schedule); three CTs (6, 18, and 36 months); or three MRIs. The primary outcome was 6-year incidence of Royal Marsden Hospital stage ≥ IIC relapse (> 5 cm), aiming to exclude increases ≥ 5.7% (from 5.7% to 11.4%) with MRI (v CT) or three scans (v 7); target N = 660, all contributing to both comparisons. Secondary outcomes include relapse ≥ 3 cm, disease-free survival, and overall survival. Intention-to-treat and per-protocol analyses were performed.

RESULTS

Six hundred sixty-nine patients enrolled (35 UK centers, 2008-2014); mean tumor size was 2.9 cm, and 358 (54%) were low risk (< 4 cm, no rete testis invasion). With a median follow-up of 72 months, 82 (12%) relapsed. Stage ≥ IIC relapse was rare (10 events). Although statistically noninferior, more events occurred with three scans (nine, 2.8%) versus seven scans (one, 0.3%): 2.5% absolute increase, 90% CI (1.0 to 4.1). Only 4/9 could have potentially been detected earlier with seven scans. Noninferiority of MRI versus CT was also shown; fewer events occurred with MRI (two [0.6%] v eight [2.6%]), 1.9% decrease (-3.5 to -0.3). Per-protocol analyses confirmed noninferiority. Five-year survival was 99%, with no tumor-related deaths.

CONCLUSION

Surveillance is a safe management approach-advanced relapse is rare, salvage treatment successful, and outcomes excellent, regardless of imaging frequency or modality. MRI can be recommended to reduce irradiation; and no adverse impact on long-term outcomes was seen with a reduced schedule.

Abstract 3014: Pharmacokinetics of the CDC7 inhibitor LY3143921 hydrate, a CRUK first-in-human phase I trial in patients with advanced solid tumors

Background: LY3143921 hydrate is an orally administered ATP-competitive inhibitor of CDC7, a serine/threonine kinase regulatory protein overexpressed in many cancer types. Following successful preclinical studies, a first-in-human phase I trial of LY3143921 hydrate was initiated in patients with advanced solid tumors. We report the pharmacokinetics of LY3143921 hydrate in this ongoing Cancer Research UK study.

Methods: Eligible patients were those with histologically proven advanced/metastatic solid tumors for which no further standard therapy options were available. Patients were administered LY3143921 hydrate as a single oral dose on Day -7, followed by daily administration (dose levels 30-270mg) or twice daily administration (dose levels 150 and 180mg) on study days 1-21. Drug administration was carried out with patients in either a fasted or fed state as shown in Table 1. Samples for pharmacokinetic analysis were obtained following a single drug dose on Day -7 at 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 48 and 72 hours. Additional samples were taken on Day 1 of treatment at doses of 150 and 180mg to investigate potential differences in pharmacokinetics in fed versus fasted states (Day -7 fed versus Day 1 fasted). Samples were analysed using a validated LC-MS/MS assay with a LLOQ of 0.1 ng/mL. Pharmacokinetic analysis was carried out using Certara WinNonlin software (version 6.3) to determine Cmax, Tmax, area under the curve (AUC), plasma half-life, apparent volume of distribution (Vz/F) and apparent clearance (CL/F) of LY3143921 hydrate. Assessment of dose proportionality was made by assessment of graphical plots of AUC versus dose level.

Table 1:Summary of LY3143921 hydrate pharmacokinetic data on Day -7 (single dose data)Dose level (mg)Number of patientsFed / fastedCmax (ng/mL)AUC0-24h (ng/mL.h)Half-life (h)CL/F (L/h)Vz/F (L)301Fasted184.44253.3570.1339601Fasted175.05022.42119.44181201Fasted113031382.1738.212018010Fasted144 - 8142505 ± 9904.2 ± 4.079.5 ± 23.9475 ± 4732704Fasted474 - 15126374 ± 14753.4 ± 1.843.8 ± 8.9226 ± 1581503Fed334 - 6321997 ± 4964.4 ± 1.977.2 ± 16.4514 ± 2881803Fed492 - 16002994 ± 9793.2 ± 0.864.2 ± 19.4290 ± 112

Results: Table 1 provides a summary of the pharmacokinetic parameters obtained on Day -7 following a single dose of LY3143921 hydrate (data expressed as range or mean ± SD as appropriate). Overall dose-dependent increases in exposure (based on Cmax and AUC) were observed. There was a general trend towards higher Cmax and AUC values following administration in a fasted versus fed state following a dose of 180 mg, but this was inconsistent across the limited number of patients for who these data were available on both Day -7 (fed) and Day 1 (fasted).

Conclusion: The pharmacokinetic data generated to date are consistent with dose dependent increases in drug exposure observed with a flat dosing regimen for LY3143921 hydrate.

Citation Format: Shelby Barnett, Melanie Griffin, Richard H. Wilson, Elizabeth R. Plummer, Jeffry T. Evans, Victoria Coyle, Sally Clive, Lisa Godfrey, Nicola Dobbs, Lesley McGuigan, Sue Brook, Gavin Halbert, Gareth J. Veal. Pharmacokinetics of the CDC7 inhibitor LY3143921 hydrate, a CRUK first-in-human phase I trial in patients with advanced solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3014.

Pevonedistat (MLN4924): mechanism of cell death induction and therapeutic potential in colorectal cancer

Pevonedistat (MLN4924), a selective inhibitor of the NEDD8-activating enzyme E1 regulatory subunit (NAE1), has demonstrated significant therapeutic potential in several malignancies. Although multiple mechanisms-of-action have been identified, how MLN4924 induces cell death and its potential as a combinatorial agent with standard-of-care (SoC) chemotherapy in colorectal cancer (CRC) remains largely undefined. In an effort to understand MLN4924-induced cell death in CRC, we identified p53 as an important mediator of the apoptotic response to MLN4924. We also identified roles for the extrinsic (TRAIL-R2/caspase-8) and intrinsic (BAX/BAK) apoptotic pathways in mediating the apoptotic effects of MLN4924 in CRC cells, as well as a role for BID, which modulates a cross-talk between these pathways. Depletion of the anti-apoptotic protein FLIP, which we identify as a novel mediator of resistance to MLN4924, enhanced apoptosis in a p53-, TRAIL-R2/DR5-, and caspase-8-dependent manner. Notably, TRAIL-R2 was involved in potentiating the apoptotic response to MLN4924 in the absence of FLIP, in a ligand-independent manner. Moreoever, when paired with SoC chemotherapies, MLN4924 demonstrated synergy with the irinotecan metabolite SN38. The cell death induced by MLN4924/SN38 combination was dependent on activation of mitochondria through BAX/BAK, but in a p53-independent manner, an important observation given the high frequency of TP53 mutation(s) in advanced CRC. These results uncover mechanisms of cell death induced by MLN4924 and suggest that this second-generation proteostasis-disrupting agent may have its most widespread activity in CRC, in combination with irinotecan-containing treatment regimens.

A CRUK first-in-human phase I trial of a CDC7 Inhibitor, LY3143921 hydrate, in patients with advanced solid tumors

TPS3167

Background: CDC7 is a protein with key roles in DNA replication initiation, the intra-S-phase checkpoint and M-phase completion. CDC7 is over-expressed in malignant compared to non-malignant cells, particularly those with TP53 mutations, making it an attractive therapeutic target. LY3143921 hydrate is an orally administered ATP-competitive CDC7 inhibitor. Pre-clinical studies in colorectal cancer (CRC) and squamous non-small cell lung cancer (sqNSCLC) demonstrate favourable anti-cancer activity, particularly in squamous NSCLC and in CRC with TP53 null and missense mutations. We hypothesise that solid tumours mutated in TP53 will be sensitive to LY3143921 therapy. Methods: This is a first-in-human, phase I trial of LY3143921 hydrate (LY3143921) monotherapy given twice daily, continuously on a 21 day schedule until disease progression, patient (pt) withdrawal or unacceptable toxicity (NCT03096054). Eligible pts have histologically proven advanced/metastatic solid tumours for which no further standard therapy exists and WHO PS 0-1. Pts have regular clinical assessment and tumour imaging every 2 cycles. Phase Ia (dose escalation) is recruiting in a 3+3 design following 3 initial single patient cohorts (starting dose 30 mg OD), enriching for patients with malignancies associated with p53 mutations (CRC, sqNSCLC, high grade serous ovarian, squamous cell oesophageal, squamous cell head & neck, urothelial, pancreatic and triple negative breast cancer). Recruitment to cohort 6 (180 mg BD) is ongoing. On determination of the maximum tolerated dose (MTD) and recommended phase II dose and schedule (RP2D), 2 expansion cohorts (≤ 25 pts each) of patients with CRC and sqNSCLC will be evaluated. Primary objectives: assess safety and tolerability of LY3143921, determine MTD and RP2D. Secondary objectives: evaluate preliminary efficacy and PK profile of LY3143921. All pts will have archival tumour tissue retrospectively analysed, while patients in phase Ib will also have pre- and on-treatment tumour biopsies. Evaluation of potential predictive and pharmacodynamic biomarkers including p53 mutations, phosphorylated MCM2, cyclin B1 and molecular subgroups of target tumours will be included. Clinical trial information: NCT03096054.

Transcriptional subtyping and CD8 immunohistochemistry identifies poor prognosis stage II/III colorectal cancer patients who benefit from adjuvant chemotherapy

Purpose

Transcriptomic profiling of colorectal cancer (CRC) has led to the identification of four consensus molecular subtypes (CMS1 to 4) that have prognostic value in stage II and III disease. More recently, the Colorectal Cancer Intrinsic Subtypes (CRIS) classification system has helped to define the biology specific to the epithelial component of colorectal tumors; however, the clinical value of these classification systems in the prediction of response to standard-of-care adjuvant chemotherapy remains unknown.

Patients and Methods

Using samples from four European sites, we assembled a novel cohort of patients with stage II and III CRC (n = 156 samples) and performed transcriptomic profiling and targeted sequencing and generated a tissue microarray to enable integrated multiomics analyses. We also accessed data from two published cohorts of patients with stage II and III CRC: GSE39582 and GSE14333 (n = 479 and n = 185 samples, respectively).

Results

The epithelial-rich CMS2 subtype of CRC benefitted significantly from treatment with adjuvant chemotherapy in both stage II and III disease (P = .02 and P < .001, respectively), whereas the CMS3 subtype significantly benefitted in stage III only (P = .001). After CRIS substratification of CMS2, we observed that only the CRIS-C subtype significantly benefitted from treatment with adjuvant chemotherapy in stage II and III disease (P = .0081 and P < .001, respectively), whereas the CRIS-D subtype significantly benefitted in stage III only (P = .0034). We also observed that CRIS-C patients with low levels of CD8⁺ tumor-infiltrating lymphocytes were most at risk for relapse in both stage II and III disease (log-rank P = .0031; hazard ratio, 12.18 [95% CI, 1.51 to 98.58]).

Conclusion

Patient stratification using a combination of transcriptional subtyping and CD8 immunohistochemistry analyses is capable of identifying patients with poor prognostic stage II and III disease who benefit from adjuvant standard-of-care chemotherapy. These findings are particularly relevant for patients with stage II disease, where the overall benefit of adjuvant chemotherapy is marginal.

Predicting response to irinotecan/5-fluorouracil (5-FU) chemotherapy for advanced colorectal cancer based on gene expression in primary tumour

e14558

Background: Despite improvements in the treatment of advanced colorectal cancer (CRC), there remains a subset of patients who fail to benefit from chemotherapy. The identification of predictive response markers has been limited by the relative scarcity of metastatic tumour samples for molecular analysis, prompting a need to consider surrogate models for generation of predictive markers. Methods: We performed gene expression profiling of archived formalin fixed paraffin-embedded (FFPE) colorectal primary tumours (dating from 2001–2007) from 40 patients who received irinotecan/5-FU chemotherapy as first line treatment for advanced disease. Patients were classified as responders/non-responders based on radiological response. Gene expression profiling was performed using the Almac Diagnostics Colorectal Disease Specific Array (DSA). Data was analysed using Genespring GX v7.3. Principal Components Analysis (PCA) was used to separate responding and non-responding patients based on the tumour- derived expression data. Predictive classifiers were constructed using several class prediction methods. The performance of the classifiers was assessed by leave-one-out cross-validation. Results: 37 samples passed data QC assessments for inclusion in predictive analysis. PCA using genes passing a t-test and 1.5-fold change filter demonstrated clear separation between responding and non-responding patients. Predictive modelling using the k-nearest neighbour and Support Vector Machine (SVM) algorithms with Fishers exact test as feature selection method each generated seven different predictive classifiers containing 5 to 35 genes; these had an average predictive accuracy of 80%. Predictive modelling of this dataset is ongoing and these encouraging initial results will be extended to a larger patient cohort. Conclusions: DNA microarray profiling has been used to generate gene signatures predictive of response to irinotecan/5-FU therapy in advanced CRC; importantly, these predictive signatures have been generated from FFPE colorectal primary tumour facilitating their independent validation in large patient cohorts and potential clinical implementation in the event of successful validation.

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