Results of the c-TRAK TN trial: a clinical trial utilising ctDNA mutation tracking to detect molecular residual disease and trigger intervention in patients with moderate- and high-risk early-stage triple-negative breast cancer.

BACKGROUND: Post-treatment detection of circulating tumour DNA (ctDNA) in early-stage triple-negative breast cancer (TNBC) patients predicts high risk of relapse. c-TRAK TN assessed the utility of prospective ctDNA surveillance in TNBC and the activity of pembrolizumab in patients with ctDNA detected [ctDNA positive (ctDNA+)]. PATIENTS AND METHODS: c-TRAK TN, a multicentre phase II trial, with integrated prospective ctDNA surveillance by digital PCR, enrolled patients with early-stage TNBC and residual disease following neoadjuvant chemotherapy, or stage II/III with adjuvant chemotherapy. ctDNA surveillance comprised three-monthly blood sampling to 12 months (18 months if samples were missed due to coronavirus disease), and ctDNA+ patients were randomised 2 : 1 to intervention : observation. ctDNA results were blinded unless patients were allocated to intervention, when staging scans were done and those free of recurrence were offered pembrolizumab. A protocol amendment (16 September 2020) closed the observation group; all subsequent ctDNA+ patients were allocated to intervention. Co-primary endpoints were (i) ctDNA detection rate and (ii) sustained ctDNA clearance rate on pembrolizumab (NCT03145961). RESULTS: Two hundred and eight patients registered between 30 January 2018 and 06 December 2019, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. Rate of ctDNA detection by 12 months was 27.3% (44/161, 95% confidence interval 20.6% to 34.9%). Seven patients relapsed without prior ctDNA detection. Forty-five patients entered the therapeutic component (intervention n = 31; observation n = 14; one observation patient was re-allocated to intervention following protocol amendment). Of patients allocated to intervention, 72% (23/32) had metastases on staging at the time of ctDNA+, and 4 patients declined pembrolizumab. Of the five patients who commenced pembrolizumab, none achieved sustained ctDNA clearance. CONCLUSIONS: c-TRAK TN is the first prospective study to assess whether ctDNA assays have clinical utility in guiding therapy in TNBC. Patients had a high rate of metastatic disease on ctDNA detection. Findings have implications for future trial design, emphasising the importance of commencing ctDNA testing early, with more sensitive and/or frequent ctDNA testing regimes.

Effect of HER2 on prognosis and benefit from peri-operative chemotherapy in early oesophago-gastric adenocarcinoma in the MAGIC trial.

BACKGROUND: Perioperative epirubicin, cisplatin and fluorouracil (ECF) chemotherapy improves survival in operable oesophago-gastric cancer [Adjuvant Gastric Cancer Infusional Chemotherapy (MAGIC) trial HR 0.75 (0.6-0.93)]. HER2 amplification is reported to predict enhanced benefit from anthracyclines in breast cancer. We sought to define whether HER2 predicts benefit from ECF in oesophago-gastric cancer. PATIENTS AND METHODS: Diagnostic biopsies and/or resection specimens were collected from 415 of 503 MAGIC trial patients (82.5%). HER2 was evaluated by immunohistochemistry (IHC) and brightfield dual in situ hybridisation (BDISH) in tissue microarrays. The prognostic and predictive impact of HER2 status was investigated. RESULTS: Concordance between HER2 over-expression (IHC3+) and amplification was 96%. Results of HER2 assessment in biopsy and resection specimens were concordant in 92.9% (145/156). HER2 positive rate (IHC3+, or IHC2+/BDISH positive) was 10.9% in the whole cohort and 10.4% in resection specimens. A further 4.0% of resections were IHC negative/BDISH positive. HER2 status was neither prognostic, nor (in pre-treatment biopsies) predicted enhanced benefit from chemotherapy [HER2 positive HR 0.74 (0.14-3.77); HER2 negative HR 0.58 (0.41-0.82), interaction P = 0.7]. However, the power of the predictive analysis was limited by the small number of HER2 positive pre-treatment biopsies. CONCLUSIONS: HER2 status is not an independent prognostic biomarker in early oesophago-gastric adenocarcinoma.

Bevacizumab with peri-operative epirubicin, cisplatin and capecitabine (ECX) in localised gastro-oesophageal adenocarcinoma: a safety report.

BACKGROUND: Peri-operative chemotherapy and surgery is a standard treatment of localised oesophagogastric adenocarcinoma; however, the outcomes remain poor. PATIENTS AND METHODS: ST03 is a multicentre, randomised, phase II/III study comparing peri-operative ECX with or without bevacizumab (ECX-B). The primary outcome measure of phase II (n = 200) was safety, specifically gastrointestinal (GI) perforation rates and cardiotoxicity. RESULTS: Two hundred patients were randomised between October 2007 and April 2010. Ninety-one/101 (90%) ECX and 86/99 (87%) ECX-B patients completed pre-operative chemotherapy; 7 ECX and 9 ECX-B patients stopped due to toxicity. Gastrointestinal perforations (3 ECX, 1 ECX-B), cardiac events (1 ECX, 4 ECX-B) and venous thromboembolic events (VTEs, 8 ECX, 7 ECX-B) were uncommon. Arterial thromboembolic events (ATEs, myocardial infarction (MI) or cerebrovascular accident) were more frequent with ECX-B (5 versus 1 with ECX). Delayed wound healing, anastomotic leaks and GI bleeding rates were similar. More asymptomatic left ventricular ejection fraction (LVEF) falls (≥15% and/or to <50%) occurred with ECX-B (21.2% versus 11.1% with ECX). Clinically significant falls (≥10% to below lower limit of normal, LLN) occurred in (15.3%) and (8.9%) respectively, with no associated cardiac failure (median 22 months follow-up). CONCLUSIONS: Addition of bevacizumab to peri-operative ECX chemotherapy is feasible with acceptable toxicity and no negative impact on surgical outcomes.

Expert UK consensus on the definition of high risk of recurrence in HER2-negative early breast cancer: A modified Delphi panel.

BACKGROUND: There is currently no standardised definition for patients at high risk of recurrence of human epidermal growth factor receptor 2 (HER2)-negative early breast cancer (eBC; stages 1-3) after surgery. This modified Delphi panel aimed to establish expert UK consensus on this definition, separately considering hormone receptor (HR)-positive and triple-negative (TN) patients. METHODS: Over three consecutive rounds, results were collected from 29, 24 and 22 UK senior breast cancer oncologists and surgeons, respectively. The first round aimed to determine key risk factors in each patient subgroup; subsequent rounds aimed to establish appropriate risk thresholds. Consensus was pre-defined as ≥70% of respondents. RESULTS: Expert consensus was achieved on need to assess age, tumour size, tumour grade, number of positive lymph nodes, inflammatory breast cancer and risk prediction tools in all HER2-negative patients. There was additional agreement on use of tumour profiling tests and biomarkers in HR-positive patients, and pathologic complete response (pCR) status in TN patients. Thresholds for high recurrence risk were subsequently agreed. In HR-positive patients, these included age <35 years, tumour size >5 cm (as independent risk factors); tumour grade 3 (independently and combined with other high-risk factors); number of positive nodes ≥4 (independently) and ≥1 (combined). For TN patients, the following thresholds reached consensus, both independently and in combination with other factors: tumour size >2 cm, tumour grade 3, number of positive nodes ≥1. CONCLUSIONS: The results may be a valuable reference point to guide recurrence risk assessment and decision-making after surgery in the HER2-negative eBC population.

Multimodality treatment for localized gastro-oesophageal cancer.

Surgery alone remains an international standard of care for early stage (Ia) oesophagogastric cancers. There is also international consensus that multimodality therapy is appropriate for more advanced stage operable disease, however there is marked geographical variation in standard practice. For gastric adenocarcinomas, adjuvant oral fluoropyrimidines became the standard of care in Japan after improved survival was demonstrated following resection with D2 nodal dissection, compared to surgery alone. Adjuvant chemoradiation improves survival following surgery with any level of nodal dissection compared to observation and is the accepted standard of care in the US. Similarly, perioperative triplet chemotherapy improves survival compared to surgery alone in gastroesophageal adenocarcinomas and is widely used across Europe and Australasia. For oesophageal adenocarcinoma, neo-adjuvant chemotherapy and neo-adjuvant chemoradiation are further accepted standards, widely utilized in the UK and US respectively, with similar survival benefits reported for each strategy. Patients with localized squamous cell carcinomas of the oesophagus benefit from chemoradiation, which may be delivered as a neo-adjuvant or definitive strategy, the latter avoiding surgical morbidity and mortality. Targeted agents are currently under evaluation in localized oesophagogastric cancer, with translational sub-studies attempting to define which patients may benefit from the addition of these high cost drugs.

Rechallenge with platinum plus fluoropyrimidine +/- epirubicin in patients with oesophagogastric cancer.

PURPOSE: There is no standard second-line therapy for patients with oesophagogastric cancer who progress following first-line chemotherapy for advanced disease or relapse following radical multi-modality therapy. The aim of this retrospective study was to evaluate survival following rechallenge with platinum plus fluoropyrimidine (PF) +/- epirubicin. METHODS: Patients treated with PF +/- epirubicin for oesophagogastric cancer at our institution were identified from the electronic prescribing database. Patients rechallenged with PF +/- epirubicin >3 months after completing initial chemotherapy were eligible. Primary endpoint was survival, calculated from day 1 of rechallenge treatment to date of death or last follow-up. Secondary endpoints were progression-free survival and response rate to PF-based re-challenge. RESULTS: Between 2000 and 2008, 950 patients treated with PF +/- epirubicin for oesophagogastric cancer were identified. 298 patients progressed or relapsed >3 months after completing chemotherapy, of whom 106 patients were rechallenged with PF-based chemotherapy. Median progression-free survival and overall survival were 5.1 and 10 months, respectively, from date of rechallenge for patients treated with initial radical intent and 3.9 and 6.6 months, respectively, in patients treated with palliative intent from diagnosis. In a survival analysis, no significant prognostic factors were identified. CONCLUSION: Selected patients with oesophagogastric cancer who relapse or progress >3 months after initial treatment with PF +/- epirubicin may benefit from re-introduction of PF-based chemotherapy.

Meta-analysis of the REAL-2 and ML17032 trials: evaluating capecitabine-based combination chemotherapy and infused 5-fluorouracil-based combination chemotherapy for the treatment of advanced oesophago-gastric cancer.

BACKGROUND: The REAL-2 and ML17032 trials demonstrated that the oral fluoropyrimidine, capecitabine, is noninferior to 5-fluorouracil (5-FU) for overall survival (OS) and progression-free survival (PFS), respectively, in advanced oesophago-gastric cancer. METHODS: Individual patient data were collected on all patients randomised within the trials (n = 1318). Kaplan-Meier survival curves were generated and the log-rank test was used to compare OS and PFS between patients receiving 5-FU combinations and capecitabine combinations. Stepwise multivariate Cox regression analysis was used to calculate corrected hazard ratios (HRs) and 95% confidence intervals (CIs) for OS and PFS. Logistic regression was used for objective response rate. Forest plots with tests of heterogeneity were generated. RESULTS: OS was superior in the 654 patients treated with capecitabine combinations compared with the 664 patients treated with 5-FU combinations; HR 0.87 (95% CI 0.77-0.98, P = 0.02). Poor performance status, age <60 and metastatic disease were independent predictors of poor survival. There was no significant difference in PFS between treatment groups on multivariate analysis. Assessable patients treated with capecitabine combinations were significantly more likely to have an objective response to treatment than those treated with 5-FU combinations; odds ratio 1.38 (95% CI 1.10-1.73, P = 0.006). CONCLUSION: OS is superior in patients treated with capecitabine combinations compared with 5-FU combinations in advanced oesophago-gastric cancer.

Biomarker analysis in oesophagogastric cancer: Results from the REAL3 and TransMAGIC trials.

BACKGROUND: REAL3 (Randomised ECF for Advanced or Locally advanced oesophagogastric cancer 3) was a phase II/III trial designed to evaluate the addition of panitumumab (P) to epirubicin, oxaliplatin and capecitabine (EOC) in untreated advanced oesophagogastric adenocarcinoma, or undifferentiated carcinoma. MAGIC (MRC Adjuvant Gastric Infusional Chemotherapy) was a phase III study which demonstrated that peri-operative epirubicin, cisplatin and infused 5-fluorouracil (ECF) improved survival in early oesophagogastric adenocarcinoma. PATIENTS AND METHODS: Analysis of response rate (RR; the primary end-point of phase II) and biomarkers in the first 200 patients randomised to EOC or modified dose (m) EOC+P in REAL3 was pre-planned to determine if molecular selection for the on-going study was indicated. KRAS, BRAF and PIK3CA mutations and PTEN expression were assessed in pre-treatment biopsies and results correlated with response to mEOC+P. Association between these biomarkers and overall survival (OS) was assessed in MAGIC patients to determine any prognostic effect. RESULTS: RR was 52% to mEOC+P, 48% to EOC. Results from 175 assessable biopsies: mutations in KRAS (5.7%), BRAF (0%), PIK3CA (2.5%) and loss of PTEN expression (15.0%). None of the biomarkers evaluated predicted resistance to mEOC+P. In MAGIC, mutations in KRAS, BRAF and PIK3CA and loss of PTEN (phosphatase and tensin homolog) were found in 6.3%, 1.0%, 5.0% and 10.9%, respectively, and were not associated with survival. CONCLUSIONS: The RR of 52% in REAL3 with mEOC+P met pre-defined criteria to continue accrual to phase III. The frequency of the mutations was too low to exclude any prognostic or predictive effect.