Abstract P2-12-01: Dose- and exposure-response relationship and biomarker correlation analysis in breast tumors from patients treated with capivasertib, an AKT inhibitor, in the STAKT randomized, placebo controlled pre-surgical study

Background: Capivasertib (AZD5363), an AKT1,2,3 inhibitor, significantly improved progression-free and overall survival when added to paclitaxel in triple negative breast cancer (BC) patients (Schmid et al. ASCO 2018). We have previously reported in STAKT, robust target inhibition at 480mg BD versus placebo, including significant decreases in the primary biomarkers (PBs) - Ki67, pPRAS40 & pGSK3β - in primary BCs (Robertson et al. SABCS 2017). We now report the dose- and exposure-response relationship of capivasertib and the correlation between primary and secondary (pAKT, pS6, nuclear FOXO3a) tumor biomarkers.

Design: STAKT was a two-stage, double blind, randomized, placebo controlled 'window-of-opportunity' trial in newly diagnosed ER+ BC patients. Stage 1 assessed capivasertib at a dose of 480mg BD p.o. versus placebo. Stage 2 assessed capivasertib at two lower doses 360mg and 240mg BD. Tumor biopsies were taken prior to 1st dose and after 4.5 days of dosing. Evaluable patients (who required pre-defined minimum baseline PD values for PBs) included placebo (n=11), capivasertib at 480mg (n=17), 360mg (n=5) and 240mg (n=6). Blood samples for pharmacokinetic (PK) studies were scheduled at pre-dose; 2, 4, optional 6 & 8 hrs post first dose on Day 1; ˜2-4 h post last dose on Day 5 (before biopsy). The % change from baseline for PBs were evaluated against the following exposure variables (placebo=0): i) Dose, ii) Observed Cmax Day 1 (˜2h post-dose), iii) Observed plasma concentration on Day 5, iv) Model-predicted plasma concentration Day 5 at time of biopsy, and v) Model-predicted AUC on Day 5. Spearman correlation coefficient measured the strength and direction of association between biomarkers.

Results:

· Significant mean reductions in % change from baseline were observed for the PBs pGSK3β (-39%; p<0.006), pPRAS40 (-50%; p<0.0001) and Ki67 (-23%; p=0.052) at 480mg versus placebo. At 360mg and 240mg, mean % changes from baseline in pGSK3β were -27% and -9%, respectively; in pPRAS40 -45% and -28%, respectively; and in Ki67 0% and +22%, respectively.

· Dose-response relationships for individual % change from baseline could be described by an Emax model for all PBs. Overall, the correlation to PK exposure (observed or predicted) was similar to the correlation to dose.

· Correlation coefficient analyses between biomarkers at capivasertib 480mg BD identified- i) Positive correlations for pGSK3β with Ki67 (ρ = 0.52, p-value < 0.05) & with pS6 (ρ = 0.54, p-value<0.05); ii) Negative correlations between FOXO3a and Ki67 (ρ = -0.75, p-value<0.001) pGSK3β (ρ = -0.71, p-value<0.001) & also pS6 (ρ = -0.61, p-value<0.001).Correlation coefficients for lower doses are not robust due to small sample size in these groups.

Conclusions

· Capivasertib caused dose- and concentration- dependent effects on biomarkers after only 4.5 days.

· Significant changes in the PBs were demonstrated at 480 mg BD. Biomarker changes was observed at 360mg and 240mg BD, but statistical analysis was limited by the small sample size at lower doses.

· Correlation between a number of tumor biomarkers (relative changes) were identified for capivasertib 480mg BD.

Citation Format: Gee J, Coleman RE, Cheung KL, Evans A, Holcombe C, Skene A, Rea D, Ahmed S, Jahan A, Horgan K, Rauchhaus P, Littleford R, Finlay P, Cheung A, Cullberg M, de Bruin E, Foxley A, Koulai L, Pass M, Schiavon G, Rugman P, Deb R, Robertson JFR. Dose- and exposure-response relationship and biomarker correlation analysis in breast tumors from patients treated with capivasertib, an AKT inhibitor, in the STAKT randomized, placebo controlled pre-surgical study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-12-01.

The presentation, management and outcome of inflammatory breast cancer cases in the UK: Data from a multi-centre retrospective review

OBJECTIVES

Inflammatory Breast cancer (IBC) is a rare but aggressive form of breast cancer. Its incidence and behaviour in the UK is poorly characterised. We collected retrospective data from hospitals in the UK and Ireland to describe the presentation, pathology, treatment and clinical course of IBC in the UK.

MATERIALS AND METHODS

Patients with IBC diagnosed between 1997-2014 at fourteen UK and Irish hospitals were identified from local breast unit databases. Patient characteristics, tumour pathology and stage, and details of surgical, systemic and radiotherapy treatment and follow-up data were collected from electronic patient records and medical notes.

RESULT

This retrospective review identified 445 patients with IBC accounting for 0.4-1.8% of invasive breast cancer cases. Median follow-up was 4.2 years. 53.2% of tumours were grade 3, 56.2% were oestrogen receptor positive, 31.3% were HER2 positive and 25.1% were triple negative. 20.7% of patients had distant metastases at presentation. Despite trimodality treatment in 86.4%, 40.1% of stage III patients developed distant metastases. Five-year overall survival (OS) was 61.0% for stage III and 21.4% for stage IV patients.

CONCLUSIONS

This is the largest series of UK IBC patients reported to date. It indicates a lower incidence than in American series, but confirms that IBC has a high risk of recurrence with poor survival despite contemporary multi-modality therapy. A national strategy is required to facilitate translational research into this aggressive disease.

Ponatinib evaluation and safety in real-life chronic myelogenous leukemia patients failing more than two tyrosine kinase inhibitors: the PEARL observational study

Ponatinib represents a remarkable progress in the treatment of heavily pretreated chronic myelogenous leukemia (CML) and de novo Philadelphia chromosome-positive ALL patients despite significant toxicity in clinical trials. To date, "real-life" data remain few and the use of ponatinib in this setting and its consequences remain mostly unknown. We report, within a national observational study, the use of ponatinib in unselected CML patients who had previously failed ≥2 lines of tyrosine kinase inhibitor (TKI) therapy (or one line if an Abelson (ABL)^T315I mutation was identified), in real-life conditions (2013-2014) in a compassionate program. Our analysis has been focused on 48 chronic phase CML patients recorded. With a median follow-up of 26.5 months since ponatinib initiation, the overall survival (OS) rates (80.5% at 3 years) and cumulative incidence of major molecular response (81.8% at 18 months) were similar to those of the phase II study, with no influence of BCR-ABL mutations nor the reason of ponatinib prescription. A specific subanalysis of the preexisting cardiovascular risk factors and events occurring on ponatinib is described. These events occurred after a median time on ponatinib of 5.8 months (excluding hypertension) and were observed in 29/48 patients (47%), even in those already on anti-aggregants/coagulants. The majority were not severe and resolved, but two cases were fatal. Other hematological or nonhematological nonvascular adverse events were similar to those previously described in trials. This observational study reports similar rates of survival, molecular responses, and a slight increase in the cardiovascular toxicity of ponatinib in real-life conditions, prompting improved control of cardiovascular risk factors and selection of patients.

Active Monitoring Versus Immediate Treatment of Women With Localised, Low-Risk Ductal Carcinoma In Situ: Does It Make Economic Sense?

Background: Controversy persists about the overdiagnosis of low risk breast cancers identified by breast cancer screening programs. Low risk ductal carcinoma in situ (DCIS) is a noninvasive breast condition with an uncertain risk of invasive progression. Standard management consists of immediate surgical treatment, with or without radiotherapy and adjuvant therapy. Active monitoring of low risk DCIS via annual mammography is proposed as an alternative strategy to immediate surgery to reduce the harm of overdiagnosis, whereby the disease is only treated upon disease progression. However, the costs and benefits of active monitoring are not well researched in the breast cancer setting. Aim: To assess the cost-effectiveness of active monitoring versus immediate surgical management in women diagnosed with low grade ductal carcinoma in situ (DCIS). Methods: A Markov state transition model was constructed for a theoretical cohort of women aged 50 years and over with low risk DCIS over a lifetime horizon. A cost-utility analysis was performed to compare a strategy of observation (active monitoring) versus immediate surgical treatment using an annual time cycle. Transition probabilities, costs and utilities were obtained from national mortality and cost data, published meta-analyses, primary data collection of utilities and expert opinion. A healthcare perspective was adopted to present the results. Primary outcomes were assessed in terms of cost per quality-adjusted-life-year (cost per QALY). Multiple sensitivity analyses were undertaken to determine effect of parameter uncertainty on results. Results: The cumulative costs and QALYs for each age cohort are presented. Active monitoring is a cost-effective strategy for the management of low risk breast cancer in older women with comorbid conditions. Sensitivity analyses revealed the ICERs for all women to be affected by baseline probability of disease progression, age, cost of surgery and utility. Conclusion: Conservative management of ductal carcinoma in situ via active monitoring may be cost-effective compared with immediate surgical treatment in a selected cohort of older women with low risk disease.

Overcoming Overdiagnosis: Women´s Preferences for Improving Breast Cancer Screening

Background: Breast cancer screening is effective in reducing breast cancer mortality, but there is increasing concern that it may also lead to overdiagnosis; the detection and treatment of a cancer that would never have presented symptomatically during the woman's lifetime. Conservative management of low-risk breast cancer may reduce the harm of overdiagnosis resulting from mammographic screening programs, yet little is known about how such strategies might impact upon quality of life. Aim: To quantify women's preferences for managing low risk breast cancers identified by breast cancer screening. Methods: Utilities (measures of preference) were obtained from women with and without a history of breast cancer for seven health states reflecting low risk screen detected ductal carcinoma in situ (DCIS) using standard gambles. Demographics and a history of prior screening participation or breast cancer diagnosis were examined as predictors of screening and treatment pathway preferences. Results: Utilities were lower for breast cancers treated with mastectomy or invasive adjuvant treatment. The impact of active monitoring on quality of life was comparable to breast conserving surgery, although women in both patient and general population groups rated active monitoring more favorably as the risk of disease spread was decreased. There was some variation in ratings across patients suggesting that individual risk aversion does affect preferences for the type of conservative management valued. Conclusion: Overdiagnosis remains a challenge for improving the current breast cancer screening program. Active monitoring of low risk ductal carcinoma in situ may provide an acceptable solution for reducing the impact of overdiagnosis and overtreatment resulting from breast cancer screening on quality of life.

Incidence, outcomes, and risk factors of pleural effusion in patients receiving dasatinib therapy for Philadelphia chromosome-positive leukemia

Dasatinib, a second-generation BCR-ABL1 tyrosine kinase inhibitor, is approved for the treatment of chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia, both as first-line therapy and after imatinib intolerance or resistance. While generally well tolerated, dasatinib has been associated with a higher risk for pleural effusions. Frequency, risk factors, and outcomes associated with pleural effusion were assessed in two phase 3 trials (DASISION and 034/Dose-optimization) and a pooled population of 11 trials that evaluated patients with chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia treated with dasatinib (including DASISION and 034/Dose-optimization). In this largest assessment of patients across the dasatinib clinical trial program (N=2712), pleural effusion developed in 6-9% of patients at risk annually in DASISION, and in 5-15% of patients at risk annually in 034/Dose-optimization. With a minimum follow up of 5 and 7 years, drug-related pleural effusion occurred in 28% of patients in DASISION and in 33% of patients in 034/Dose-optimization, respectively. A significant risk factor identified for developing pleural effusion by a multivariate analysis was age. We found that overall responses to dasatinib, progression-free survival, and overall survival were similar in patients who developed pleural effusion and in patients who did not. clinicaltrials.gov identifier 00481247; 00123474.

Abstract 3385: ETNK1 mutations promote ROS production and DNA damage through increased mitochondrial activity

Atypical chronic myeloid leukemia (aCML) is a clonal disorder belonging to the myelodysplastic/myeloproliferative syndromes. About 13% of aCML cases carry somatic mutations in ETNK1 gene, encoding for H243Y, N244S, and G245V substitutions. We previously showed that ETNK1 mutations cause a decreased catalytic activity of the enzyme. Despite this evidence however, their oncogenic role remained largely unexplained. Since ETNK1 activity is essential for the synthesis of phosphatidylethanolamine (PE) and given that PE is one of the most abundant phospholipids in the inner membrane of mitochondria, we focused our attention on mitochondrial activity. In order to characterize the oncogenic effect of ETNK1 variants we generated CRISPR/Cas9 clones carrying heterozygous N244S mutation and homozygous ETNK1 deletion (KO cells) on the 293 Flp-In™ cell-line. Both N244S and KO cells showed a significant increase in mitochondrial activity (1.78 and 2.13 fold increase, respectively; p= 0.0096 and p=0.0050) compared to WT, as assessed by MitoTracker™ Red. In line with this finding, electron microscopy revealed a significant modification in mitochondria morphology for N244S and KO cells, changing from an elongated, tubular shape to a round, swollen one. ATP (1.67 and 1.68 fold; p<0.0001; ATPlite Luminescence Assay System) and ROS production (1.66 and 1.74 fold increase; p<0.0001; CellROX™ Green Reagent) were similarly increased. Histone H2AX phosphorylation (γ-H2AX) analysis revealed a higher number of foci in N244S and KO cells (2.60±0.22 and 2.89±0.27; p<0.0001) compared to WT (0.56±0.08). A similar increase in γ-H2AX (3.6 fold; p=0.0037) was present in primary samples from aCML patients carrying ETNK1 mutation compared to ETNK1-WT ones.

In line with these data, a higher mutation rate was detected in N244S and KO cells (8.09*10-7±9.6*10-8 and 8.20*10-7±1.28*10-7; p=0.0060 and p=0.0264) compared to WT (2.98*10-7±8.2*10-8) by 6-thioguanine assay.

The reconstruction of the hierarchy of somatic mutations in ETNK1-mutated aCML patients revealed that ETNK1 variants invariably occur very early in the evolution history of the aCML patients.

Taken together, our results show that impairment of ETNK1 function causes an increase in mitochondrial activity, which in turn leads to increased ROS production driving the accumulation of DNA mutations. Since the characterization of aCML subclonal architecture indicates ETNK1 mutations as a very early event in the history of the disease, we hypothesize that ETNK1 could contribute to the onset of aCML through the activation of a mutant phenotype, which in turn would accelerate the accumulation of further oncogenic mutations.

Citation Format: Diletta Fontana, Mario Mauri, Antonio Niro, Luca Massimino, Mayla Bertagna, Giovanni Zambrotta, Mario Bossi, Stefania Citterio, Barbara Crescenzi, Giovanni Signore, Vincenzo Piazza, Cristina Mecucci, Guido Cavaletti, Delphine Rea, Carlo Gambacorti-Passerini, Rocco Piazza. ETNK1 mutations promote ROS production and DNA damage through increased mitochondrial activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3385.

SETBP1 induces transcription of a network of development genes by acting as an epigenetic hub

SETBP1 variants occur as somatic mutations in several hematological malignancies such as atypical chronic myeloid leukemia and as de novo germline mutations in the Schinzel–Giedion syndrome. Here we show that SETBP1 binds to gDNA in AT-rich promoter regions, causing activation of gene expression through recruitment of a HCF1/KMT2A/PHF8 epigenetic complex. Deletion of two AT-hooks abrogates the binding of SETBP1 to gDNA and impairs target gene upregulation. Genes controlled by SETBP1 such as MECOM are significantly upregulated in leukemias containing SETBP1 mutations. Gene ontology analysis of deregulated SETBP1 target genes indicates that they are also key controllers of visceral organ development and brain morphogenesis. In line with these findings, in utero brain electroporation of mutated SETBP1 causes impairment of mouse neurogenesis with a profound delay in neuronal migration. In summary, this work unveils a SETBP1 function that directly affects gene transcription and clarifies the mechanism operating in myeloid malignancies and in the Schinzel–Giedion syndrome caused by SETBP1 mutations.

SETBP1 variants occur as somatic mutations in several malignancies and as de novo germline mutations in developmental disorders. Here the authors provide evidence that SETBP1 binds to gDNA in AT-rich promoter regions to promote target gene upregulation, indicating SETBP1 functions directly to regulate transcription.

Disease-free and overall survival at 3.5 years for neoadjuvant bevacizumab added to docetaxel followed by fluorouracil, epirubicin and cyclophosphamide, for women with HER2 negative early breast cancer: ARTemis Trial

Background

The ARTemis trial previously reported that addition of neoadjuvant bevacizumab (Bev) to docetaxel (D) followed by fluorouracil, epirubicin and cyclophosphamide (D-FEC) in HER2 negative breast cancer improved the pathological complete response (pCR) rate. We present disease-free survival (DFS) and overall survival (OS) with central pathology review.

Patients and methods

Patients were randomized to 3 cycles of D followed by 3 cycles of FEC (D-FEC), ±4 cycles of Bev (Bev + D-FEC). DFS and OS were analyzed by treatment and by central pathology reviewed pCR and Residual Cancer Burden (RCB) class.

Results

A total of 800 patients were randomized [median follow-up 3.5 years (IQR 3.2–4.4)]. DFS and OS were similar across treatment arms [DFS hazard ratio (HR)=1.18 (95% CI 0.89–1.57), P = 0.25; OS HR = 1.26 (95% CI 0.90–1.76), P = 0.19). Both local pathology report review and central histopathology review confirmed a significant improvement in DFS and OS for patients who achieved a pCR [DFS HR = 0.38 (95% CI 0.23–0.63), P < 0.001; OS HR = 0.43 (95% CI 0.24–0.75), P = 0.003]. However, significant heterogeneity was observed (P = 0.02); larger improvements in DFS were obtained with a pCR achieved with D-FEC than a pCR achieved with Bev + D-FEC. As RCB class increased, significantly worse DFS and OS was observed (P for trend <0.0001), which effect was most marked in the ER negative group.

Conclusions

The addition of short course neoadjuvant Bev to standard chemotherapy did not demonstrate a DFS or OS benefit. Achieving a pCR with D-FEC is associated with improved DFS and OS but not when pCR is achieved with Bev + D-FEC. At the present time therefore, Bev is not recommended in early breast cancer.

ClinicalTrials.gov number

NCT01093235.

Pharmacokinetics of multiple doses of transdermal flunixin meglumine in adult Holstein dairy cows

A transdermal formulation of the nonsteroidal anti-inflammatory drug, flunixin meglumine, has been approved in the United States and Canada for single-dose administration. Transdermal flunixin meglumine was administered to 10 adult Holstein cows in their second or third lactation at the label dose of 3.33 mg/kg every 24 hr for three total treatments. Plasma flunixin concentrations were determined using high-pressure liquid chromatography with mass spectroscopy (HPLC-MS). Pharmacokinetic analysis was completed on each individual animal with noncompartmental methods using computer software. The time to maximum drug concentration (Tmax) was 2.81 hr, and the maximum drug concentration was 1.08 μg/ml. The mean terminal half-life (T½) was determined to be 5.20 hr. Clearance per fraction absorbed (Cl/F) was calculated to be 0.294 L/hr kg^-1 , and volume of distribution of fraction (Vz/F) absorbed was 2.20 L/kg. The mean accumulation factor was 1.10 after three doses. This indicates changes in dosing may not be required when giving multiple doses of flunixin transdermal. Further work is required to investigate the clinical efficacy of transdermal flunixin after multiple daily doses.

Abstract P4-04-06: AZD5363, an AKT inhibitor, significantly inhibits key biomarkers of the AKT pathway and Ki67, in a randomized, placebo, controlled study (STAKT) in human breast cancers

Background: AKT is an important intracellular control point through which Type 1 growth factors and IGFR signal. Mutations in PIK3CA, AKT and PTEN are prevalent in estrogen receptor positive (ER+) breast cancer (BC) and have been implicated in resistance to endocrine therapies. AZD5363 is an inhibitor of AKT 1, 2 and 3 currently in Phase 2 trials for BC and other solid cancers.

Design: The study examined whether AZD5363 impacts on key biomarkers within the AKT pathway and their subsequent effects on Ki67, a marker of tumor proliferation. STAKT is a multi-center, two-stage, double blind, randomized, placebo controlled, biomarker 'window-of-opportunity' trial in women with newly diagnosed, previously untreated ER+ BC who were deemed would require chemotherapy as part of their primary treatment regimen. Stage 1 assessed AZD5363 at a dose of 480mg bd p.o. versus matching placebo. Up to 30 patients per arm were permitted, to allow 12 subjects per arm with evaluable paired biopsies - obtained at baseline, and after 4.5 days of AZD5363 / placebo. Primary endpoint markers were pPRAS40, pGSK3β and Ki67 assessed by immunohistochemistry. pPRAS40 and pGSK3β were assessed by H-scores and measured separately for cytoplasmic (cyto), nuclear (nuc) and total (cyto+nuc) staining. Ki67 was assessed as % positive staining of 500 tumor nuclei. Laboratory staff were blinded to treatment arm and whether the biopsies were taken before or after AZD5363/placebo. Changes in marker expression (both absolute and %) between biopsies were calculated, and compared between the two groups. An ANOVA test was applied for normally distributed data and Wilcoxon Mann-Whitney used if not normally distributed.

Results: 28/36 patients were evaluable with patient & tumor characteristics as follows: 17 received AZD5363 and 11 placebo; the median ages were 48 & 49 years respectively. 27 patients were Caucasian and 1 African-American. Tumors were all ER+. For HER2 status 8 were positive & 9 negative in the AZD5363 treated group compared to 2 & 9 respectively in the placebo group.

For pPRAS40 and pGSK3β cyto was the predominant staining while for Ki67 staining was nuclear. Changes in each marker with associated p-values are shown in the table.

MarkerType of change vs baselineDegree of change in AZD5363 arm (n=17)p-value versus placebo arm (n=11)pPRAS40 (H-score)TotalAbsolute-83.8&lt;0.0001Total%-50.2&lt;0.0001CytoAbsolute-90.0&lt;0.0001Cyto%-55.8&lt;0.0001NucAbsolute+6.90.42Nuc%+8.90.94pGSK3β (H-score)TotalAbsolute-55.30.006Total%-39.00.006CytoAbsolute-53.60.006Cyto%-39.20.006NucAbsolute-2.80.065Nuc%-36.50.058Ki67 (% cells+)Absolute-9.60.031%-29.40.052

Conclusions• AZD5363 for 4.5 days caused highly significant falls in pGSK3β and pPRAS40, key markers of AKT pathway activation

• AZD53643 also caused a significant decline in Ki67 even after only 4.5 days of drug. This is one of the shortest 'window'-studies to report such an early effect on proliferation.

• Placebo controlled 'window' studies of this short duration can provide important evidence of the therapeutic potential early in a drug's development.

Citation Format: Robertson JFR, Coleman RE, Cheung KL, Evans A, Holcombe C, Skene A, Rea D, Ahmed S, Jahan A, Kelly S, Horgan K, Rauchhaus P, Littleford R, Foxley A, Lindemann JPO, Pass M, Rugman P, Deb R, Finlay P, Gee JMW. AZD5363, an AKT inhibitor, significantly inhibits key biomarkers of the AKT pathway and Ki67, in a randomized, placebo, controlled study (STAKT) in human breast cancers [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-04-06.

Abstract P4-15-13: When is cancer not really cancer? The PREvent ductal carcinoma in situ invasive overtreatment now (PRECISION)* initiative

Background

Ductal carcinoma in situ (DCIS) now represents 20-25% of all breast neoplasia due to large-scale detection by widely adopted population-based breast cancer screening programs. As a result, thousands of women are confronted with DCIS each year: more than 8,000 in the UK, 2,500 in the Netherlands, and some 50,000 in the US. Conventional management includes surgery, supplemented by radiotherapy and/or endocrine therapy, but overtreats the majority of DCIS as ˜1% recur annually and breast cancer mortality is ˜3% at 20 years. Uncertainty as to which DCIS lesions will progress to invasive cancer or, after excision, which will return with recurrent DCIS or invasive breast cancer drives this overtreatment. This urges us to learn how to distinguish DCIS that may progress to invasive breast cancer from the majority of indolent DCIS. Such distinction may be best achieved by synergistic international collaboration between leading global experts from various disciplines, driven by the essential input from patient voices as full members of the research team.

Aim

PRECISION (PREvent ductal Carcinoma In Situ Invasive Overtreatment Now) aims to save thousands of women with low risk DCIS the burden of intensive inappropriate treatment of DCIS (surgery, radiation therapy, hormonal therapies) through the discovery of new data and development of novel tests that promote informed and shared decision-making between patients and clinicians, without compromising the excellent outcomes for DCIS management presently achieved.

Methods

First, three large DCIS cohorts and supplementary resources will be collected enabling in depth molecular studies. Second, extensive genomic characterization, immune profiling and imaging analysis will be performed. In vivo and in vitro modeling will be performed to study the biology of DCIS in detail. Finally, all clinical, immune, and molecular data will be incorporated into a clinical risk prediction model. This risk prediction model will be validated in three prospective randomized DCIS trials in the US (COMET trial), UK (LORIS trial), and mainland Europe (LORD trial).

How the results of this research will be used

The discoveries from our laboratory studies, including a risk stratification model, will be cross-validated in three prospective trials of DCIS active surveillance versus conventional treatment (the COMET, LORIS and LORD trials). As such, the main result of this study will be that we can identify a group of women for which active surveillance for DCIS could be a safer alternative to intensive treatment. Ultimately, this may also contribute to a more reassuring perception of risk regarding non-life threatening precancerous lesions in general, reducing anxiety and preserving quality of life.

* The PRECISION Team is a Cancer Research UK Grand Challenge Award 2017 winning team and will be jointly funded by Cancer Research UK and the Dutch Cancer Society.

Citation Format: Wesseling J, Thompson A, Nik-Zainal S, Futreal A, Hwang S, Jonkers J, Lips E, Rea D, On Behalf of the PRECISION Team. When is cancer not really cancer? The PREvent ductal carcinoma in situ invasive overtreatment now (PRECISION)* initiative [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-13.

Abstract P2-09-17: Evaluation of the oncomine comprehensive assay for the identification of actionable mutations for therapeutic stratification from the TEAM pathology cohort

Large-scale sequencing initiatives have revealed a wealth of common and novel variants as well as copy-number aberrations, across different malignancies. This growing list of variants/aberrations can sometimes be matched to specific therapeutics. Such “actionable mutations/changes” hold promise for personalized treatment in the future, with treatments tailored to molecular abnormalities. Presently, women with hormone positive early breast cancer continue to experience improved survival on adjuvant anti-hormone therapy, but a significant number of women continue to progress. Therefore, there is a need to identify those women for whom current therapies are insufficient and to identify alternative therapeutic interventions. We explored the used of genetic profiling using a comprehensive solid tumor next generation sequencing (NGS) assay (the Oncomine Comprehensive Assay, OCA) to characterize early invasive breast cancer. The OCA is based on the Ion Torrent™ NGS platform and Ion AmpliSeq™ library preparation technology, coupled to the Oncomine™ Knowledgebase, for target selection, variant calling, and data annotations. The OCA includes 87 genes for hotspot mutation detection, 48 genes for full length sequencing and 43 genes for focal copy number assessment. The OCA provides a standardized informatics workflow and quality control (QC) parameters to process samples in a translational clinical research setting. To explore the application of the OCA to early invasive breast cancers, we performed a retrospective pilot study in a subset of cases from the TEAM trial. From the TEAM pathology samples, 420 were chosen in a case-control fashion, 413 samples were analyzed, 388 samples passed standard QC metrics, and 254 samples (65%) were found to contain 368 variants with Oncomine Knowledgebase annotations. Briefly, variants of PIK3CA were most frequent at 42.7% (157/368), followed by TP53 at 27.2% (100/368), PTEN at 5.7% (21/368), BRCA2 at 3.8% (14/368), SF3B1 (12/368), AKT1 (11/368) and PTCH1 (11/368) at 3.3%, 3.0%, 3.0%; respectively. Other variants were detected in ATM, ERBB2, RB1, FGFR2, NF1, CDKN2A, PIK3R1 and others. Amongst the 43 genes assessed for copy-number, 23 showed copy-number changes across 132 samples totalling 167 CNVs. 256 samples showed no copy-number alterations in any of the genes on the panel. ERBB2 was most frequently altered at 28.1% (47/167), followed by FGFR1 at 23.4% (39/167), CCND1 at 15.0% (25/167) and MDM2 at 10.2% (17/167). Copy-number losses were identified in TP53, RB1, PTEN, BRCA2 at 0.6% each; as well as CDKN2A at 1.8% (3/167). Analytical validation of a subset of gene variants and copy-number changes will be presented in addition to the evidence of potential future application of the Oncomine Comprehensive Assay to precision oncology goals.

Citation Format: Bayani J, Crozier C, Quintayo MA, Amemiya Y, Zhang X, Larivière M, Sadis S, Smith JM, Hasenburg A, Kieback D, Markopoulos C, Dirix L, Yaffe M, Seth A, Feilotter H, Rea D, Bartlett JMS. Evaluation of the oncomine comprehensive assay for the identification of actionable mutations for therapeutic stratification from the TEAM pathology cohort [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-17.

Leukemic stem cell persistence in chronic myeloid leukemia patients in deep molecular response induced by tyrosine kinase inhibitors and the impact of therapy discontinuation

During the last decade, the use of tyrosine kinase inhibitor (TKI) therapy has modified the natural history of chronic myeloid leukemia (CML) allowing an increase of the overall and disease-free survival, especially in patients in whom molecular residual disease becomes undetectable. However, it has been demonstrated that BCR-ABL1- expressing leukemic stem cells (LSCs) persist in patients in deep molecular response. It has also been shown that the discontinuation of Imatinib leads to a molecular relapse in the majority of cases. To determine a possible relationship between these two phenomena, we have evaluated by clonogenic and long-term culture initiating cell (LTC-IC) assays, the presence of BCR-ABL1-expressing LSCs in marrow samples from 21 patients in deep molecular response for three years after TKI therapy (mean duration seven years). LSCs were detected in 4/21 patients. Discontinuation of TKI therapy in 13/21 patients led to a rapid molecular relapse in five patients (4 without detectable LSCs and one with detectable LSCs). No relapse occurred in the eight patients still on TKI therapy, whether LSCs were detectable or not. Thus, this study demonstrates for the first time the in vivo efficiency of TKIs, both in the progenitor and the LSC compartments. It also confirms the persistence of leukemic stem cells in patients in deep molecular response, certainly at the origin of relapses. Finally, it emphasizes the difficulty of detecting residual LSCs due to their rarity and their low BCR-ABL1 mRNA expression.

How I manage relapse of chronic myeloid leukaemia after stopping tyrosine kinase inhibitor therapy

During the last 10 years, clinical trials formally demonstrated that about 50% of patients with chronic phase (CP) chronic myeloid leukaemia (CML) who achieve and maintain deep molecular responses for a prolonged period of time during treatment with imatinib or new generation tyrosine kinase inhibitors (TKIs) may successfully stop their anti-leukaemic therapy. Based on the accumulated knowledge from abundant clinical trial experience, TKI discontinuation is becoming an important goal to achieve and is about to enter clinical practice. This review focuses on relapse definition, laboratory tests to identify relapse and relapse management after TKI discontinuation.

Ponatinib in chronic myeloid leukemia (CML): Consensus on patient treatment and management from a European expert panel

Five tyrosine kinase inhibitors (TKIs) are currently approved in the European Union for treatment of chronic myeloid leukemia (CML) and all have considerable overlap in their indications. While disease-specific factors such as CML phase, mutational status, and line of treatment are key to TKI selection, other important features must be considered, such as patient-specific comorbidities and TKI safety profiles. Ponatinib, the TKI most recently approved, has demonstrated efficacy in patients with refractory CML, but is associated with an increased risk of arterial hypertension, sometimes severe, and serious arterial occlusive and venous thromboembolic events. A panel of European experts convened to discuss their clinical experience in managing patients with CML. Based on the panel discussions, scenarios in which a CML patient may be an appropriate candidate for ponatinib therapy are described, including presence of the T315I mutation, resistance to other TKIs without the T315I mutation, and intolerance to other TKIs.