PEARL Trial Research Articles

Abstract PO1-15-10: Lower pre-treatment B-cell gene expression signatures correspond with improved overall survival with palbociclib + endocrine therapy in HR+/HER2- metastatic breast cancer: a biomarker analysis from the GEICAM/2013-02 PEARL trial

Abstract Introduction: CDK4/6 inhibitors (CDK4/6i) with endocrine therapy (ET) is standard-of-care for HR+/HER2- metastatic breast cancer (MBC), but little is known about which gene expression and microenvironment features are associated with benefit from CDK4/6i or differentiate response compared to chemotherapy. We examined the relationship of gene expression signatures (GES) to progression-free (PFS) and overall survival (OS) in the GEICAM/2013-02 PEARL phase III randomized study of palbociclib + ET vs. capecitabine in aromatase inhibitor-resistant HR+/HER2- MBC (NCT02028507). Methods: RNA sequencing (RNAseq) was performed on baseline tumor samples from 328 patients. Intrinsic subtype was derived by the PAM50 predictor after HER2/estrogen receptor subgroup-specific normalization. Correlations to intrinsic subtype signatures, PAM50 proliferation signature, CCNE1 expression, and 10 GES were selected for analysis. After excluding 15 Normal-like samples, Cox models were fitted for PFS and OS endpoints on each selected variable for the combined study population as well as for each treatment arm, adjusted for disease site, prior ET sensitivity, prior chemotherapy for MBC, number of involved sites, treatment arm, and intrinsic subtype. P-values were adjusted based on the Bonferroni method, with an adjusted p-value < 0.05 defined as significant. Results: PAM50 intrinsic subtype (54.95% Luminal A, 38.98% Luminal B and 6.07% non-luminal (4.79% Her2-enriched and 1.28% Basal-like)) was associated with worse PFS with palbociclib + ET for non-luminal vs. Luminal A tumors (HR 3.19, 95% CI 1.65-6.16) and for Luminal B vs. Luminal A tumors (HR 1.90, 95% CI 1.28-2.82). PAM50 luminal status (Luminal A vs. Luminal B vs. non-luminal) was significantly associated with PFS with palbociclib + ET (p=0.0003) but not capecitabine (p=0.89). In the palbociclib + ET arm, lower expression of two B-cell-associated signatures (BCAS) correlated with improved OS - the Immune1 TCGA BRCA GES (PMID: 32573490) (HR 1.52, 95% CI 1.20-1.92, p=0.009) and the B-cell/T-cell cooperativity GES (PMID: 31730857) (HR 1.42, 95% CI 1.14-1.79, p=0.04). Interaction analysis for OS showed that when stratified by low and high expression using the median, the Immune1 TCGA BRCA GES had a significant interaction with treatment arm (p=0.014). On comparison of outcomes between treatment arms, low Immune1 TCGA BRCA GES expression was significantly associated with improved OS with palbociclib + ET compared to capecitabine (HR 0.44, 95% CI 0.26-0.74, p=0.03), whereas high expression was not associated with a significant OS difference (HR 1.73, 95% CI 1.07-2.79, p=0.40). Further exploratory analysis of 164 immune GES found that, after adjustment for confounders, the top eight GES associated with OS with palbociclib + ET were BCAS (unadjusted p-values < 0.005), including our pre-selected Immune1 TCGA BRCA and B-cell/T-cell cooperativity GES, and all eight negatively correlated with OS. In the capecitabine arm, this exploratory analysis failed to demonstrate a similar association between the immune GES and OS. Conclusion: PAM50 intrinsic subtype was significantly associated with PFS with second-line palbociclib + ET. Lower expression of BCAS was associated with improved OS outcomes with palbociclib + ET independent of intrinsic subtype, and for the Immune1 TCGA BRCA GES, lower expression corresponded with improved OS with palbociclib + ET compared to capecitabine. This informs recent findings that in HR+/HER2- breast cancer, tumor immune activity may be a negative predictor of CDK4/6i benefit. Citation Format: Yash Agrawal, Aranzazu Fernandez-Martinez, Miguel Gil-Gil, Christoph Zielinski, Manuel Ruíz- Borrego, Eva Ciruelos, Montserrat Muñoz, Mireia Margelí, Begoña Bermejo, Antonio Antón, Zsuzsanna Kahan, Tibor Csöszi, José L Alonso-Romero, Jose Angel García-Sáenz, Pedro Sánchez-Rovira, Elena Álvarez, J. Ignacio Chacón, Santiago González-Santiago, César A Rodríguez, Sonia Servitja, Adam D. Pfefferle, Jesús Herranz, Yuan Liu, Lisa A. Carey, Isabel Romero - Camarero, Rosalía Caballero, Charles M. Perou, Miguel Martín. Lower pre-treatment B-cell gene expression signatures correspond with improved overall survival with palbociclib + endocrine therapy in HR+/HER2- metastatic breast cancer: a biomarker analysis from the GEICAM/2013-02 PEARL trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-15-10.

Abstract PO1-04-10: Body Mass Index and Treatment Efficacy in advanced Luminal Breast Cancer: Insights from the GEICAM/2013-02 (PEARL) trial

Abstract Background: Endocrine therapy (ET) and treatment directed against molecular targets (CDK 4/6, PI3K, mTOR) constitute the basis of initial treatments for patients with advanced luminal breast cancer. Most of these treatments are oral and have been developed at a fixed dose, without weight adjusted dosing. There is little evidence on the influence that patients’ weight might have on clinical outcomes of these oral drugs in the context of a randomized clinical trial. The present study analyzes the potential impact of the weight of patients treated in the two cohorts of the PEARL trial (NCT02028507) on Progression-Free Survival (PFS), Overall Survival (OS) and the incidence of side effects in each treatment arm. Methods: GEICAM/2013-02 (PEARL) is a multicenter, phase III randomized clinical trial that enrolled patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer (MBC) who progressed to a prior aromatase inhibitor. Patients were randomized 1:1 to receive ET + palbociclib or capecitabine. Patient weight was assessed based on baseline body mass index (BMI) categories: normal (BMI ≤25 Kg/m2), overweight (BMI 25-29.9 Kg/m2) and obesity (BMI ≥30 Kg/m2). Cox's stratified proportional hazard model was used for survival analysis. Adverse events were assessed and graded according to National Cancer Institute common terminology criteria for adverse events (NCI-CTCAE) version 4.0. Results: A total of 600 patients were included in the study and all were evaluable for the weight-based analysis, including 301 in the ET +palbociclib arm and 299 in the capecitabine arm. The distribution of patient’s weights is shown in Table 1. For the Intention-to-treat (ITT) population, no significant difference in the median OS was found between the different weight categories (Normal: 32.8 months vs overweight: 31.9 months, [p=0.467]; obese: 32 months [p=0.407]). Specifically, for patients with normal weight, the median PFS was 9.3 months in the ET + palbociclib group compared to 9.0 months in the capecitabine group (hazard ratio (HR) 0.83, 95% confidence interval [CI]: 0.61-1.13; p=0.23). In the overweight group, the PFS was 7.5 months in the ET+palbociclib group and 11.1 months in the capecitabine group (HR 1.17, 95% CI: 0.87-1.58; p=0.30) while for the obese group, the PFS was 5.7 months vs 11.7 months (HR 1.14, 95% CI: 0.82-1.59; p=0.43), respectively. No substantial differences in the incidence of grade ≥ 3 events were observed when considering weight categories in the different treatment groups (capecitabine arm (Normal: 60%, Overweight: 70.4%, Obese: 61.6%) and ET+palbociclib arm (Normal: 74.5%, Overweight: 76.1%, Obese: 51.6%). Conclusions: Our findings, despite not finding statistically significant differences, suggest a potentially clinically relevant trend towards improved PFS with capecitabine in overweight and obese patients compared to those receiving palbociclib plus ET. The impact of weight on the outcomes with fixed-dose oral drugs warrants further investigation in future studies. Table 1. Citation Format: Manuel Alva, Sara López-Tarruella, Christoph Zielinski, Manuel Ruíz - Borrego, Nicholas Turner, Eva Ciruelos, Montserrat Muñoz, Begoña Bermejo, Mireia Margelí, Antonio Antón, Zsuzsanna Kahan, Tibor Csöszi, Maribel Casas, Laura Murillo, Serafin Morales Murillo, Emilio Alba, Einav Nili-Gal Yam, Angel Guerrero, Lourdes Calvo, Juan de la Haba-Rodríguez, Manuel Ramos, Isabel Álvarez, Andrés García-Palomo, María Koehler, José Ángel García-Sáenz, J. Ignacio Chacón, Claire Swift, Christiane Thallinger, Miguel Gil-Gil, Miguel Martín. Body Mass Index and Treatment Efficacy in advanced Luminal Breast Cancer: Insights from the GEICAM/2013-02 (PEARL) trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-04-10.

Baseline mutations and ctDNA dynamics as prognostic and predictive factors in ER-positive/HER2-negative metastatic breast cancer patients.

Prognostic and predictive biomarkers to CDK4/6 inhibitors are lacking. Circulating tumour DNA (ctDNA) can be used to profile these patients and dynamic changes in ctDNA could be an early predictor of treatment efficacy. Here, we conducted plasma ctDNA profiling in patients from the PEARL trial comparing palbociclib+fulvestrant versus capecitabine to investigate associations between baseline genomic landscape and on-treatment ctDNA dynamics with treatment efficacy. Correlative blood samples were collected at baseline (C1D1) and prior to treatment (C1D15). Plasma ctDNA was sequenced with a custom error-corrected capture panel, with both univariate and multivariate Cox models used for treatment efficacy associations. A pre-specified methodology measuring ctDNA changes in clonal mutations between C1D1 and C1D15 was used for the on-treatment ctDNA dynamic model. 201 patients were profiled at baseline, with ctDNA detection associated with worse PFS/OS. Detectable TP53 mutation showed worse PFS and OS in both treatment arms, even after restricting population to baseline ctDNA detection. ESR1 mutations were associated with worse OS overall, which was lost when restricting population to baseline ctDNA detection. PIK3CA mutations confer worse OS only to patients on the palbociclib+fulvestrant treatment arm. ctDNA dynamics analysis (n=120) showed higher ctDNA suppression in the capecitabine arm. Patients without ctDNA suppression showed worse PFS in both treatment arms. We show impaired survival irrespective of endocrine or chemotherapy-based treatments for patients with HR+/HER2- MBC harbouring plasma TP53 mutations. Early ctDNA suppression may provide treatment efficacy predictions. Further validation to fully demonstrate clinical utility of ctDNA dynamics is warranted.

Cyclin E cytoplasmatic isoform to predict outcome and benefit to capecitabine treatment in patients with HR+/HER2- metastatic breast cancer from the GEICAM/2013-02 PEARL study.

1023 Background: Cytoplasmic cyclin E protein expression, serving as a surrogate for the low molecular weight cyclin E isoform (LMW-E), is a biomarker associated with aggressive breast cancer and predicts resistance to aromatase inhibitors in luminal breast cancer. We investigated the prognostic and predictive value of cytoplasmic and nuclear isoforms of cyclin E in HR+/HER2- metastatic breast cancer (MBC) patients receiving palbociclib CDK4/6 inhibitor and endocrine therapy (PALBO+ET) versus capecitabine (CAPE) in the GEICAM/2013-02 PEARL trial (NCT02028507). Methods: Expression of Cytoplasmic and Nuclear isoforms of cyclin E were assessed by immunohistochemistry (IHC). An H-score based on the proportion and intensity of stained cells was explored using median value to categorize in Low / High expression the Nuclear and Cytoplasmic scores (N and C, respectively). In addition, N and C were independently assigned according to staining intensity (1 = no staining, 2 = weak, 3 = intermediate and 4 = strong staining) and then, combined in 4 phenotypes (Ph): Ph1 (N-/C-); Ph2 (N+/C-); Ph3 (N+/C+); and Ph4 (N-/C+), where negative=1-2, and positive=3-4. Cox regression models’ analysis were assessed to predict outcome and benefit to treatment, in terms of PFS and OS. Multivariate models were adjusted for confounders: age, site of disease, sites of metastasis, prior chemotherapy for MBC and treatment. Interaction analysis with treatment arm were performed. Results: Cyclin E protein was obtained from 344 tumors, with 73% being primary tumors and 27% metastatic. High expression of the Nuclear isoform was independently associated with significantly worse OS (median OS [mOS]=34.23 months [m] for low expression vs 25.72m for high expression; adjusted HR=1.48; p-value=0.016). Phenotype analysis supported this finding, with Ph3 (N+/C+) and Ph4 (N-/C+) demonstrating the worst (mOS=19.55m) and best (mOS=37.19m) outcomes, respectively (using Ph1 as reference, Ph3 HR=2.92; p-value=0.0013). The interaction between the treatment arm and Cytoplasmic cyclin E expression was significant (p=0.0052). Patients with high expression of the Cytoplasmic isoform had significantly better PFS with CAPE (mPFS=14.8m) than with PALBO + ET (mPFS=5.73m) (HR=1.9, p-value=0.0418). Ph4 (N-/C+) had also significantly better PFS for CAPE (mPFS=22.67m) than for PALBO + ET (mPFS=8.51m) (HR=2.94; p-value=0.036). Conclusions: This study confirms Cyclin E as a poor prognostic marker associated with worse overall survival in luminal MBC patients. Low molecular weight Cyclin E, detected as Cytoplasmic Cyclin E, identifies luminal MBC that benefit more from CAPE than from PALBO + ET. The low molecular weight Cyclin E isoform appears to be a promising predictive biomarker for the benefit of CAPE and resistance to PALBO + ET treatments in this population. Clinical trial information: NCT02028507 .

FDG PET-CT for response-adapted radiotherapy planning in HPV+ oropharyngeal SCC: Initial experience from the PEARL trial

Category: Head and neck

Baseline and longitudinal ctDNA biomarkers in GEICAM/2013-02 (PEARL) trial cohort 2 comparing palbociclib and fulvestrant (PAL + FUL) versus capecitabine (CAPE).

1019 Background: The randomized PEARL trial found no superiority of PAL plus endocrine therapy over CAPE in patients (pts) with metastatic HR-positive, HER2-negative breast cancer resistant to aromatase inhibitors (Martin M, Ann Oncol 2020). We investigated associations between baseline genomic landscape and on-treatment plasma ctDNA dynamics with progression free survival, in pts from cohort 2 of the trial. Methods: Plasma was collected for ctDNA analysis from -7 days to cycle 1-day 1 (C1D1) for baseline prognostic analysis and cycle 1-day 15 (C1D15) when available, and sequenced with an in-house error-corrected targeted capture panel encompassing 21 genes commonly altered in breast cancer. For predictive ctDNA dynamics analysis, a pre-specified criteria of 14 minimum days of treatment in first cycle was required and variants with VAF <0.5% in C1D1, set as limit of detection, were excluded. The circulating DNA ratio (CDR) was calculated as a weighted mean for potentially clonal mutations at C1D1. The optimal cut-off for predicting PFS was assessed by fitting a range of cut-offs, identifying the one with lower p-value on the log-rank test. Adjusted p-values, potential overestimation corrected by a shrinkage factor and bootstrapping techniques to calculate the CI95% were used in the cutpoint Cox regression model. Results: A total of 201 pts had a C1D1 sample sequenced for baseline prognostic analysis, 146 (73%) had baseline mutations identified and 55 (27%) had no mutations. 187 (93%) pts had a paired C1D15 sample for CDR calculations. Of these, 134 (72%) had baseline mutations detected, 120 of them (90%) above 0.5%, 14 (10%) had no calls, 1 pair failed sequencing. Both baseline and CDR subsets were representative of the overall study population. Pts with TP53 mutations had worse PFS in the overall population (4.4 vs 9.3 months, logrank p= 0.04), with no differences between treatments. For on-treatment ctDNA dynamic analysis, median CDR (suppression) was lower in the CAPE arm (0.07 vs 0.21, p<0.01). There was an association between optimal cut-offs predicting PFS both in CAPE (suppressed 16.6 months vs high ctDNA 4.2 months, HR 2.37, CI95% 0.96-5.83, p=0.05) and PAL + FUL arms (suppressed 15.7 months vs high ctDNA 5.5 months, HR 2.14, CI95% 0.92-5, p=0.06). More ctDNA suppression associated with likelihood of objective responses (median CDR 0.1 in objective responders vs median CDR 0.2 in progressive disease p=0.03), with no statistical significance when stratified per treatment. Conclusions: In PEARL cohort 2, TP53 mutations associated with poor outcome regardless of treatment allocation, suggesting aggressive behaviour not specifically linked to endocrine resistance. Lack of ctDNA suppression associated with worse outcome in both patient groups. Capecitabine resulted in greater ctDNA suppression at C1D15, likely reflecting faster ctDNA suppression.

Abstract PD10-01: The PEARL trial: Pre-operative pembrolizumab with radiation therapy in early stage triple negative breast cancer

Abstract Background: Anti-PD(L)1 in addition to neoadjuvant chemotherapy (NAC) can achieve pathologic complete response (pCR) rates of up to 65% in patients with early stage triple negative breast cancer (TNBC). However, patients with non-pCR can have dismal prognosis. Innovative strategies that render the tumor microenvironment more sensitive to anti-PD(L)1 may confer benefit. Preclinical studies have shown that hypofractionated radiation therapy (RT) delivered to an in-situ breast tumor, when combined with immune checkpoint blockade, stimulates anti-tumor immune responses and induces long-term, tumor-specific memory. Here, we report the first results of a phase II study that established the feasibility and efficacy of this approach in the pre-operative treatment setting for TNBC. Methods: Fifty patients with stage I-III TNBC, defined as ER<10%,PR<10%, HER2-negative, were enrolled between 12/17-4/21. Study treatment consisted of one cycle (C1) of pembro (200 mg iv q 3wks), followed by cycle 2 (C2) of pembro + RT (24Gy) delivered to a breast primary, followed by NAC regimen per MD choice, surgery and adjuvant therapy. Paired tumor biopsies and blood were collected at 3 serial time points: 1) baseline (pre-treatment); 2) after pembro C1; 3) after pembro C2 + RT (prior to initiation of NAC). All patients received breast and axillary surgery and postoperative RT to the chest wall and regional lymph nodes. Dual primary endpoints were: 1) feasibility, defined by the number of patients who did not necessitate a >4-week delay in initiating NAC after pembro C2 + RT; 2) change in tumor infiltrating lymphocyte (TIL) score. Secondary endpoints included pCR, defined as ypT0/TisypN0, in addition to toxicity and cosmesis evaluations. Results: To date, 50 patients are evaluable with a median follow up of 12 months (range 6-12). Median age of cohort is 55y (range 26-76). The majority (92%) were clinical stage II; 2% stage I and 6% stage III. 34% of the cohort had biopsy-proven, node positive disease. All patients received a taxane, 52% carboplatin and 74% anthracycline. 12% did not complete the planned course of NAC due to toxicities. No patients experienced a delay in initiating NAC. 50% received breast-conserving surgery and 50% mastectomy. Grade 1 or 2 toxicities consisted of fatigue (76%), nausea (66%), maculopapular rash (32%), diarrhea (38%), colitis (2%), hypothyroidism (8%) and peripheral neuropathy (40%). Four patients had grade 3 toxicities that were attributable to pembro: hyponatremia(1), colitis (1), adrenal insufficiency(1) and pneumonitis (1). Three patients had grade 4 neutropenia which were not attributable to pembro. The overall rate of pCR was 74% (37/50). Among the 13 patients with non-pCR, 0% were RCB 1, 16% RCB 2 and 10% RCB 3. Among the 17 N+ patients, 13 converted to ypN0, 1 ypN1mic and 3 ypN1a. No patients progressed during treatment. Changes in TIL count, PD-L1 and other biomarkers after pembro +/- RT and their association with treatment response, will be presented at the meeting. Conclusions: The novel combination of pre-operative pembro followed by the addition of RT to pembro prior to NAC is not only feasible, but also achieves pCR rates that are higher-than-expected compared to the pembro arm of KEYNOTE-522. AEs were consistent with known safety profiles of each agent. If confirmed by larger, randomized studies, this combination will be paradigm-changing for the treatment of TNBC. Citation Format: Heather L McArthur, Stephen Shiao, Scott Karlan, Reva Basho, Farin Amersi, Michele Burnison, Amin Mirhadi, Alice Chung, Cathie T Chung, Catherine Dang, Heather Richardson, Armando E Giuliano, Nimmi Kapoor, Brigid Larkin, Hector Godinez, Samantha A Dunn, Negin Habibi Khameneh, Simon Knott, Philomena McAndrew, Monica Mita, Dorothy J Park, Christina Abaya, Jonathan H Chen, Amy Ly, Veerle Bossuyt, Alice Ho. The PEARL trial: Pre-operative pembrolizumab with radiation therapy in early stage triple negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD10-01.

FDG positron emission tomography imaging and ctDNA detection as an early dynamic biomarker of everolimus efficacy in advanced luminal breast cancer

Biomarkers to identify patients without benefit from adding everolimus to endocrine treatment in metastatic breast cancer (MBC) are needed. We report the results of the Pearl trial conducted in five Belgian centers assessing 18F-FDG-PET/CT non-response (n = 45) and ctDNA detection (n = 46) after 14 days of exemestane-everolimus (EXE-EVE) to identify MBC patients who will not benefit. The metabolic non-response rate was 66.6%. Median PFS in non-responding patients (using as cut-off 25% for SUVmax decrease) was 3.1 months compared to 6.0 months in those showing response (HR: 0.77, 95% CI: 0.40–1.50, p = 0.44). The difference was significant when using a “post-hoc” cut-off of 15% (PFS 2.2 months vs 6.4 months). ctDNA detection at D14 was associated with PFS: 2.1 months vs 5.0 months (HR-2.5, 95% CI: 1.3–5.0, p = 0.012). Detection of ctDNA and/or the absence of 18F-FDG-PET/CT response after 14 days of EXE-EVE identifies patients with a low probability of benefiting from treatment. Independent validation is needed.

CCNE1 mRNA and cyclin E1 protein expression as predictive biomarkers for efficacy of palbociclib plus fulvestrant versus capecitabine in the phase III PEARL study.

1014 Background: The randomized PEARL trial found no superiority of palbociclib plus endocrine therapy over capecitabine in patients (pts) with metastatic HR-positive, HER2-negative breast cancer resistant to prior aromatase inhibitors (Martin M, Ann Oncol 2020). Gene expression analysis showed high CCNE1 mRNA ( CCNE1) conferring relative resistance to palbociclib in the PALOMA-3 trial (Turner N, JCO 2019), but further validation is needed. Cyclin E1 protein (cyclin E1) expression in this context has not been studied in randomized trials. We explored CCNE1 and cyclin E1 as predictive biomarkers in tumor samples from the PEARL study. Methods: Formalin-fixed paraffin-embeded tumor samples were retrieved from pts enrolled in PEARL cohort 2 (palbociclib (PAL) + fulvestrant (FUL) vs capecitabine (CAPE)). We measured CCNE1 using the HTG EdgeSeq Oncology Biomarker Panel (HTG Molecular Diagnostics). Cyclin E1 immunohistochemistry (IHC) staining was performed using specific mouse monoclonal antibody HE12 (Abcam) and scored as percentage of invasive nuclei stained (0-100%). CCNE1 and cyclin E1 correlations were explored using Pearson coefficients. Cox regression models were used for progression free-survival (PFS) analyses using expression levels split by median, to define high ( > median values) vs. low expression. Site of disease and prior chemotherapy were used as confounders in multivariate models. Results: Analyses were conducted in 219 pts (47% receiving PAL + FUL and 53% CAPE) with available tumors, with the analysed patients representative of the overall study. Most samples were from the archival primary (72%), obtained > 5 years before this analysisº (74%). CCNE1 and cyclin E1 were only moderately correlated (r = 0.5). Median CCNE1 was higher in metastatic vs primary (7.37 vs 6.94, p < 0.01), and in luminal B and non-luminal subtypes compared to luminal A (p < 0.001). In patients with high CCNE1 expression, median PFS on CAPE was 10.35 and PAL + FUL was 5.68 (HR = 1.63, 95% CI 1.02-2.59, p = 0.042). In patients with low CCNE1 expression, median PFS on CAPE was 9.43 and PAL + FUL was 8.97 (adjusted HR = 0.93, 95% CI 0.59-1.48, p = 0.762, interaction p = 0.072). Median cyclin E1 protein was higher in luminal B and non-luminal subtypes compared to luminal A (p < 0.01). Cyclin E1 protein expression was not predictive of treatment effect (high cyclin E1 expression CAPE vs PAL + FUL HR = 1.17, low cyclin E1 expression CAPE vs PAL + FUL HR = 1.21, interaction p = 0.977). Conclusions: High tumor CCNE1 mRNA expression identified patients with relative resistance to palbociclib plus fulvestrant, validating prior observations although without statistical significance for interaction. Assessment of Cyclin E1 protein expression did not show predictive value. Investigation treatments to enhance CDK4/6 inhibitor efficacy in tumors with high CCNE1 expression is warranted. Clinical trial information: NCT02028507 .

Abstract PS2-01: Plk1 expression & efficacy of palbociclib in advanced hormonal receptor-positive breast cancer patients from PEARL study (GEICAM 2012-03)

Abstract Background: CDK 4/6 inhibitors (CDK 4/6i) with endocrine therapy (ET) combination therapy have improved outcomes in patients (pts) with hormonal receptor positive (HR+)/human epidermal growth factor receptor negative (HER2-) advanced breast cancer (ABC). However, most pts eventually develop resistance to these drugs, and one third never respond. Aside from HR positivity, predictive markers of clinical benefit from CDK 4/6i remains elusive. We aimed to identify biomarkers of response to palbociclib (PAL) and analyze potential therapeutic targets to reverse resistance. Methods: PEARL trial is a multicenter phase 3 study that assigned 601 postmenopausal HR+/HER2- ABC pts, whose disease progressed on aromatase inhibitors (AIs), to receive PAL + ET vs capecitabine (CAPE). We performed a differential gene expression analysis in pre-treatment tumors in extreme responders to PAL using the HTG EdgeSeq Oncology Biomarker Panel (HTG Molecular Diagnostics, Inc.), containing 2534 cancer related genes. Samples were subset in 2 categories: refractory (progressive disease as best response) vs sensitive (progression-free survival (PFS) within the upper quartile). Cox regression and Significance Analysis of Microarrays (SAM) analysis adjusting for multiple comparisons were performed. Results: We analyzed 455 (75.7%) pts with pre-treatment tumors available [from them, PAL + ET arm: 229 (50.3%) pts; CAPE arm: 226 (49.7%) pts]. Fifty genes (false discovery rate (FDR)<0.05) were differentially expressed in pts sensitive vs refractory to PAL (E2F target genes, epithelial-to-mesenchymal transition (EMT) and cell cycle genes, mainly). Unsupervised hierarchical clustering of pts based on the expression of these genes revealed two clusters. Cluster 1 is composed mostly of resistant tumors, highly proliferative (Ki67≥20%: 70%) with a great proportion of luminal B (59%) and non-luminal tumors (19%). Cluster 2 is composed of sensitive, low proliferative (Ki67<20%: 58%), mostly luminal A tumors (75%). There was no difference in ESR1 mutations distribution between the two clusters (Table 1). Forty genes were up-regulated and associated with resistance, including CCNE1 and PLK1 (Polo Like Kinase 1). In the whole cohort, pts with high levels (> median) of PLK1 (PLK1-high) treated with PAL, had a worse PFS in a multivariate model (5.7 months (m) vs 9.3 m of median PFS in PLK1-High vs -Low; HR=1.64, 95% CI (1.25-2.34), p=0.0008; adjusted model for confounders: age, site of disease, sites of metastasis, prior chemotherapy and Ki67). There were no differences in population treated with CAPE (9.9 m vs 9.4 m, PLK1-High vs -Low; HR=0.82, 95% CI (0.56-1.21), p=0.3189). In the METABRIC cohort, PLK1-High was associated with worse overall survival in HR+/HER2- BC but not in triple negative nor in HER2+ tumors. Among HR+/HER2- tumors, PLK1 expression was higher in luminal B and HER2-enriched intrinsic subtypes. We interrogated DepMap database and found that in BC cells lines there was an inverse correlation between PLK1 expression and effect on cell viability of CDK4 CRISPR knock-out (Pearson correlation r:0.54, p=0.009), but not of CDK6 knock-out. Also, HR+/HER2-/High Ki67 BC cell lines (HCC1428, EFM19 and MCF7) showed resistance to PAL on cell proliferation assays but sensitivity to the PLK1 inhibitor BI-2536. Conclusion: High expression of PLK1 is associated with intrinsic resistance to PAL and ET, this might be overcome with PLK1 inhibition. Table 1PATIENT CHARACTERISTICSCluster 1Cluster 2ALLn=57n=47n=104RespondersSensitive42 (73.68%)14 (29.79%)56 (53.85%)Refractory15 (26.32%)33 (70.21%)48 (46.15%)ESR1Mutated9 (15.79%)13 (27.66%)22 (21.15%)Wild type45 (78.95%)34 (72.34%)79 (75.96%)Unknown3 (5.26%)0 (0%)3 (2.88%)PriorQTN42 (73.68%)31 (65.96%)73 (70.19%)Y15 (26.32%)16 (34.04%)31 (29.81%)SubtypeLumA43 (75.44%)10 (21.28%)53 (50.96%)LumB14 (24.56%)28 (59.57%)42 (40.38%)Non Luminal0 (0%)9 (19.15%)9 (8.65%)MetastasisOne21 (36.84%)15 (31.91%)36 (34.62%)Multiple36 (63.16%)32 (68.09%)68 (65.38%)KI67 20%KI67<2033 (57.89%)7 (14.89%)40 (38.46%)KI67≥2016 (28.07%)33 (70.21%)49 (47.12%)Unknown8 (14.04%)7 (14.89%)15 (14.42%)Objective ResponseComplete1 (1.75%)0 (0%)1 (0.96%)Partial16 (28.07%)6 (12.77%)22 (21.15%)Progressive15 (26.32%)33 (70.21%)48 (46.15%)Stable25 (43.86%)8 (17.02%)33 (31.73%) Citation Format: Angel Guerrero- Zotano, Christoph Zielinski, Miguel Gil-Gil, Manuel Ruiz-Borrego, Eva M. Ciruelos, Montserrat Munoz, Begoña Bermejo, Mireia Margeli, Antonio Antón, Tibor Csöszi, Andrés García-Palomo, Ana Santaballa, Jose Luis Alonso, Antonio Fernández, Massimo Corsaro, Jesús Herranz, Paula López, Rosalia Caballero, Christiane Thallinger, Miguel Martin. Plk1 expression & efficacy of palbociclib in advanced hormonal receptor-positive breast cancer patients from PEARL study (GEICAM 2012-03) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS2-01.

Prevention of hepatic encephalopathy by administration of rifaximin and lactulose in patients with liver cirrhosis undergoing placement of a transjugular intrahepatic portosystemic shunt (TIPS): a multicentre randomised, double blind, placebo controlled trial (PEARL trial)

IntroductionCirrhotic patients with portal hypertension can suffer from variceal bleeding or refractory ascites and can benefit from a transjugular intrahepatic portosystemic shunt (TIPS). Post-TIPS hepatic encephalopathy (HE) is a common...

Abstract P1-19-22: Pearl or the use of FDG positron emission tomography imaging as an early dynamic biomarker of everolimus efficacy in advanced luminal breast cancer

Abstract Background: The combination of everolimus and an endocrine agent has shown a progression-free survival (PFS) benefit but also significant toxicity in locally advanced and/or metastatic breast cancer (MBC) patients. Disappointingly, all translational research efforts conducted so far on primary/metastatic tissue or baseline ctDNA samples have failed to identify clinically useful biomarkers of benefit with the possible exception of p4EBP1 which requires fresh metastatic biopsies (Bachelot at al, ASCO 2019). Methods: Forty-seven patients were included in the PEARL trial in six Belgian centres. All patients underwent one baseline and one “early” 18FDG-PET/CT on day 14 (blinded to the treating oncologist) after treatment initiation. Eligible patients had prior progression on NSAI and at least one measurable lesion on baseline 18FDG-PET/CT (fulfilling PERCIST). Twenty seven of the 47 patients were treated in a pilot phase aiming to characterize 18FDG-PET/CT metabolic responses 14 and 28 days after treatment initiation. Day 14 18FDG-PET/CT was selected for the second phase in which 20 more patients were included to answer the primary endpoint of the trial, namely the potential of an early FDG-PET/CT to select patients who will not derive a long-term benefit from everolimus-exemestane combination. We considered as “metabolic responders” those patients in whom at least a 25% homogenous decrease in SUVmax was seen in all their target lesions; the so called “consistent” patient-based response, here correlated to PFS. Results: Seventy-four percent of the patients had visceral metastasis, 26% were pretreated with CDK 4/6 inhibitors and 58% with at least one line of chemotherapy (28% ≥ 2 lines) for the treatment of MBC. Metabolic non-response rate on day 14 was 64%. Two patients were considered non-evaluable because they stopped everolimus 3 and 8 days before early 18FDG-PET/CT respectively. The median PFS in non-responding patients was 2.3 months compared to 6 months in those who showed a consistent metabolic response (HR-1.96, 95%CI: 0.98-3.95, p=0.05). We’ll be able to assess whether day 14 ctDNA measurements add predictive value to imaging. Conclusion: Absence of 18FDG-PET/CT metabolic response after 14 days of everolimus-exemestane combination is associated with a low probability to derive benefit from this treatment. The advanced stage of the patients included in this trial (75% visceral metastasis) and their extensive prior treatments can explain the poorer outcome seen with exemestane-everolimus compared to the Bolero2 trial. Citation Format: Andrea Gombos, Martine Piccart-Gebhart, Lieveke Ameye, Peter Vuylsteke, Patrick Neven, Vincent Richard, Francois P Duhoux, Marianne Paesmans, Michail Ignatiadis, Patrick Flamen, Géraldine Gebhart. Pearl or the use of FDG positron emission tomography imaging as an early dynamic biomarker of everolimus efficacy in advanced luminal breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-19-22.

488P - Randomized trial of prophylactic minocycline for erlotinib-associated skin rash in non-small cell lung cancer (PEARL trial)

BackgroundAcneiform rash as an adverse event often affects the treatment by EGFR-TKIs. Since minocycline has been suggested to reduce the rash, we assessed the efficacy and safety of prophylactic administration of minocycline simultaneously during erlotinib treatment. MethodsPatients of ECOG performance status 0-2 with advanced NSCLC, who had not been treated with EGFR-TKIs and would receive erlotinib treatment were randomized 1:1 into either group A, with minocycline or group B, without minocycline. The patients assigned to group A were started on minocycline 100mg/day orally for 8 weeks with erlotinib. Primary end point was the frequency of grade ≥2 rash acneiform by independent assessment in first 8 weeks. We expected the prophylactic minocycline decreased the incidence of grade ≥2 skin rash from 50% to 30%. The planned sample size was 280 patients with a = 0.025 (one-sided) and b = 0.10. ResultsPatients accrual was started in March 2015 and ended in June 2018 because of slow accrual. Ninety-four patients were finally enrolled and 93 were full-analysis set. The median age of the patients was 71 years old (range 45 to 89),58 patients were female. EGFR mutation status positive/negative/unknown=78/13/2 patients. The frequency of grade ≥2 rash acneiformby independent assessment was 33.3% [95%C.I. 20.0-49.0%] in group A vs. 44.2% [95%C.I. 29.1-60.1%] in group B (p = 0.296). The frequency by physicians’ evaluation was 31.3% [95%C.I. 18.7-48.8%] and 45.5% [95%C.I. 30.4-61.2%] (p = 0.161). However, the frequency of grade ≥2 rash acneiform on day 15 by physicians’ evaluation was significantly decreased (4.4% [95%C.I. 5.3-14.8%] in group A vs. 25.0% [95%C.I. 13.2-40.3%] in group B (p = 0.005)). As for toxicity, the incidence of any grade skin-related toxicity as pruritus (39.6% vs. 63.6%) and pain of skin (14.6% vs. 25.0%) was less common in group A. Hence, anorexia (41.7% vs 20.5%), nausea (25.0% vs 4.5%), and dysgeusia (22.9% vs 15.9%) occurred more frequently. ConclusionsAlthough the frequency of acneiform rash tended to decrease, prophylactic administration of minocycline is not recommended because of increasing gastrointestinal toxicity. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureT. Kozuki: Honoraria (self), Research grant / Funding (self): AstraZeneca; Honoraria (self), Research grant / Funding (self): Chugai Pharmaceutical Co.; Honoraria (self), Research grant / Funding (self): Eli-Lilly Japan; Honoraria (self): Taiho Pharmaceutical Co.; Honoraria (self): Ono Pharmaceutical Co.; Honoraria (self): Bristol-Myers Squibb; Honoraria (self), Research grant / Funding (self): MSD; Honoraria (self): Boehringer Ingelheim; Honoraria (self): Kyowa-Hakko Kirin; Honoraria (self): Pfizer; Honoraria (self): Nippon-kayaku; Research grant / Funding (self): Merck Biopharma. M. Takenoyama: Honoraria (self), Research grant / Funding (self): Chugai Pharmaceutical. All other authors have declared no conflicts of interest.

170: Photodynamic therapy for the prevention of lung cancer (The PEARL trial)

170: Photodynamic therapy for the prevention of lung cancer (The PEARL trial)

Additive effects of nutraceuticals to non-pharmacologic intervention to improve lipid profile in the real world clinical practice in European countries — The PIN (Portugal Italy Nutraceutical) Study

PEARL trial. Patientswere randomly assigned to atorvastatin (20 mg day, N= 50) or rosuvastatin (10 mg day, N= 50) for 30 days. After another 1-week wash-out period to avoid any carryover effect, cross-over was performed, and patients were switched to the other drug which was continued for 30 days. Platelet reactivity (expressed as P2Y(12) reaction units (PRU) by the point-of-care VerifyNow assay [Accumetrics, San Diego, California]) was measured before and at the end of each 30-day treatment period. High platelet reactivity after clopidogrel was defined as a PRU value N 208. Results: After the 30-day treatment with atorvastatin, platelet reactivity did not significantly change as compared with baseline, pre-treatment evaluation (119 ± 66 vs 136 ± 59 PRU, NS), with 2 patients only showing a PRU N 208. Similarly, after 30-day treatment with rosuvastatin, platelet reactivity was unchanged as compared with baseline (135 ± 46 vs 128 ± 62 PRU, NS), with PRU N 208 occurring in 3 patients. Conclusion: Atorvastatin does not negatively affect DAPT as compared with rosuvastatin when is given to stable CAD patients with baseline normal platelet reactivity while on DAPT. (ClinicalTrials.gov Identifier: NCT01567774).

Pharmacodynamic effects of atorvastatin vs. rosuvastatin in coronary artery disease patients with normal platelet reactivity while on dual antiplatelet therapy

Background: Levels of platelet reactivity in patients on Dual Antiplatelet Therapy (DAPT) can potentially be influenced by concomitant treatment with statins that inhibit the CYP3A4 system involved in the activation of clopidogrel. Recent studies have shown that a high platelet reactivity during co-administration of clopidogrel and a CYP3A4-metabolized statin (i.e atorvastatin) can be lowered by switching to a non-CYP3A4-metabolized statin (i.e rosuvastatin). Aim of this study was to verify if atorvastatin and rosuvastatin have different pharmacodynamic effects also when they are given to patients with Coronary Artery Disease (CAD) with baseline normal platelet reactivity while on DAPT. Methods: A total of 100 stable CAD patients receiving DPAT (clopidogrel 75 mg plus aspirin 100 mg) who had evidence of normal platelet reactivity after a 1-week statin wash-out period entered the PEARL trial. Patients were randomly assigned to atorvastatin (20 mg day, N=50) or rosuvastatin (10 mg day, N=50) for 30 days. After another 1-week wash-out period to avoid any carryover effect, cross-over was performed, and patients were switched to the other drug which was continued for 30 days. Platelet reactivity (expressed as P2Y (12) reaction units (PRU) by the point-of-care VerifyNow assay [Accumetrics, San Diego, California]) was measured before and at the end of each 30-day treatment period. High platelet reactivity after clopidogrel was defined as a PRU value>208. Results: After the 30-day treatment with atorvastatin, platelet reactivity did not significantly change as compared with baseline, pre-treament evaluation (119±66 vs 136±59 PRU, NS), with 2 patients only showing a PRU>208. Similarly, after 30-day treatment with rosuvastatin, platelet reactivity was unchanged as compared with baseline (135±46 vs 128±62 PRU, NS), with PRU>208 occurring in 3 patients. Conclusion: Atorvastatin does not negatively affect DAPT as compared with rosuvastatin when is given to stable CAD patients with baseline normal platelet reactivity while on DAPT. ClinicalTrials.gov Identifier: [NCT01567774][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01567774&atom=%2Fehj%2F34%2Fsuppl_1%2FP4849.atom

A case of latent tuberculosis reactivation in a patient treated with ustekinumab without concomitant isoniazid chemoprophylaxis in the PEARL trial

A case of latent tuberculosis reactivation in a patient treated with ustekinumab without concomitant isoniazid chemoprophylaxis in the PEARL trial

Third-Generation SERMs May Face Uphill Battle

Lasofoxifene, a third-generation selective estrogen receptor modulator (SERM), has emerged from the phase III PEARL trial with what could be considered flying colors. Compared with placebo, the drug reduced breast cancer risk in postmenopausal women with osteoporosis as effectively as firstgeneration tamoxifen and second-generation raloxifene, prevented more kinds of fractures than raloxifene, and did not raise the risk of endometrial cancer like tamoxifen. As reported in this issue of the Journal, lasofoxifene was particularly effective in reducing risk in higherrisk women and those with high estradiol levels. But don’t look for lasofoxifene as an immediate option in breast cancer chemoprevention. The drug, made by Pfi zer, has approval in Europe, but only as an osteoporosis treatment. In the U.S., the company has withdrawn its application to the Food and Drug Administration despite the PEARL trial results. According to its most recent fi ling with the Securities and Exchange Commission, in August, Pfi zer is now “exploring strategic options for [lasofoxifene], including but not limited to out-licensing or sale.”

The response of bone turnover markers to lasofoxifene: The PEARL trial

The response of bone turnover markers to lasofoxifene: The PEARL trial

Clinical issues regarding cardiovascular disease and selective estrogen receptor modulators in postmenopausal women

Selective estrogen receptor modulators (SERMs) have offered the promise of reducing the burden of coronary artery disease (CAD) in postmenopausal women, based on the positive effects recorded on intermediate markers (blood lipids and markers of inflammation). The effects of raloxifene, bazedoxifene and lasofoxifene on cardiovascular endpoint markers are presented as reported in recent, randomized, controlled trials. Raloxifene failed to significantly lower the risk of CAD in postmenopausal osteoporotic women, without any effect on stroke or early harm, but doubling the risk of venous thromboembolism. The risk of CAD was lowered in a subgroup of patients at risk of CAD. In a large randomized, controlled trial with CAD as the primary endpoint in patients at risk of CAD, raloxifene failed to significantly reduce CAD, while significantly increasing the incidence of fatal stroke and venous thromboembolism. Bazedoxifene, in an osteoporosis trial, had similar effects on the cardiovascular system when compared to raloxifene. Lasofoxifene has only been studied in postmenopausal osteoporotic women in the PEARL trial. Lasofoxifene reduced the risk of coronary heart disease events as well as the risk of stroke, while the risk of deep vein thrombosis remained in line with other SERMs. These results will need to be confirmed in a study with primary cardiovascular endpoints. Until then, it is unlikely that SERMs will play a major role in strategies aimed at the prevention of coronary heart disease in postmenopausal women.