Biomarker Data from the Phase III KATHERINE Study of Adjuvant T-DM1 versus Trastuzumab for Residual Invasive Disease after Neoadjuvant Therapy for HER2-Positive Breast Cancer

PURPOSE

In KATHERINE, adjuvant T-DM1 reduced risk of disease recurrence or death by 50% compared with trastuzumab in patients with residual invasive breast cancer after neoadjuvant therapy (NAT) comprised of HER2-targeted therapy and chemotherapy. This analysis aimed to identify biomarkers of response and differences in biomarker expression before and after NAT.

EXPERIMENTAL DESIGN

Exploratory analyses investigated the relationship between invasive disease-free survival (IDFS) and HER2 protein expression/gene amplification, PIK3CA hotspot mutations, and gene expression of HER2, PD-L1, CD8, predefined immune signatures, and Prediction Analysis of Microarray 50 intrinsic molecular subtypes, classified by Absolute Intrinsic Molecular Subtyping. HER2 expression on paired pre- and post-NAT samples was examined.

RESULTS

T-DM1 appeared to improve IDFS versus trastuzumab across most biomarker subgroups, except the HER2 focal expression subgroup. High versus low HER2 gene expression in residual disease was associated with worse outcomes with trastuzumab [HR, 2.02; 95% confidence interval (CI), 1.32-3.11], but IDFS with T-DM1 was independent of HER2 expression level (HR, 1.01; 95% CI, 0.56-1.83). Low PD-L1 gene expression in residual disease was associated with worse outcomes with trastuzumab (HR, 0.66; 95% CI, 0.44-1.00), but not T-DM1 (HR, 1.05; 95% CI, 0.59-1.87). PIK3CA mutations were not prognostic. Increased variability in HER2 expression was observed in post-NAT versus paired pre-NAT samples.

CONCLUSIONS

T-DM1 appears to overcome HER2 resistance. T-DM1 benefit does not appear dependent on immune activation, but these results do not rule out an influence of the tumor immune microenvironment on the degree of response.

Abstract P2-11-07: Association of PIK3CA mutations with efficacy in HER2-positive first-line metastatic breast cancer: a meta-analysis

BACKGROUND: PIK3CA mutations have been shown to be associated with poor prognosis in HER2-positive breast cancer (BC). We combined data from three completed Phase III Roche-sponsored randomized trials of HER2-targeted therapy for the first-line treatment of HER2-positive metastatic BC (MBC); this allowed for exploration of the prognostic impact of PIK3CA mutations observed in the three individual trials across subgroups of interest.

METHODS: Data from CLEOPATRA (pertuzumab + trastuzumab + docetaxel [PHD] vs. placebo [Pla] + HD; NCT00567190; N = 808), MARIANNE (HD vs. ado-trastuzumab emtansine [K] + Pla vs. K + P; NCT01120184; N = 1095), and PUFFIN (PHD vs. Pla + HD; NCT02896855; N = 243) were included. An individual patient data (IPD) meta-analysis was performed to test the association between PIK3CA mutation status in tumor tissue (mutated vs. wild type [WT]) and efficacy (progression-free and overall survival [PFS/OS]) in different biomarker and clinical subgroups. Confounder adjustment was conducted for age, Eastern Cooperative Oncology Group Performance Status, body mass index, treatment, disease type, and number of metastases (all at baseline). “Study” was included as a random effect in the IPD meta-analysis model to account for variability between studies.

A landmark analysis was conducted on fast and non-fast progressors (cutoff of >137 days [i.e., after six chemotherapy cycles]) from CLEOPATRA and PUFFIN only, since they include the current standard-of-care regimens (PHD), by using Day 137 as the landmark time with separate Cox proportional hazards models.

RESULTS: PIK3CA mutation data were available for 1905/2146 patients (89%; ~80% from primary tissue); mutation prevalence was 27% (n = 521). PIK3CA-mutated vs. WT in association with PFS in pooled treatment arms is shown in the table. OS data were consistent.

CONCLUSIONS: PIK3CA mutations were associated with a worse prognosis across subgroups of interest, including in fast and non-fast progressors, in the two PHD-containing studies as compared with the overall ITT population.

Table: PIK3CA-mutated vs. WT in association with PFS in pooled treatment arms

Citation Format: Sandra Swain, Javier Cortés, Binghe Xu, Chiara Lambertini, Laurent Essioux, Adam Knott, Eleonora Restuccia, Katrin Madjar, Sanne Lysbet De Haas. Association of PIK3CA mutations with efficacy in HER2-positive first-line metastatic breast cancer: a meta-analysis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-07.

HER2 Copy Number and Resistance Mechanisms in Patients with HER2-positive Advanced Gastric Cancer Receiving Initial Trastuzumab-based Therapy in JACOB Trial

PURPOSE

In JACOB trial, pertuzumab added to trastuzumab-chemotherapy did not significantly improve survival of patients with HER2-positive metastatic gastric cancer, despite 3.3 months increase versus placebo. HER2 copy-number variation (CNV) and AMNESIA panel encompassing primary resistance alterations (KRAS/PIK3CA/MET mutations, KRAS/EGFR/MET amplifications) may improve patients' selection for HER2 inhibition.

EXPERIMENTAL DESIGN

In a post hoc analysis of JACOB on 327 samples successfully sequenced by next-generation sequencing (NGS; Oncomine Focus DNA), HER2 CNV, HER2 expression by IHC, and AMNESIA were correlated with overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) by univariable/multivariable models.

RESULTS

Median HER2 CNV was 4.7 (interquartile range, 2.2-16.9). HER2 CNV-high versus low using the median as cutoff was associated with longer median PFS (10.5 vs. 6.4 months; HR = 0.48; 95% confidence interval: 0.38-0.62; P < 0.001) and OS (20.3 vs. 13.0 months; HR = 0.54; 0.42-0.72; P < 0.001). Combining HER2 CNV and IHC improved discriminative ability, with better outcomes restricted to HER2-high/HER2 3+ subgroup. AMNESIA positivity was found in 51 (16%), with unadjusted HR = 1.35 (0.98-1.86) for PFS; 1.43 (1.00-2.03) for OS.In multivariable models, only HER2 CNV status remained significant for PFS (P < 0.001) and OS (P = 0.004). Higher ORR was significantly associated with IHC 3+ [61% vs. 34% in 2+; OR = 3.11 (1.89-5.17)] and HER2-high [59% vs. 43% in HER2-low; OR = 1.84 (1.16-2.94)], with highest OR in the top CNV quartile. These biomarkers were not associated with treatment effect of pertuzumab.

CONCLUSIONS

HER2 CNV-high assessed by NGS may be associated with better ORR, PFS, and OS in a JACOB subgroup, especially if combined with HER2 3+. The negative prognostic role of AMNESIA requires further clinical validation.

Tumor biomarkers and efficacy in patients treated with trastuzumab emtansine + pertuzumab versus standard of care in HER2-positive early breast cancer: an open-label, phase III study (KRISTINE)

BACKGROUND

KRISTINE is an open-label, phase III study of trastuzumab emtansine + pertuzumab (T-DM1 + P) versus docetaxel + carboplatin + trastuzumab + pertuzumab (TCH + P) in patients with HER2-positive, stage II-III breast cancer. We investigated the association of biomarkers with clinical outcomes in KRISTINE.

METHODS

Patients were randomized to receive neoadjuvant T-DM1 + P or TCH + P and assessed for pathologic complete response (pCR; ypT0/is, ypN0). HER2 status (per central assessment), hormone receptor status, PIK3CA mutation status, HER2/HER3 mRNA levels, tumor-infiltrating lymphocyte levels, PD-L1 status, and NanoString data were analyzed. pCR rates by treatment arm were compared across biomarker subgroups. Analyses were descriptive.

RESULTS

Biomarker analyses included data from all 444 patients (T-DM1 + P, n = 223; TCH + P, n = 221) enrolled in KRISTINE. Biomarker distribution was balanced across treatment arms. All subgroups with higher HER2 amplification/expression and immune marker levels showed numerically higher pCR rates in both arms. Mutated versus non-mutated PIK3CA tumors were associated with numerically lower pCR rates in the T-DM1 + P arm but not in the TCH + P arm. In a multivariate analysis, Prediction Analysis of Microarray with the 50-gene classifier (PAM50) HER2-enriched subtype, HER2 gene ratio ≥ 4, and PD-L1-positive status positively influenced the pCR rate. Biomarkers associated with lower pCR rates (e.g., low HER2 levels, positive hormone receptor status, mutated PIK3CA) were more likely to co-occur. Dynamic on-treatment biomarker changes were observed. Differences in the treatment effects for T-DM1 + P versus TCH + P were similar to those observed in the intent-to-treat population for the majority of the biomarker subgroups.

CONCLUSIONS

Although our biomarker analysis did not identify a subgroup of patients that benefited from neoadjuvant T-DM1 + P versus TCH + P, the data revealed that patients with higher HER2 amplification/expression and immune marker levels had improved response irrespective of treatment arm. These analyses confirm the role of HER2 tumor biology and the immune microenvironment in influencing pCR in the neoadjuvant setting and reaffirm the molecular diversity of HER2-positive breast cancer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02131064. Registered 06 May 2014.

ASTEFANIA: adjuvant ado-trastuzumab emtansine and atezolizumab for high-risk, HER2-positive breast cancer

There is a strong rationale for combining HER2-targeted therapies with cancer immunotherapy to increase efficacy in breast cancer, particularly in the early-stage setting, where the immune system has not been weakened by heavy pretreatment. ASTEFANIA aims to evaluate the efficacy of adjuvant atezolizumab in combination with ado-trastuzumab emtansine in patients with high-risk, HER2-positive early breast cancer and residual disease following HER2-based neoadjuvant therapy. Eligible patients will be randomized to receive ado-trastuzumab emtansine in combination with either atezolizumab or placebo for 14 cycles within 12 weeks of primary surgery. The primary outcome is invasive disease-free survival and secondary outcomes include additional efficacy end points, safety and pharmacokinetics. The study plans to enroll 1700 patients across 32 counties. Clinical Trial Registration: NCT04873362 (ClinicalTrials.gov).

Atezolizumab With Neoadjuvant Anti-Human Epidermal Growth Factor Receptor 2 Therapy and Chemotherapy in Human Epidermal Growth Factor Receptor 2-Positive Early Breast Cancer: Primary Results of the Randomized Phase III IMpassion050 Trial

Combining standard of care (pertuzumab-trastuzumab [PH], chemotherapy) with cancer immunotherapy may potentiate antitumor immunity, cytotoxic activity, and patient outcomes in high-risk, human epidermal growth factor receptor 2 (HER2)–positive early breast cancer. We report the phase III IMpassion050 primary analysis of neoadjuvant atezolizumab, PH, and chemotherapy in these patients.

Abstract P3-13-04: Clinical features and genetic alterations in patients (pts) with HER2-positive breast cancer (BC) and central nervous system (CNS) metastases (mets) in the real world

Introduction: Pts with HER2-positive metastatic BC (mBC) often develop CNS mets, which is associated with poor prognosis and negative impact on quality of life. Resistance to anti-HER2 treatment can lead to disease progression; furthermore, many therapies do not cross the blood-brain barrier, leading to an unmet need for effective CNS mets treatment. In this real world study, we explored the molecular profile and clinical features of pts with CNS and non-CNS mets to better understand tumor biology in these populations. Methods: This retrospective, cross-sectional, observational study evaluated pts with CNS mets or non-CNS mets at the time of HER2-positive mBC diagnosis using the Flatiron Health-Foundation Medicine Clinico-Genomic Database (FH-FMI CGDB). The database comprised de-identified data from ~280 US cancer clinics (~800 sites of care), and included pts with FMI comprehensive genomic profiling assays covering &gt;300 cancer-related genes. Descriptive analyses were conducted for baseline demographic, clinical, and biomarker characteristics, as well as genetic alterations including single nucleotide variants (SNVs), copy number alterations (CNAs), and rearrangements. T-tests were used to compare continuous variables, chi-squared tests for categorical variables, and non-parametric tests for non-normal distributions. Results: Of 8204 pts with BC in the CGDB, 6111 females 18+ yrs were diagnosed with mBC on or after 1-1-2011, of whom 919 had HER2-positive mBC, and 314 had an FMI assay up to 120 days after mBC diagnosis. This study population included 45 pts with CNS mets and 269 pts with non-CNS mets (Table). FMI data were derived from the primary tumor (29% from breast) or a metastatic lesion (19%, 12%, and 4% from liver, lymph nodes, and brain, respectively). Pts with CNS vs non-CNS mets were significantly younger at initial and at mBC diagnosis (p=0.04). At mBC diagnosis, a higher percentage of pts with CNS vs non-CNS mets had ≥3 sites of mets (p=0.01) and mets sites in adrenal glands (p=0.01), while there was a trend toward lower rates of lung and liver mets (not significant [NS]). Pts with CNS mets were more likely to be hormone receptor-negative vs pts with non-CNS mets (NS). Missing data for HER2 results by IHC or FISH, tumor grade, and histology limited the interpretation of any observed differences. Pts with CNS vs non-CNS mets were more likely to have SNVs in TP53 (82% vs 64%, p=0.03) and CNAs in ERBB2 (60% vs 43%, p&lt;0.05). The most common mutations in pts with CNS mets were TP53 (82%) and PIK3CA (29%), followed by ERBB2, BRCA1, ESR1, CDH1, MLL2, and ATRX (&lt;9% each). The most common CNAs in pts with CNS mets were ERBB2 (60%) and MYC (20%), followed by CCND1, FGF19, FGF3, FGF4, and CCNE1 (13% each). Rearrangements were rare and no clear differences were observed between pts with CNS and non-CNS mets. Conclusions: Despite its small sample size, our analysis is one of the largest real world genomic studies in HER2-positive pts with CNS mets to date. Pts with CNS mets at mBC diagnosis showed potential distinguishing clinical and genetic features, including younger age, a higher proportion with adrenal gland mets and ≥3 sites of mets, and a higher prevalence of SNVs in TP53 and CNAs in ERBB2. Cautious interpretation is needed due to the small sample, unique pt population, and heterogeneity in tissue location. Further analyses can help elucidate the biology of CNS mets in these pts with a high unmet need.

Table. Demographic, clinical, and genetic characteristics of the study populationVariableCNS mets (n=45)Non-CNS mets (n=269)Total (N=314)p-valueMedian age at mBC diagnosis, years (interquartile range [IQR])55 (47-62)60 (51-68)59 (49-68)0.04Median age at early BC diagnosis, years (IQR)51 (43-60)55 (48-64)55 (46-64)0.04&lt;45 years14 (31)54 (20)68 (22)45-64 years24 (53)148 (55)172 (55)≥65 years7 (16)67 (25)74 (24)Race, n (%)White23 (51)174 (65)197 (63)0.09Black/Asian4 (9)31 (12)35 (11)Other10 (22)43 (16)53 (17)Missing8 (18)21 (8)29 (9)Group stage at initial diagnosis, n (%)aI&lt;4 (&lt;9)25 (9)26 (8)0.12II22 (49)88 (33)110 (35)III11 (24)76 (28)87 (28)IV6 (13)59 (22)65 (21)Missing5 (11)21 (8)26 (8)Number of metastatic sites, n (%)111 (24)110 (41)121 (39)0.01213 (29)90 (34)103 (33)≥321 (47)69 (26)90 (29)SNVs (selected a priori), n (%)bTP5337 (82)173 (64)210 (67)0.03PIK3CA13 (29)97 (36)110 (35)0.45ERBB2&lt;4 (&lt;9)21 (8)24 (8)1ESR1&lt;4 (&lt;9)7 (3)10 (3)1PTEN&lt;4 (&lt;9)12 (4)14 (4)1CNAs (most common in all pts), n (%)bERBB227 (60)115 (43)142 (45)0.047MYC9 (20)61 (23)70 (22)0.84FGF196 (13)45 (17)51 (16)0.72aGroup stage is documented at the time of initial diagnosis in the pt health record or determined based on T, N, and M stage based on AJCC version at the time of the patient’s diagnosis, and does not include staging collected after systemic/radiation therapy, progression, and/or neoadjuvant treatment, if any.bp-values were not adjusted for multiple comparisons. Data not shown: additional univariate analyses of 129 genes on SNVs, CNAs and rearrangements yielded the following genes with the highest prevalence in pts with CNS mets: TP53 (82%), PIK3CA (29%), ERBB2 (&lt;9%), CDH1 (&lt;9%), ESR1 (&lt;9%), BRCA1 (&lt;9%), MLL2 (&lt;9%), ATRX (&lt;9%), and GATA3 (&lt;9%) for SNVs; ERBB2 (60%), MYC (20%), CCND1 (13%), FGF19 (13%), FGF3 (13%), FGF4 (13%), and CCNE1 (13%) for CNAs; and CDK12 (&lt;9%) and NF1 (&lt;9%) for rearrangements.

Citation Format: Preet K. Dhillon, Peter Lambert, Thibaut Sanglier, Adam Knott, Eleonora Restuccia, Sanne L. de Haas, Chiara Lambertini. Clinical features and genetic alterations in patients (pts) with HER2-positive breast cancer (BC) and central nervous system (CNS) metastases (mets) in the real world [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 P3-13-04.

Water immersion vs. air insufflation in canine duodenal endoscopy: is the future underwater?

Endoscopy represents a commonly employed technique for canine enteropathies. Different trials in human intestinal endoscopy have suggested that the introduction of water for luminal distension, in place of air, improves the visualization of the mucosal texture and decreases pain. The aim of the study was to compare water immersion (WI) vs. air insufflation (AI) during duodenoscopy in anesthetized dogs in terms of mucosal visualization and nociception. Twenty-five dogs undergoing duodenoscopy were included. The same image of the descending duodenum was recorded applying WI and AI. Each pair of images was analyzed using morphological skeletonization, an image entropy evaluation, and a subjective blind evaluation by three experienced endoscopists. To evaluate differences in nociception related to the procedure applied, heart rate and arterial blood pressure were measured before, during and after WI/AI. To compare the two methods, a t-test for paired data was applied for the image analysis, Fleiss' Kappa evaluation for the subjective evaluation and a Friedman test for anesthetic parameters. No differences were found between WI and AI using morphological skeletonization and entropy. The subjective evaluation identified the WI images as qualitatively better than the AI images, indicating substantial agreement between the operators. No differences in nociception were found. The results of the study pointed out the absence of changes in pain response between WI and AI, likely due to the sufficient control of nociception by the anesthesia. Based on subjective evaluation, but not confirmed by the image analysis, WI provided better image quality than AI.

Biomarker data from KATHERINE: A phase III study of adjuvant trastuzumab emtansine (T-DM1) versus trastuzumab (H) in patients with residual invasive disease after neoadjuvant therapy for HER2-positive breast cancer

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Background: The phase 3 KATHERINE study (NCT01772472) compared adjuvant T-DM1 versus H in patients with residual invasive breast cancer after neoadjuvant chemotherapy plus HER2-targeted therapy. Here we report exploratory analyses of the relationship between invasive disease-free survival (IDFS) and biomarkers potentially related to response. Methods: Formalin fixed paraffin-embedded tissue samples were collected before neoadjuvant treatment and/or at surgery. Surgical samples were used for analyses, except when only pre-treatment samples were available (~20% of cases). DNA was derived to identify PIK3CA hotspot mutations and gene expression (RNA) analysis was used to detect HER2, PD-L1, CD8 and predefined immune signatures including 3-gene, 5-gene, Teffector, chemokine signaling, and checkpoint inhibitor signatures. RNA analysis was adjusted for tumor content and expression levels were dichotomized at the median into low (≤) and high (>) groups. The effect of treatment and biomarkers on IDFS was assessed. Results: PIK3CA mutation (mut) status was available from 1363 (91.7%) patients. T-DM1 IDFS benefit was independent of PIK3CA mut status (mut: HR 0.54; 95%CI 0.23–0.90; non-mut: HR 0.48; 95%CI 0.35–0.65) and no impact of PIK3CA mut was observed within either treatment arm. Gene expression data were available from 1059 (71.3%) patients. Similar gene expression levels were observed between treatment arms, but, unlike the surgical samples (n = 815), the pre-treatment samples (n = 244) were not representative of the ITT population. Thus, subsequent analyses were based on surgical samples (H n = 398; T-DM1 n = 417). Consistent treatment benefit with T-DM1 vs H was observed across the single-gene and immune gene-signature subgroups as in the ITT population. High vs low HER2 expression was associated with worse outcome (HR 2.02; 95% CI 1.32–3.11) within the H arm, but not within the T-DM1 arm (HR 1.01; 95% CI 0.56–1.83). High vs low PD-L1 expression was associated with better outcome within the H arm (HR 0.66; 95% CI 0.44–1.00) but not within the T-DM1 arm (HR 1.05; 95% CI 0.59–1.87). Similar trends were observed in the checkpoint inhibitor subgroups. Conclusions: These exploratory analyses provide the first data on the relationship between biomarker expression in residual disease after HER2-targeted therapy and outcomes. PIK3CA mut status did not influence outcomes with H or T-DM1. T-DM1 benefit appeared to be independent of all biomarkers assessed. Clinical trial information: NCT01772472 .

Abstract PD5-11: Association of immune gene expression with outcome in the MARIANNE phase 3 clinical trial in HER2-positive metastatic breast cancer (MBC)

Introduction: Although HER2+ breast cancer (BC) is considered a moderately immunogenic tumor, several studies have shown a role of pre-existing immunity associated with favorable long-term prognosis and better response to treatment. In this study, we performed exploratory analyses to assess whether the efficacy of HER2 targeted treatment in the MARIANNE trial correlated with immune gene expression. Methods: MARIANNE (NCT01120184) is a phase 3 study in patients (pts) with centrally confirmed HER2+ local advanced/metastatic BC naïve to prior treatments in the advanced disease. Pts were randomized (1:1:1) to trastuzumab+taxane (HT), T-DM1, or T-DM1+Petuzumab (P) and the trial showed noninferior PFS of T-DM1 and T-DM1+P vs HT. Gene expression (RNA) analysis was performed on tumor samples by a custom 800-gene codeset on the nCounter platform. PD-L1, CD8 expressions and immune gene signatures (sign) analyses were assessed by multivariate Cox regression models using median (cut-off) as categorical variable and adjusted by prior HT, presence of visceral disease, world region, baseline ECOG, measureable disease at baseline, therapy setting, HER2 mRNA expression, PIK3CA mutation status. Results: MARIANNE randomized 1095 pts (HT, n=365; T-DM1, n=367; T-DM1+P, n=363). Gene expression results were available for 671 pts (61.3% of the intent-to-treat [ITT] population) which was representative of ITT. In ITT, HR below 1 was observed when comparing pts with high (&gt;median) vs low (≤median) immune gene expression by clinical outcome suggesting a potential association of high immune marker expression with improved PFS (Table 1) and to some extent with OS (data not shown). This association was primarily observed in the T-DM1 arm where the HR suggested a risk reduction of disease progression(PD)/death especially in the high Teff, high PD-L1 and high CD8 subgroups, and to some extent in the HT arm (Table 1). When assessing the predictive impact on PFS by comparing T-DM1 vs HT, HR below 1 was observed especially in pts with high Teff signature, high PD-L1 and high CD8 expressions (HR 0.67 (95% CI (0.47-0.95)), HR 0.68 (95% CI (0.48-0.97), and HR 0.64 (95%CI 0.44-0.93), respectively). When comparing T-DM1+P vs. HT, HR below 1 was observed especially in pts with low Teff signature and low PD-L1 expression (HR 0.70 (95% CI (0.50-0.99), and HR 0.68 (95% CI (0.48-0.96) respectively). No clear differences between immune gene expression subgroups was observed when comparing treatment arms in regards to OS (data not shown). Conclusions: In the exploratory analysis from the MARIANNE study, high immune gene expression, especially in the high PD-L1, CD8 and Teff subgroups, showed an association with improved clinical benefit with HRs reflecting for a risk reduction of PD/death for PFS and partially for OS. This association was less obvious in the T-DM1+P arm. When comparing the treatments effect, the data showed a potential impact of high Teff signature, and high CD8 and PD-L1 expressions on T-DM1 and less on HT. The potential opposite association of low Teff signature and low PD-L1 expression with improved benefit in the T-DM1+P arm was unexpected and needs further investigation.

Table 1: Prognostic biomarker effect on PFSBiomarker by categories (&gt;Median vs ≤Median)HR (95% CI) ITT n=671HR (95% CI) HT n=220HR (95% CI) T-DM1 n=227HR (95% CI) T-DM1+P n=224Teff sign0.89 (0.73-1.09)0.97 (0.68-1.38)0.64 (0.45-0.91)1.09 (0.75-1.58)Th1 cytokine sign0.91 (0.74-1.11)0.92 (0.64-1.31)0.78 (0.55-1.11)0.96 (0.67-1.36)Checkpoint inhibitor sign0.95 (0.78-1.15)0.91 (0.64-1.29)0.90 (0.64-1.26)1.02 (0.71-1.47)PD-L10.80 (0.66-0.98)0.79 (0.55-1.13)0.62 (0.44-0.87)1.07 (0.74-1.55)CD80.91 (0.75-1.11)1.10 (0.77-1.57)0.66 (0.46-0.93)0.98 (0.68-1.41)

Citation Format: Edith A Perez, Sanne Lysbet de Haas, Carlos H Barrios, Wolfgang Eiermann, Masakazu Toi, Young-Hyuck Im, Pier Franco Conte, Miguel Martin, Tadeusz Pienkowski, Xavier B Pivot, Howard A Burris III, Chiara Lambertini, Silke Hoersch, Monika Patre, Paul Anthony Ellis. Association of immune gene expression with outcome in the MARIANNE phase 3 clinical trial in HER2-positive metastatic breast cancer (MBC) [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 PD5-11.

Abstract A46: Inhibition of PIK3CA with BYL719 can overcome resistance to cetuximab in squamous cell carcinoma of the head and neck (SCCHN)

Background: Preclinical data suggest squamous cell tumors, such as SCCHN, are driven by epidermal growth factor receptor (EGFR) overexpression. However, many patients are refractory to anti-EGFR treatment due to intrinsic and acquired resistance. PI3K/AKT/mTOR pathway activation is a potential mechanism of resistance to EGFR-directed therapy.

BYL719, a selective α-isoform PI3K inhibitor, enhances cetuximab (EGFR inhibitor) activity in SCCHN cell lines. A Phase Ib/II study combining BYL719 with cetuximab in patients with recurrent/metastatic SCCHN is testing this hypothesis (Razak et al, ASCO 2014, abst 6044; NCT01602315).

Here, we outline the preclinical rationale for combining BYL719 with cetuximab in the setting of cetuximab-resistant squamous cell carcinoma, highlight Phase Ib safety and efficacy data in patients with SCCHN who have received prior cetuximab, and describe the design of the Phase II portion of the study, which is assessing both cetuximab-naive and -pretreated patients.

Methods: The combination of BYL719 and cetuximab was tested in vivo in two xenograft models of esophageal squamous cell carcinoma: KYSE180 (cetuximab-sensitive model) and KYSE180_CR (cetuximab-resistant, induced by long-term in vivo treatment). In the Phase Ib study, BYL719 was administered once daily (QD) in 28-day cycles with standard weekly (QW) cetuximab (400 mg/m2 on Cycle 1 Day 1; 250 mg/m2 QW thereafter) to adults with histologically/cytologically confirmed recurrent/metastatic SCCHN resistant/intolerant to platinum-based chemotherapy (prior cetuximab therapy was allowed).

Results: In the KYSE180 model, the addition of BYL719 to cetuximab demonstrated an additive effect leading to tumor regression; furthermore, in the KYSE180_CR model, adding BYL719 to cetuximab completely restored sensitivity and led to similar activity as seen in the cetuximab-sensitive model, suggesting that inhibiting PIK3CA signaling may overcome resistance to cetuximab.

In the Phase Ib study, as of March 10, 2014, 37 patients were treated with BYL719 300 mg QD (n=32) or 400 mg QD (n=5) and cetuximab. Frequent adverse events (&gt;30%; all-grade/Grade 3/4) were hyperglycemia (54/24), stomatitis (38/5), and dermatitis acneiform (35/3). Best overall response (BOR) per RECIST v1.1 in the full population (n=37) was 4 partial responses (PRs), 16 stable disease (SD; of which 5 were unconfirmed PRs), 10 unknown (UNK) responses, and 1 non-complete response/non-progressive disease (PD) at 300 mg or 400 mg. Six patients had PD as BOR. The overall response rate (ORR) in the full population was 4/37 (11%) and the disease control rate (DCR) was 20/37 (54%). Within this population, 7 patients had received prior cetuximab therapy (6 in the metastatic/recurrent setting and 1 curative; BOR: 4 SD, 1 PR, 1 PD, and 1 UNK). Of these 7 patients, 1 had a confirmed PR, 2 had unconfirmed PRs, 2 had SD, and 1 had PD with BYL719 and cetuximab. One patient with prior cetuximab therapy had an UNK response due to death from tumor lysis syndrome after 1 week in the study. The ORR among patients with prior cetuximab was 1/7 (14%) and DCR was 5/7 (71%).

Phase II tests the combination of BYL719 at the recommended Phase II dose of 300 mg QD in two second-line SCCHN patient populations. Patients who are cetuximab-naive are randomized to cetuximab alone or to BYL719 in combination with cetuximab, while patients who have received cetuximab and platinum therapy in the first-line setting are enrolled in a single arm to receive BYL719 with cetuximab.

Conclusion: Combined inhibition of PI3Kα and EGFR by BYL719 and cetuximab, respectively, overcame cetuximab resistance in the preclinical setting, was well tolerated, and demonstrated encouraging antitumor activity in both cetuximab-naive and -pretreated patients with SCCHN. The Phase II part of the study in both patient populations is ongoing.

Citation Format: Pamela Munster, Moshe Elkabets, Jill Gilbert, Albiruni R Abdul Razak, Myung-Ju Ahn, Chia-Jui Yen, Se-Hoon Lee, Hung-Ming Wang, Carla van Herpen, Wan-Teck Lim, David Demanse, Rupam Ranjan Pal, Alan Huang, Qing Sheng, Chiara Lambertini, Malte Peters, Christina Coughlin, Maurizio Scaltriti, José Baselga, George Blumenschein. Inhibition of PIK3CA with BYL719 can overcome resistance to cetuximab in squamous cell carcinoma of the head and neck (SCCHN). [abstract]. In: Proceedings of the AACR Special Conference: Targeting the PI3K-mTOR Network in Cancer; Sep 14-17, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(7 Suppl):Abstract nr A46.

Evaluation of somatostatin receptor subtype expression in human neuroendocrine tumors using two sets of new monoclonal antibodies

INTRODUCTION

The expression and reliable detection of somatostatin receptor subtypes (SSTR1-5) is a prerequisite for the successful use of somatostatin analogs in neuroendocrine tumors (NETs). Two sets of monoclonal antibodies (mAbs) against human SSTR1, 2A, 3 and 5 have recently been developed by two independent laboratories using rabbit and mouse hybridomas. Our aim was to evaluate the usefulness of both sets of mAbs for detection of SSTRs in NET samples as they are routinely collected in clinical practice.

METHODS

Mouse and rabbit mAbs were characterized in SSTR1, 2A, 3 and 5-transfected HEK293 cells and human archival samples of pancreatic tissue and NET. Comparative analysis of mAbs was also conducted by immunostaining of a tissue microarray composed of 75 cores of NET.

RESULTS

Immunohistochemical analysis of HEK293 cells showed that both rabbit and mouse mAbs specifically detect their cognate receptor subtype, with mild cytoplasmic cross-reactivity observed for rabbit mAbs. Both sets of mAbs labeled normal pancreatic islets and showed similar patterns of immunoreactivity in NET controls. Direct comparison of mAb sets using a NET tissue microarray revealed strong correlation between rabbit and mouse mAbs against SSTR1 and 5, and moderate correlation for SSTR3. The rabbit mAb against SSTR2A showed higher affinity for its cognate receptor than the corresponding mouse mAb, resulting in a more reliable detection of this SSTR.

CONCLUSIONS

mAbs from both sets are reliable tools for the detection of SSTR1, 3 and 5, whereas the rabbit mAb against SSTR2A is recommended for use in routine clinical testing due to its superior binding affinity.

Abstract 92: Comparative expression analysis of somatostatin receptor subtypes in human neuroendocrine tumors using two sets of new monoclonal antibodies

The expression and reliable detection of somatostatin receptor subtypes (SSTR1-5) is a prerequisite for the successful use of somatostatin analogues in neuroendocrine tumors (NET). Two sets of monoclonal antibodies (mAbs) against human SSTR1, 2A, 3 and 5 have recently been developed by two independent laboratories using rabbit and mouse hybridomas. Our aim was to evaluate the usefulness of both sets of mAbs for detection of SSTRs in NET samples as they are routinely collected in clinical practice. Mouse and rabbit mAbs were characterized in SSTR1, 2, 3 and 5-transfected HEK293 cells and human archival pancreatic tissue and NET samples. Comparative analysis of mAbs was also conducted by immunostaining of a tissue microarray composed of 75 cores of NET. Immunohistochemical analysis of HEK293 cells showed that both rabbit and mouse mAbs specifically detect their cognate receptor subtype, with mild cytoplasmic cross-reactivity observed for rabbit mAbs. Both sets of mAbs labeled normal pancreatic islets and showed similar patterns of immunoreactivity in NET controls. Direct comparison of mAb sets using a NET tissue microarray revealed a strong correlation between rabbit and mouse mAbs against SSTR1 and 5, and moderate correlation for SSTR3. The rabbit mAb against SSTR2A showed higher affinity for its cognate receptor than the corresponding mouse mAb, resulting in more reliable detection of this SSTR. In conclusion, mAbs from both sets are reliable tools for the detection of SSTR1, 3 and 5, whereas the rabbit mAb against SSTR2A is recommended for use in routine clinical testing due to its superior binding affinity.

Citation Format: Chiara Lambertini, Patrizia Barzaghi-Rinaudo, Lisa D'Amato, Stefan Schulz, Paolo Nuciforo, Herbert A. Schmid. Comparative expression analysis of somatostatin receptor subtypes in human neuroendocrine tumors using two sets of new monoclonal antibodies. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 92. doi:10.1158/1538-7445.AM2013-92

Will PAXgene substitute formalin? A morphological and molecular comparative study using a new fixative system

Aims

In this study we aimed to evaluate this new tissue preservation technique in comparison with formalin fixation and fresh frozen tissue samples.

Methods

12 melanoma biopsy samples were divided and fixed simultaneously with formalin, PAXgene or fresh frozen in liquid nitrogen and analysed with regard to morphology, immunohistochemistry,  DNA and RNA content and quality. Markers of melanocytic differentiation and tumour cell proliferation were used.

Results

Morphology was well preserved in PAXPE samples. However, 5 out of 11 immunohistochemical markers showed significantly lower overall staining and staining intensity with PAXPE tissues in comparison with formalin-fixed, paraffin-embedded (FFPE). Increasing membrane permeability through adding a detergent did proportionally increase staining intensity in PAXPE samples. Amplification of different mRNA amplicons showed a direct relationship with the size of the amplicon with greater template integrity observed in PAXPE samples. Sequencing and mutational analysis of DNA samples were comparable for all the different fixation methods, while the level of DNA fragmentation seemed to be lower in PAXPE compared with FFPE tissues.

Conclusions

The switch from formalin to PAXgene fixation would require a re-evaluation of immunohistochemical markers and staining procedures originally developed for FFPE tissues. Our data demonstrate that PAXPE fixation offers some advantages concerning molecular analysis. However, these advantages would not justify substituting formalin fixation in any routine pathology laboratory.

Monoclonal antibodies against the human somatostatin receptor subtypes 1-5: development and immunohistochemical application in neuroendocrine tumors

BACKGROUND

Activation of somatostatin receptors (sstr1-5) by somatostatin and its analogues exerts an inhibitory effect on hormone secretion and provides the basis for the treatment of a range of endocrine diseases such as acromegaly, Cushing's disease and neuroendocrine tumors (NET). The lack of well-characterized commercially available sstr subtype-specific antibodies prevents routine identification of the sstr expression profile in patients.

METHODS

We generated and characterized new mouse monoclonal antibodies (mAbs) targeting the five human sstr subtypes using ELISA and immunohistochemistry, and tested their suitability in formalin-fixed and paraffin-embedded (FFPE) human tissues and archival samples of normal pancreatic tissue and NET.

RESULTS

All mAbs were highly specific with no cross-reactivity. The sstr1-5 immunoreactivity in gastrointestinal NET (n=67) was correlated with clinicopathologic data. With the exception of sstr3, NET were highly positive for all receptor subtypes (42, 63, 6, 32 and 65% of tumors were positive for sstr1, sstr2a, sstr3, sstr4 and sstr5, respectively). sstr1, sstr2a and sstr5 were present at the plasma membrane and in the cytoplasm of tumor cells, whereas sstr3 and sstr4 were almost exclusively cytoplasmic. Immunoreactivity of sstr1, sstr2a and sstr4 tended to decrease as tumor aggressiveness increased. sstr5 showed an opposite pattern, with higher staining in well-differentiated carcinomas compared with well-differentiated tumors. sstr5 immunoreactivity was correlated with the presence of metastases and angioinvasion, suggesting a possible association with more aggressive behavior.

CONCLUSION

Determination of the sstr1-5 by immunohistochemistry using subtype-specific mAbs is feasible in FFPE tissue and may provide a tool for routine clinical practice.

Hybridization of common reed in North America? The answer is blowing in the wind

BACKGROUND AND AIMS

We review evidence for hybridization of Phragmites australis in North America and the implications for the persistence of native P. australis ssp. americanus populations in North America. We also highlight the need for an updated classification system, which takes P. australis intraspecific variation and hybridization into account.

METHODOLOGY

We reviewed available published, in press and in preparation literature to assess the likelihood of hybridization and interbreeding in genotypes of P. australis present in North America.

PRINCIPAL RESULTS

Experimental results demonstrate that hybridization among introduced and native haplotypes is possible within the genus Phragmites, yet evidence that hybridization has occurred naturally is only starting to emerge. The lag in identifying hybridization in Phragmites in North America may be related to under-sampling in some parts of North America and to a lack of molecular tools that provide the capability to recognize hybrids.

CONCLUSIONS

Our understanding of the gene flow within and between species in the genus Phragmites is moving at a fast pace, especially on the east and Gulf coasts of North America. More attention should also be focused on the Great Lakes region, the southwestern and the west coast of the USA, where sympatry has created opportunities for hybridization. Where hybridizations have been detected, there are currently no published data on how hybridization affects plant vigour, morphology, invasiveness or conservation of the genetic integrity of the North American native subspecies. We conclude that the detection of more hybridization is highly likely and that there is a need to develop new markers for the different Phragmites species and lineages to fill current knowledge gaps. Finally, we suggest that the classification system for P. australis should be updated and published to help clarify the nomenclature.

Abstract P3-10-24: Fibroblast Growth Factor Receptor 1 Amplification and Overexpression in Breast Cancer Tissue Microarrays Using Chromogenic In Situ Hybridization and Immunohistochemistry

Fibroblast growth factor receptors 1 (FGFR1) belongs to a subfamily of receptor tyrosine kinases (RTKs), which are involved in proliferation and apoptosis. FGFR1 amplification and mRNA overexpression occurs in ∼10% of breast cancers and has been associated with poor outcome. However, studies assessing FGFR1 amplification and protein overexpression in a large collection of breast tumors are lacking. In this prospective, we examined a series of primary breast cancers samples derived from the BCIRG trials assembled into 15 tissue microarrays. FGFR1 gene amplification was studied using chromogenic in situ hybridization (CISH) and evaluated with respect to association with level of protein expression and clinicopathological parameters. FGFR1 gene amplification was significantly associated with high protein levels as determined by immunohistochemistry (P&lt;0.0001, 3294 pts with available matched CISH and IHC records). Overall, the incidence of FGFR1 amplification found was 9.7% (160 out of 1646 pts. with available clinicopathological records) without a statistically significant difference between Her2- (78 out 720 pts., 11%) and Her2+ (82 out of 926 pts., 9%) cancers. In both cohorts, the hormone receptor-positive (ER+/PR+) cancers showed statistically significant higher levels of FGFR1 amplification compared to hormone receptor-negative tumors. In the analysis of the association of FGFR1 and the presence of PIK3CA mutations, the incidence of FGFR1 amplificationwas greatly reduced in mutant vs. wt PI3KCA tumors. In these cohorts, a clear relationship between FGFR1 amplification status and clinical outcome was not detected. Data from this large study confirms recently reported incidences of FGFR1 amplification in breast cancer and shows for the first time an association between FGFR1 gene amplification and protein overexpression. Moreover, the lower incidence of FGFR1 amplification in PIK3CA mutated cancers suggests that these are largely exclusive molecular events that could benefit from different targeted therapies.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-24.

Differential control of Notch1 gene transcription by Klf4 and Sp3 transcription factors in normal versus cancer-derived keratinocytes

In specific cell types like keratinocytes, Notch signaling plays an important pro-differentiation and tumor suppressing function, with down-modulation of the Notch1 gene being associated with cancer development. Besides being controlled by p53, little else is known on regulation of Notch1 gene expression in this context. We report here that transcription of this gene is driven by a TATA-less “sharp peak” promoter and that the minimal functional region of this promoter, which extends from the −342 bp position to the initiation codon, is differentially active in normal versus cancer cells. This GC rich region lacks p53 binding sites, but binds Klf4 and Sp3. This finding is likely to be of biological significance, as Klf4 and, to a lesser extent, Sp3 are up-regulated in a number of cancer cells where Notch1 expression is down-modulated, and Klf4 over-expression in normal cells is sufficient to down-modulate Notch1 gene transcription. The combined knock-down of Klf4 and Sp3 was necessary for the reverse effect of increasing Notch1 transcription, consistent with the two factors exerting an overlapping repressor function through their binding to the Notch1 promoter.

In vitro activity of cyclin-dependent kinase inhibitor CYC202 (Seliciclib, R-roscovitine) in mantle cell lymphomas

BACKGROUND

Mantle cell lymphoma (MCL) has the worst prognosis of all B-cell lymphomas and has poor response to conventional therapy. It is characterized by the presence of a chromosomal translocation t(11:14) (q13;q32) which results in deregulated cyclin D1 expression. Since defects in cell cycle regulation and apoptosis are primary events in MCL, small-molecule inhibitors of cdks-cyclins may play an important role in the therapy of this disorder. CYC202 (Seliciclib, R-roscovitine; Cyclacel Ltd., Dundee, UK) is a purine analogue and a selective inhibitor of the cdk2-cyclin E as well as cdk7-cyclin H and cdk9-cyclin T.

MATERIALS AND METHODS

The activity of CYC202 was tested in four human MCL cell lines: REC, Granta-519, JeKo-1 and NCEB-1. The effect of CYC202 on the cell cycle and on apoptosis-, cell-cycle- and transcription-regulation-related proteins was assessed.

RESULTS

The IC50 was 25 microM for REC, Granta-519 and JeKo-1 cells and 50 microM for NCEB-1 cells. CYC202 caused an accumulation of cells in the G2-M phase of the cell cycle and apoptosis. CYC202 caused down-regulation of cyclin D1 and Mcl-1 protein levels, possibly because of the inhibition of transcription elongation.

CONCLUSIONS

Our data suggest that CYC202 is an active agent in MCL. The concomitant decrease of the phosphorylated and total forms of RNA polymerase II suggests that this could be the main mechanism mediating the biological effects of CYC202 in MCL cells. The drug might represent a new therapeutic agent in this lymphoma subtype.