Abstract PD4-07: PET imaging of PARP-1 expression in breast cancer

18F-FluorThanatrace ([18F]-FTT) is a novel radiotracer shown to quantify Poly [ADP-ribose] polymerase 1 (PARP-1) expression in vitro and in vivo through a receptor-ligand interaction. A recent study at the University of Pennsylvania in women with ovarian cancer demonstrated in vivo visualization of PARP-1 expression in tumors using this radiotracer that closely correlated with an in vitro assay of PARP-1 in tumor tissue (Makvandi, M. J. Clin. Invest. 128:2116, 2018). A radioligand with PARP-1 specificity, [125I]-KX1, was also developed as a companion tool for ex vivo evaluation of PARP-1 expression and PARP inhibitor (PARPi) drug occupancy by radioligand binding assay (Makvandi, M. Cancer Res. 76:4516, 2016). As the first step in validating this biomarker in breast cancer, we performed a prospective clinical trial comparing in vivo [18F]-FTTuptake and ex vivo PARP-1 expression in women with primary breast cancer.

Methods: 24 patients with Stage I-IV primary breast cancer were imaged with [18F]-FTT prior to any therapy including surgery. We correlated in vivo uptake with ex vivo immunohistochemistry (IHC) for PARP-1 and [125I]-KX1 autoradiography in untreated surgical specimens. Tumors were analyzed for alterations in DNA repair genes, copy number-based as well as mutational signatures indicative of homologous recombination deficiency (HRD) and mutational burden, using our established protocol (Maxwell, KN, Nature Commun. 8:319, 2017).

Results: [18F]-FTT uptake was visualized above background in all primary breast tumors and known metastases. Two areas of unexpected uptake revealed an unknown contralateral breast cancer and an ovarian carcinoid, respectively. We expected that uptake might be highest in triple negative breast cancer (TNBC), where PARPi have been most heavily studied. However, a range of tracer uptake was observed in tumors independent of breast cancer subtype (hormone receptor positive/HER2 negative, TNBC, HER2+) and BRCA status. Uptake ratios (SUVmax tumor/SUV max opposite breast) ranged from 1.2-10.5 with a median 4.0. Ex vivo[125I]-KX1 autoradiography was performed on a subset of untreated primary tumors (n=5) and compared with IHC staining for PARP-1 on sequential sections. This revealed a close spatial correspondence between elevated PARP-1 expression by IHC and regions of elevated [125I]-KX1 binding radiographically. There was also a strong positive correlation between in vivo [18F]-FTT uptake and ex vivo quantitative [125I]-KX1 autoradiography (r=0.78). Genomic analysis of HRD in all tumors is pending and will be reported.

Conclusion: Initial analyses support the ability of [18F]-FTT to visualize and measure PARP-1 expression in breast cancer. This is the first step toward developing an imaging companion diagnostic to help guide PARP inhibitor treatment in breast cancer. Ongoing studies are expanding upon these results, testing the extent to which expression of PARP-1 by [18F]-FTT can predict response to PARP inhibitors and measure target engagement during therapy.

Citation Format: McDonald ES, Carlin S, Maxwell KN, Nayak A, Doot RK, Pantel AR, Farwell MD, Pryma DA, Clark AS, Shah P, DeMichele AM, Ziober A, Schubert EK, Palmer K, Lee HS, Matro J, de la Cruz L, Tchou J, Anderson DN, Feldman MD, Sheffer RE, Knollman H, Schnall MD, Makvandi M, Domchek S, Hubbard RA, Mach RH, Mankoff DA. PET imaging of PARP-1 expression in breast cancer [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 PD4-07.

Abstract CS1-3: Moderate penetrance mutations: What to do?

Genetic testing for breast and ovarian cancer susceptibility has expanded beyond sequencing of BRCA1 and BRCA2. Panel testing has allowed for rapid, affordable, and routine testing of multiple genes simultaneously. There is no one standard “panel” – panels range in types and number of genes tested and panel composition is at the discretion of the ordering provider. Some of the genes commonly included have been long associated with specific genetic syndromes with high lifetime risks of the associated cancers, e.g. mutations in PTEN and Cowden's Syndrome, TP53 and Li Fraumeni Syndrome, STK11 and Peutz-Jeghers Syndrome, and CHD1 and Hereditary Diffuse Gastric Cancer. The inclusion of these “high penetrance genes” on broad cancer panels can lead to challenges regarding discussion and management when detected in families which are not syndromic (for example, the discussion of prophylactic gastrectomy in individuals with CDH1 mutations and no family history of gastric cancer). Mutations in other genes are clearly associated with breast cancer but with lower lifetime risks than for BRCA1 and BRCA2; for example, the lifetime risk of breast cancer for a PALB2 mutation is approximately 40-50%, whereas for ATM and truncating CHEK2 mutations this risk is 25-30%. Mutations in BRIP, RAD51C, and RAD51D are clearly associated with ovarian cancer with lifetime risks of approximately 10% (significantly lower than for BRCA1 mutations). This lecture will address the current understanding of associated cancer risks for mutations in genes included in hereditary cancer panels with a focus on implications for risk reduction and treatment.

Citation Format: Domchek S. Moderate penetrance mutations: What to do? [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 CS1-3.

Abstract OT2-06-03: METAMORPH: METAstatic markers of recurrent tumor PHenotype for breast cancer

Up to 30% of patients diagnosed with breast cancer will develop recurrent disease within their lifetime, and currently this form of the disease is incurable. There are unmet needs to better understand underlying metastatic biology, identify new therapeutic targets and develop better methods for monitoring changes in disease, both to monitor response and elucidate resistance mechanisms. To address these needs, the METAMORPH Study encompasses a comprehensive approach that combines serial molecular tissue profiling at the RNA and DNA level with circulating markers (DTCs, CTCs, plasma tumor DNA), and ongoing assessment of therapeutic response.

METAMORPH is a prospective cohort study of women with suspected or confirmed recurrent breast cancer and accessible tumor by standard clinical biopsy, who are enrolled at the University of Pennsylvania prior to starting a new therapy for recurrent metastatic disease. The aims of this trial are to (1) evaluate the mechanisms through which recurrent breast cancer are genetically distinct from the primary tumor, (2) evaluate the circulating tumor biomarker trajectory of recurrent disease, (3) elucidate “escape pathways” of progressing tumors that emerge during the selective pressure of therapy, and (4) explore clinical utility of tumor and blood testing. The study protocol integrates research aims into clinical care, including a standardized approach to disease assessment and biopsy, pathologic confirmation of histology and receptor subtype, panel-based CLIA-approved genomic profiling, collection of research specimens, and standardized reporting of results, which are returned to patients and physicians. Patients are followed for treatment and outcome, and serial samples are collected at progression. A companion protocol, COMET, provides education about genomic testing and assesses patient understanding and impact of results. To date, 155 patients have enrolled, 142 (92%) have been biopsied, 120 (77%) have had sufficient DNA for molecular profiling and 109 (70%) have had genomic panel testing. Accrual is ongoing, with an initial target of 300 patients. Multiple sites within the UPHS Health System are enrolling. Contact information: angela.demichele@uphs.upenn.edu.

Key words: Metastatic disease, tumor profiling.

Citation Format: DeMichele A, Soucier-Ernst DJ, Clark C, Shih N, Stavropoulos W, Maxwell KN, Feldman M, Lierbamen D, Morrissette JJD, Paul MR, Pan T-C, Wang J, Belka GK, Chen Y, Yee S, Carpenter E, Fox K, Matro J, Clark A, Shah P, Domchek S, Bradbury A, Chodosh L. METAMORPH: METAstatic markers of recurrent tumor PHenotype for breast cancer [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 OT2-06-03.

Evaluation of a web-based weight loss intervention in overweight cancer survivors aged 50 years and younger

Purpose

Half of adult cancer survivors under age 50 years are obese. Excess body weight is associated with cancer recurrence, and effective weight loss interventions for younger cancer survivors are needed. Commercially available, online weight loss programmes are readily accessible, but few have been studied in this population. This study employed a single‐arm, pre‐post intervention (baseline‐6 month/baseline‐12 month comparisons) to preliminarily explore feasibility, efficacy and safety of an online, commercially available weight loss programme in breast (n = 30) and testicular (n = 16) cancer survivors under age 50 years.

Methods

The intervention included three daily components: exercise, nutritional/behavioural modification strategies and health lessons. Intention‐to‐treat and completers analyses were conducted. Feasibility was measured by participation (number of participants enrolled/number screened), retention (number of participants attending 6/12 month study visit/number of enrolled) and self‐reported adherence rates (average of mean percent adherence to each of the three intervention components). Efficacy was assessed by changes in initial weight (percent weight loss). Safety was assessed by adverse events.

Results

The mean participation rate was 42%. The retention rate was 59% at 6 and 49% at 12 months. The adherence rate for all participants (completers/dropouts/lost‐to‐follow‐up) was 50.1% at 6 and 44% at 12 months. Completers reported adherence rates of 68% at 12 months. Study participants lost 5.3% body weight at 12 months; completers lost 9%. Only three unexpected adverse events (unrelated to the intervention) were reported.

Conclusion

Clinically significant weight loss was observed, although retention rates were low. Findings generally support preliminary feasibility, efficacy and safety of this online weight loss programme, and future randomized control trials should be explored.

Abstract P2-08-03: Targeting inflammatory pathways: A phase 2 trial of the JAK-inhibitor ruxolitinib in combination with exemestane for aromatase inhibitor-resistant, estrogen receptor-positive breast cancer

Background: In vitro mechanisms link IL-6 to poor outcome in breast cancer via inflammatory pathways, activated JAK/STAT tumor signaling and upregulation of aromatase, leading to an aggressive tumor phenotype. Epidemiological data from our group and others support these mechanisms in women with ER-positive (+) disease. We therefore hypothesized that the JAK inhibitor, ruxolitinib (RUX, INCB018424; Incyte), would enhance activity of exemestane (EXE) in women with ER+ breast cancer who relapsed after non-steroidal aromatase inhibitor therapy, particularly among carriers of a germ-line polymorphism in IL-6, conferring elevated levels of IL-6 in the tumor microenvironment.

Methods: The “JAKEE trial” is a phase II trial to determine the safety and efficacy of RUX + EXE in postmenopausal women with relapsed, ER+ advanced breast cancer. Eligible patients were required to have progressed on a non-steroidal AI and either measureable or bone-only disease. CRP, a putative biomarker of tumor microenvironment inflammation, was measured at baseline and serially during treatment. Using a Simon 2-stage design, we treated 15 patients with RUX at 25 mg BID and EXE at 25mg daily on a continuous 28-day schedule. First stage results were previously presented (AACR, 2014). Accrual proceeded to second stage after no patient met the pre-defined stopping rule of grade (G) 3/4 toxicity requiring discontinuation from the study within the first treatment cycle. Due to the substantial rate of anemia requiring dose reductions, however, RUX dose was reduced to 15 mg BID in second stage.

Results: A total of 25 patients were enrolled; 24/25 had progressed on AI in metastatic setting; 1 relapsed on adjuvant AI. RUX+EXE was well-tolerated overall, with only 2 G4 events (creatinine elevation, hepatic failure); both were due to disease progression. 16% had G3 fatigue, anemia or hypertension; 12% had G3 neutropenia or depression. Other lower grade toxicities in >20% included musculoskeletal pain, increased ALT, and headache. Overall, patients stayed on therapy for a median of 3 cycles (range 2 – 21). There were no CR or PR, but 6/25 (24%) had prolonged disease control (SD> 6 months). Median CRP at study entry was 6.4 (range 0.3-38.9), with 8/25 (32%) having CRP>10. Achieving SD>6 months was not associated with baseline CRP (CRP>10 in 32% with vs. 33% without SD>6 months, p(exact)=1.0). A novel pharmacodynamic assay to assess STAT3 phosphorylation in peripheral blood mononuclear cells after RUX exposure demonstrated differential effects in patients with response.

Conclusions: Targeting JAK/STAT signaling in AI-resistant breast cancer with RUX+EXE was safe and well-tolerated. 24% of patients had prolonged SD, but baseline CRP level did not predict response. Correlative studies to determine whether host and/or tumor biomarkers predict response to therapy, including germline IL-6 genotype, immune profiles, p-STAT3 and estradiol levels, are currently underway.

Citation Format: DeMichele AM, Clark AS, Holmes R, Volpe M, Medrano C, Troxel A, Fox K, Domchek S, Matro J, Bradbury A, Shih N, Feldman M, Hexner E, Bromberg J. Targeting inflammatory pathways: A phase 2 trial of the JAK-inhibitor ruxolitinib in combination with exemestane for aromatase inhibitor-resistant, estrogen receptor-positive breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-08-03.

Abstract P6-01-02: Flourine-18-fluorodeoxyglucose positron emission tomography for the evaluation of response to therapy in bone-dominant metastatic breast cancer: Examination in patients enrolled on UPCC 17113

Background: Response of bone-only (BO) and bone-dominant (BD) metastatic breast cancer (mBC) to therapy is difficult to assess by conventional imaging. UPCC 17113 is a single institution prospective cohort study evaluating FDG PET at early and conventional follow up intervals, 4 and 12 weeks respectively, in patients with hormone receptor (HR) positive mBC receiving endocrine therapy. The objective of this study is to assess the relationship between changes relative to baseline in standard uptake values (SUV) of specific bone lesions and progression free survival (PFS). We will also explore change in SUV as it relates to overall survival (OS) and skeletal related events (SRE). We present interim results.

Methods: Enrolled patients were ≥18 years with biopsy proven or documented clinically obvious HR-positive BD/BO mBC due to start new endocrine therapy. Any line endocrine therapy was allowed. FDG PET was performed at baseline, 4 and 12 weeks after initiation of new therapy. SUVmax for the 5 most metabolically active osseous lesions, excluding sites previously treated by radiation or surgery, were recorded at baseline, 4- and 12- week time-points. Average index lesion SUVmax (sum SUVmax/#lesions) and % change from baseline were calculated. Decline of ≥30% from baseline was defined as significant.

Results: As of 6/1/2015, 11 patients were enrolled. All patients have completed the 4-week scan and 8 have completed the 12-week scan. Five and 6 out of the 11 patients had BO and BD HR-positive mBC respectively. Detectable changes in SUV from baseline were noted in all patients at both 4 and 12 weeks, with a 37% overall decline in average index lesion SUVmax at 4 weeks. 8 of 11 patients had a ≥30% decline, in SUV at 4 weeks averaging 46%. Five of the 6 patients in this group who completed the 12-week scan had a sustained decline averaging 50% from the baseline. Of note, the average decline between 4 and 12 weeks in this group was only 8%. Despite having an overall decline from baseline of 44%, the sixth patient in this group had an increase between 4 and 12 weeks of 22%. Three of the 11 patients had a <30% decline at 4 weeks with an average decline of 12%. Of the two patients in this group with 12 week scans, both had average increase of 25% from 4 weeks to 12 weeks, and an average overall increase from baseline of 12%.

Conclusions: There are detectable changes in FDG SUV of osseous lesions at 4 and 12 weeks following initiation of endocrine therapy in patients with BO or BD HR positive mBC. Our interim results demonstrate the emergence of 3 groups of patients: (1) those who have a <30% decline at 4 weeks and increase of SUV at 12 weeks, (2) those who have a ≥30% decline in SUV at 4 weeks with sustained decline at 12 weeks, and (3) those who have a ≥30% reduction in SUV at 4 weeks but who do not have a sustained decline at 12 weeks. These interim results suggest that early FDG PET/CT may provide information on mBC response to endocrine therapy and insight into timing of response and progression. As more patients are enrolled and complete the studies, clearer patterns will emerge which will be correlated with PFS, OS and SRE.

Citation Format: Lynch MC, Mankoff D, Bradbury AR, Domchek S, Glick JH, Matro J, DeMichele A, Clark AS. Flourine-18-fluorodeoxyglucose positron emission tomography for the evaluation of response to therapy in bone-dominant metastatic breast cancer: Examination in patients enrolled on UPCC 17113. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-01-02.

Abstract P6-13-08: Palbociclib and paclitaxel on an alternating schedule for advanced breast cancer: Results of a phase Ib trial

Background: Palbociclib (P) is an oral CDK 4/6 inhibitor (CDKi) that was recently FDA approved in combination with endocrine therapy for metastatic breast cancer. We have performed a Phase I trial of P in combination with paclitaxel (T) based on preclinical studies suggesting that P synergizes with T when given on an alternating schedule, enabling cell cycle synchronization in tumor cells. We now present the dose expansion cohort.

Methods: Patients (Pts) enrolled on the trial had Rb-expressing tumors of any estrogen/progesterone/HER2 receptor type, adequate organ function, and ≤3 prior chemotherapy regimens for metastatic breast cancer (mBC). Prior adjuvant or metastatic taxane was allowed. Dose escalation led to expansion at P100mg or 75mg, starting with 3 days of P (run-in) and reduction of P dosing from 5-day to 3-day intervals (days 2-4, 9-11, 16-18 of each 28 day cycle). T at 80mg/m2 was given weekly for 3 cycles; thereafter, T was administered days 1, 8 and 15 of 28 day cycle. Weekly toxicity assessments were performed; RECIST 1.0 response was assessed every 2 cycles as partial response (PR), stable disease (SD) or progressive disease (PD). Pts had the option to discontinue T and continue on P alone (3 on/1 off schedule) if they attained SD after cycle 6.

Results: 27 pts enrolled on study (15- dose escalation, 12- dose expansion). Results are shown in the Table. 21 pts had received prior taxane; pts had received a median of 2 chemotherapy regimens for mBC. DLTs were grade 3 AST/ALT (n=1, at 125 mg) and febrile neutropenia (FN) (n=1, at 100 mg). Uncomplicated grade 3/4 NTP was common and frequently led to dose reduction or dose interruption during the first cycle of therapy. Frequency of NTP did not change with reducing the days of P. Among 24 evaluable patients, 14 (58%), had PR or SD ≥ 6 months across all dose levels. Of 14 pts who responded, 10 (71%) had received prior taxane. 20 pts are off study; 19 for PD, and 2 for toxicity (NTP in cycle 17 and FN in cycle 1); 7 pts remain on study. Prolonged tumor responses were seen.

Conclusions: P and T can be safely combined on an alternating dosing schedule; the optimal combination dose is 75 mg of P and 80mg/m2 of weekly T. The high response rate warrants a randomized trial to determine the incremental benefit over T alone. Additional mechanistic studies are in progress to understand the in vivo effects of the alternating dosing schedule on cell cycle activity and tumor proliferation.

Starting Dose Level P (mg)Number (Total 27)DLTGrade 3/4 NTP (n)Final Dose P mg (n)Dose Interruption (n)Best Response (n)5030050 (1) 50 (1) 50 (1)No (2) Yes (1)PR (1) SD (1) PD (1)7530275 (1) 50 (1) 25 (1)No (1) Yes (2)PR (2) SD (1)100605100 (2) 75 (3) 25 (1)No (1) Yes (5)PR (2) SD (1) PD (3)12531- LFT375 (1) 50 (2)No (0) Yes (3)PR (1) SD (2)75 (Run-In)60175 (5) 50 (1)No (4) Yes (2)PR (1) SD (2) PD (1) N/A (2)*100 (Run-In)61- FN5100 (1) 75 (4) 25(1)No (1) Yes (5)PR (4) SD (1) N/A (1)^*2 pts not yet evaluable. ^1 pt went off study due to FN after cycle 1.

Citation Format: Clark AS, O'Dwyer P, Troxel A, Lal P, Feldman M, Gallagher M, Driscoll A, Colameco C, Lewis D, Rosen M, Matro J, Bradbury A, Domchek S, Fox K, DeMichele A. Palbociclib and paclitaxel on an alternating schedule for advanced breast cancer: Results of a phase Ib trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-13-08.

Abstract P6-07-05: Mutational spectrum and tumor response in metastatic breast cancer

Background: While several comprehensive genomic sequencing tests are clinically available for breast cancer(BC), little is known about the spectrum of findings reported in the general population and clinical utility of findings for patients(pts). Here we report tumor sequencing from the METAMORPH study, a comprehensive genomic testing approach in pts with metastatic(met) BC.

Methods: Pts with either known or suspected BC mets consented to and clinically underwent concurrent diagnostic and research tumor biopsies(bx). FFPE specimens were profiled via Illumina TruSeq Cancer Panel next generation sequencing platform covering 212 amplicons in 47 cancer genes. Pathology, treatment and outcome data were prospectively collected and tracked. Aside from Her2-directed treatment, therapy was not mutation (mut)-matched.

Results: 64 pts enrolled between 11/2013 – 05/2015. Of these, 48 had bx successfully sequenced (75%). Of those without sequencing, 5 had negative/insufficient tissue, 2 had insufficient DNA, remainder no bx/pending. Median age of those sequenced was 56 (range 31-78); 81% Caucasian, 17% African American. 25% (12 pts) presented with de novo stage IV disease. Of those with recurrence (n=36), 83% had prior adjuvant chemotherapy; 81% hormone receptor positive(HR+) had prior endocrine therapy. Median # prior lines of therapy for met disease was 2 (IQR 0 – 8). Tumor characteristics, including mut analyses, are shown in Table 1. # muts did not differ significantly by subtype(p=0.22). Frequency of TP53 and PIK3CA hotspot muts was nearly identical to TCGA. Median # muts was 1 for pts with both de novo mets and recurrence(p=0.79). # of muts was not associated with time to recurrence(p=0.80). Excluding pts found to have TP53 mut only or ERBB2 alterations in known Her2+ disease, 42% of pts were identified as having at least one potentially actionable alteration (PIK3CA mut, AKT1 mut or EGFR amplification). Median time to treatment failure(TTF) on subsequent therapy was 4.1 months for overall group, and 4.1, 6.2, and 1.6 months for HR+/Her2-, any Her2+ and TN, respectively, adjusted for line of therapy(p=0.03). After adjustment for # lines of prior met therapy, TTF was 4.7 vs. 4.1 months for pts with any mut vs. none(p=0.89); 5.7 vs 4.1 months for PIK3CA+ vs. not (p=0.94); 3.3 vs. 6.5 months for TP53+ vs. not (p=0.03).

Conclusion: Pts with met BC have frequent and potentially actionable muts.While overall # of muts did not affect response, tumors with TP53 muts had shorter response to subsequent therapy in this cohort. Additional data are needed to determine the clinical utility of mut testing in met BC, for both standard and mut-matched therapy.

 Total (n=48)HR+/Her2- (n=28)Any HER2+ (n=7)TN (n=13)Receptor concordant with primary 100%78%77%# Mutations Median (Range)1 (0-4)1 (0-3)1 (1-2)1 (0-4)014 (29%)10 (36 %)04 (31%)118 (38%)11 (39%)4 (57%)3 (23%)213 (27%)5 (18%)3 (43%)5 (38%)3+3 (6%)2 (7%)01 (8%)Prevalent Mutations (>20%)TP53 (38%), PIK3CA (35%)PIK3CA (50%), TP53 (25%)TP53 (60%), ERBB2amp (86%)TP53 (62%),PIK3CA (23%)Other Alterations (#)ATM (1), KIT (1), PDGFRA (1), PTEN(1), RB1 (1), SMAD4 (1), SMO (1), STK11 (1)AKT1 (1), ATM VUS (1), ERBB2 (1), PTEN (1), SMAD4 VUS (1), SMO VUS (1)ERBB2 (1), STK11(1)EGFR amp (2), KIT amp (1),PDGFRA amp (1), RB1 VUS (1)

Citation Format: Soucier-Ernst D, Colameco C, Troxel AB, Clark C, Shih N, Maxwell KN, Morrissette J, Lieberman D, Feldman M, Goodman N, Bradbury A, Clark A, Domchek S, Fox K, Glick J, Matro J, Nathanson K, Chodosh L, DeMichele A. Mutational spectrum and tumor response in metastatic breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-07-05.

Abstract P2-16-20: Biomarkers to predict response to the CDK 4/6 inhibitor, palbociclib (PD 0332991) in a single-agent phase II trial in advanced breast cancer

Background: The Cyclin D1-CDK4/6 complex is critical in regulating the G1/S checkpoint and phosphorylation of retinoblastoma protein (Rb); palbociclib is a highly-selective CDK 4/6 inhibitor. CCND1, the gene encoding Cyclin D1, is amplified in 15% of breast tumors; p16, the endogenous inhibitor of the complex is lost in up to half of breast tumors. We hypothesized that breast tumors containing either alteration or a high proliferative rate would have enhanced sensitivity to palbociclib. We conducted a single-agent, phase II trial of palbociclib in patients with advanced breast cancer (UPCC03909). In this trial, the clinical benefit rate (partial response [PR] + stable disease ≥6 months [6mSD]) was 17% (DeMichele, ASCO, 2013). The current analysis was a secondary endpoint to determine whether Rb expression, p16 loss, Ki-67 index or CCND1 amplification predicted response in the phase II trial.

Methods: Enrollment on UPCC03909 required archival tumor collection from either primary tumor or metastatic lesions. Fresh frozen paraffin-embedded (FFPE) tumor sections were tested for expression of Rb, Ki-67 and p16 by immunohistochemistry (IHC), and CCND1 amplification by fluorescence in situ hybridization. Categorical variables based on% tumor staining and intensity scores (negative defined as 0 or 1+ intensity staining, equivocal defined as 2+ staining or 3+ in <30%, or positive defined as 3+ staining intensity in 30%) were generated for Rb and p16 nuclear staining. Fisher's Exact test was used to test for associations between nominal factors, the Cochran-Mantel-Hænszel test for associations between ordinal factors, and the Cox proportional hazard model for association of progression-free survival (PFS) with biomarkers.

Results: Thirty-seven patients were enrolled; response evaluation is available in 36/37. All had FFPE tumor available for Rb, 33/37 (89%)for CCND1 amplification and 29/37 (78%) for Ki-67 and p16 analyses. For complete results see Table 1.

Conclusions: These results provide preliminary evidence that breast tumors more likely to respond to palbociclib may have higher Rb nuclear expression, lower Ki67 indices and/or loss of p16. Larger studies are needed to confirm these results.

Table 1: Biomarker Summary and ResponseBiomarkerBiomarker CategoizationFrequency (%)Response Rate PR+6mSD/total (%)PFS Hazard Ratio (95%CI)Overall Population (n = 37)  6/36 (17%) Ki-67 (n = 29)≤ 10 (n = 20)69%4/19 (21%)1.00 > 10 (n = 9)31%1/9 (11%)1.20 (0.50, 2.88)Rb (n = 37)Nuclear Score: Negative (n = 11)30%0/11 (0%)1.00 Equivocal (n = 15)40%2/14 (14.3%)0.72 (0.28, 1.84) Positive (n = 11)30%4/11 (36.4%)0.71 (0.28, 1.80)p16 (n = 29)Loss or Low Expression (n = 16)55%4/16 (25%)1.00 Moderate or High Expression (n = 13)45%1/12 (8.3%)1.08 (0.47, 2.49)CCND1 Amplification (n = 34)Non-amplified (n = 25)88%4/25 (16%)1.00 Amplified (n = 9)12%1/8 (12.5%)1.06 (0.46, 2.4)

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-20.

Abstract P4-01-08: Effect of bilateral salpingo-oophrectomy on breast MRI fibroglandular volume and background parenchymal enhancement for BRCA 1/2 mutation carriers

PURPOSE: Bilateral salpingo-oophrectomy (BSO) reduces breast cancer risk in women with BRCA1/2 mutations by approximately 50%. Annual screening for these high-risk women includes breast MRI and mammography. It is unknown whether BSO affects fibroglandular volume (FG) and background enhancement (BG) on breast MRI in this population. The purpose of this study is to assess the difference in FG and BG in BRCA1/2 mutation carriers before and after BSO on breast MRI.

METHOD AND MATERIALS: We compared FG and BG on contrast-enhanced breast MRI before and after BSO. Two readers blinded to both clinical and imaging history scored FG according to the BI-RADS criteria from 1–4: fatty, scattered, heterogeneously dense, or extremely dense. BG was graded based on the MRI BI-RADS scale from 1–4: minimal, mild, moderate, and marked. Average BIRADS scores of each reader were used to calculate mean FG and BG (±SD) before and after BSO, and compared using a paired t-test for significance.

RESULTS: We examined 60 women with BRCA1/2 mutations who underwent breast MRI before and after BSO from 2001–2011 at our institution. Five patients were excluded from the final analysis as they underwent mastectomy or bilateral radiation therapy before post-BSO MRI. Mean time to post-BSO MRI was 8.3 months ± 7 months. Mean pre- and post-operative FG were 2.64±0.78 and 2.58±0.75, respectively (p = 0.622). Mean pre- and post-operative BG were 2.46±0.93 and 1.87±0.81, respectively (p = 0.0001). Breast cancer was detected in 8 women at a median time of 3.4 years following BSO. In these 8 women, mean pre- and post-operative FG were 3.10±0.57 and 2.55±0.69, respectively. Mean pre- and post-operative BG were 3.20±0.67 and 2.35±0.71, respectively.

CONCLUSION: In this population of 55 BRCA1/2 mutation carriers who underwent breast MRI before and after BSO, there was a significant reduction in BG following BSO. There was no difference in FG on MRI following BSO. For the 8 patients in this cohort who were diagnosed with breast cancer after BSO, there was a trend toward higher FG and BG both before and after BSO, in comparison to the patients who were not diagnosed with breast cancer, suggesting that rates of higher FG and BG may be associated with increased risk for developing breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-01-08.

P1-17-06: A Phase II Trial of the CDK 4/6 Inhibitor PD0332991 in Women with Advanced Breast Cancer

Background: Dysregulation of the G1/S checkpoint of the cell cycle is a feature of many breast cancers. PD0332991, a potent oral inhibitor of cyclin-dependent kinases (CDKs) 4 and 6 is well-tolerated and has demonstrated activity in a phase I trial in a variety of solid tumors at a phase II dose of 125 mg daily on a 3 week on/1 week off schedule. Preclinical data suggest that this agent is most active in ER+ (luminal) breast cancers. We are performing a phase II study of PD0332991 in women with advanced breast cancer, one of several parallel disease cohorts under study.

Methods: Patients with histologically-confirmed stage IV breast cancer were eligible if they had primary or metastatic tumor which stained positive for retinoblastoma (Rb) protein by immunohistochemistry, disease measureable by RECIST criteria and adequate organ function/performance status. Treatment was initiated with PD0332991 at 125 mg orally, days 1 - 21 of a 28-day treatment cycle. Tumor assessments occurred after every 2 cycles (8-week intervals). The primary objective was to determine the safety and response rates in cohorts of 15 patients per tumor type; 15 patients per arm provided 80% power to detect a 15% (1/15) response rate per disease that would lead to further cohort expansion. Secondary objectives include PK, PD and predictive biomarker assessment.

Results: 36 patients were screened, 32 (89%) stained positive for Rb, and 14 have enrolled on study. The only reported toxicites are neutropenia (7 patients, 4 grade 3/4), thrombocytopenia (1 patient, grade 1) and fatigue (1 patient, grade 2). 3 patients (23%) have had dose interruptions and 5 (38%) have had dose-reduction for neutropenia, though no episodes of febrile neutropenia have occurred. Among 11 patients assessable for response to date, there is 1(7%) partial response (PR), 6 (43%) with stable disease (SD) and 4 (29%) with progressive disease (PD). 3 of 6 patients with stable disease have received greater than 6 months of therapy, and these sustained responses have occurred with dosing as low as 50 mg/day. All PR/SD have occurred in patients with ER+ tumors; all PD have been in patients with triple negative (ER-/PR-/Her2-) disease. The cyclin D1 status of all patients are being assessed. Of the 10 ER+ patients, 3 are cyclin D1 amplified, 5 are non-amplified and 2 are pending assessment. 2 in 4 cyclin D1 non-amplified patients had SD, while 2 of 2 evaluable patients with amplification had SD. PK and PD analyses are in progress.

Conclusions: PD 0332991 is an extremely well-tolerated, oral CDK 4/6 inhibitor that demonstrates prolonged single-agent activity in ER+ breast cancer patients who have progressed on hormonal therapy. These data have prompted expansion of this breast cancer cohort to further delineate activity and translational studies examining predictors of response are underway.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-17-06.

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study

OBJECTIVE

To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported.

PATIENTS AND METHODS

Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation.

RESULTS

In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant.

CONCLUSIONS

The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

Effect of genetic counseling and testing for BRCA1 and BRCA2 mutations in African American women: a randomized trial

BACKGROUND

Limited empirical data are available on the effects of genetic counseling and testing among African American women.

OBJECTIVE

To evaluate the effects of genetic counseling and testing in African American women based on different levels of exposure: (a) women who were randomized to culturally tailored (CTGC) and standard genetic counseling (SGC) to women who declined randomization (non-randomized group), (b) participants and non-participants in genetic counseling, and (c) BRCA1 and BRCA2 (BRCA1/2) test result acceptors and decliners.

DESIGN

Randomized trial of genetic counseling conducted from February 2003 to November 2006.

MEASURES

We evaluated changes in perceived risk of developing breast cancer and cancer worry.

RESULTS

Women randomized to CTGC and SGC did not differ in terms of changes in risk perception and cancer worry compared to decliners. However, counseling participants had a significantly greater likelihood of reporting reductions in perceived risk compared to non-participants (p = 0.03). Test result acceptors also had a significantly greater likelihood of reporting decreases in cancer worry (p = 0.03). However, having a cancer history (p = 0.03) and a BRCA1/2 prior probability (p = 0.04) were associated with increases in cancer worry.

CONCLUSIONS

Although CTGC did not lead to significant improvements in perceived risk or psychological functioning, African American women may benefit from genetic counseling and testing. Continued efforts should be made to increase access to genetic counseling and testing among African American women at increased risk for hereditary disease. But, follow-up support may be needed for women who have a personal history of cancer and those with a greater prior probability of having a BRCA1/2 mutation.

Local Therapy in BRCA1/2 Carriers with Operable Breast Cancer: Comparison of Breast Conservation and Mastectomy

Background: Women with inherited germline BRCA1/2 mutations have a 55-85% cumulative risk of breast cancer (BC) by age 70. Thus, knowledge of expected outcomes following various treatments is needed to advise these patients should they be diagnosed with BC. It is unclear whether breast conservation (BCT) offers similar rates of tumor control as mastectomy (M) in BRCA1/2 carriers and it is doubtful whether a randomized trial comparing these options could be performed. Thus, this analysis compares the outcomes between similarly staged women with BRCA1/2 mutations treated with BCT vs. M.Methods: Women with deleterious BRCA1/2 mutations diagnosed with operable BC and who consented to longitudinal studies were identified at 10 institutions in the US, Australia, Spain and Israel. Patient, clinical and treatment characteristics were compared between those receiving BCT and those receiving M +/- RT. Time-to-event endpoints included first failure of treatment, diagnosis of contralateral breast cancer (CBC), and overall and BC-specific survival. Cox regression models were constructed to detect significant associations between patient and clinical characteristics and time-to-event endpoints.Results: Clinical characteristics and outcomes for 302 BCT and 353 M patients were compared. With a median F/U of 8.2 years for BCT patients and 8.9 years following M, 15-year local failure as first failure was significantly higher with BCT vs. M (23.5% vs. 5.5%, p<0.0001). Multivariate analysis indicted choice of local therapy as the only factor significantly predicting local recurrence, with a 4.5-fold risk of local failure with BCT compared to M (p<0.0001). Local failure analyses by cohort revealed the presence of a BRCA2 mutation (HR 2.8; p=0.024) and no use of adjuvant chemotherapy (HR 5.4; p=0.0001) as significant predictors within the BCT group; presence of invasive lobular cancer (HR 9.9; p=0.004) was the only significant predictor within the M cohort. No significant differences were seen in distant failure, BC-specific or overall survival by local therapy. 15-year estimates of CBC were 52.1% with BCT; 41.4% with M; and 37.9% with M+RT (p=0.44). Analyses of BCT vs. M +/- RT and surgery +/- RT did not reveal significant differences in CBC by cohort.Conclusions: The higher risk of local failure in BRCA1/2-associated BC treated with BCT compared to M did not translate into an increased risk of distant failure or mortality. RT did not result in a detectable increase in CBC at 15 years above baseline elevated rates. These results at both the involved and contralateral breasts should be discussed when patients with BRCA1/2-associated BC are considering local treatment options.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 959.

Phase II trial of the oral PARP inhibitor olaparib in BRCA-deficient advanced breast cancer

CRA501

Background: Olaparib (AZD2281; KU-0059436) is a novel, orally active PARP inhibitor that induces synthetic lethality in homozygous BRCA-deficient cells. A phase I trial identified 400 mg bd as the maximum tolerated dose (MTD) with an initial signal of efficacy in BRCA-deficient ovarian cancers (ASCO 2008; abst 5510). The primary aim of this study was to test the efficacy of olaparib in confirmed BRCA1/BRCA2 carriers with advanced refractory breast cancer. The secondary aim was to assess safety and tolerability in this population. Methods: In an international, multicenter, proof-of-concept, single-arm, phase II study, two sequential patient (pt) cohorts received continuous oral olaparib in 28-day cycles initially at the MTD, 400 mg bd (27 pts), and subsequently at 100 mg bd, a previously identified PARP inhibitory dose (27 pts). Eligibility criteria included confirmed BRCA1/BRCA2 mutation and recurrent, measurable chemotherapy-refractory breast cancer. The primary efficacy endpoint was best objective response rate (ORR; RECIST) post baseline. Progression-free survival (PFS) and clinical benefit rate were secondary endpoints. All adverse events were reported using CTCAE v3. Results: On November 20, 2008, 54 pts exposed to a median of three prior lines of chemotherapy had been enrolled. 27 pts were dosed at 400 mg bd (18 BRCA1 deficient and 9 BRCA2 deficient), and 24 of these had databased RECIST assessments. The ORR (currently based on unconfirmed responses) was 38% (9/24) (400 mg bd). Causally-related toxicity was mainly mild (grade 1–2) in severity; 9/27 pts (33%) had fatigue; 7/27 (26%) had nausea; 4/27 (15%) had vomiting; and 1/27 (4%) had anemia. Causally-related grade 3 or higher toxicities were seen in 5 pts (19%) with fatigue (3 pts), nausea (2 pts), and anemia (1 pt). 27 pts were treated in the subsequent 100 mg bd cohort where no data are currently available. Conclusions: Olaparib at 400 mg bd is well tolerated and highly active in advanced chemotherapy-refractory BRCA-deficient breast cancer. Toxicity in BRCA1/BRCA2 carriers was similar to that reported previously in non-carriers. This first study with olaparib in BRCA-deficient breast cancers provides positive proof of concept for high activity and tolerability of a genetically defined targeted therapy.

[Table: see text]

Phase II trial of the oral PARP inhibitor olaparib in BRCA-deficient advanced breast cancer

CRA501

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]

Genetic counseling for BRCA1 and BRCA2 mutations in African American women

Abstract #1099

Background: Efforts are now focused on increasing access to genetic counseling and testing for BRCA1 and BRCA2 (BRCA1/2) mutations to address cancer disparities in African American women; however, limited empirical data are available on the effects of these services. Therefore, we evaluated the effects of genetic counseling among African American women at increased risk for hereditary disease.
 Materials and Methods: This study was conducted between February 2003 and November 2006. Participants were African American women (n=139) at increased risk for having a BRCA1 or BRCA2 (BRCA1/2) mutation. The effects of genetic counseling, including culturally tailored (CTGC) versus standard (SGC) counseling, on changes in risk perception and psychological functioning were evaluated.
 Results: Women who participated in genetic counseling had a significantly greater likelihood of reporting reductions in perceived risk compared to non-participants (P=0.03). Women who received BRCA1/2 results also had a significantly greater likelihood of reporting decreases in cancer worry (P=0.03). Similar effects were found among women who had a high prior probability of having a BRCA1/2 mutation (P=0.03) and those affected with cancer (P=0.04). There were no differences in CTGC and SGC in study outcomes.
 Discussion: African American women may experience some benefit from receiving BRCA1/2 test results. Participation in counseling and receiving test results may be especially beneficial to African American women who have high prior probability of having a BRCA1/2 mutation and those affected with cancer. Continued efforts should be made to increase access to genetic counseling and testing among African American women at increased risk for hereditary disease.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1099.

Contralateral prophylactic mastectomy in affected carriers of deleterious BRCA1 or BRCA2 mutations: Does timing of genetic testing matter?

10512

Introduction: Prophylactic mastectomy (PM) reduces breast cancer risk by >90% in women who are carriers of deleterious BRCA1 or BRCA2 mutations. Genetic testing prior to breast cancer surgery has been reported to affect PM decision in high-risk patients. The ideal timing of genetic testing as well as the clinical characteristics of affected mutation carriers electing PM remain unclear. This is a pilot study to identify significant clinical characteristics associated with affected carriers who had undergone PM. Methods: Retrospective chart review was performed on 103 breast cancer affected BRCA1 or BRCA2 mutation carriers that were seen at our high risk clinic who had undergone genetic testing between 1995 and 2005. Clinical characteristic, initial surgery treatment modalities, and dates of genetic testing and prophylactic mastectomy were collected and analyzed using the chi-square or Fisher exact tests. Results: Of the 103 affected mutation carriers, 30 (29%) underwent prophylactic mastectomy (PM) where as 73 (71%) did not (no PM). Ethnicity, age of diagnosis, tumor size, nodal status, family history and initial breast cancer surgery types (BCT vs. mastectomy) were not significantly different between the two groups. Of the 30 women who underwent PM, 19 (63%) vs. 9 (30%) underwent PM before and after their genetic testing respectively. Of the 19 women who had PM before their genetic testing, 4 (21%) had BCT as initial treatment whereas 15 (78.9%) had mastectomy as initial treatment and 9 of 15 (60%) had synchronous contralateral prophylactic mastectomy. For the 9 women who had PM after their genetic testing, 5 (56%) had BCT vs. 4 (44%) had mastectomy as their initial surgical treatment (p < 0.001). Conclusion: In this study, we found a significant correlation between the initial breast cancer surgical modality of mastectomy with women undergoing prophylactic mastectomy. The impact of family history of breast cancer does not appear to be significant. Physician recommendations or patient preference are unknown. Our data suggest that high risk women who elect mastectomy as their initial surgical management to treat their breast cancer are more likely to undergo prophylactic mastectomy regardless of knowledge of their mutation status.

No significant financial relationships to disclose.

Internet use is associated with utilization of genetic counseling for BRCA 1/2 mutations in women with a family history of breast or ovarian cancer

10654

Background: Women obtain breast cancer risk information from a variety of sources including mass media, the internet and personal and professional sources. Little is know about how internet use for health information influences choices about breast cancer risk evaluation and decision making. Methods: Case control study of 408 women with a family history of breast or ovarian cancer, of whom 217 underwent genetic counseling for BRCA 1/2 testing (cases) and 191 women who did not (controls). Participants received primary care within a large health system in greater Philadelphia, PA. Results: Women with a family history of breast or ovarian cancer who reported frequent use of the internet for health information (>1–2 times a month) were significantly more likely to undergo genetic counseling for BRCA 1/2 testing than women that rarely used the internet to obtain health information (<2 times a year) (odds ratio 2.6; 95% CI 1.7–4.0). This association persisted after adjustment for age, race, education and Gail risk (adjusted odds ratio 2.1; 95% CI 1.05–4.2) Conclusions: Frequent use of the internet for health care information is associated with higher use of genetic counseling for BRCA 1/2 mutations in women with a family history of breast or ovarian cancer. The association can not be explained by differences in education, cancer risk, age or race. A possible hypothesis for this association is that internet use exposes women to more information about genetic testing, BRCA testing opportunities and the experiences of other women who have utilized BRCA counseling services.

No significant financial relationships to disclose.