Abstract PD1-08: Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 for estrogen receptor-positive (ER+) advanced breast cancer (ABC) with progression on endocrine therapy (ET)

Background: LSZ102 is an orally bioavailable SERD that inhibits ER gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This study is evaluating LSZ102 as a single agent and in combination with the CDK 4/6 inhibitor ribociclib (LEE011) or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with ER+ ABC. The LSZ102 single agent data are presented below; combination data are not discussed.

Methods: In the dose-escalation phase evaluating single-agent LSZ102 (Arm A), pts (age ≥18 years; ECOG PS 0-1) with histologically confirmed ER+ ABC and progression on endocrine therapy (ET) received LSZ102. The starting dose was 200 mg once daily. The primary objective of Arm A was to characterize the safety and tolerability of LSZ102 and identify a recommended dose for expansion (RDE). Secondary objectives included preliminary antitumor activity and pharmacokinetics (PK).

Results: As of January 22, 2018, 57 pts were enrolled to Arm A (LSZ102 200 mg, n=4; 400 mg, n=6; 450 mg fasted, n=15; 450 mg with food, n=6; 600 mg, n=20; 900 mg, n=6). Median age was 60 years, 75% (n=43) of pts had an ECOG PS of 0, 56% (n=32) had received prior fulvestrant, and 58% (n=33) had received prior CDK4/6 inhibitors; median number of prior lines of therapy (all settings) was 6. At data cut-off, 48 pts had discontinued treatment, most (n=45, 94%) due to disease progression. Dose-limiting toxicities across treatment groups included diarrhea (2 pts in the 900-mg group), vomiting (1 pt in the 600-mg group), and AST and ALT elevation (1 pt in the 450-mg with food group). The most common treatment-related adverse events (AEs) in the treatment period were diarrhea (60%), nausea (56%), and vomiting (30%). In the treatment period, treatment-related grade 3 AEs (12%) were infrequent, and there were no such grade 4 events. Six pts (11%) required dose reduction due to AEs (nausea, vomiting or diarrhea); 4/6 of the dose reductions occurred at 900 mg. Preliminary PK assessment showed rapid absorption and dose-proportional increases in LSZ102 exposure; trough concentrations were above the predicted tumorostatic concentrations at doses of ≥400 mg. Based on PK results for the 450-mg fasted and fed cohorts, LSZ102 exposure does not appear to be affected by dosing with a regular meal. Evidence of ER modulation by immunohistochemistry was observed in paired baseline and on-treatment biopsies. 18F-fluoroestradiol positron emission tomography (FES-PET) analysis (n=6) demonstrated abrogation of FES-PET signal for pts in the 450-mg and 600-mg dose groups. Seventeen pts (29.8%) had a best response of stable disease, and 1 pt, who happened to be in the 600-mg group, achieved a partial response.

Conclusion: In heavily pretreated pts, LSZ102 was well tolerated, demonstrated antitumor activity, and achieved effective exposure levels based on PK and pharmacodynamics. Food intake did not appear to significantly alter the PK profile of LSZ102. Dose escalation for LSZ102 in combination with ribociclib or alpelisib is ongoing and will be reported in a future analysis. An update on the recommended single agent dose and schedule will be presented.

Citation Format: Jhaveri K, Curigliano G, Yap Y-S, Cresta S, Duhoux FP, Terret C, Takahashi S, Ulaner GA, Kundamal N, Baldoni D, Liao S, Crystal A, Juric D. Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 for estrogen receptor-positive (ER+) advanced breast cancer (ABC) with progression on endocrine therapy (ET) [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 PD1-08.

Abstract OT1-03-01: Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 in combination with alpelisib (BYL719) in estrogen receptor-positive (ER+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) with progression on endocrine therapy (ET)

Background: Although ET remains the basis of therapy for ER+, HER2– ABC, treatment resistance frequently occurs. Novel strategies to target the receptor and/or alternative pathways to overcome therapeutic resistance are under investigation. LSZ102 is a novel, orally bioavailable, nonsteroidal SERD. Preclinically, LSZ102 inhibits ER gene transcription, induces receptor degradation, blocks ER-dependent cell growth, and has synergistic activity with the phosphoinositide 3-kinase (PI3K)-alpha inhibitor alpelisib (BYL719). The present study is evaluating the safety and tolerability of LSZ102 plus alpelisib in patients with ER+, HER2– ABC with progression on ET.

Trial Design: This phase 1/1b, open-label study is enrolling ˜18-30 patients (men and women of any menopausal status) in Arm C of the dose-escalation part of the study, which investigates the combination of LSZ102 and alpelisib; additional study arms will investigate LSZ102 as a single agent or in combination with ribociclib. Enrollment in Arm C started after identification of a safe and tolerable single-agent dose for LSZ102. Alpelisib dosing began at 200 mg/day and will not be escalated beyond the maximum tolerated dose (MTD) determined in the alpelisib single-agent arm of study CBYL719X2101 (400 mg/day). Dose escalation of alpelisib in combination with LSZ102 is guided by BLRM and integrates Cycle 1 DLT rates, lower grade and later cycle AE, PK, PD and preliminary activity to identify a recommended dose for expansion (RDE). Patients will receive treatment until disease progression, unacceptable toxicity, or withdrawal of consent. For inclusion in the study, patients must have histologically confirmed ER+, HER2– ABC and disease progression after ET for ABC or recurrence on/within 12 months of completion of adjuvant ET. In the escalation part of the study, patients are eligible regardless of PIK3CA status. Premenopausal women must receive concomitant treatment with a gonadotropin-releasing hormone agonist. Eligible patients must have adequate bone marrow and organ function, Eastern Cooperative Oncology Group performance status of 0 or 1, and have completed and recovered from acute toxicities of radiotherapy and/or prior anticancer therapy. Exclusion criteria include symptomatic central nervous system metastases, clinically significant cardiac disease or impaired cardiac function (including a QT interval corrected for heart rate using Fridericia's formula [QTcF] >460 ms in women or >450 ms in men), uncontrolled diabetes mellitus type II (or type I), and prior treatment with a PI3K inhibitor. The primary objectives are characterization of safety and tolerability for the combination and identification of a recommended dose. Secondary objectives include characterization of pharmacokinetic properties and pharmacodynamic effects. Recruitment for Arm C is ongoing. NCT02734615

Citation Format: Curigliano G, Cresta S, Yap Y-S, Juric D, Duhoux FP, Terret C, Takahashi S, Layman RM, Kundamal N, Baldoni D, Liao S, Crystal A, Jhaveri K. Phase 1/1b study of novel oral selective estrogen receptor degrader (SERD) LSZ102 in combination with alpelisib (BYL719) in estrogen receptor-positive (ER+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) with progression on endocrine therapy (ET) [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 OT1-03-01.

Abstract P5-21-04: Phase I/Ib study of the SERD LSZ102 alone or in combination with ribociclib in ER+ breast cancer

Background: LSZ102 is an orally bioavailable selective estrogen receptor degrader (SERD) that inhibits estrogen receptor (ER) gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This Phase I/Ib, open-label study is evaluating LSZ102 as a single agent and in combination with the CDK4/6 inhibitor ribociclib (LEE011) or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with locally advanced/metastatic ER-positive (ER+) breast cancer (BC).

Methods: The primary objective is to characterize the safety and tolerability, and identify a recommended dose and regimen of LSZ102 alone (Arm A) or in combination with ribociclib (Arm B) or alpelisib (Arm C). Secondary objectives include evaluation of preliminary antitumor activity and pharmacokinetics (PK). Eligible pts (aged ≥18 yrs; ECOG PS 0-1) have histologically confirmed ER+ BC that has progressed after endocrine therapy.

Results: As of March 14, 2017, dose escalation evaluating 16 pts in Arm A (LSZ102 200 mg [n=4], 400 mg [n=6], and 600 mg [n=6]) had completed (median age 57.5 yrs; 81% ECOG PS 0; 63% received prior fulvestrant). Five pts (median age 59.0 yrs; 80% ECOG PS 0; 60% received prior fulvestrant) had enrolled in the first cohort of Arm B (LSZ102 200 mg QD + ribociclib 300 mg 3 weeks on/1 week off) with evaluation ongoing. Arm C (LSZ102 + alpelisib) had yet to open. As of March 14, 2017, 9/16 (56%) pts in Arm A had discontinued treatment, all due to progressive disease (PD); in Arm B all pts were still receiving treatment. There were no dose-limiting toxicities in either arm at the dose levels evaluated; dose escalation is ongoing. The most common drug-related adverse events (AEs) were diarrhea (Grade [Gr] 1: 7/16; Gr 2: 2/16 pts), nausea (Gr 1: 6/16; Gr 2: 2/16 pts), and vomiting (Gr 1: 3/16 pts) in Arm A, and hot flush, nausea, vaginal discharge (all Gr 1: 2/5 pts), thrombocytopenia (Gr 1: 1/5; Gr 2: 1/5 pts), and neutropenia (Gr 2: 1/5, Gr 3: 1/5 pts) in Arm B. There were no drug-related Gr 3/4 AEs reported in Arm A; in Arm B, Gr 3 neutropenia, leukopenia, and lymphopenia each occurred in 1/5 pts. Preliminary PK assessment showed single-agent LSZ102 exposure increased dose-proportionally from 200 to 600 mg QD. In combination with ribociclib, exposures were consistent with those of the single agent at the same dose. In Arm A, preliminary evidence of antitumor activity was observed. Efficacy data for Arms B and C were not available as of March 14, 2017. One pt, whose tumor harbored an ESR1 D538G mutation, had been treated with multiple prior therapies in the metastatic setting, including letrozole, exemestane, tamoxifen, exemestane + everolimus, and anastrozole, as well as fulvestrant for 120 days prior to PD, and letrozole + palbociclib for 94 days prior to PD. As of March 14, 2017, this pt had been on LSZ102 treatment (400 mg QD) for 167 days, with a best response of stable disease (14% reduction in sum of diameter of target lesions).

Conclusions: Oral single-agent LSZ102 appears well-tolerated, with a manageable safety profile. Preliminary data also suggest tolerability when combined with ribociclib. Preliminary evidence of single-agent antitumor activity was seen in heavily pretreated pts with ER+ BC in a post-fulvestrant setting.

Citation Format: Juric D, Curigliano G, Cresta S, Yap Y-S, Terret C, Duhoux FP, Takahashi S, Kundamal N, Bhansali S, Liao S, Crystal A, Jhaveri K. Phase I/Ib study of the SERD LSZ102 alone or in combination with ribociclib in ER+ 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 P5-21-04.

Chlamydia in colposcopy clinics: to screen or not to screen?

The objective of the study was to assess the prevalence of Chlamydia trachomatis in our colposcopy clinic. A total of 337 consecutive patients newly referred to the colposcopy clinic between May and November 2003 were screened for chlamydia trachomatis. All our patients were referred by their GPs and none of the patients had had a recent chlamydia test performed. Four patients screened positive, overall giving a prevalence of 1.2% [95% CI 0.04-2.36%]. Three of those with positive results were in the 21 - 30 year age group (139 in the group, which equals 2.2% prevalence [95% CI 0 - 4.6%]). The fourth positive result was in the group over the age of 60. None of those screened in the other age groups was positive (< or =20, 31 - 40, 41 - 50, 51 - 60 years). Numbers screened in each of those groups were: 14, 115, 53 and 12, consecutively. Our study, though small in sample size, supports the view that the prevalence of chlamydia is not high in all colposcopy clinic attenders. Women younger than 30 years old are more likely to be infected than older women; hence opportunistic screening should target this age group. The prevalence rate may be low due to the enzyme linked immunosorbent assay giving a poor detection rate for chlamydia screening.

A locus affecting obesity in human chromosome region 10p12

AIMS/HYPOTHESIS

Obesity is a complex trait influenced by multiple genes. We evaluated linkage in three regions of human chromosome 10 previously linked to obesity-related phenotypes.

METHODS

We conducted non-parametric linkage analysis of obesity-related phenotypes in cohorts of 170 European-American and 43 African-American families having extremely obese and normal weight subjects.

RESULTS

We found support for linkage of an obesity phenotype (BMI > or = 27 kg/m2) in both cohorts, as well as in a combined analysis (European-American cohort, Z = 1.90, p = 0.03; African-American cohort, Z = 2.25, p = 0.014; combined cohort, Z = 2.55, p = 0.005).

CONCLUSION/INTERPRETATION

These results confirm previous reports of linkage in French and German families. The consistency of results across these four cohorts supports the localization of a quantitative trait locus influencing obesity to human chromosome region 10p12.

No evidence for genetic association or linkage of the cathepsin D (CTSD) exon 2 polymorphism and Alzheimer disease

Two recent case-control studies have suggested a strong association of a missense polymorphism in exon 2 of the cathepsin D gene (CTSD) and Alzheimer disease (AD). However, these findings were not confirmed in another independent study. We analyzed this polymorphism in two large and independent AD study populations and did not detect an association between CTSD and AD. The first sample was family-based and included 436 subjects from 134 sibships discordant for AD that were analyzed using the sibship disequilibrium test (SDT, p = 0.68) and the sib transmission/disequilibrium test (Sib-TDT, p = 0.81). The second sample of 200 AD cases and 182 cognitively normal controls also failed to show significant differences in the allele or genotype distribution in cases versus controls (chi2, p = 0.91 and p = 0.88, respectively). In addition, two-point linkage analyses in an enlarged family sample (n = 670) did not show evidence for linkage of the chromosomal region around CTSD. Thus, our analyses on more than 800 subjects suggest that if an association between the CTSD exon 2 polymorphism and AD exists, it is likely to be smaller than previously reported.

Evidence against association of the FE65 gene (APBB1) intron 13 polymorphism in Alzheimer's patients

A genetic polymorphism in intron 13 of the FE65 gene (APBB1) was reported to be associated with Alzheimer's disease (AD). Our analyses of this polymorphism, both in a family-based or a case-control sample, fail to support the association between the FE65 intron 13 polymorphism and AD. We performed the sibship disequilibrium test (SDT, P=0.77) and the sib transmission/disequilibrium test (Sib-TDT, P=0.56) in a family-based study which included 526 subjects from 158 sibships. In addition, we compared the genotype and allele frequencies of this biallelic polymorphism in 311 AD patients to those of a control group consisting of 260 subjects and found no significant difference (chi(2), P=0.847 and P=0.586, respectively). Furthermore, our two-point linkage analysis in a family-based sample was in agreement with a genome wide scan for linkage to AD and showed no evidence for linkage to the short arm of chromosome 11 where the FE65 gene is located. We conclude that the association of the FE65 intron 13 polymorphism with AD, if any, is smaller than previously reported.

Candidate genes showing no evidence for association or linkage with Alzheimer's disease using family-based methodologies

Alzheimer's disease (AD) is a genetically complex and heterogeneous disorder. To date, a large number of candidate genes have been associated with the disease, however none of these findings has been consistently replicated in independent datasets. In this study we report the results of family-based analyses for polymorphisms of five such candidates on chromosomes 2 (interleukin-1beta, IL-1B), 3 (butyrylcholinesterase, BCHE), 11 (cathepsin D, CTSD; Fe65, APBB1) and 12 (lipoprotein receptor-related protein-1, LRP1) that were all suggested to be associated with AD in recent case-control studies. To minimize the possibility of spurious findings due to population admixture, we used a family-based design applying the sibship disequilibrium test (SDT) as well as two-point parametric linkage analyses on families from the National Institute of Mental Health (NIMH) Genetics Initiative. Contrary to the initial reports, none of the polymorphisms that were analyzed showed evidence for association or linkage with AD in our families. Our results suggest that the previously reported associations from case-control studies are either (a) false positive results, e.g. due to type I error or population admixture, (b) smaller than initially proposed, or (c) due to linkage disequilibrium with an as yet unidentified polymorphism nearby.