Christopher Colameco

CDK 4/6 Inhibitor Palbociclib (PD0332991) in Rb+ Advanced Breast Cancer: Phase II Activity, Safety, and Predictive Biomarker Assessment

Purpose: The G1–S checkpoint of the cell cycle is frequently dysregulated in breast cancer. Palbociclib (PD0332991) is an oral inhibitor of CDK4/6. Based upon preclinical/phase I activity, we performed a phase II, single-arm trial of palbociclib in advanced breast cancer. Experimental Design: Eligible patients had histologically confirmed, metastatic breast cancer positive for retinoblastoma (Rb) protein and measureable disease. Palbociclib was given at 125 mg orally on days 1 to 21 of a 28-day cycle. Primary objectives were tumor response and tolerability. Secondary objectives included progression-free survival (PFS) and assessment of Rb expression/localization, KI-67, p16 loss, and CCND1 amplification. Results: Thirty-seven patients were enrolled; 84% hormone-receptor (HR)+/Her2−, 5% HR+/Her2+, and 11% HR−/Her2−, with a median of 2 prior cytotoxic regimens. Two patients had partial response (PR) and 5 had stable disease ≥ 6 months for a clinical benefit rate (CBR = PR + 6moSD) of 19% overall, 21% in HR+, and 29% in HR+/Her2− who had progressed through ≥2 prior lines of hormonal therapy. Median PFS overall was 3.7 months [95% confidence interval (CI), 1.9–5.1], but significantly longer for those with HR+ versus HR− disease (P = 0.03) and those who had previously progressed through endocrine therapy for advanced disease (P = 0.02). Grade 3/4 toxicities included neutropenia (51%), anemia (5%), and thrombocytopenia (22%). Twenty-four percent had treatment interruption and 51% had dose reduction, all for cytopenias. No biomarker identified a sensitive tumor population. Conclusions: Single-agent palbociclib is well tolerated and active in patients with endocrine-resistant, HR+, Rb-positive breast cancer. Cytopenias were uncomplicated and easily managed with dose reduction. Clin Cancer Res; 21(5); 995–1001. ©2014 AACR.

Self-renewal of CD133(hi) cells by IL6/Notch3 signalling regulates endocrine resistance in metastatic breast cancer.

The mechanisms of metastatic progression from hormonal therapy (HT) are largely unknown in luminal breast cancer. Here we demonstrate the enrichment of CD133hi/ERlo cancer cells in clinical specimens following neoadjuvant endocrine therapy and in HT refractory metastatic disease. We develop experimental models of metastatic luminal breast cancer and demonstrate that HT can promote the generation of HT-resistant, self-renewing CD133hi/ERlo/IL6hi cancer stem cells (CSCs). HT initially abrogates oxidative phosphorylation (OXPHOS) generating self-renewal-deficient cancer cells, CD133hi/ERlo/OXPHOSlo. These cells exit metabolic dormancy via an IL6-driven feed-forward ERlo-IL6hi-Notchhi loop, activating OXPHOS, in the absence of ER activity. The inhibition of IL6R/IL6-Notch pathways switches the self-renewal of CD133hi CSCs, from an IL6/Notch-dependent one to an ER-dependent one, through the re-expression of ER. Thus, HT induces an OXPHOS metabolic editing of luminal breast cancers, paradoxically establishing HT-driven self-renewal of dormant CD133hi/ERlo cells mediating metastatic progression, which is sensitive to dual targeted therapy.

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. Citation Format: Clark AS, O9Dwyer 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 LB-236: Self-renewal of CD133hi cells by IL6/Notch3 signaling regulates endocrine resistance in metastatic breast cancers

The mechanisms of metastatic progression from hormonal therapy (HT)-induced tumour dormancy to hormonal therapy resistance is largely unknown in luminal breast cancer. Analysis of clinical specimens revealed the enrichment of CD133hi/ERlo cancer cells in primary tumours following neo-adjuvant endocrine therapy and in HT refractory metastatic disease. We developed spontaneous experimental models of metastatic luminal breast cancer and determined that endocrine therapy can promote the generation of HT- resistant, self-renewing CD133hi/ERlo/IL6hicells. Dual pharmacological inhibition of IL6R-IL6 (tocilizumab) and ER (HT) abrogated the establishment of CD133hi/ERlo/IL6hi cancer stem cells (CSCs), restoring endocrine sensitivity to hormone-refractory metastatic disease, in both experimental and patient-derived endocrine-resistant bone metastasis. Hormonal therapy, initially abrogated oxidative phosphorylation (OXPHOS) generating dormant (self-renewal deficient-CD133hi/ERlo/OXPHOSlo) cancer cells, These cells exited metabolic dormancy via an IL6 driven feed-forward ERlo-IL6hi-Notchhi loop, activating OXPHOS, in the absence of ER activity. Importantly, the inhibition of IL6R/IL6-Notch pathways switched the self-renewal of CD133hi CSCs, from an IL6/Notch-dependent one to an ER-dependent one, through the re-expression of ER. Thus, HT induces an OXPHOS metabolic editing of luminal breast cancers, paradoxically establishing HT-driven self-renewal of dormant CD133hi/ERlo cells mediating metastatic progression, which is sensitive to dual targeted therapy. Citation Format: Pasquale Sansone, Ceccarelli Claudio, Marjan Berishaj, Qing Chang, Rajasekhar Vinagolu, Fabiana Perna, Robert Bowman, Michele Vidone, Laura Daly, Jennifer Nnoli, Donatella Santini, Taffurelli Mario, Natalie Shih, Michael Feldman, Jun James Mao, Christopher Colameco, Jinbo Chen, Angela DeMichele, Nicola Fabbri, John Healey, Monica Cricca, Giuseppe Gasparre, David Lyden, Massimiliano Bonafe, Jacqueline F. Bromberg. Self-renewal of CD133hi cells by IL6/Notch3 signaling regulates endocrine resistance in metastatic breast cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-236.

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. 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 CT114: A phase II trial of exemestane and ruxolitinib for aI-resistant ER+ breast cancer: Interim safety, efficacy, and biomarker analysis

Resistance to aromatase inhibitors in ER+ breast cancer leads to recurrence and progression in the metastatic setting. JAK/STAT pathway activation is a resistance mechanism that could potentially be overcome with the use of JAK inhibitor therapy. Methods: We performed a phase II trial of exemestane, 25 mg daily, and ruxolitinib, 25 mg BID, in postmenopausal women with advanced, ER+ breast cancer who had progressed on a non-steroidal aromatase inhibitor and had either measureable or bone-only disease. A Simon 2-stage design was employed. A “go” decision to second stage would occur if fewer than 5/15 patients experienced any grade 3/4 toxicity requiring discontinuation from the study within the first treatment cycle. Results: Fifteen patients were enrolled; during cycle 1, no patient discontinued for toxicity and 1 patient went off study for progression of bone disease. 36 grade 3 events occurred; anemia was most common (n = 5), requiring transfusion in all patients. 47% required dose reduction. No partial or complete responses occurred; 3/15 (20%) had stable disease ≥6 months (clinical benefit, CB). Baseline CRP ≥8 was significantly associated with CB (3/3 CB vs. 1/11 non-CB; p = 0.011); other markers, including baseline ESR, IL-6 genotype status and primary tumor phosphoSTAT3 expression were not associated with CB in this small sample, though high tumoral pSTAT3 was seen in 66% of CB and 33% of non-CB. A novel pharmacodynamic (PD) assay to assess STAT3 phosphorylation in peripheral blood mononuclear cells after ruxolitinib exposure demonstrated differential effects in patients with CB vs. those without CB. Conclusions: The combination of exemestane and the JAK2 inhibitor ruxolitinib met safety criteria for continued enrollment. Anemia, an expected toxicity of R, was common and the high rate of severe anemia and need for dose reductions has led to a decision to reduce the starting dose of ruxolitinib to 15 mg BID moving forward. Promising predictive markers, including CRP, tumor pSTAT3 and a novel PD assay for pSTAT3 will be further evaluated. Citation Format: Angela M. DeMichele, Christopher B. Colameco, Anna Kalota, Andrea B. Troxel, Robin Holmes, Rebecca Cimildoro, Kelly Zafman, Kevin R. Fox, Susan M. Domchek, Keerthi Gogineni, Angela R. Bradbury, Jennifer M. Matro, Natalie Shih, Michael D. Feldman, Amy S. Clark, Elizabeth O. Hexner, Jacqueline F. Bromberg. A phase II trial of exemestane and ruxolitinib for aI-resistant ER+ breast cancer: Interim safety, efficacy, and biomarker analysis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT114. doi:10.1158/1538-7445.AM2015-CT114

Abstract 618: Comparison of mutational spectra in metastatic tumors and cell-free DNA in breast cancer patients

Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA While massively parallel sequencing technology has greatly expanded the number of molecular genetic tests available in oncology, little is known about the spectrum and clinical utility of findings obtained from testing tumors and circulating tumor material in specific patient populations. Here we report findings from the METAMORPH study, in which stage IV breast cancer patients had metastatic tumor biopsies (metDNA) and concurrently collected cell-free circulating tumor DNA (cfDNA). Illumina TruSeq Cancer Panel (for metDNA) and Guardant360 (for cfDNA) were performed. 28 patients had both tests; results are shown in the Table. 68% of patients had at least one alteration in metDNA and 86% in cfDNA. PIK3CA mutations were most common, occurring in 43% and 36% of patients’ metDNA and cfDNA, respectively. Overall, 16 of 28 (57%) of patients had the same alterations identified in both metDNA and cfDNA. Excluding ERBB2 amplifications in HER2+ patients, 43% of patients’ metDNA and 57% of patients’ cfDNA contained pathogenic mutations or variants of uncertain significance (VUS) for which there are approved targeted therapies or clinical trials. Overall, 80 alterations were identified, 23 of which were detected by both assays. Multiple reasons for discordance in calls between metDNA and cfDNA assays were identified. While biological phenomena (e.g. tumor heterogeneity) may contribute to discordance, technical issues played an important role. Additional studies using whole exome sequencing and other platforms to further assess biological evolution of metastatic disease and clinical utility of molecular profiling of metastatic tumors and cell-free DNA are needed. Table 1 | | Tumor DNA (metDNA) | Cell-free DNA (cfDNA) | |:----------------------------------------------------------------------------------------- | ---------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- | | # pts with alteration (%) | 19/28 (68%) | 24/28 (86%) | | ER+/Her2- (n = 17) | 10/17 | 15/17 | | Her2+ (n = 4) | 4/4 | 2/4 | | TNBC (n = 7) | 5/7 | 7/7 | | Total # alterations in # genes | 31 in 7 genes | 72 in 19 genes | | Genes w/alterations (total); Bold: genes for which exists a possible targeted therapeutic | PIK3CA (13), TP53 (10), ERBB2 (4), EGFR, RB1, SMAD4, STK11 | PIK3CA (14), TP53 (14), EGFR (9), ERBB2 (6), BRAF (6), MET (6), JAK2 (3), NOTCH1 (2), FBXW7 (2), ARAD, FGFR2, JAK3, KRAS, MYC, NPM1, PROC, RET, SMAD4, SMARCB1 | | Variants only covered by one assay | | 33 | | Variants detected in both but only reported by one assay | 3 (2 indels, 1 VUS) | 1 (1 synonymous) | | Variants detected by only one assay | 1 amplification at 7-fold; 4 SNVs (AF range 19-75%) | 2 amplifications at <3-fold; 13 SNVs (AF range 0.1-0.8%) | Citation Format: Kara N. Maxwell, Danielle J. Soucier-Ernst, Erica L. Carpenter, Andrea B. Troxel, Christopher Colameco, Candace Clark, Michael D. Feldman, Bijal Kakrecha, Melissa Langer, Joy Lee, David A. Lewis, David Lieberman, Jennifer Morrissette, Tien-chi Pan, Stephanie S. Yee, Natalie Shih, Lewis A. Chodosh, Angela M. DeMichele. Comparison of mutational spectra in metastatic tumors and cell-free DNA in breast cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 618. doi:10.1158/1538-7445.AM2015-618

Abstract 4719: Associations between IL-6 genotype and IL-6-related tumor alterations in ER+ breast cancer: results from ECOG2190/Int0121

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Background: Despite overall favorable prognosis, a subset of patients with ER+ breast cancer will subsequently relapse, and there is a need to identify mechanisms associated with recurrence. Interleukin-6 (IL-6) is a cytokine that has been implicated in progression and metastatic behavior in breast cancer. We previously demonstrated that genotypic variants in the IL-6 promotor associated with high IL-6 production are associated with poor prognosis in a subset of non-metastatic, ER+ breast cancers (Cancer Res, 2009). In the current study, we sought to determine whether patients with these “high-producer” (HP) genotypes (GT) had tumors that were enriched for IL-6 related alterations in membrane receptors, signaling pathways and cell cycle control. Methods: We identified patients with tumor blocks available from the ECOG 2190/INT0121 trial subjects in which we previously had obtained germline DNA and performed GT/haplotype (HT) analysis, and tumor microarrays (TMAs) were prepared. Expression of IL-6/gp130 membrane receptors, tumoral IL-6 content, cytoplasmic signaling through expression of phosphorylated signaling proteins (p-STAT3, p-AKT and p-ERK) and alterations in nuclear cell cycle marker expression (cyclin D, cyclin E and p27) were assessed by immunohistochemistry. Patients had previously been GT for IL-6-174, -572, -597 and the -373 variable repeat as well as assigned HT combining the HP alleles. Chi2 and Fishers exact tests were used to compare proportions. All tests were 2-sided. Results: From the previously GT ER+ patients in E2190 (n=205), we recovered assessable tumor in 84 (41%) patients. Those with tumor did not differ from the overall or ER+ GT cohorts by any tumor/patient characteristics, genotype frequencies or recurrence rate at 10 years (63% with tumor vs. 60% overall). Gp130 membrane receptor positivity was significantly associated with all IL-6 HP GT (-174GG p=0.012; -572GG p=0.01; -597GG p=0.007 and -373non8A12T p=0.008), though IL-6 receptor or IL-6 tumor content were not, and none were associated with HT. Tumor expression of p-STAT3 was seen exclusively in tumors of patients with any of the four IL-6 HP genotypes (rate 10 - 14% for HP GT vs. 0% for all other GT) and within those with the intermediate and HP HT (p=0.03), and p-AKT expression was significantly higher among those with IL6-174GG (p=0.06) and -373non8A12T (p=0.04) GT. Tumor cyclin D levels were significantly higher in those with IL6-174GG (p=0.02), -597GG (p=0.02) and HT (p=0.04). No associations were seen with p-ERK, cyclin E or p27 expression. Conclusions: These data suggest that patients with ER+ breast cancer who have “high-producer” IL-6 genotypes and poor prognosis have tumors enriched for the IL-6 gp130 receptor, JAK/STAT signaling and cyclin D overexpression, suggesting targets for intervention in these patients. Citation Format: Angela M. Demichele, Michelle Donelson, Sara Komrokian, Christopher Colameco, Jinbo Chen, Lu Chen, Robert Gray, Jennifer Nnoli, William Vaughan, Karen Anderson, Jacqueline Bromberg. Associations between IL-6 genotype and IL-6-related tumor alterations in ER+ breast cancer: results from ECOG2190/Int0121. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4719. doi:10.1158/1538-7445.AM2014-4719