Kosiorek, Heidi

Yacoub et al report excellent responses to pegylated interferon alfa-2a in patients with hydroxyurea-resistant/intolerant polycythemia vera or essential thrombocythemia.

A robust personalized ctDNA test, TARDIS, achieves high accuracy for residual disease after completion of neoadjuvant therapy.

Abstract A limited number of drugs are available to treat patients with polycythemia vera (PV) and essential thrombocythemia (ET). We attempted to identify alternative agents that may target abnormalities within malignant hematopoietic stem (HSCs) and progenitor cells (HPCs). Previously, MDM2 protein levels were shown to be upregulated in PV/ET CD34+ cells, and exposure to a nutlin, an MDM2 antagonist, induced activation of the TP53 pathway and selective depletion of PV HPCs/HSCs. This anticlonal activity was mediated by upregulation of p53 and potentiated by the addition of interferon-α2a (IFN-α2a). Therefore, we performed an investigator-initiated phase 1 trial of the oral MDM2 antagonist idasanutlin (RG7388; Roche) in patients with high-risk PV/ET for whom at least 1 prior therapy had failed. Patients not attaining at least a partial response by European LeukemiaNet criteria after 6 cycles were then allowed to receive combination therapy with low-dose pegylated IFN-α2a. Thirteen patients with JAK2 V617F+ PV/ET were enrolled, and 12 (PV, n = 11; ET, n = 1) were treated with idasanutlin at 100 and 150 mg daily, respectively, for 5 consecutive days of a 28-day cycle. Idasanutlin was well tolerated; no dose-limiting toxicity was observed, but low-grade gastrointestinal toxicity was common. Overall response rate after 6 cycles was 58% (7 of 12) with idasanutlin monotherapy and 50% (2 of 4) with combination therapy. Median duration of response was 16.8 months (range, 3.5-26.7). Hematologic, symptomatic, pathologic, and molecular responses were observed. These data indicate that idasanutlin is a promising novel agent for PV; it is currently being evaluated in a global phase 2 trial. This trial was registered at www.clinicaltrials.gov as #NCT02407080.

5063 Background: The systemic therapies available to patients with metastatic prostate cancer (mPC) have improved dramatically over the past decade. Prior to 2010, the only agents with a proven survival benefit for patients with metastatic disease were androgen deprivation therapy and docetaxel. Since then, five new agents have been FDA approved and have proven survival benefit in phase III trials. Anecdotal experience suggests that the increased available lines of therapy have changed the profile of mPC to include a higher prevalence of visceral metastases. Methods: A retrospective review of 474 patients with prostate cancer who died in 2009 and in 2016 was performed. Patients with metastatic disease who had imaging within 6 months of death were included. A total of 164 patients were eligible for analysis. Results: Mean age at death overall was 77.4 years (SD 9.5) and did not differ signifiantly by cohort. Overall rates of visceral and distant metastases to include lung, liver, adrenal, brain, renal, spleen, and thyroid, were higher in patients who died in 2016 as compared to those who died in 2009 (40.0% and 26.1%, respectively, p = 0.07). Lung metastases were more prevalent in patients who died in 2016 versus in 2009 at 26.3% and 13.0%, respectively (p = 0.05). Patients who died in 2009 received a median of 3 (range 1-10) systemic treatments versus 4 (range 0-13) in those who died in 2016 (p = 0.005). Forty-four percent of patients who died in 2016 used five or more lines of systemic treatments compared to 26.1% of patients in 2009. Conclusions: The emergence of new systemic therapies for mPC is changing the natural history of the disease. Forty percent of patients now develop visceral metastases compared to 26% in the past. These changes will drive the need for new treatment approaches targeting visceral metastases. [Table: see text]

Abstract Background: Circulating tumor DNA (ctDNA) analysis holds potential for minimal residual disease (MRD) detection in early stage breast cancer. However, sensitivity for MRD is limited due to low ctDNA levels in early stage patients and limited blood volumes. Loss of input DNA during library preparation, limited multiplexing or low sensitivity of current molecular methods further limit accuracy. To address this gap, we have developed TARgeted DIgital Sequencing (TARDIS), a novel method for simultaneous analysis of multiple patient-specific mutations in plasma DNA. Methods: Using tumor exome sequencing, we identify and prioritize somatic founder mutations, design nested primers and evaluate them for multiplex performance. Using 5-10 ng input plasma DNA, we perform 1) targeted linear pre-amplification to improve downstream molecular conversion, 2) single-stranded adapter ligation to incorporate unique molecular identifiers (UMIs) and 3) targeted PCR to prepare sequencing-ready libraries. The resulting sequencing reads have fixed target-specific ends and variable ligation ends. We utilize fragment size and UMIs to group sequencing reads into read families. To ensure specificity, we require targeted mutations are supported by 2 or more read families. Results: To assess analytical performance, we targeted 8 mutations in cell-free DNA reference samples with 0.25%-2% mutation allele fractions (AFs). Precision across 7-16 replicates at each AF level agreed with expectations of Poisson distribution, demonstrating effective analysis of ˜70% of input DNA. At 2%, 1%, 0.5% and 0.25% AFs, variant-level sensitivity was 96.4%, 96.4%, 91.1% and 65.8%, approaching the theoretical limit given input DNA. At 0.25% AF, 3-7 mutations were detected per sample, achieving 100% sample-level sensitivity. In 16 wild-type replicates, no targeted mutations were called (100% specificity). Averaging multiple mutations improved precision in sample-level AF estimates. Mean AFs from 8 mutations for the 2% sample were 2.34%-2.80% (5.8% CV). In 6 patients with breast cancer treated with neoadjuvant therapy (NAT), we analyzed 8-18 patient-specific mutations (mean 11.8). Before treatment, ctDNA was detected in 5/6 patients at mean AFs of 0.02%-1.19% (mean 0.40%), supported by 2-10 mutations (mean 5.6). Of these 5 patients, 4 had residual disease after NAT and ctDNA was detected pre-operatively or during NAT in 3/4 patients. 1 patient achieved pathological Complete Response and ctDNA was undetectable after NAT. Conclusions: Preliminary results suggest TARDIS enables accurate MRD detection after neoadjuvant therapy in patients with early stage breast cancer. On-going work is expanding this analysis to include additional patients and investigate the clinical validity of peri-operative ctDNA monitoring. Summary of clinical resultsPatientPre-NAT Stage (TNM)SubtypeNo. of Mutations TargetedBaseline ctDNA (AF%, No. of Mutations)ctDNA after or during NAT (AF%, No. of Mutations)Residual Tumor (TNM)1T3 N1ER+ PR+ HER2-8+ (0.02%, 2)-T2 N12T3 N0TNBC12+ (0.29%, 6)+ (0.01%, 1)T1a N03T2 N1TNBC18+ (1.19%, 10)+ (0.01%, 1)T1mi N04T3 N1TNBC10+ (0.02%, 3)+ (0.05%, 3)T3 N15T2 N0TNBC9+ (0.46%, 7)-pathCR6T1c N1TNBC14--pathCR Citation Format: McDonald BR, Contente-Cuomo T, Sammut S-J, Ernst B, Odenheimer-Bergman A, Perdigones N, Chin S-F, Farooq M, Cronin PA, Anderson KS, Kosiorek H, Northfelt D, McCullough A, Patel B, Caldas C, Pockaj B, Murtaza M. Multiplexed targeted digital sequencing of circulating tumor DNA to detect minimal residual disease in early and locally advanced 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 P4-01-21.

Abstract Background Survivors of ER-expressing operable breast cancer (ER+BC) generally do not receive hormone replacement therapy for menopausal symptoms due to concern about provoking recurrence of disease. Single dose depomedroxyprogesterone acetate (MPA) 400 mg IM has previously been shown (Loprinzi CL, et al. J Clin Oncol 2006;24:1409) to be the most effective non-estrogen therapy available for menopausal hot flashes (HF) but long-term evidence of safety in survivors of ER+BC is lacking. Methods Consecutive patients previously diagnosed with ER+BC who received MPA for HF between January 2007 and December 2012 were retrospectively identified in the breast cancer patient database at Mayo Clinic Arizona. Medical records were audited for breast cancer outcomes in these cases and in contemporaneous control patients with ER+BC who did not receive MPA, matched for age, stage of disease, and year of diagnosis. Statistical comparisons of local-regional recurrence and event-free survival were performed. Results 92 patients who received MPA were identified and matched 1:1 with contemporaneous controls. Median follow-up duration was 5.7 years in cases and 4.5 years in controls. Estimated local-regional recurrence free survival at 10 years was 85% (95% CI, 72-100%) in cases and 95% (95% CI, 86-100%) in controls. Matched pairs hazard ratio was 1.0 (95% CI, 0.06-16.0) for local-regional recurrence free survival. Estimated event-free survival at 10 years was 81% (95% CI, 69-97%) in cases and 76% (95% CI, 64-92%) in controls. Matched pairs hazard ratio was 0.38 (95% CI, 0.10-1.41) for event-free survival. The majority (77%) of case patients experienced satisfactory relief of hot flashes from MPA injection. Conclusion In this retrospective case-control study we were unable to identify a detrimental effect of MPA therapy for HF in survivors of ER+BC. MPA may be acceptable for management of HF in this population. Citation Format: Ertz-Archambault N, Rogoff L, Kosiorek H, Ernst B, Anderson K, Pockaj B, Gray R, Northfelt D. Depomedroxyprogesterone therapy for hot flashes in survivors of ER-expressing breast cancer: Impact on recurrence and survival [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 P1-11-13.