Neratinib + fulvestrant + trastuzumab for HR-positive, HER2-negative, HER2-mutant metastatic breast cancer: outcomes and biomarker analysis from the SUMMIT trial

BACKGROUND

HER2 mutations are targetable alterations in patients with hormone receptor-positive (HR+) metastatic breast cancer (MBC). In the SUMMIT basket study, patients with HER2-mutant MBC received neratinib monotherapy, neratinib + fulvestrant, or neratinib + fulvestrant + trastuzumab (N + F + T). We report results from 71 patients with HR+, HER2-mutant MBC, including 21 (seven in each arm) from a randomized substudy of fulvestrant versus fulvestrant + trastuzumab (F + T) versus N + F + T.

PATIENTS AND METHODS

Patients with HR+ HER2-negative MBC with activating HER2 mutation(s) and prior cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) therapy received N + F + T (oral neratinib 240 mg/day with loperamide prophylaxis, intramuscular fulvestrant 500 mg on days 1, 15, and 29 of cycle 1 then q4w, intravenous trastuzumab 8 mg/kg then 6 mg/kg q3w) or F + T or fulvestrant alone. Those whose disease progressed on F + T or fulvestrant could cross-over to N + F + T. Efficacy endpoints included investigator-assessed objective response rate (ORR), clinical benefit rate (RECIST v1.1), duration of response, and progression-free survival (PFS). Plasma and/or formalin-fixed paraffin-embedded tissue samples were collected at baseline; plasma was collected during and at end of treatment. Extracted DNA was analyzed by next-generation sequencing.

RESULTS

ORR for 57 N + F + T-treated patients was 39% [95% confidence interval (CI) 26% to 52%); median PFS was 8.3 months (95% CI 6.0-15.1 months). No responses occurred in fulvestrant- or F + T-treated patients; responses in patients crossing over to N + F + T supported the requirement for neratinib in the triplet. Responses were observed in patients with ductal and lobular histology, 1 or ≥1 HER2 mutations, and co-occurring HER3 mutations. Longitudinal circulating tumor DNA sequencing revealed acquisition of additional HER2 alterations, and mutations in genes including PIK3CA, enabling further precision targeting and possible re-response.

CONCLUSIONS

The benefit of N + F + T for HR+ HER2-mutant MBC after progression on CDK4/6is is clinically meaningful and, based on this study, N + F + T has been included in the National Comprehensive Cancer Network treatment guidelines. SUMMIT has improved our understanding of the translational implications of targeting HER2 mutations with neratinib-based therapy.

Evaluation of safety and efficacy of p53MVA vaccine combined with pembrolizumab in patients with advanced solid cancers

BACKGROUND

Vaccination of cancer patients with p53-expressing modified vaccinia Ankara virus (p53MVA) has shown in our previous studies to activate p53-reactive T cells in peripheral blood but without immediate clinical benefit. We hypothesized that the immunological responses to p53MVA vaccine may require additional immune checkpoint blockade to achieve clinically beneficial levels. We therefore conducted a phase I trial evaluating the combination of p53MVA and pembrolizumab (anti-PD-1) in patients with advanced solid tumors.

PATIENTS AND METHODS

Eleven patients with advanced breast, pancreatic, hepatocellular, or head and neck cancer received up to 3 triweekly vaccines in combination with pembrolizumab given concurrently and thereafter, alone at 3-week intervals until disease progression. The patients were assessed for toxicity and clinical response. Correlative studies analyzed p53-reactive T cells and profile of immune function gene expression.

RESULTS

We observed clinical responses in 3/11 patients who remained with stable disease for 30, 32, and 49 weeks. Two of these patients showed increased frequencies and persistence of p53-reactive CD8+ T cells and elevation of expression of multiple immune response genes. Borderline or undetectable p53-specific T cell responses in 7/11 patients were related to no immediate clinical benefit. The first study patient had a grade 5 fatal myocarditis. After the study was amended for enhanced cardiac monitoring, no additional cardiac toxicities were noted.

CONCLUSION

We have shown that the combination of p53MVA vaccine with pembrolizumab is feasible, safe, and may offer clinical benefit in select group of patients that should be identified through further studies.

Abstract P6-16-04: A self-administered geriatric assessment tool for Spanish-speaking older women with breast cancer

Background: Almost a quarter of older adults in the United States will identify themselves as Hispanic/Latino by 2060. Our group has previously developed and validated a self-administered geriatric assessment tool which can be used to identify functional, psychological, social and cognitive impairments among older patients with various types of cancer. Among English-speaking older adults, completing this tool using paper/pencil or a tablet takes a median of 15-21 minutes (min), with < 10% needing assistance to answer it (Hurria, JOP 2016). However, the utilization of this tool among Spanish-speaking older adults has not been tested. We assessed the feasibility of administering a translated and validated Spanish version of our geriatric assessment tool for older Hispanic women with breast cancer, and identified their preferred format (tablet or paper/pencil).

Methods: Spanish-speaking women aged ≥ 65 years with a diagnosis of breast cancer completed the geriatric assessment twice on the same day. Patients were randomized into 3 groups: paper/pencil twice; tablet and paper/pencil in random order; and tablet twice. We assessed the proportion of patients requiring assistance to complete the geriatric assessment, the time needed to complete it, and the proportion of patients who thought the geriatric assessment was difficult/very difficult.

Results: 140 older women with breast cancer completed the geriatric assessment twice and were evaluable. Mean age was 71.6 years (SD 5.8), 53% had ≤ 8th grade education, 43% were married, 45% were retired, 32% were homemakers, and 6% were employed. The participants came from 13 different Spanish-speaking countries, although 70% were born in Mexico. For 90%, Spanish was their primary language, and 75% spoke only in Spanish at home. Regarding computer skills, 64% of the patients said they had none. 39% (n = 54) were unable to complete the geriatric assessment on their own; mean time to complete the geriatric assessment was 29 min (range 8-90); and 28% (n = 39) thought the geriatric assessment was difficult/very difficult. The most common reasons for needing assistance were difficulty understanding questions (39%) and visual problems (31%). Patients with ≤ 8th grade education took longer to complete the geriatric assessment (mean 37.2 vs 29.4 min, p < 0.01), and more often needed help completing the assessment (51% vs 19%, p < 0.01) than those with ≥9th grade education. 53% of the participants preferred using a tablet to answer the geriatric assessment, while 47% preferred paper/pencil.

Conclusions: A substantial proportion of Spanish-speaking older women with breast cancer required assistance to complete our self-administered geriatric assessment tool. This may be a consequence of the low educational level we found among this patient population. Tailoring assessments for diverse populations with particular attention to educational level is needed in multicultural settings.

Citation Format: Soto-Perez-de-Celis E, Vazquez J, Kim H, Sun C-L, Somlo G, Yuan Y, Waisman JR, Mortimer JE, Kruper L, Taylor L, Patel NH, Moreno J, Charles K, Roberts E, Uranga C, Levi A, Katheria V, Paredero-Perez I, Mitani D, Hurria A. A self-administered geriatric assessment tool for Spanish-speaking older women with 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 P6-16-04.

Abstract P6-18-18: Phase I trial of eribulin and everolimus in patients with metastatic triple negative breast cancer

Background: Alteration of PI3K/Akt/mTOR pathway is the most common genomic abnormality detected in triple negative breast cancer (TNBC). Everolimus acts synergistically with eribulin in inducing apoptosis in TNBC cell lines and xenografts in our preclinical study. This phase I trial was designed to test the safety and tolerability of combining eribulin and everolimus in patients (pts) with metastatic TNBC.

Methods: The overall objective of this study was to describe the safety and toxicities of the combination. The secondary objective was to assess activity based on response rate (RR) and progression free survival (PFS). Eligibility criteria included pts with metastatic TNBC, ECOG 0-2, 0-3 lines of prior chemotherapy in metastatic setting, and prior treatment with anthracycline and/or taxane therapy. The study utilized the toxicity equivalence range (TEQR) design with a target equivalence range for dose-limiting toxicities (DLTs) of 0.20-0.35. The recommended phase 2 dose (RP2D) will be the dose closest to the target of 0.25 below 0.51 based on isotonic regression.Three dosing levels of the combinations were tested: level A1 (everolimus 5mg daily; eribulin 1.4 mg/m2 days 1, 8 every 3 weeks), level A2 (everolimus 7.5mg daily; eribulin 1.4 mg/m2, days 1, 8 every 3 weeks), level B1(everolimus 5mg daily; eribulin 1.1 mg/m2 days 1, 8 every 3 weeks). Nanostring RNA analysis and genomic mutation analysis were conducted in 16 pts with available tumor tissue.

Results: A total of 27 pts were enrolled. Median age was 55 years (range 36-76). Two pts were ineligible due to HER2+ on repeat biopsy and were only included in the toxicity analysis. Dose level B1 (everolimus 5mg daily and eribulin 1.1 mg/m2 days 1, 8 every 3 weeks) was determined to be the RP2D doses. The DLTs were neutropenia, stomatitis and hyperglycemia. Across all cycles, 59% (16/27) had a ≥ Gr3 toxicity attributed to treatment at the possible or above level. 44% (12/27) had Gr3 heme-toxicities. The most common toxicities were ≥ Gr3 neutropenia (10 pts), Gr3 lymphopenia (6 pts) and ≥ Gr3 leukopenia (7 pts). 33% (9/27) had Gr3 non-heme toxicities. The most common were Gr3 stomatitis (3 pts), Gr3 hyperglycemia (3 pts) and Gr3 fatigue (5 pts). The median number of cycles completed was 4 (0-8). 68% (17/25) had a dose modification or hold, 14 of 25 (56%) were for eribulin and 15 of 25 (60%) were for everolimus. Of 25 eligible pts, 8 (32%) achieved a best response as partial response, 11 (44%) had stable disease and 6 (24%) had progression. 80% (20/25) experienced progression by RECIST or showed clinical progression, and the median time to progression was 2.7 mo (95% CI (2.2, 4.6)). At the time of this analysis, 16 participants had died, median OS was 6.3 mo (95% CI (5.3, undefined)). Two pts are still being followed on treatment. PI3K-Akt-mTOR pathway genes and mutations profiles were studied.

Conclusion: Eribulin 1.1 mg/m2 days 1, 8 and everolimus 5mg daily was defined as the RP2D. Genomic analysis is currently underway to understand the molecular mechanisms of resistance.

Citation Format: Yuan Y, Yost S, Blanchard S, Yin H, Li M, Robinson K, Tang A, Martinez N, Leong L, Somlo G, Tank Patel N, Waisman J, Portnow J, Hurria A, Luu T-H, Mortimer J. Phase I trial of eribulin and everolimus in patients with metastatic triple negative 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 P6-18-18.

Abstract P6-17-18: Pathologic complete response (pCR) in locally advanced HER2+ (HER2+) breast cancer (BC) treated with anthracycline-free neoadjuvant therapy

Background: Response to neoadjuvant therapy is a predictor of progression-free and overall survival in HER2+. To decrease treatment associated toxicities in patients with HER2+ breast cancers we utilized a non-anthracycline regimen with pertuzumab (pert), trastuzumab (trast), and nab-paclitaxel (nab). Pre- neoadjuvant therapy biopsies were procured to evaluated possible biological predictors of pathologic complete response (pCR).

Methods: Women with locally advanced HER2 positive breast cancers were recruited from our breast cancer clinics. After obtaining informed consent for this IRB-approved trial, patients were treated with 6 cycles of pertuzumab (day 1 every 21 days [d]), and weekly trastuzumab 2 mg/kg with and nab-paclitaxel 100 mg/m2. Formalin fixed paraffin embedded (FFPE) or frozen biopsies pre-NT and post-NT were collected, along with blood samples at pre-treatment, and at the end of study for correlative analysis.

Results: Accrual is complete, with 42 of the 45 HER2+ patients assessed for pCR rate (3 too early to evaluate). The median age was 54 yrs (range 31-77 years). 12 patients were stage 3, 26 stage 2, and 1 stage 1 patient. The pCR rate was 64.2% (27/42), with 73.7% (14/19) in ER/PR negative patients and 56.5% (13/23) in ER/PR positive patients. The initial primary tumor size was similar for in those who achieved pCR and non-pCR patients (mean 4.1 cm vs 3.2 cm, respectively). Most patients required dose modifications. Grade 3 AEs reported included 6 patients with hypertension, 3 patients with hematological AEs, 3 patients with elevated LFTs, and 2 patients with diarrhea.

Conclusions: This anthracycline-free regimen in HER2+ BC can achieve promising pCR response rates, with toxicities well-managed with dose modifications. Results of correlative analysis will be presented.

Citation Format: Somlo G, Waisman J, Yuan Y, Kruper L, Frankel P, Jones V, Lusi T, Schmolze D, Yim J, Hurria A, Mortimer J. Pathologic complete response (pCR) in locally advanced HER2+ (HER2+) breast cancer (BC) treated with anthracycline-free neoadjuvant therapy [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 P6-17-18.

Abstract P1-15-07: Phase II trial of neoadjuvant carboplatin and nab-paclitaxel in patients with locally advanced triple negative breast cancer

Background: Response to neoadjuvant therapy (NT) predicts progression-free and overall survival in triple negative breast cancer (TNBC). Carboplatin has shown efficacy in patients with TNBC. The current phase II prospective neoadjuvant trial was designed to decrease toxicities and improve efficacy.

Methods: Patients with TNBC received carboplatin (carb) and nab-paclitaxel (nab). Pre-NT biopsies were procured to evaluate for biological predictors of pathological complete response (pCR). Newly diagnosed stage II-III patients with TNBC were treated with 4 cycles of carb (AUC 6, day 1 of 28 day cycle) and weekly nab 100 mg/m2 x 16. Targeted accrual goal is 70. RNA extracted from formalin fixed paraffin embedded (FFPE) biopsies pre-NT was tested for MammaPrint/BluePrint and custom Agilent full genome microarrays for gene expression (GE, by Agendia Inc). The raw gMeanSignal was log2 transformed and normalized to the 75thpercentile for GE analysis. Association between MammaPrint/ BluePrint results and pCR was tested by Fisher exact test. The linear model from R limma package was applied. Ingenuity Pathway Analysis (IPA) was applied to assess functional pathways associated with pCR. Cellular distribution by CIBERSORT analysis was carried out to estimate the abundance of 22 different cell types in each patient sample, and test whether the distribution of cell types is different between pCR and non-responders.

Results: A total of 64 patients were enrolled. Two patients were deemed ineligible (Her2+), and three were too early, resulting in 59 patients evaluable for pathological response. The pCR rate was 47% (RCB0, 28/59). Eight patients had RCB I. RCB0 plus RCBI reached 61%. Sufficient quality RNA and DNA were available from the first 43 of 55 pts with TNBC. 44/59 (75%) required dose modifications (mostly hematologic), 5 patients had grade 3 peripheral neuropathy (PN), 3 had grade 2 PN, and 3 patients had grade 2 LFTs. In the 53 pts with GE assessment, pCR was inversely associated with luminal BluePrint type (p=0.04). With fold change >1.5 and p-value < 0.05, 36 genes were differentially expressed (DE) in TNBC. CIBERSORT analysis suggested that T-cell regulatory cells (TREGS) were associated with pCR in TNBC, and 5 cell types (plasma cells, TREGS, macrophage, dendritic cells and neutrophils) presented differently between all pCR and non-pCRs with P-value <0.05. TDP analysis to assess correlation with pCR is ongoing.

Conclusions: The combination of carboplatin and nab-paclitaxel given in the neoadjuvant setting reached a promising pCR rate of 47%. The MammaPrint non-luminal BluePrint subtype was predictive of pCR in TNBC. Preliminary analysis suggested that a 36-gene signature for TNBC was associated with pCR. CIBERSORT analysis revealed 5 cell types with different abundance between the pCR and non-responders, suggesting the need to target the tumor microenvironment.

Citation Format: Yuan Y, Frankel P, Li M, Kruper L, Jones V, Treece T, Waisman J, Yim J, Tumyan L, Schmolze D, Hurria A, Yeon C, Mortimer J, Somlo G. Phase II trial of neoadjuvant carboplatin and nab-paclitaxel in patients with locally advanced triple negative 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 P1-15-07.

Abstract P6-15-07: Not presented

This abstract was not presented at the symposium.

Abstract OT1-05-02: A phase II clinical trial of the combination of pembrolizumab and selective androgen receptor modulator GTx-024 in patients with advanced androgen receptor positive triple negative breast cancer

Background: Androgen receptor (AR) targeted therapy and immunotherapy represent one of the most promising strategies for metastatic triple negative breast cancer (mTNBC), which accounts for 15-20% of all breast cancers. As a nonsteroidal selective androgen receptor modulator (SARM), GTx-024 demonstrated preclinical activity in AR+ TNBC PDX model. Pembrolizumab is a highly selective humanized monoclonal antibody of the programmed cell death 1 receptor (PD-1). The complementary modes of action and low potential for overlapping toxicity make the combination promising in patients with AR+ mTNBC.

Trial Design: This is an open-label Phase 2 study for AR+ mTNBC. Eligible participants receive pembrolizumab 200mg IV every 3 weeks in combination with GTx-024 18mg po daily.

Eligibility Criteria: Eligible patients must have AR+ (>10%, 1+ by IHC) TNBC; failed up to 2 lines of therapy in metastatic setting; and have measurable disease per RECIST1.1. Patients are excluded if they have had prior checkpoint inhibitors or AR targeted agents. Patients with current or prior use of testosterone, testosterone-like agents, androgenic compounds, or anti-androgens (including systemic steroids and immunosuppressive medications)are excluded, as well as current or prior history of noninfectious pneumonitis requiring systemic steroid therapy.

Specific Aims: The primary objective is to evaluate the safety/tolerability of GTx-024 and pembrolizumab and determine the response rate (CR or PR via RECIST 1.1) in patients with advanced AR+ TNBC. We will use clinical benefit rate (CBR), duration of response (DOR), PFS, and OS to test the efficacy of this novel drug combination.

Statistical Design: A Simon's MiniMax two-stage Phase 2 design will be utilized. Based on the previously reported response rate associated with single agent pembrolizumab (19%), we consider a response rate of 19% for the combination as discouraging, and a 39% response rate as encouraging. As a result, we will initially accrue 15 patients (including 6 patients from safety lead-in treated at the tolerable dose). If 2 or fewer patients respond, we will stop accrual for futility. Otherwise, the study will accrue an additional 14 patients for a total of 29 patients. With 29 patients, if only 8 or fewer respond (≤27.6%), the study will be considered discouraging unless secondary evidence of clinical benefit is substantial. With more than 8 patients responding out of the 29 patients, the combination would be considered promising. This design has 85% power to declare a true response rate of 39% as promising (power), and a 10% probability of declaring a true 19% response rate as encouraging (type I error). The probability of early termination if the true response rate is 19% is 44%.

Target Accrual: 29

Study Contact: Yuan Yuan MD PhD, City of Hope Comprehensive Cancer Center; Duarte, CA 91030; Email: yuyuan@coh.org

Citation Format: Yuan Y, Frankel P, Synold T, Lee P, Yost S, Martinez N, Tang A, Mendez B, Schmolze D, Apple S, Hurria A, Waisman J, Somlo G, Tank N, Sedrak M, Mortimer J. A phase II clinical trial of the combination of pembrolizumab and selective androgen receptor modulator GTx-024 in patients with advanced androgen receptor positive triple negative 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 OT1-05-02.

Abstract P5-21-08: Tolerability of the combination of lapatinib and trastuzumab in older patients with HER2 positive metastatic breast cancer

Background: Older adults are less likely to be included in clinical trials leading to the approval of novel cancer treatments. The Institute of Medicine and ASCO have identified therapeutic phase II trials as a key research priority to increase the evidence base for older adults with cancer. While targeted therapies may represent a less toxic option for older patients, few trials have studied their tolerability and efficacy in older adults. Here, we present a phase II study (NCT01273610) of the combination of trastuzumab and lapatinib in older patients with HER2+ metastatic breast cancer (MBC), incorporating geriatric oncology principles in the study design.

Methods: Patients age ≥ 60 years with MBC and any number of prior chemotherapy (CT) lines received trastuzumab (either 4mg/kg loading dose followed by 2mg/kg weekly or 8mg/kg followed by 6mg/kg q/3 weeks) plus lapatinib 1000 mg/m2 daily in 21-day cycles. Patients completed a pre-treatment geriatric assessment including measures of function, comorbidity, cognition, nutrition, and psychosocial status. A toxicity risk score developed for older adults receiving cytotoxic CT was calculated for each patient (Hurria et al. JCO 2011 & 2016). Relationships between tolerability (dose reductions and grade (G) ≥ 3 toxicity attributed to treatment) and risk score analyzed using a log2 transformation were assessed using generalized linear models, Student's t tests, and Fisher's exact test. Response rate (RR) and progression free survival (PFS) were evaluated.

Results: 40 patients (mean age 72 [60-92]) were accrued from 04/11 to 05/15. 25% (n = 10) were ≥ 75 years of age. 65% of patients (n = 26) had HR+ tumors and 35% (n = 14) were receiving ≥ 3rd line treatment. Median number of cycles was 4 (0-28). RR was 23% (n = 9, 95% CI 11-38%; 1 complete, 8 partial). 23% (n = 9) achieved stable disease. PFS was 2.7 months (95% CI 2.5-12). Based on the toxicity risk score, 21% (n = 8), 54% (n = 21), and 26% (n = 10) were at low, intermediate, and high risk. 70% (n = 28) of patients had G ≥ 2 toxicities and 20% (n = 8) G ≥ 3 toxicities. G 2 and 3 diarrhea occurred in 28% (n = 11) and 5% (n = 2) respectively. 5% (n = 2) were hospitalized due to treatment-related toxicity. No G ≥ 3 cardiac toxicities were observed. 23% of patients (n = 9) had treatment delays, and 43% (n = 17) required a lapatinib dose reduction. The mean toxicity risk score was higher in patients who required dose reductions (Student's t: p = 0.02). No statistically significant relationship was found between toxicity risk scores and the presence of G ≥ 3 treatment toxicity (logistic regression: OR = 3.08, 95% CI [0.54, 21.2], p = 0.22).

Conclusions: Among older patients with MBC (79% at intermediate or high risk of G ≥ 3 cytotoxic CT toxicity), trastuzumab and lapatinib were well tolerated, with only 20% experiencing G3 toxicities. The toxicity risk score was not found to be significantly related with treatment toxicity, which may be explained by the very low incidence of G3 events. Patients with a low toxicity risk score were not likely to require a lapatinib dose reduction.

Citation Format: O'Connor T, Soto-Perez-de-Celis E, Blanchard S, Chapman A, Kimmick G, Muss H, Luu T, Waisman JR, Li D, Mortimer J, Yuan Y, Somlo G, Stewart D, Katheria V, Levi A, Hurria A. Tolerability of the combination of lapatinib and trastuzumab in older patients with HER2 positive metastatic 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 P5-21-08.

Abstract P1-08-04: Not presented

This abstract was not presented at the symposium.

Abstract OT2-01-03: Phase II Trial of the addition of pembrolizumab to letrozole and palbociclib in patients with metastatic estrogen receptor positive breast cancer who have stable disease on letrozole and palbociclib

Background: The combination of palbociclib and letrozole has become the standard of care for patients with newly diagnosed estrogen receptor positive (ER+) metastatic breast cancer (MBC), with promising prolongation of progression free survival (PFS). However, nearly half of all patients achieved stable disease only after the first 6 months of therapy. Check-point inhibitor pembrolizumab was effective in ER+ MBC with a response rate of 13-17%, this study will evaluate the efficacy of adding pembrolizumab for patients with ER+ MBC who have achieved stable disease (SD) on letrozole and palbociclib.

Trial Design:This is an open-label single institutional study. Patient will receive letrozole (2.5 mg) once a day and palbociclib (125 mg, 100 mg, or 75 mg as established tolerated dose) once a day for 3 weeks on and 1 week off. Pembrolizumab will be given at 200 mg IV every 3 weeks.

Eligibility Criteria: Eligible patients must be postmenopausal women with ER+ MBC with measurable disease by RECIST1.1, ECOG performance status 0-1; must have received letrozole and palbociclib for at least 6 months, and have documented SD per RECIST 1.1. Up to3 lines of previous systemic therapy including endocrine therapy and/or chemotherapy are allowed. Patients are excluded if they had prior treatment with anti--PD1 or anti-PD-L1therapy, immunodeficiency; currently using systemic steroids active tuberculosis infection; major surgery within 28 days; active or untreated CNS metastases; history of interstitial lung disease; active infection requiring systemic therapy; or active cardiac disease.

Specific Aims: The primary objective is to evaluate the objective response rate(ORR). The secondary objective is to determine the safety and tolerability of pembrolizumab plus the letrozole/palbociclib combination. We will use clinical benefit rate (CBR), duration of response (DOR), PFS, and OS to test the efficacy of this novel drug combination.

Statistical Design: We will employ a three-at-risk design (modified rolling design) for the initial cohort of this Phase II study to insure the triplet is well-tolerated. This design permits only 3 patients to be a risk for DLT at any one time during the “safety lead-in” .When the first 6 patients have completed the observation period and treatment with ≤1 DLT, the safety lead-in for the triplet will be considered successful, and accrual will proceed to a total of 18 patients. Response (CR or PR by RECIST version 1.1) in patients who have demonstrated only SD on letrozole and palbociclib can be reasonably attributed to the addition of pembrolizumab. As a result, we set the probability of a response occurring without the addition of pembrolizumab as 3% or less. With 18 patients, a true response rate of 20% would result in at least 2 responders with 90% power and a type I error of 10%. With 18 patients, the response can be estimated with a 95% CI half-width of 23%.

Target Accrual: 18.

Citation Format: Yuan Y, Frankel P, Synold T, Yost S, Lee P, Waisman J, Somlo G, Hurria A, Mortimer J. Phase II Trial of the addition of pembrolizumab to letrozole and palbociclib in patients with metastatic estrogen receptor positive breast cancer who have stable disease on letrozole and palbociclib [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 OT2-01-03.

Abstract OT1-02-05: Phase II clinical trial of neratinib in patients 60 and older with HER2 over-expressed or mutated breast cancer: Trial design considerations for older adults

Background: This study addresses a key knowledge gap identified by the Institute of Medicine report on quality cancer care. Although there has been a growth in the number of targeted agents approved for the treatment of breast cancer, there are limited data regarding the efficacy, toxicity, and management of side effects in older adults. Neratinib is a potent oral small molecule tyrosine kinase inhibitor. Early clinical data have demonstrated the activity of neratinib in patients who have already progressed through HER2 targeted therapies. This study is designed to evaluate the tolerability and toxicity profile of neratinib in older adults with metastatic breast cancer (MBC) incorporating geriatric oncology design considerations.

Trial Design: This is an open label, single arm, phase II study of single agent neratinib in patients with HER2 positive MBC. Neratinib is given at 240mg orally in 28 day cycles. Unique factors of this geriatric oncology trial design include: 1) pre-treatment and on-treatment geriatric assessment; 2) additional nurse toxicity visits; 3) an algorithm for aggressive management of diarrhea; 4) measurements of the pharmacokinetics (PK) of neratinib; 5) inclusion of biomarkers of aging; 6) measurement of patient adherence; and 7) evaluation of quality of life.

Eligibility Criteria: Patients must be age≥60 with histologically-proven HER2 positive MBC or MBC with HER2 receptor activating mutations. There is no limitation on the number of previous lines of therapy, but patients must have adequate organ and bone marrow functions, and a baseline LVEF ≥ 50%. Exclusion Criteria include: prior treatment with neratinib; major surgery within 28 days; uncontrolled cardiac disease; concurrent use of digoxin; or chronic diarrhea.

Specific Aims: The primary objective of this study is to identify the rate of grade 2 or higher toxicities attributed to neratinib in adult age ≥60 with HER2 over-expressing breast cancer. The secondary objectives are to describe the full toxicity profile (including all grades of gastrointestinal toxicities); to estimate the rate of dose reduction, holds and hospitalizations; to describe the PK parameters; to estimate the adherence rate to neratinib; and to estimate the overall response, clinical benefit rate, progression-free and overall survival. Furthermore, we will explore the role of a cancer-specific geriatric assessment and serum biomarkers of aging (IL-6, CRP, and D-dimer) in predicting treatment toxicities and PK parameters.

Statistical Design: We plan to enroll 40 patients age ≥60 (at least 5 patients age 75 years or older, and no more than 15 patients 60-70) in order to assure that our sample is representative of the entire age range of older adults. Given a sample size of 40 subjects, the widest half-width of the 95% confidence limits for the rate of grade 2 or higher toxicities will be less than or equal to 0.16. An interim analysis will be performed after 20 subjects have been on study for at least one cycle.

Accrual goal: 40

Contact information: Yuan Yuan MD PhD, Email: yuyuan@coh.org.

Citation Format: Yuan Y, Blanchard S, Li D, Mortimer J, Waisman J, Somlo G, Yost S, Katheria V, Hurria A. Phase II clinical trial of neratinib in patients 60 and older with HER2 over-expressed or mutated breast cancer: Trial design considerations for older adults [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 OT1-02-05.

Abstract P4-21-35: Phase II trial of pertuzumab, trastuzumab, and nab-paclitaxel in patients (pts) with HER2 overexpressing (HER2+) locally advanced or inflammatory breast cancer (LABC) or untreated stage IV metastatic breast cancer (MBC)

Background: Pathologic complete response (pCR) to HER2-targeting neoadjuvant therapy (NT) predicts for improved survival (Cortazar et al, Lancet, 2014). The addition of pertuzumab to trastuzumab and docetaxel increased pCR rates, and, as first line treatment for MBC led to longer overall survival ([OS] Swain et al, NEJM 2015). Avoidance of anthracyclines in the adjuvant setting for HER2+ BC reduced the risk of secondary hematologic malignancies without a detriment to OS (Slamon et al, NEJM, 20111). Finally, nab-paclitaxel (nab) might provide an advantage over other taxanes via decreased use of steroids and may lead to increased response rates (RR). We designed a study of pertuzumab (pert), trastuzumab (trast), and nab, testing the feasibility and efficacy of this regimen in the LABC and metastatic breast cancer settings.

Materials and Methods: Pts with Stages II-III LABC received six cycles of NT with pert (day 1 q 21 days), trast, and nab 100 mg/m2 (both given IV, weekly). Pts with untreated MBC received the same regimen until progression, toxicities, or patient or physician preference led to stopping therapy. Primary endpoints included pCR (LABC) and RR and progression-free survival (PFS) in MBC. Forty pts with LABC and 25 pts with MBC were to be accrued. The study was designed to test whether the pCR rate of Neosphere (Gianni et al, Lancet Oncol, 2012, > 45.8%) and the PFS rate of CLEOPATRA (median of > 18.5 months) can be matched or exceeded. Procurement of serial samples for assessment of tumor gene expression, circulating tumor cells, miRNA, and serum DNA profiling for exploratory biomarker analysis was carried out.

Results:Twenty-two of 28 already enrolled pts with LABC (clinical stage II:15, stage III: 7) completed NT. The median age was 53 (34-77). The pCR rate was 86% (6/7) for hormone receptor negative (HR-) and 40% (6/15) for HR+ pts, with an overall pCR of 55%. Three pts without pCR following NT had residual BC with a HER2 negative phenotype. Eighteen of 22 pts required nab dose modifications. The most frequent toxicities following NT included elevated liver function tests:27%, peripheral neuropathy:23%, hematological toxicities:17%, diarrhea:18%, infusion reactions:18%. In the MBC cohort there were 13 of 16 enrolled pts with > 2 months of follow-up. The median age was 47 (31-65), 62% had HR+ disease. A CR rate of 4/13 (31%) and confirmed RR of 77% were observed. The median number of cycles with pert, trast, nab was 9 (3+ to 41); 11 of 13 pts required dose modifications or delays (3 of the delays were due to primary breast surgery performed upon response to treatment). At a median follow-up of 19 months, PFS and OS estimates are 63% (95% CI 0.09-0.93), and 89% (95% CI 0.61-1.0).

Conclusion: The non-anthracycline-containing regimen of pertuzumab, trastuzumab, and nab-paclitaxel induced a high pCR rate in HER2+ BC. PFS is encouraging in MBC. Outcome of the fully accrued cohorts inclusive of residual cancer burden scores in the LABC cohort, and correlative data with exploratory biomarker analysis will be presented.

Citation Format: Somlo G, Frankel P, Yeon C, Yuan Y, Yim J, Kruper L, Taylor L, Mortimer J, Waisman J, Jones V, Vito C, Paz B, Huria A, Li D, Gaal C, Tong T, Tumyan L. Phase II trial of pertuzumab, trastuzumab, and nab-paclitaxel in patients (pts) with HER2 overexpressing (HER2+) locally advanced or inflammatory breast cancer (LABC) or untreated stage IV metastatic breast cancer (MBC) [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 P4-21-35.

Abstract P1-14-10: Phase II trial of neoadjuvant chemotherapy with carboplatin and nab-paclitaxel in patients with triple negative locally advanced and inflammatory breast cancer

Background: Pathologic complete response (pCR) and residual cancer burden (RCB scores of 0 [pCR] or 1[near CR]) after neoadjuvant chemotherapy (NCT) may predict for improved survival (Symmans et al. J Clin Oncol 25:4414-22, 2007). We set out to test the pCR rate with an anthracycline-free regimen of carboplatin (carb) and nab-paclitaxel (nab) in patients (pts) with triple negative breast cancer (TNBC).

Materials and Methods: Forty-nine pts with stages II-III BC were to receive carb (AUC 6) on day 1 of a 28 day cycle, and nab 80 mg/m2 weekly, for a total of 4 cycles. Core biopsies were performed prior to NCT. Blood procurement for circulating tumor cell (CTC) analysis using the CellSearch platform was carried out pre-treatment, mid-treatment, and at surgery. We set out to assess the predictive value of Mammaprint (poor vs. good), BluePrint (basal, vs. luminal, vs. HER2) molecular subtype as well as microarray RNA and miRNA profiling, for pCR. Responses were also dichotomized as complete or near complete response (Symmans RCB scores of 0-1) vs. suboptimal response (RCB score > 1).

Results: The median age was 53 (28-75). Pts presented with clinical stages II (63%) and III (37%). So far, 38 of the 49 pts accrued between 2/2012 and 6/2015, have undergone surgery, 68% of whom underwent modified radical mastectomy. The pCR rate (breast and lymph nodes in CR) was 53%, and RCB 0 and 1 were seen in 68% of pts. Toxicites included grade ¾ anemia (45%), thrombocytopenia (13%) and neutropenia (53%,1 pt with neutropenic fever). Dose adjustments were needed in over 80% of pts. Grades 2 or 3 peripheral neuropathy were seen in 8% each, and grades 3-4 fatigue (13%), hypokalemia (3%), and hyponatremia (3%) were observed. The median number of CTCs (pre-NCT) observed in 7 CTC positive pts of the first 27 pts who completed surgery was 1 (0-7), and 2 of the 7 pts continued to have CTCs at the time of surgery (1 CTC each), while 2 pts without CTCs pre-NCT had CTCs (1 each) detected at surgery. The final pt enrolled is expected to complete surgery by 10/2015. Results of sequential CTC assessments, MammaPrint/Blueprint and RNA/miRNA analysis of pre- and post-treatment specimens and their correlation with pCR will be presented.

Conclusion: The non-anthracycline-containing regimen of carb and nab-paclitaxel induced a high pCR rate in TNBC, in preliminary analysis. Ongoing profiling may allow for future subset-specific modification of this regimen to increase pCR across all molecular subtypes of TNBC.

Citation Format: Somlo G, Chung S, Frankel P, Hurria A, Koehler S, Kruper L, Mortimer JE, Paz B, Robinson K, Taylor L, Vito C, Waisman J, Yeon C, Yim J, Yuan Y, Tong T. Phase II trial of neoadjuvant chemotherapy with carboplatin and nab-paclitaxel in patients with triple negative locally advanced and inflammatory 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 P1-14-10.

Abstract P3-07-26: Biomarker comparison between androgen receptor – Positive-triple-negative breast cancer (AR+ TNBC) and quadruple-negative breast cancer (QNBC)

Background: Quadruple-negative breast cancer (QNBC) is a subgroup of triple-negative breast cancer (TNBC) that lacks androgen receptor (AR) expression. While TNBC patients with AR expression have shown a promising response to AR-targeted therapies, QNBC patients' treatment options remain limited, with no targeted therapy We investigated the biomarker profiles of large cohorts of AR+TNBC and QNBC to identify their molecular differences.

Method: TNBC tumors (defined as negative by IHC for ER, PR, Her2 and ISH for Her2) referred to Caris Life Sciences (Phoenix, AZ) between 2009 and 2015 were evaluated by board-certified pathologists with a combination of immunohistochemistry (AR, cKIT, cMET, EGFR, ER, ERCC1, Her2, MGMT, PD-1, PD-L1, PGP, PR, PTEN, RRM1, SPARC, TLE3, TOPO2A, TOPO1, TS and TUBB3), fluorescent/chromogenic in-situ hybridization (cMET, EGFR, Her2, TOP2A), and sequencing (Next-generation and Sanger). Tumors evaluated included a mix of primary tumors and metastases. QNBC tumors were defined as TNBC tumors that showed negative AR expression (<10% of cells staining).

Results: Among 2,071 TNBC tumors identified, 1,952 tumors had AR IHC performed, out of which 1,612 (83%) were QNBC and 340 (17%) were AR+ TNBC tumors. Tumor expression of PD-L1 (Ab: SP142, Spring Bioscience/130021, R&D Systems, cutoff used: 2+, 5%) was significantly higher in QNBC compared to AR+TNBC tumors (18% vs. 8%, p=0.01), while PD-1 (Ab: NAT105, Ventana) expression on tumor-infiltrating lymphocytes was comparable between the two cohorts (60% vs. 62%). QNBC tumors were significantly more likely to express proteins of cKIT (26% vs. 15%, p=0.01), EGFR (69% vs. 56%, p=0.03), TS (49% vs. 33%, p<0.0001) and TOPO2A (85% vs. 65%, p<0.0001) compared to AR+TNBC. TLE3 expression was significantly higher in AR+TNBC cohorts (48% vs. 32%, p<0.0001). Sequencing reveals that QNBC tumors carried significantly higher mutation rate of TP53 (71% vs. 55%, p<0.0001) while AR+TNBC tumors showed significantly higher mutation rates of PIK3CA (42% vs. 12%, p<0.0001), AKT1 (13% vs. 1%, p<0.0001) as well as ERBB2 (5% vs. 1%, p=0.0003).

Conclusion:

Biomarker comparisons between two molecular subgroups of the TNBC tumors confirm the molecular heterogeneity of this aggressive type of breast cancer. Our biomarker results suggests that for AR+TNBC tumors, future clinical trial design can consider fluoropyrimidines, taxanes, and agents targeting PI3K/AKT/mTOR pathway as well as pan-HER inhibitors, and those agents may be combined with anti-androgen therapies. On the other hand, clinical trials for immune checkpoint inhibitors, TOP2A inhibitors, as well as agents that target cKIT and EGFR should be considered for QNBC tumors. Our findings highlight the molecular differences that should be considered in the design of future clinical trial strategies, warranting further investigation for improving targeted therapy and outcomes in TNBC.

Citation Format: Xiu J, Obeid E, Gatalica Z, Reddy S, Goldstein LJ, Link J, Waisman J. Biomarker comparison between androgen receptor – Positive-triple-negative breast cancer (AR+ TNBC) and quadruple-negative breast cancer (QNBC). [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 P3-07-26.

Abstract P3-07-27: Distinct biomarker features in triple-negative breast cancer metastases to the brain, liver and bone

Background: Triple-negative breast cancer (TNBC) is characterized by its aggressive nature and accounts for a disproportionate number of metastatic disease cases and breast cancer-related deaths. Despite recent improvements, TNBC patients who develop metastatic diseases have limited treatment options. We investigated biomarkers from brain, liver and bone metastases collected from TNBC patients to identify therapeutic options and to examine molecular differences between the metastatic sites.

Method: Triple-negative breast cancer tumors referred to Caris Life Sciences (Phoenix, AZ) between 2009 and 2015 were tested with a combination of immunohistochemistry, fluorescent/chromogenic in-situ hybridization and sequencing (Next-generation and Sanger).

Result: 1570 TNBC tumors were analyzed, including 1297 tumors taken from breast, 54 from brain, 172 from liver and 47 from bone. Select biomarker frequencies of protein overexpression (IHC), gene amplification (ISH) and mutations (SEQ) are summarized in Table 1. Brain metastases showed the highest protein expression of TOPO2A and PDL1; liver metastases showed the highest expression of AR and SPARC, as well as the highest mutation rate of PIK3CA. Bone metastases showed the lowest expression of TS, RRM1 and ERCC1. BRCA1 and BRCA2 mutation rates ranged from 0-11% in various specimen sites.

Table 1Biomarker and MethodBreast Metastases (%)Brain Metastases (%)Liver Metastases (%)Bone Metastases (%)p value[pound]TOP2A IHC76100[sect]7339<0.0001PDL1 IHC1540[sect]8170.03AR IHC151036[sect]260.0005SPARC IHC173040[sect]150.0027PIK3CA SEQ165.329[sect]250.036TS IHC[dagger]49542415[sect]<0.0001RRM1 IHC[dagger]39433216[sect]0.006ERCC1 IHC[dagger]35554816[sect]0.002BRCA1 SEQ708n/ansBRCA2 SEQ11114n/ans[sect]:the group with the highest frequency of actionable results; [pound]:p values are calculated from comparing the group with the highest frequency with the lowest frequency using two tailed Fisher-Exact test, further detailed statistical analysis will be presented;[dagger]:low levels predict response to associated drugs; Ns: non-significant, i.e., p >0.05; n/a: data not available due to low N

Conclusion: Distinct biomarker features identified in different metastatic sites in TNBC present the rationale to investigate differential treatment strategies. Based on biomarker results, etoposide, immune-modulatory agents may seem promising for brain metastases; anti-androgen therapies and nab-paclitaxel may be promising in treating liver metastases; while fluoropyrimidines, gemcitabine and platinum may be considered for TNBC patients with bone metastases.

Citation Format: Xiu J, Gatalica Z, Reddy S, Waisman J, Link J. Distinct biomarker features in triple-negative breast cancer metastases to the brain, liver and bone. [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 P3-07-27.

Abstract P5-16-04: A phase I study of a DNA plasmid based vaccine encoding the HER-2/neu intracellular domain in subjects with HER2+ breast cancer

HER2+ breast cancer (BC) is associated with early disease relapse, usually to distant sites. This would suggest relapse is due to residual microscopic disease. Generation of vaccine-induced HER2-specific CD4+ T helper immunity (Th1) may result in immunologic eradication of residual HER2+ tumor cells and subsequent development of immunologic memory and epitope spreading (ES), which has been associated with a survival benefit in vaccinated BC patients. We have shown HER2 peptide-based vaccines can generate immunity in BC however, more recently we developed a plasmid DNA based vaccine (pNGVL3-hICD) which may have additional advantages over synthetic peptides. DNA vaccines offer a strategy to immunize against multiple tumor antigens and are able to elicit both CTL and Th1 immunity. Plasmid DNA can also remain at the vaccine site, providing a constant source of antigen. Intradermal (i.d.) delivery of DNA vaccines with GM-CSF as adjuvant may enhance immunogenicity due to local influx of dermal Langerhans cells. We have recently completed a phase I trial utilizing pNGVL3-hICD in optimally treated stage III and IV HER2+ BC patients and have defined vaccine safety profile, optimal dose and schedule; and demonstrated vaccine biologic activity.

Methods: A total of 66 subjects with stage III and IV HER2+ BC in complete remission were enrolled sequentially into 1 of 3 pNGVL3-hICD dose arms (22 subjects/arm): Arm 1=10µg, Arm 2=100 µg, and Arm 3 = 500µg. All vaccines were admixed with 100µg GM-CSF and given i.d. monthly for a total of 3 vaccines. Toxicity was assessed at baseline, during vaccination and at follow-up. Immune responses to HER ICD and ECD were assessed with IFN-γ ELISPOT at baseline and serially through week 60 post-vaccination. Linear regression analysis was used to compare differences in immune responses from baseline over the whole study period between dose arms. Vaccine site skin biopsies and peripheral lymphocytes were serially analyzed for plasmid persistence via RT-PCR.

Results: 64 subjects (20 in Arm 1; 22 in Arm 2; 22 in Arm 3) completed 3 vaccines. Age, stage/status, number of previous chemotherapy regimens, and use of bisphosphonate and trastuzumab therapies was similar across dose arms. Vaccine-related toxicity was primarily Grade 1/2 injection site reactions, myalgias, arthralgias and not significantly different between arms; no cardiac or grade IV toxicity was observed. Immune responses to HER2 ICD were significantly better in Arms 2 and 3 vs Arm 1 (p = 0.001 and 0.002, respectively) but not statistically different between Arms 2 and 3. 38 patients had DNA plasmid persistence at the vaccination site with no difference between arms. There has been no detection of DNA plasmid in lymphocytes from patients in all arms. Analyses of survival and ES (HER ECD immune responses) are on-going and will be presented.

Conclusions: pNGVL3-hICD was safe and effectively induced persistent HER2 ICD specific Th1 immunity without increased cardiac toxicity. Moreover, immunity was present more than 1 year after end of vaccination, indicative of vaccine-induced immunologic memory.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-16-04.

Phase I-II Study of Denileukin Diftitox (ONTAK®) in Patients with Advanced Refractory Breast Cancer

Background: CD4+CD25+Foxp3+ regulatory T cells (Tregs) are potent suppressors of CD4+ and CD8+ T cells, produce the immunosuppressive cytokine TGF-β; and as such, may down-regulate immune responses to tumor antigens. Additionally, Tregs are increased in the peripheral blood (PB) and tumors of breast cancer patients; and are associated with poor prognosis. Depletion of PB and tumor-associated Tregs may induce anti-tumor immunity by augmenting anti-tumor effector T cells and enhancing endogenous tumor specific immunity. ONTAK®, a diphtheria/IL-2R fusion protein depletes PB Tregs when given intravenously (IV) and selectively targets tumor cells that overexpress IL-2R. Breast tumors have been shown to overexpress IL-2R which is associated with their malignant potential. We hypothesized that ONTAK® could (1) have direct anti-tumor activity in breast cancers that overexpress IL-2R, and (2) deplete Tregs resulting in generation of functional immune effector cells and enhanced anti-tumor immunity. A phase I-II study was conducted to evaluate the safety of IV ONTAK® and assess its effect on Tregs and endogenous immunity in patients with advanced refractory breast cancer.Materials and Methods: 15 patients with progressive stage IV breast cancer following standard therapy were sequentially enrolled and received IV ONTAK® 18 mcg/kg/day on Days1-5 every 21 days for a total of 6 cycles and/or maximal tumor response. Toxicity was evaluated on Days 1 8, and 14 of each cycle per CTEP CTCAE v3.0. Tumor response was evaluated per RECIST at baseline, and after cycles 3 and 6. PB was collected at baseline and after cycles 2, 4, and 6 for evaluation of Tregs, sIL-2R, and endogenous tumor-antigen specific T cell immunity to HER-2/neu (HER2), CEA, and MAGE-3 via RT-PCR, LUMINEX and IFN-γ ELISPOT assay, respectively. Expression of IL-2R in patient paraffin embedded tumor samples was analyzed by IHC analysis.Results: 15 subjects have been enrolled and 14/15 have completed treatment; median age is 58 years (range, 32-69) and median salvage regimens is 3 (range, 2-8). 7/14 subjects had triple negative tumors. 7 subjects completed 1-2 and 7 completed 3-6 ONTAK® cycles, respectively. 4 subjects who completed 6 cycles of ONTAK® had SD or PR per RECIST. ONTAK®-related toxicities have been primarily grade I and II fatigue, nausea, and headache; and transient grade 3 hypoalbuminemia and lymphopenia. Preliminary data in 2 subjects shows enhanced tumor-antigen specific T cell immunity defined as mean tumor antigen-specific T cell precursors:PBMC to CEA (pre- ONTAK® 1:250,000; post- ONTAK® 1:15,000) and HER2 (pre- ONTAK® 1:63,000; post- ONTAK® 1:6,312). Immunologic analyses are ongoing and will be presented along with clinical data on all patients.Conclusions: ONTAK® is well-tolerated when used as a salvage regimen in heavily pretreated breast cancer patients. Additionally, ONTAK® treatment can enhance endogenous immunity to known breast cancer antigens and potentially lead to more effective eradication of tumor.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4130.

Phase II Study of a HER-2/Neu (HER2) Intracellular Domain (ICD) Vaccine Given Concurrently with Trastuzumab in Patients with Newly Diagnosed Advanced Stage Breast Cancer

HER2 is a tumor antigen in breast cancer and several trials have demonstrated that breast cancer patients can be immunized against this protein. We have developed HER2 peptide based vaccines that are aimed at eliciting CD4+ Th1 tumor antigen specific T cell responses. Th1 effectors provide immunologic memory, enhance cross priming which will allow the elaboration of tumor specific CD8+ T cells, and stimulate epitope spreading which we have shown to be a potential biomarker of clinical response. 52 patients will be enrolled with the primary objective to determine relapse free survival after active immunization. Eligible patients are newly diagnosed with Stage III (B or C) or Stage IV breast cancer and begin vaccination within 6 months of starting maintenance trastuzumab. This interim report will present data on the first 25 patients enrolled; 21 stage IV and 4 locally advanced patients. The vaccine is well tolerated with all adverse events (AE) being Grade I or 2. The most common AE is injection site reaction. Moreover, the combination of HER2 vaccination with trastuzumab did not result in additive cardiac toxicity in these patients. Immune responses were evaluated by IFN-gamma ELISPOT. To date, 88% of patients immunized developed significant immunity to the components of the ICD vaccine. The majority, 75%, developed robust immunity to the HER2 protein. Our group has recently demonstrated that a broadening of immunity throughout the HER2 protein, to components of the protein that weren't in the vaccine, i.e. epitope spreading, may be associated with improved survival in vaccinated patients. 63% of immunized patients demonstrated evidence of intramolecular epitope spreading. We questioned whether such high frequencies of homing Type 1 T cells might modulate the immunosuppressive tumor microenvironment, so we evaluated whether circulating serum immunosuppressive cytokines were impacted by immunization. TGF-beta is an immunosuppressive cytokine secreted by tumor stroma and regulatory T cells. We found that the levels of serum TGF-beta decreased significantly in the majority of patients after vaccination. We further analyzed the correlation between the change of serum levels of TGF-beta post vaccination and HER2 ICD vaccine-induced T cell responses. We found that the greater the magnitude of the HER2 specific T cell response, as demonstrated by IFN-gamma secretion, the greater the decrease in serum TGF-beta (p=0.0045, r=0.742). The correlation between the increased epitope spreading T cell response and decreased levels of TGF-beta was even more significant (p=0.0003). The median overall survival has not been reached with 100% of patients alive at this time. Relapse free survival data will be presented.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5102.

A phase I study of a DNA plasmid based vaccine encoding the HER2/neu (HER2) intracellular domain (ICD) in subjects with HER2+ breast cancer

3054

Background: HER2 is overexpressed in 25% of breast cancers and plays a role in the malignant transformation of cells. Vaccine-induced immunity against the HER2 ICD correlates with antitumor responses in animal models. DNA-based vaccines offer a strategy to immunize against multiple tumor antigens and are able to elicit both CTL and T helper immune responses. Plasmid DNA can also remain at the vaccine site, providing a constant source of antigen. However, DNA vaccines have been poorly immunogenic due in part to inefficient APC transfection. Intradermal (i.d.) delivery of DNA vaccines with GM-CSF as adjuvant may enhance immunogenicity due to local influx of dermal Langerhans cells. A phase I study was conducted to evaluate the safety and immunogenicity of a DNA-based vaccine encoding the HER2 ICD. Methods: 44 subjects with stage III and IV HER2+ breast cancer in complete remission were enrolled sequentially into 2 vaccine arms (22 subjects/arm) and received 10μg pNGVL3-hICD (Arm 1) or 100μg pNGVL3-hICD (Arm 2). All vaccines were admixed with 100μg GM-CSF and given i.d. monthly for a total of 3 vaccines. Toxicity was assessed at baseline, during vaccination, and at follow-up. Immune responses were assessed with IFN-γ ELISPOT at baseline and post-vaccination. Vaccine site biopsies were analyzed for plasmid persistence via RT-PCR, 1 and 6 months after vaccination. Results: 43 subjects (21 in Arm 1; 22 in Arm 2) completed 3 vaccines. Vaccine-related toxicity in both arms was primarily grade I/II; no cardiac or grade IV toxicity was observed. 13/21 (62%) subjects in Arm 1 developed T-cell immunity, defined as HER2-specific T cell precursors:PBMC, to the HER2 protein (median 1:5,972, range 1:717–1:3,000,000) and to p776, a HER2 pan DR binding epitope (median 1:3,150, range 1:543–1:108,696). 13/19 (68%) subjects in Arm 1 had persistent plasmid DNA at the vaccine site. ELISPOT and RT-PCR analysis for Arm 2 are on-going. Conclusions: Immunization with a DNA plasmid-based HER2 vaccine is safe and immunogenic. Moreover, plasmid DNA persists at the vaccine site post-immunization and HER2+ cancer patients are able to develop immunity to the HER2 ICD.

No significant financial relationships to disclose.

Phase I study of infusion of HER2/neu (HER2) specific T cells in patients with advanced-stage HER2 overexpressing cancers who have received a HER2 vaccine

3000

Background: Adoptive T-cell therapy has shown promise in the treatment of advanced-stage melanoma. We have previously reported that expansion of HER2-specific T cells from peripheral blood mononuclear cells (PBMC) can be greatly facilitated by vaccine-priming. In this study, we evaluated the safety and clinical efficacy of infusion of HER2-specific T cells in patients with advanced HER2 overexpressing cancers. Methods: 10 patients with progressive HER2+ metastatic breast and ovarian cancer, not considered curable by conventional therapies, will be enrolled in this study. The patients must have been pre-immunized with a HER2-specific vaccine. Three escalating doses of T cells are given at 10-day intervals. Cyclophosphamide or denileukin diftitox is administrated before the first dose of T cells. Results: To date, 5 of 10 subjects have been enrolled. T cells were expanded with HER2-specific class II restricted peptides. After in vitro expansion cell products were >95% CD3+ with an average of 35% CD4+ and 60% CD8+ T cells. The maximal doses infused were 1x109-41x109 cells (median 10x109). Subjects tolerated the infusions well with the primary toxicity being related to the conditioning agent. Objective tumor regression has been observed in 2 of the 5 treated patients. One other patient has had stable disease after treatment. In patients with tumor regression, the magnitude of HER2-specific T cells in the infused product was 8-fold higher than that in patients without clinical responses. The total number of HER2-specific T cells infused was 43-fold higher in responding patients than in nonresponding patients. Moreover, HER2-specific CD4+ and CD8+ T cells persisted over a year and even augmented in magnitude post-infusion in responding patients. Conclusions: Adoptive transfer of autologous HER2 specific polyclonal T cells generated from PBMC after vaccine-priming is well tolerated and has shown evidence of some clinical efficacy in patients with advanced-stage HER2+ cancers.

No significant financial relationships to disclose.

Association of the level of HER2/neu (HER2) gene amplification in breast cancer and the magnitude of antigen specific T-cell immunity achieved after HER2 vaccination

3059

Background: Studies have demonstrated that the level of HER2 gene amplification in breast cancer, assessed by fluorescence in situ hybridization (FISH), correlates with favorable clinical response after treatment with trastuzumab. We questioned whether HER2 gene amplification impacted the development of HER2-specific T-cell immunity following immunization with a HER2 vaccine. Methods: Patients with HER2+ stage III or IV breast cancer, treated to complete remission or stable bone only disease, were enrolled in one of two concurrent clinical trials of HER2-specific vaccines. Eligibility criteria between the two studies were similar. Patients received either a plasmid DNA-based vaccine encoding the HER2 intracellular domain or a peptide-based vaccine composed of 3 HER2 class II epitopes. Peripheral blood was assessed for HER2-specific T-cell responses by interferon gamma (IFN-g) ELISPOT prior to, immediately after, and 6 months to 1 year after the end of vaccinations. Both immune response and FISH data were available on 31 patients. Results: Correlation of FISH levels to IFN-g spots/well in evaluable patients revealed the level of HER2 gene amplification was not related to the presence of pre-existent HER2-specific T-cell immunity prior to vaccination (p=0.43), the generation of a HER2-specific immune response after vaccination (p=0.35), or the persistence of the HER2-specific T-cell response (p=0.33). However, the magnitude of the T-cell response achieved was less as HER2 gene amplification increased (p=0.05). Conclusions: The level of HER2 gene amplification in the primary tumor can adversely impact the magnitude of HER2-specific T-cell immunity achieved after vaccination.

No significant financial relationships to disclose.

Sources of referral to early phase clinical trials: a case for putting all your eggs in one basket

Abstract #3116

Background: Studies suggest that only 2% to 3% of all adult cancer patients and approximately 5% of breast cancer patients enroll in clinical trials. To better understand the factors that contribute to enrollment we collected data from patients on sources that prompted them to contact us.
 Methods: From Jan 2005 to Apr 2008 we screened nearly 400 patients for 8 Phase I/II clinical trials focused on immunotherapy of breast and ovarian cancer. We queried subjects about informational sources that led them to consider our clinical studies. Patients learned about our trials from sources including: Clinicians, the Internet (advocacy group websites, search engines, government/university sites), Other patients, Family/friends, Media, Community events and Postings seeking research participants. Many patients who cited a clinician as their referral source specifically referenced a private, multi-site breast cancer clinic in Southern California with which our clinical group has formed a partnership, or consortium. To ensure that this was represented in the data and because the clinician category comprised a large percentage of the referral sources we split the category into 2 groups-one being the private practice in California (to be referred to as “consortium”) and the other being all other clinicians.
 Results: Of the 399 patients screened, 336 (84%) were considered potentially eligible for study. A total of 72 patients, or 18% of those screened have enrolled in one of our trials to date.
 Among patients screened, most learned about our trials from clinicians outside the consortium (34%), the Internet (27%), and consortium clinicians (15%). Patients most often named her2support.org (35%) and clinicaltrials.gov (23%) as their specific Internet sources. The remaining sources, family/friends, patients, media sources, community events and postings in medical facilities, were each cited by <5% of patients.
 Although consortium clinicians were responsible for only 15% of referrals, 50% of their referrals enrolled in a study. Only 16% of patients referred by other clinicians and 9% referred via the Internet were enrolled. Though other clinicians and the Internet are the most common referral sources, referrals from our consortium were significantly more likely to enroll than any other source (p<0.001).
 This may be due to the fact that patients referred by the consortium were more likely to meet eligibility criteria. Relative to 93% of consortium referrals, 87% of other clinician and 79% of Internet referrals were potentially eligible for trial (p<0.05). Patients referred by our consortium were significantly more likely to meet study criteria relative to those referred by other sources.
 Discussion: Physician referrals often lead to higher accrual to clinical trials relative to other referral sources. Our data reveal that accrual can be further improved by forming a close collaborative relationship with a single select practice of clinicians.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3116.

A phase I/II study of a HER2/neu (HER2) peptide vaccine plus concurrent trastuzumab

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Background: HER2 is a tumor antigen in breast and ovarian cancer. Vaccines targeting both Class I and II epitopes of HER2 can elicit long-lived cellular immunity. Trastuzumab increases the activity of HER2-specific T cells in vitro. This study examines the safety and immunogenicity of a HER2 peptide vaccine given with trastuzumab to augment HER2-specific immune responses in vivo. Methods: 20 HLA-A2+ subjects will be enrolled on this Phase I/II single institution trial. Eligible subjects must have stage IV HER2 overexpressing breast or ovarian cancer, stable or no evident disease on maintenance trastuzumab and a normal baseline MUGA. Subjects must have ECOG performance status 0–1, creat ≤ 2.0, bili < 1.5 × ULN, SGOT < 2 × ULN. The HER2 vaccine used in this study has been previously reported and is composed of 3 HER2 Class II epitopes encompassing Class I epitopes in their natural sequence. (Knutson et al, J Clin Investigation 107:477–484, 2001). Subjects receive 6 vaccinations + GM-CSF at monthly intervals. Primary endpoints are safety and immunogenicity. Results: To date, 14 of 20 subjects have been enrolled. A total of 77 vaccinations have been given. Of 276 reported toxicities, 88% were Grade 1; most common were constitutional symptoms (25%), injection site reactions (14%), and cytopenias (14%). 11% of toxicities were Grade 2; most common were lymphopenia (34%) and headache (19%). There was one Grade 3 toxicity (syncope 5 hours after vaccination) and one Grade 4 toxicity (stroke secondary to brain metastases in long-term follow up). Cardiac toxicity included two Grade 2 asymptomatic decreases in LVEF (54 to 49% and 64 to 45%.) The average decrease in LVEF between baseline and 9 month post-vaccine follow up was 5% ± 5.85 (n = 10). Of the 10 patients who have had immunologic analysis performed at multiple time points, 5 have developed significant T cell immunity to either HER2 overlapping peptide pools and/or HER2 peptides. Complete immunologic analysis will be presented. Conclusions: Subjects with HER2 overexpressing Stage IV cancer can be safely immunized with a HER2 peptide vaccine while receiving concurrent trastuzumab without additional cardiac toxicity. In addition, the approach is immunogenic, generating significant levels of HER2-specific T cells in the peripheral blood.

No significant financial relationships to disclose.

Multidrug-resistant tuberculosis outbreak among transvestite sex workers, Buenos Aires, Argentina

We describe the first outbreak of multidrug-resistant tuberculosis (MDR-TB) that occurred in Argentina among transvestite sex workers, and actions undertaken for its control. In Buenos Aires city, transmission was documented between 2001 and 2004 by conventional and molecular methods in a hotel where transvestites used to reside and work. The source case was traced back to 1998. Six secondary cases were diagnosed and treated. Thirty-two contacts were investigated. The outbreak strain had formerly caused nosocomial transmission in Rosario, a city 300 km from Buenos Aires. Our findings highlight the difficulties controlling MDR-TB in Argentina.