Validation of a Molecular Diagnostic Test for Circulating Tumor DNA by Next-Gen Sequencing

A modified version of the PGDx elioTM Plasma Resolve assay was validated as a laboratory-developed test (LDT) for clinical use in the Molecular Diagnostics Laboratory at Fox Chase Cancer Center. The test detects single nucleotide variants (SNVs) and small insertions and deletions (indels) in 33 target genes using fragmented genomic DNA extracted from plasma. The analytical performance of this assay was assessed with reference standard DNA and 29 samples from cancer patients and detected 66 SNVs and 23 indels. Using 50 ng of input DNA, the sensitivity was 95.5% to detect SNVs at 0.5% allele frequency, and the specificity was 92.3%. The sensitivity to detect indels at 1% allele frequency was 70.4%. A cutoff of 0.25% variant allele frequency (VAF) was set up for diagnostic reporting. An inter-laboratory study of concordance with an orthologous test resulted in a positive percent agreement (PPA) of 91.7%.

A phase 1 study of nivolumab in combination with interferon-gamma for patients with advanced solid tumors

This phase I, dose-escalation trial evaluates the safety of combining interferon-gamma (IFN-γ) and nivolumab in patients with metastatic solid tumors. Twenty-six patients are treated in four cohorts assessing increasing doses of IFN-γ with nivolumab to evaluate the primary endpoint of safety and determine the recommended phase two dose (RP2D). Most common adverse events are low grade and associated with IFN-γ. Three dose limiting toxicities are reported at the highest dose cohorts. We report only one patient with any immune related adverse event (irAE). No irAEs ≥ grade 3 are observed and no patients require corticosteroids. The maximum tolerated dose of IFN-γ is 75 mcg/m², however based on a composite of safety, clinical, and correlative factors the RP2D is 50 mcg/m². Exploratory analyses of efficacy in the phase I cohorts demonstrate one patient with a complete response, and five have achieved stable disease. Pre-planned correlative assessments of circulating immune cells demonstrate intermediate monocytes with increased PD-L1 expression correlating with IFN-γ dose and treatment duration. Interestingly, post-hoc analysis shows that IFN-γ induction increases circulating chemokines and is associated with an observed paucity of irAEs, warranting further evaluation. ClinicalTrials.gov Trial Registration: NCT02614456.

Cancer Associated Macrophage-like Cells Are Prognostic for Highly Aggressive Prostate Cancer in Both the Non-Metastatic and Metastatic Settings

Despite advancements in the early-stage detection and expansion of treatments for prostate cancer (PCa), patient mortality rates remain high in patients with aggressive disease and the overtreatment of indolent disease remains a major issue. Prostate-specific antigen (PSA), a standard PCa blood biomarker, is limited in its ability to differentiate disease subtypes resulting in the overtreatment of non-aggressive indolent disease. Here we assess engorged cancer-associated macrophage-like cells (CAMLs), a ≥50 µm, cancer-specific, polynucleated circulating cell type found in the blood of patients with PCa as a potential companion biomarker to PSA for patient risk stratification. We found that rising PSA is positively correlated with increasing CAML size (r = 0.307, p = 0.004) and number of CAMLs in circulation (r = 0.399, p < 0.001). Over a 2-year period, the presence of a single engorged CAML was associated with 20.9 times increased likelihood of progression (p = 0.016) in non-metastatic PCa, and 2.4 times likelihood of progression (p = 0.031) with 5.4 times likelihood of death (p < 0.001) in metastatic PCa. These preliminary data suggest that CAML cell monitoring, in combination with PSA, may aid in differentiating non-aggressive from aggressive PCas by adding biological information that complements traditional clinical biomarkers, thereby helping guide treatment strategies.

A Phase II Trial of Guadecitabine plus Atezolizumab in Metastatic Urothelial Carcinoma Progressing after Initial Immune Checkpoint Inhibitor Therapy

PURPOSE

Based on preclinical evidence of epigenetic contribution to sensitivity and resistance to immune checkpoint inhibitors (ICI), we hypothesized that guadecitabine (hypomethylating agent) and atezolizumab (anti-PD-L1) together would potentiate a clinical response in patients with metastatic urothelial carcinoma (UC) unresponsive to initial immune checkpoint blockade therapy.

PATIENTS AND METHODS

We designed a single arm Phase II study (NCT03179943) with a safety run-in to identify the recommended phase II dose of the combination therapy of guadecitabine and atezolizumab. Patients with recurrent/advanced urothelial carcinoma who had previously progressed on ICI therapy with PD-1 or PD-L1 targeting agents were eligible. Pre-planned correlative analysis was performed to characterize peripheral immune dynamics and global DNA methylation, transcriptome, and immune infiltration dynamics of patient tumors.

RESULTS

Safety run-in enrolled 6 patients and Phase II enrolled 15 patients before the trial was closed for futility. No dose-limiting toxicity was observed. Four patients, with best response of stable disease, exhibited extended tumor control (8-11 months) and survival (>14 months). Correlative analysis revealed lack of DNA demethylation in tumors after 2 cycles of treatment. Increased peripheral immune activation and immune infiltration in tumors after treatment correlated with progression-free survival and stable disease. Furthermore, high IL-6 and IL-8 levels in the patients' plasma associates with short survival.

CONCLUSIONS

No RECIST responses were observed after combination therapy in this trial. Although we could not detect the anticipated tumor-intrinsic effects of guadecitabine, the addition of hypomethylating agent to ICI therapy induced immune activation in a few patients, which associated with longer patient survival.

A phase II trial of risk-enabled therapy after initiating neoadjuvant chemotherapy for bladder cancer (RETAIN)

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Background: Cisplatin-based neoadjuvant chemotherapy (NAC) followed by cystectomy or chemoradiation is the standard of care for urothelial carcinoma (UC) patients with MIBC. Both cystectomy and chemoradiation have short and long-term toxicity and QOL implications. Mutations in DNA damage repair/response genes are associated with pathologic downstaging after NAC. We hypothesized that a combination of biomarker selection and clinical staging would identify patients prospectively for a cystectomy or chemoradiation avoidance algorithm. Methods: We conducted a single-arm, phase II, non-inferiority trial (NCT02710734) to evaluate a risk-adapted approach for MIBC. Patients with cT2-T3N0M0 UC underwent NAC with accelerated MVAC. Pre-NAC TURBT specimens were sequenced (Caris) for mutations in ATM, ERCC2, FANCC or RB1. Patients with ≥ 1 mutations and no clinical evidence of disease by restaging TUR, urine cytology and imaging post-NAC began pre-defined active surveillance (AS). Remaining patients underwent bladder-directed therapy. The primary endpoint was metastasis-free survival (MFS) at 2 years for the entire cohort. The risk-adapted approach would be declared non-inferior to the standard of care if the lower bound of an exact 1-sided 95% CI for MFS was > 64%. The study required 70 patients with a 4.5% type I error and 81.6% power. Results: 71 (ITT) patients were enrolled over 33 months at four academic centers. Median age was 70 years (47-83), 74% were male, 92% Caucasian, 81% ECOG PS 0 and 79% cT2. 90% completed 3 cycles of MVAC with 17% grade 3-4 TRAEs. In the ITT population, 33 (46%) had a relevant mutation and 26 (37%) began AS. With a median follow-up of 41 months, 47 patients (66%) are metastasis-free (CI 54%-77%). The 2-year MFS for the ITT patients (primary endpoint) was 72% (lower bound exact 1-sided 95% CI=62%). On post hoc analysis, the 2-year MFS was 65% in the AS group (CI 44%-83%) and 76% (CI 60%-87%) in the remaining patients (P=0.42). In the AS group, 18 patients (69%) had some UC recurrence, 8 had a cystectomy, 2 chemoradiation, and 13 (50%) are metastasis-free with an intact bladder. Of the 10 patients (38%) on AS who developed metastatic disease, 9 recurred with localized disease first. The 2-year OS is 83% (CI 72%-90%) and 89% (CI 68%-96%) in the ITT and AS groups, respectively. Associations between mutation presence and MFS or UC recurrence were not observed. Conclusions: The 72% 2-year MFS rate in this MIBC cohort treated with a risk-adapted approach did not satisfy the pre-specified non-inferiority condition. 38% of AS patients developed metastatic disease, with most patients first recurring locally in the bladder. With a median follow-up of 41 months, although 50% of AS patients have been able to avoid cystectomy without metastatic disease, further refinement of this approach is necessary. Clinical trial information: NCT02710734 .

Tracking changes in circulating stromal cells and circulating tumor cells predicts responsiveness of new line induction in metastatic breast cancer after 1 cycle of therapy

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Background: In metastatic Breast Cancer (mBC), Circulating Tumor Cells (CTCs) are established prognostic indicators of patients (pts) not responding to new lines of therapy and who have poor clinical outcomes. However, CTCs are typically found in < 20% of mBC pts and many pts without CTCs will also progress. Recently an inflammatory pro-tumorigenic macrophage emanating from tumor stroma (i.e. Cancer associated macrophage-like cell [CAML]) was found in > 90% of mBC pts and were also indicative of poor clinical outcomes. As CTCs & CAMLs are isolated in conjunction from a single blood sample, and both are prognostic for therapy response, we evaluated CTCs & CAMLs before and after initiation of new therapies in mBC to determine their combined prognostic/predictive values. Methods: An observational prospective 2-year multi-institutional study was undertaken to evaluate CTCs & CAMLs before, and after, induction of any new line of therapy in pts with diagnosed mBC (n = 101). Anonymized and blinded blood samples were taken at baseline (BL), prior to starting a new systemic therapy, and a 2nd sample (T1) taken after therapy initiation (̃30 days). Blood was filtered by CellSieve filtration. The quantities and subtypes of CTCs & CAMLs were analyzed based on RECIST v1.1 for progression-free survival (PFS) and overall survival (OS) hazard ratios (HRs) by censored univariate & multivariate analysis at 2 years. Results: CTCs were identified in 35% (n = 35/101) of pts at BL & 24% (n = 24/101) at T1, with a single CTC at T1 being highly prognostic for worse PFS HR = 6.2 95%CI 3.0-13.2, p < 0.001 & OS (HR = 5.1 95%CI 2.0-13.4, p = 0.002. In parallel, CAMLs were found in 93% of BL and 86% of T1 samples, and whose decreases were significantly prognostic for improved PFS (HR = 2.7, 95%CI 1.4-5.1, p = 0.006) and OS (HR = 4.4 95%CI 1.5-13.2, p = 0.018) when CTCs were absent. Overall ≥1 CTC at T1 (n = 24) had median PFS = 2.4 & mOS = 4.8 months (mos), however, in pts without CTCs plus an increase in CAMLs (n = 36) had mPFS = 5.9 & mOS = 14.1 mos, while in pts without CTCs plus a decrease in CAMLs (n = 41) had mPFS = 14.8 & mOS = 18.8 mos. Conclusions: Our data confirms that pts with persistent CTCs have the worst clinical outcomes. Further, simultaneous CAML quantification provided a new dynamic predictive blood based biomarker in pts without detectable CTCs which may be useful to better individualize therapy and improve outcomes, though future studies are need to validate these findings.

A phase I/II study of nivolumab and axitinib in patients with advanced renal cell carcinoma

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Background: Combination systemic therapy with tyrosine kinase inhibitors (TKIs) and an immune checkpoint inhibitor (IO) are an established standard of care for patients with metastatic renal cell carcinoma (mRCC). We performed a phase I/II study to investigate the safety and efficacy combining the TKI axitinib (axi) with the IO agent nivolumab (nivo). Methods: This phase I/II study investigated the combination of axi and nivo in an initial dose finding phase I portion with a 3+3 design to determine the recommended phase 2 dose (RP2D) of axi. The phase II portion included 2 parallel arms: treatment naïve mRCC patients and mRCC patients previously treated with TKIs alone or IO/IO combination (NCT03172754). We are presenting results from the treatment naïve arm only. Included patients had to have histology with any clear cell component, ECOG performance status of 0-1, no known or symptomatic brain metastases, and no history of autoimmune disease. The RP2D of axi was 5 mg BID from the phase I portion and patients could be treated for up to 2 years. The primary endpoint of the phase II portion was objective response rate (ORR) per investigator assessment. Results: Forty-four patients were accrued to the treatment naïve arm. One withdrew consent and was replaced but is included in the safety analysis, while 42 patients are evaluable for efficacy. The median age was 65 yrs (range: 42-84 yrs) and the group was predominantly male (83.7%) and white (95.3%). Using the IMDC risk group grading, 18 patients (41.9%) were favorable risk, 22 patients (51.2%) were intermediate risk and 3 patients (7 %) were poor risk. Median follow-up was 11.5 months. Best response data is shown in the table and is notable for an ORR of 69.0%, with only 1 patient (2.4%) experiencing primary progressive disease, for a disease control rate of 97.6%. Median progression free survival was 16.4 months (95% CI: 10.6 - 21.9 mo), and median overall survival (OS) was not reached. OS at 12 months was 86.7%. Adverse event (AE) data was similar to published data for IO/TKI combinations, with no grade 4-5 AEs. Twenty-nine patients experienced a grade 3 AE (70.7%), the most common of which was hypertension, and 14.0% discontinued the study due to treatment-related toxicity. Conclusions: The combination of axi/nivo for treatment naïve patients with mRCC demonstrated efficacy comparable to available IO/TKI combinations with a similar safety profile. Clinical trial information: NCT03172754. [Table: see text]

Abstract P1-24-02: Genetic variants and tumor microenvironment in inflammatory breast cancer: Clues for targeted therapies

Background: Inflammatory breast cancer (IBC) is characterized by a young age at diagnosis, high metastatic potential, and poor overall survival. To better understand the etiology of this aggressive disease, we performed a retrospective study to evaluate genomic alterations and tumor microenvironment in IBC patients. Methods: Targeted next generation sequencing (NGS) was performed using blood cell-free DNA (cfDNA) (n=32), paired DNA from tumor tissues (n=29) and DNA from whole blood or normal tissue (n=20). We also characterized the tumor infiltrating lymphocytes (TILs) in tumor tissue biopsies by studying several markers (CD4, CD8, FoxP3, CD20, PD-1 and PD-L1) through immunohistochemistry (IHC) staining. Results: Our results shown a high incidence of germline variants in patients with IBC that could be associated with an increased risk of developing the disease. Germline variants were found more frequently in patients with TN (38.9%) than non-TN IBC (28.6%). IHC staining revealed that in 7 of 24 (29%) patients, tumor biopsies were positive for PD-L1 and PD-1 expression on TILs. Patients with PD-L1&PD-1 positive biopsies had a lower OS (31 months) than patients with PD-L1&PD-1 negative (38 months) tumors, though the difference was not statistically significant. PD-L1&PD-1 positive tumors had significantly more CD8+ (cytotoxic T-cells), CD20+ (B-cells) and FoxP3+ (Tregs) cells than PD-L1&PD-1 negative ones. Furthermore, most IBC patients showed to have deficiencies in the homologous recombination repair (HRR) pathway (BRCA1, BRCA2, PALB2, RAD51C, ATM, BARD1) making them sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors. All tumor biopsies showed positive staining for p-FAK1(Tyr 397). Conclusion: A subset of IBC patients (29%) expressed both PD-L1 and PD-1 on tumor immune cells infiltrates, providing rationale for testing PD-1/PD-L1 blocking therapies. IBC patients could have benefits from PD-1/PD-L1 blocking therapies alone or in combination with PARP or FAK (Tyr397) kinase inhibitors, both having the capacity of altering the tumor microenvironment.

Citation Format: Maria F. Arisi, Yulan Gong, Rajeswari Nagarathinam, Lorenzo Gerratana, Jianming Pei, Kathy Q. Cai, Jennifer Winn, Zachary Hasse, Elias Obeid, Julio Noriega, Christopher Sebastiano, Eric Ross, R. Katherine Alpaugh, Massimo Cristofanilli, Sandra V Fernandez. Genetic variants and tumor microenvironment in inflammatory breast cancer: Clues for targeted therapies [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-24-02.

Feasibility of Fitness Tracker Usage to Assess Activity Level and Toxicities in Patients With Colorectal Cancer

PURPOSE

Performance status (PS) is a subjective assessment of patients' overall health. Quantification of physical activity using a wearable tracker (Fitbit Charge [FC]) may provide an objective measure of patient's overall PS and treatment tolerance.

MATERIALS AND METHODS

Patients with colorectal cancer were prospectively enrolled into two cohorts (medical and surgical) and asked to wear FC for 4 days at baseline (start of new chemotherapy [± 4 weeks] or prior to curative resection) and follow-up (4 weeks [± 2 weeks] after initial assessment in medical and postoperative discharge in surgical cohort). Primary end point was feasibility, defined as 75% of patients wearing FC for at least 12 hours/d, 3 of 4 assigned days. Mean steps per day (SPD) were correlated with toxicities of interest (postoperative complication or ≥ grade 3 toxicity). A cutoff of 5,000 SPD was selected to compare outcomes.

RESULTS

Eighty patients were accrued over 3 years with 55% males and a median age of 59.5 years. Feasibility end point was met with 68 patients (85%) wearing FC more than predefined duration and majority (91%) finding its use acceptable. The mean SPD count for patients with PS 0 was 6,313, and for those with PS 1, it was 2,925 (122 and 54 active minutes, respectively) (P = .0003). Occurrence of toxicity of interest was lower among patients with SPD > 5,000 (7 of 33, 21%) compared with those with SPD < 5,000 (14 of 43, 32%), although not significant (P = .31).

CONCLUSION

Assessment of physical activity with FC is feasible in patients with colorectal cancer and well-accepted. SPD may serve as an adjunct to PS assessment and a possible tool to help predict toxicities, regardless of type of therapy. Future studies incorporating FC can standardize patient assessment and help identify vulnerable population.

Hyper engorged cancer associated macrophage-like cells in circulation predict for multi-organ metastatic disease in solid tumors

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Background: Patients with multiple organ metastases have poorer prognoses than those with a single organ metastasis, are frequently associated with drug resistance, and have higher tumor burden. Engorged (≥50um) Cancer Associated Macrophage-Like Cells (CAMLs) are a circulating stromal cell subtype detected in the blood of patients with solid tumors at high risk for recurrence or progression. While numerous studies have shown that ≥50um CAMLs predict poor clinical outcomes, meta-analysis of these studies have also suggested that hyper engorged CAMLs ≥100um (heCAMLs) may be associated with multifocal metastatic disease and even worse outcomes. In this prospective study, we evaluated the presence of heCAMLs in patients with metastatic disease and demonstrated a strong relationship with multi organ spread, which also correlated with shorter Progression Free Survival (PFS) and Overall Survival (OS). Methods: We prospectively recruited 151 patients with metastatic (m) mbreast (n = 58), mlung (n = 34), mprostate (n = 39), and mrenal (n = 20) cancers. Peripheral blood was collected prior to the induction of new treatment for metastatic cancer. Cells were isolated following standard CellSieve techniques, then imaged and measured in ZenBlue. Multi organ metastasis was defined as spread to ≥2 distant organ sites, or any spread to the brain. Single factor ANOVA was conducted to compare heCAML presence in multi organ metastatic patients versus patients with single organ site metastasis. Univariate and multivariate analysis was run to evaluate for PFS and OS against heCAMLs, and all known clinical parameters. Results: 150 viable samples (excluding 1 failed sample) were obtained. Multi organ metastases were present in 55% (n = 83/150) of patients. heCAMLs were found in 59% (n = 49/83) of the multi organ metastatic population, but only in 16% (n = 11/67) of the single site metastatic cohort (p < 0.001). heCAML presence appeared to differentiate multi organ vs single organ metastases in mbreast (85% vs. 52%, p = 0.006), mlung (71% vs. 26%, p = 0.025), mprostate (75% vs. 37%, p = 0.029), and mRCC (88% vs. 36%, p = 0.025). Further, in all n = 150 patients, heCAML presence predicted a significantly shorter median PFS of 4.5 versus 7.2 months, 24 month PFS (HR = 1.67, 95%CI = 1.13-2.45, p = 0.013), and significantly shorter median OS of 13.1 versus 20.4 months, 24 month OS (HR = 2.05, 95%CI = 1.24-3.39, p = 0.008). Conclusions: We examined a non-invasive prognostic blood based assay to determine its relationship to multi organ metastatic spread as well as its prognostic value in several solid cancers. These results showed patients with heCAMLs had higher rates of multi organ metastases, and appear to predict for shorter PFS and OS. Studies of larger cohorts are needed for prospective validation of these initial findings.

A phase II trial of risk enabled therapy after initiating neoadjuvant chemotherapy for bladder cancer (RETAIN BLADDER): Interim analysis

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Background: Cisplatin-based neoadjuvant chemotherapy (NAC) followed by cystectomy (Cx) or chemoradiation (CRT) is the standard of care for urothelial carcinoma (UC) pts with muscle invasive bladder cancer (MIBC). Both Cx and CRT have potential short and long-term toxicity and QOL implications. Mutations in DNA damage repair/response genes are associated with pathologic downstaging after NAC. Methods: We conducted a phase II, multi-institutional clinical trial (NCT02710734) to evaluate a risk-adapted approach to treatment of MIBC. Pts with cT2-T3N0M0 UC of the bladder, ECOG PS 0-1 and CrCl≥50 mL/min, underwent NAC with accelerated methotrexate, vinblastine, doxorubicin, and cisplatin (AMVAC). Pre-NAC TURBT specimens were sequenced (Caris Life Sciences) for mutations (pathogenic or VUS) in ATM, ERCC2, FANCC or RB1. Pts with at least one mutation and no clinical evidence of disease by restaging TUR and imaging post-NAC began pre-defined active surveillance (AS). Remaining pts underwent bladder-directed therapy: intravesical therapy ( < cT2 post-NAC), CRT or Cx. The primary endpoint was metastasis-free survival (MFS) at 2 years which is not mature. We herein report key interim results of clinically-meaningful intermediate endpoints. Results: Seventy-one (ITT) pts were enrolled over 33 months at four academic centers. Median age was 70 years (47-83), 74% were male, 92% Caucasian, 81% ECOG PS 0 and 79% cT2. 90% completed 3 cycles of NAC and with 17% grade 3-4 TRAEs and one death during AMVAC. At the time of data cut-off (September 11, 2020), for the ITT pts, 32 pts have had a Cx, 5 underwent CRT and 7 underwent intravesical therapy, at some point during the trial. Thirty-three pts (46%) had a mutation of interest and 28 pts (39%) started AS (2 of the 28 pts on AS did not have a mutation but elected to start AS after achieving cT0 post AMVAC). 76% of those with a mutation were cT0 at post-NAC TURBT. With a median follow-up of 14.9 mo (range: 3.1-35.3 mo), 14 AS pts recurred (50%). Of the 14 recurrences, 2 recurred with locally advanced or metastatic disease and have died, 5 had MIBC with one eventual metastatic recurrence, and 7 had NMIBC. Six (14%) non-AS pts have died. Out of the 40 pts who did not go to upfront Cx [AS (N = 28), CRT (N = 5), intravesical tx (N = 7)], 3 (7.5%) (all in the AS group) went on to Cx later. The bladder preservation rate is 55% for ITT pts and 89% for the AS group. In the AS cohort, mutations were seen in RB1 (50%), ATM (42%), ERCC2 (31%), FANCC (4%) with lowest rate for recurrence in ERCC2 (25% recurrence) vs RB1 (62% recurrence). Conclusions: Interim results of a phase II trial of risk enabled therapy utilizing a selection of clinical and genomic factors in pts with cT2-T3 MIBC demonstrates a 50% rate of any UC recurrence and a 11% rate of locally advanced/metastatic disease in the AS group. 89% of AS pts have retained their bladder. Follow-up continues for the primary endpoint of 2-year MFS. Clinical trial information: NCT02710734.

Impacts of pembrolizumab therapy on immune phenotype in patients with high-grade neuroendocrine neoplasms

High grade neuroendocrine neoplasms (G3 NENs) are rare aggressive tumors with limited treatment options. Twenty-one previously treated patients with metastatic extra-pulmonary G3 NENs were treated with pembrolizumab. Baseline tumor samples were assessed for PD-L1 and tumor infiltrating lymphocytes (TIL). Peripheral blood samples drawn pre-treatment, prior to cycle three, and at disease progression were analyzed by flow cytometry. One patient achieved partial response, two had stable disease, and 18 exhibited progressive disease. The partially responding patient did not progress after 392 days, and the median progression-free survival (PFS) was 59 days. Longer PFS correlated independently with higher pre-treatment peripheral blood T-cell counts and lower pre-treatment activation state (CD69 expression) of naïve T cells and NK cells. Peripheral T-cell viability was reduced in patients with greater TILs. Post-treatment, T cells had reduced numbers of CD4⁺ cells, reduced PD-1 expression, increased activation of effector (CD62L^-) cells, and increased expression of TIGIT. Baseline TIGIT expression on peripheral T cells also correlated positively with Ki67 in tumor. Patients with higher baseline T-cell expression of TIM-3 had shorter PFS. Despite limited activity of pembrolizumab, this study highlights the immune phenotype in this rare tumor type before and after treatment. High baseline peripheral T-cell count and reduced activation of T and NK cell subsets were associated with improved outcomes. Furthermore, increased post-treatment TIGIT and elevated baseline TIM-3 expression suggest that these may limit the efficacy of pembrolizumab, providing a rationale for combination immunotherapy (PD-1 with TIGIT and/or TIM-3 antibodies) to treat extra-pulmonary G3 NENs.

Immune phenotype of patients with stage IV metastatic inflammatory breast cancer

Background

Inflammatory breast cancer (IBC) is a rare but aggressive carcinoma characterized by severe erythema and edema of the breast, with many patients presenting in advanced metastatic disease. The “inflammatory” nature is not due to classic immune-mediated inflammation, but instead results from tumor-mediated blockage of dermal lymphatic ducts. Previous work has shown that expression of PD-L1 on tumor cells can suppress T cell activation in triple-negative (TN) non-IBC breast cancer. In the present work, we investigated immune parameters in peripheral blood of metastatic IBC patients to determine whether cellular components of the immune system are altered, thereby contributing to pathogenesis of the disease. These immune parameters were also compared to PD-1 and PD-L1 expression in IBC tumor biopsies.

Methods

Flow cytometry-based immune phenotyping was performed using fresh peripheral blood from 14 stage IV IBC patients and compared to 11 healthy age-similar control women. Immunohistochemistry for CD20, CD3, PD-1, and PD-L1 was performed on tumor biopsies of these metastatic IBC patients.

Results

IBC patients with Stage IV disease had lymphopenia with significant reductions in circulating T, B, and NK cells. Reductions were observed in all subsets of CD4⁺ T cells, whereas reductions in CD8⁺ T cells were more concentrated in memory subsets. Immature cytokine-producing CD56^bright NK cells expressed higher levels of FcγRIIIa and cytolytic granule components, suggesting accelerated maturation to cytolytic CD56^dim cells. Immunohistochemical analysis of tumor biopsies demonstrated moderate to high expression of PD-1 in 18.2% of patients and of PD-L1 in 36.4% of patients. Interestingly, a positive correlation was observed between co-expression levels of PD-L1 and PD-1 in tumor biopsies, and higher expression of PD-L1 in tumor biopsies correlated with higher expression of cytolytic granule components in blood CD4⁺ T cells and CD56^dim NK cells, and higher numbers of CD8⁺ effector memory T cells in peripheral blood. PD-1 expression in tumor also correlated with increased infiltration of CD20⁺ B cells in the tumor.

Conclusions

Our results suggest that while lymphocyte populations are severely compromised in stage IV IBC patients, an immune response toward the tumor had occurred in some patients, providing biological rationale to evaluate PD-1/PD-L1 immunotherapies for IBC.

Supplementary information

The online version contains supplementary material available at 10.1186/s13058-020-01371-x.

Abstract B29: Use of deep sequencing of urinary DNA as a biomarker of residual disease status at the time of radical cystectomy

Background: Retention of a normally functioning bladder would likely improve patient quality of life in the treatment of muscle-invasive bladder cancer (MIBC). Detection of residual cancer in bladder-sparing approaches relies on TURBT/bladder biopsy and clinical assessment. Historically, there is a 15-50% salvage cystectomy or metastasis rate with bladder sparing after chemotherapy alone or chemoradiotherapy. We hypothesized that clinical recurrence in bladder-sparing approaches was due to undetected subclinical disease at the time of (false) cT0 bladder assessment. We designed a next-generation sequencing (NGS) test to determine if residual mutations detected in the urine might be a surrogate for residual disease in MIBC patients undergoing RC.

Methods: Patient samples were collected on IRB-approved protocols. DNA was isolated from whole urine (n=4 precystectomy samples), urine supernatant (n=17 prechemotherapy specimens, 15 precystectomy specimens, n=18 patients total), and germline (n=22) and sequenced using a targeted NGS panel of commonly mutated bladder cancer genes with sample indices and unique molecular barcodes. Twenty-one patients had neoadjuvant chemotherapy. TURBT tissue collected prior to neoadjuvant chemotherapy also underwent whole-exome sequencing (WES; n=17) as a benchmark. Single-nucleotide variants in urine (SNVU) and in TURBT tissue (SNVT) were compared. Persistence or clearance of SNVU was correlated to residual disease status at the time of radical cystectomy.

Results: In benchmark samples from 15 patients, 46/76 SNVT identified by WES were also identified as SNVU in prechemotherapy urine samples. In precystectomy urine samples, absence of SNVU occurred in 5/6 patients achieving pT0 cystectomy specimens. In comparison, SNVU were detected in the precystectomy urine in 12/13 patients with residual disease. Absence/presence of SNVU was associated with residual disease status (p=0.0029, Fisher). In addition, TERT promoter hotspot mutations that are not detectable using WES-based approaches were detected in 9 of 22 patients in at least one urine specimen, and additional SNVU were detected that were not detected in tumor tissue.

Conclusion: Presence/absence of SNVU strongly associates with residual disease status. Additional samples from urothelial cancer patients are currently being analyzed to determine the optimal urine compartment (cell-free vs. pellet vs. whole urine). Validation studies may encourage the use of urine biomarkers to improve residual disease detection in cystectomy avoidance algorithms.

Citation Format: Phillip H. Abbosh, Uttam Satyal, David Liu, Ilsiya Ibragimova, Lauren Szeto, Benjamin Miron, James Ford, Daniel Parker, Aeen Asgar, Daniel M. Geynisman, R. Katherine Alpaugh, Paul Cairns, Costas D. Lallas, Edouard J. Trabulsi, Jean Hoffman-Censits, Eliezer M. Van Allen, Alexander Kutikov, Elizabeth R. Plimack. Use of deep sequencing of urinary DNA as a biomarker of residual disease status at the time of radical cystectomy [abstract]. In: Proceedings of the AACR Special Conference on Bladder Cancer: Transforming the Field; 2019 May 18-21; Denver, CO. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(15_Suppl):Abstract nr B29.

Circulating stromal cells as a potential blood-based biomarker for screening invasive solid tumors

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Background: Peripheral blood allows for a simple non-invasive method for isolating various cancer associated circulating stromal cells (CStCs) which may predict for cancer presence. Cancer Associated Macrophage-Like cells (CAMLs), a specific CStC, are phagocytic myeloid cells that derive from an immunological response to cancer and emanate from primary tumors. Using a filtration platform we screened the peripheral blood of untreated newly diagnosed cancer patients (n = 308) for CAMLs. In parallel, we screened patients with newly diagnosed non-malignant diseases, i.e. lupus, benign cysts, etc. (n = 39), and healthy control samples (n = 76). We found that CAMLs are highly prevalent (87%) in the blood of cancer patients, but uncommon in non-malignant conditions (20%) & absent in healthy individuals (0%). Methods: Anonymized peripheral blood were taken from 308 cancer patients after confirmation of invasive malignancy [stage I (n = 76), stage II (n = 73), stage III (n = 72), stage IV (n = 65) and unstaged non-metastatic (n = 22)] with pathologically confirmed lung (n = 65), pancreas (n = 53), breast (n = 52), prostate (n = 40), esophageal (n = 30), renal cell (n = 18), hepatocellular (n = 15), neuroblastoma (n = 10), melanoma (n = 8), and other (n = 17). Further, anonymized blood was taken from patients with untreated non-malignant conditions including benign breast masses (n = 19), lupus (n = 11), liver cirrhosis (n = 5), benign prostatic hyperplasia (BPH) (n = 3), and viral infection (n = 1); or from healthy control volunteers (n = 76). CAMLs were isolated from whole peripheral blood by the CellSieve™ microfiltration technique and defined as enlarged, multinuclear cells with cytokeratin and/or CD45/CD14 positive. Results: CAMLs were found in 87% of all cancer patients regardless of stage, ~5.4 CAMLs/7.5mL blood. Specifically, CAMLs were found in 80% of Stage I, 90% Stage II, 89% Stage III, and 97% Stage IV patients. No CAMLs were found in any healthy controls, but were found in 26% of benign breast masses, 18% of lupus, 0% of BPH and 0% of cirrhosis. In total, CAML sensitivity in cancer vs healthy was 87% (CI95% 82-90%), specificity = 100% (CI95% 95-100%), PPV = 100% (CI95% 100%), NPV = 67% (CI95% 58-71%). CAML sensitivity in cancer vs benign was 87% (CI95% 82-90%), specificity = 80% (CI95% 64-91%), PPV = 97% (CI95% 95-98%), NPV = 43% (CI95% 35-51%). Conclusions: CAMLs, a Circulating Stromal Cell subtype, is a sensitive blood based biomarker found in all stages of cancer that is rare in non-malignant conditions and absent in healthy individuals.

Defects in DNA Repair Genes Confer Improved Long-term Survival after Cisplatin-based Neoadjuvant Chemotherapy for Muscle-invasive Bladder Cancer

Cisplatin-based neoadjuvant chemotherapy (NAC) has demonstrated an overall survival (OS) benefit in muscle-invasive bladder cancer (MIBC). However, only a subset of patients (25-50%) have a pathologic complete response at cystectomy. Using a cohort of 58 patients from two phase 2 trials, our group previously reported that mutations in the ATM, RB1, and FANCC genes correlate with complete response to cisplatin-based NAC, and consequently improve OS and disease-specific survival (DSS). These trials enrolled patients with T2-4 (N0 or N1) MIBC and treated them with accelerated/dose-dense NAC with methotrexate, vinblastine, adriamycin, and cisplatin, or gemcitabine and cisplatin, with a plan for curative cystectomy. Updated long-term follow-up (median 74 mo) shows that significantly greater OS and DSS was maintained for patients with ATM, RB1, or FANCC mutations. The 5-yr survival rate for patients with at least one mutation was 85%, compared to 45% for patients without a mutation. On the basis of the associations with response and long-term OS and DSS, we propose that these alterations may be useful as predictive biomarkers to allow clinicians to prioritize patients who are most likely to benefit from NAC before radical cystectomy. PATIENT SUMMARY: In this report we looked at outcomes for patients with muscle-invasive bladder cancer treated with cisplatin-based chemotherapy before surgery (neoadjuvant) who had mutations in a set of DNA damage repair genes (ATM, RB1, FANCC) compared to those who did not. We found that patients who had at least one mutation in one of these genes survived longer after receiving cisplatin chemotherapy before surgery than patients who did not.

Abstract SY05-03: Dissecting genomic correlates of response and resistance to chemotherapy in bladder cancer through clinical computational oncology

Approximately 20,000 new cases of muscle-invasive bladder cancer (MIBC), a localized but potentially lethal stage of disease, are diagnosed annually in the US alone. Standard-of-care therapy for MIBC includes neoadjuvant cisplatin-based chemotherapy followed by definitive bladder resection. In prior work, we identified and validated genomic alterations in DNA repair genes such as ERCC2, which predict response to cisplatin-based chemotherapy (Van Allen et al. Cancer Discovery 2014; Liu et al. JAMA Oncology 2016). However, the majority of patients have disease resistant to chemotherapy with a poor prognosis of &lt;40% survival at 5 years, and the genomic basis of chemotherapy resistance has not been well-characterized. In this study, our goal was to analyze matched pre-treatment and resistant post-chemotherapy cystectomy tumor samples to identify genomic correlates of cisplatin-based chemotherapy exposure and resistance. We identified 56 MIBC patients with matched pre-chemotherapy biopsy samples and resistant tumor samples from cystectomy. Along with matched normal samples (blood), we performed whole exome sequencing (WES) on these “trios” of pre, post, and normal tissue, and called somatic variants using standardized pipelines including single nucleotide variants (SNVs), short insertions and deletions, allelic copy number alterations (CNAs), tumor purity and ploidy, and purity- and ploidy-corrected copy number variants. After quality control, including contamination estimation &lt; 5%, mean target coverage &gt; 50x, and a tumor purity minimum threshold of 10%, we had data from 30 trios available for analysis. We hypothesized that DNA-damaging chemotherapy may lead to increased mutational load in the post-treatment tumor. However, we observed that while some tumors gained mutations, others lost mutations, with no overall change (mean change = -17.3 mutations, paired t-test p = 0.20) in total mutational load. We found that clonal mutations (found in all tumor cells) were virtually unchanged from matched pre- to post-treatment tumors. In contrast, subclonal mutations (found only in a subset of tumor cells) were private to pre- and post-treatment tumors. These pre- and post-treatment mutation differences may reflect tumor sampling heterogeneity (i.e. taking from different parts of the tumor), but may be also due to selection pressure from therapy (e.g. loss of subclones) and cisplatin-induced mutations.To investigate the latter possibility, we adapted a non-negative matrix factorization (NMF) approach (Lee and Seung Nature 1999) to discover mutational signatures (Alexandrov et al Nature 2013) in the mutations unique to post-treatment tumors. Along with signatures known to be operant in bladder cancers, we discovered a mutational signature dissimilar to any other previously described mutational signature which accounted for ~15% of post-treatment mutations. This signature exhibited a transcriptional strand bias consistent with known mechanisms of cisplatin-induced DNA damage and repair, and was enriched in subclonal mutations consistent with the relatively short time frame between cisplatin exposure and cystectomy. This signature also exhibited similar activity to a cisplatin-induced mutational signature derived in a preclinical model (DT40) exposed to cisplatin therapy (Pearson rho = 0.95, empiric p = 0.004). Finally, we were able to validate this signature in a separate cohort of pre- and post-cisplatin treated bladder cancers (Faltas et al Nature Genetics 2016). We further hypothesized that the degree of tumor heterogeneity itself may be a prognostic factor. We calculated two different measures of intratumor heterogeneity: (1) the proportion of mutations in each tumor that was subclonal; and (2) the number of unique subclones in each tumor, and examined the association of survival with these measures of intratumor heterogeneity using Cox survival analyses. We found that overall survival was associated with heterogeneity, with a 6.6% increase in mortality rate for each 10% increase in post-treatment proportion of subclonal mutations (p=0.013), and 64% increase in mortality rate for each additional inferred subclone (p=0.02). Tumor heterogeneity continued to be associated with survival after adjusting for clinical covariates (p=0.03, p=0.014, respectively).Finally, we analyzed our tumors for genomic alterations associated with resistance. While we did not discover highly recurrent post-treatment mutations in specific genes, we found drivers of cell cycle progression (E2F3 amplification, JUN amplification), biallelic loss of FBXW7 (regulator of protein degradation of multiple onco-proteins including c-MYC, Notch, Cyclin E, and c-JUN), and focal amplification of PD-L1/2 in individual post-treatment resistant tumors.In this study, we found that cisplatin-based chemotherapy did not induce a large increase in the number of mutations. Thus, while there is good empiric data for the efficacy of combination of chemotherapy and immune checkpoint inhibition in specific tumor type and clinical settings (e.g. platinum-doublet therapy + ICB in first-line therapy of non-small cell lung cancer (NSCLC)), our data suggests that alternative mechanisms other than increased neoantigen burden are responsible. We discovered a cisplatin-induced mutational signature in post-treatment tumors which has subsequently been found in other cisplatin-treated tumors (e.g. NSCLC and ovarian cancer). Interestingly, the proportion of mutations inferred to be cisplatin-induced was quite different between resistant tumors, and an area for further inquiry is whether these differences could be associated with different mechanisms of resistance (e.g. upregulation of efflux pumps vs. anti-apoptotic adaptations). Tumor heterogeneity, which has been associated with worse outcomes and resistance in multiple contexts, was prognostic for survival in our cohort, suggesting that this may be clinically useful as part of a prognostic biomarker. We discovered additional association of drivers of cell-cycle progression with resistance, and further identified acquisition of a focal amplification in a region containing PD-L1/PD-L2, suggesting a potential biomarker for a subset of bladder cancers for response to immune checkpoint blockade. Broadly, this study represents the development of algorithms to dissect genomic features associated with survival and resistance in a carefully curated cohort of matched patient tumors within a specific clinical context. These types of approaches can be applied across tumor types, therapies, and clinical contexts to shed light onto biological mechanisms underpinning response and resistance and inform the development of biomarkers to guide clinical management.

Citation Format: David Liu, Philip Abbosh, Daniel Keliher, Brendan Reardon, Diana Miao, Kent Mouw, Amaro Weiner-Taylor, Stephanie Wankowicz, Garam Han, Min-Yuen Teo, Catharine Cipolla, Jaegil Kim, Gopa Iyer, Hikmat Al-Ahmadie, Essel Dulaimi, David Y.T. Chen, R. Katherine Alpaugh, Jean Hoffman-Censits, Levi A. Garraway, Gad Getz, Scott L. Carter, Joaquim Bellmunt, Elizabeth Plimack, Jonathan E. Rosenberg, Eliezer M. Van Allen. Dissecting genomic correlates of response and resistance to chemotherapy in bladder cancer through clinical computational oncology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr SY05-03.

Circulating tumor cell and cell-free RNA capture and expression analysis identify platelet-associated genes in metastatic lung cancer

Background

Circulating tumor cells (CTC) and plasma cell-free RNA (cfRNA) can serve as biomarkers for prognosis and treatment response in lung cancer. One barrier to the selected or routine use of CTCs and plasma cfRNA in precision oncology is the limited quantity of both, and CTCs are only seen in metastatic disease. As capture of CTCs and plasma cfRNA presents an opportunity to monitor and assess malignancies without invasive procedures, we compared two methods for CTC capture and identification, and profiled mRNA from CTCs and plasma cfRNA to identify potential tumor-associated biomarkers.

Methods

Peripheral blood was collected from ten patients with small cell lung cancer (SCLC), ten patients with non-small cell lung cancer (NSCLC) and four healthy volunteers. Two methods were used for CTC capture: the standard epithelial cell adhesion molecule (EpCam) CellSearch kit (unicapture) and EpCAM plus HER2, EGFR and MUC-1 specific combined ferrofluid capture (quadcapture). For the quadcapture, anti-cytokeratin 7 (CK7) was additionally used to assist in CTC identification. NanoString analysis was performed on plasma cfRNA and on mRNA from combined ferrofluid isolated CTCs. Expression data was analyzed using STRING and Reactome.

Results

Unicapture detected CTCs in 40% of NSCLC and 60% of SCLC; whereas, quadcapture/CK7 identified CTCs in 20% of NSCLC and 80% of SCLC. Bioinformatic analysis of NanoString data identified high expression of a platelet factor 4 (PF4)-related group of transcripts.

Conclusions

Quadcapture ferrofluid reagent did not significantly improve CTC capture efficacy. NanoString analysis based on CTC and plasma cfRNA data highlighted an intriguing PF-4-centric network in patients with metastatic lung cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5795-x) contains supplementary material, which is available to authorized users.

Real-time monitoring of circulating stromal cells in the blood to predict responsiveness of new-line therapies in metastatic breast cancer

e14048

Background: Cancer associated macrophage like cells (CAMLs), a circulating stromal cell subtype, has been shown as an independent prognostic indicator of survival in late stage metastatic breast cancer when cells enlarge to ≥50µm. However, no study has evaluated the clinical relationship between changes in CAML size and their ability to predict treatment response. While CAMLs are prognostic for progression, we hypothesized that monitoring changes in CAMLs after initiation of therapy may be predictive for responsiveness of new treatment regimens. Methods: A prospective 12 months blind multi-institutional pilot study was undertaken to evaluate CAMLs before, and after, induction of a new line of investigational therapy based on CT scans. Patients with progressive metastatic breast cancer (n = 29) who had failed at least 2 prior therapies were recruited. A baseline (BL) blood sample was taken prior to induction of a new therapy and a 2nd sample (T1) taken after initiation (~30 days). Blood was filtered by CellSieve filtration.The quantities and sizes of CAMLs were analyzed based on PFS hazard ratios (HRs) by censored univariate analysis. Results: CAMLs were found in 97% of BL samples and 93% of T1 samples. At first CT scan, after the assigned dose of investigational treatment, 17 of 29 patients had clinical progression with 14/17 (82%) patients having an increased CAML size and 3/17 (18%) having a decreased CAML size. The remaining 12 of 29 patients saw clinically stable, or regression, of disease with 10/12 (83%) having decreased CAML size and 2/12 (17%) having increased CAML size. Overall CAML size change after therapy induction was 83% accurate at predicting response or progression based on CT scans. Further, patients with increasing CAML size at T1 had a 4 month mPFS vs 10 month mPFS for decreasing CAMLs, with a lower 12 month PFS HR = 3.7 (95%CI = 1.5-10.1, p = 0.020). Conclusions: Our data suggests that in metastatic breast cancer, monitoring CAMLs changes over the first 30 days of treatment accurately predicts responsiveness of disease to new treatments. Further, we suggests using blood sampling may increase the clinical value of blood based diagnostics by rapidly predicting the benefit of subsequent therapies.

Defects in DNA repair genes and long-term survival in cisplatin-based neoadjuvant chemotherapy for muscle invasive bladder cancer (MIBC)

4536

Background: Although cisplatin-based neoadjuvant chemotherapy (NAC) has demonstrated an overall survival (OS) benefit in MIBC, only a subset of patients have pathologic complete response (pT0) at cystectomy. ATM, RB1 and FANCC mutations have shown correlation with pT0 to cisplatin-based NAC, as previously published. We now report updated OS and disease specific survival (DSS) from two phase II trials using these gene alterations as biomarkers. Methods: Patients with stage T2-T4 (N0 or N1) MIBC were enrolled in phase II trials of dose-dense NAC with MVAC (methotrexate, vinblastine, adriamycin, and cisplatin; NCT01031420) or GC (gemcitabine and cisplatin; NCT01611662). Patients were treated with NAC with plan for curative cystectomy. DNA from pretreatment tumor tissue was sequenced for coding exons of 287 cancer-related genes and analyzed for mutations. Survival in patients with one or more mutations in ATM, RB1, or FANCC genes was compared to those without mutations. Results: Of 58 pts treated, 38% (22/58 pts) had relevant mutations in the combined group of MVAC (13/34 pts) and GC (9/24 pts) trials. At a median follow-up of 56 months and minimum follow up of 16 months, patients with mutations had statistically significantly greater OS (p = 0.0043) and DSS (p = 0.0015). Median OS/DSS was not reached for patients with a mutation in any group. At 5 years post treatment, OS/DSS were greater in mutated vs non-mutated patients in all groups (see table). Conclusions: Long-term follow up reveals that previously reported improved responses to cisplatin-based NAC associated with mutations in ATM, RB1 and FANCC also confer a clinically meaningful and statistically significant survival benefit in these patients. These alterations may be useful as predictive biomarkers to allow clinicians to prioritize patients most likely to benefit from NAC prior to radical cystectomy. [Table: see text]

Phase II Study of the PD-1 Inhibitor Pembrolizumab for the Treatment of Relapsed or Refractory Mature T-cell Lymphoma

BACKGROUND

Programmed cell death-1 (PD-1) and programmed death-ligand 1 (PD-L1) are frequently expressed in T-cell lymphomas. This provides a rationale for exploration of immune checkpoint inhibitors in the management of T-cell lymphomas.

PATIENTS AND METHODS

In this phase II single-arm multicenter trial, patients with relapsed or refractory systemic T-cell lymphoma were treated with 200 mg pembrolizumab intravenously every 21 days. The primary endpoint was progression-free survival (PFS). The secondary endpoints were response rate, overall survival, response duration, and safety. We assessed PD-L1, p-AKT expression, and peripheral blood immune cells as potential predictive biomarkers.

RESULTS

Of 18 enrolled patients, 13 were evaluable for the primary endpoint. The trial was halted early after a preplanned interim futility analysis. The overall response rate was 33% (95% confidence interval [CI], 9%-55%); 4 patients achieved a complete response (27%; 95% CI, 5%-49%). The median PFS was 3.2 months (95% CI, 1.2-3.7 months), and the median overall survival was 10.6 months (95% CI, 3.2-100 months). The median duration of response was 2.9 months (95% CI, 0-10.1 months). Two of the 4 complete responders remain in remission > 15 months. Rash was the most common adverse event (17%; n = 3). The most common ≥ grade 3 treatment-emergent adverse events were rash and pneumonitis (11%; n = 2 each). Neither PD-L1 nor p-AKT expression were associated with outcomes. However, a higher relative frequency of CD4⁺ T lymphocytes pre-treatment was associated with improved PFS (hazard ratio, 0.15; 95% CI, 0.03-0.74).

CONCLUSION

Pembrolizumab demonstrated modest single-agent activity in relapsed or refractory T-cell lymphoma.

Neoadjuvant Dose-dense Gemcitabine and Cisplatin in Muscle-invasive Bladder Cancer: Results of a Phase 2 Trial

Background

Accelerated (also termed dose-dense, DD) chemotherapy regimens such as accelerated methotrexate, vinblastine, doxorubicin, and cisplatin have shown better efficacy and tolerability in the metastatic setting, and shortened the time to surgery in the neoadjuvant setting compared to standard-schedule regimens. We hypothesized that a DD schedule of gemcitabine and cisplatin (GC) would shorten the time to surgery and yield similar pathologic complete response rates (pT0) in patients with muscle-invasive bladder cancer (MIBC) compared with historical controls with standard GC.

Objective

To determine the safety and efficacy of neoadjuvant DDGC in MIBC.

Design setting and participants

Patients with cT2-4a, N0-1, M0 MIBC were eligible and received three 14-d cycles of DDGC with pegfilgrastim support followed by radical cystectomy with lymph node dissection. The primary end point was the pT0 rate. Molecular subtypes were assigned and correlated with survival.

Results and limitations

Thirty-one patients were evaluable for toxicity and response, of whom 58% had baseline clinical stage >T2N0M0; the median age was 69 yr. Ten patients (32%, 95% confidence interval [CI] 16-49%) achieved ypT0N0 status at cystectomy. Another four patients (13%, 95% CI 1-25%) were downstaged to non-muscle-invasive (<pT2N0) disease. Most patients (54.8%) experienced only grade 1-2 treatment-related toxicities. However, seven patients (23%) had clinically significant vascular events, leading to early closure of the study. Thirty patients (94%) underwent cystectomy. The median time from the start of chemotherapy to cystectomy was 9.3 wk. There was no correlation between molecular subtypes and survival.

Conclusions

DDGC yielded a similar pT0 rate to that noted retrospectively with standard GC. Vascular events precluded, delayed, or increased the risk of surgery for 23% of patients, resulting in early closure of the study. Additional prospective studies with embedded biomarker correlatives of GC in the neoadjuvant setting are critical to accurately define both the activity and toxicity of this combination in MIBC.

Patient summary

Neoadjuvant chemotherapy before cystectomy is the standard of care for muscle-invasive bladder cancer (MIBC). This prospective phase 2 study tested a dose-dense schedule of gemcitabine and cisplatin in MIBC. The study was closed early because of a higher than expected rate of vascular events. These data suggest that caution is required in using this regimen, particularly when there is better prospective evidence for the safety and efficacy of alternative regimens such as dose-dense or accelerated methotrexate, vinblastine, doxorubicin, and cisplatin.

A phase II trial of risk-adapted treatment for muscle invasive bladder cancer after neoadjuvant accelerated MVAC

TPS537

Background: Cisplatin-based neoadjuvant chemotherapy (NAC) followed by cystectomy (Cx) or chemoradiation (CRT) is the standard of care for urothelial carcinoma (UC) pts with muscle invasive bladder cancer (MIBC). Both Cx and CRT carry potential short and long-term toxicity and quality of life implications. Recent work has shown that mutations in DNA damage repair/response genes are predictive of pathologic downstaging after NAC at the time of Cx, with those pts achieving pT0 disease demonstrating excellent long-term survival (Van Allen et al. Cancer Discov. 2014; Plimack et al. Eur Urol. 2015; Liu et al. JAMA Oncol. 2016; Teo et al. CCR. 2017). Sparing pts Cx or CRT after NAC without compromising oncologic outcomes would improve quality of life and decrease morbidity. Methods: A phase II, parallel arm, multi-institutional clinical trial (NCT02710734) is being conducted to evaluate a risk-adapted approach to treatment of MIBC. Pts with cT2-T3N0M0 UC of the bladder, ECOG PS 0-1 and CrCl≥50 mL/min, undergo NAC with accelerated methotrexate, vinblastine, doxorubicin, and cisplatin. Simultaneously, the pre-NAC TURBT specimen is submitted for deep sequencing to identify variants in a panel of cancer-relevant genes (Caris Life Sciences, Phoenix, AZ). Those with an alteration in ATM, RB1, FANCC or ERCC2 and no clinical evidence of disease by restaging TUR and imaging post-NAC will begin a pre-defined active surveillance regimen that includes urinary cytological, cystoscopic, and radiographic evaluations. The remaining pts will undergo bladder-directed therapy at the discretion of the pt and clinician applying either intravesical therapy ( < cT2 post-NAC), CRT or Cx (≤cT2 post-NAC) or Cx (≥cT3 post-NAC). The primary objective is metastasis-free survival (MFS) at 2 years for all enrolled and evaluable pts. The trial has a non-inferiority design with a 14% margin between risk-adapted treatment (MFS = 78%) and standard-of-care (MFS = 64%) with a sample size of 70 pts, 82% power and a type I error of 0.045. Key secondary and translational objectives: assess the rate of UC recurrence in active surveillance pts; validate biomarkers of response to NAC; evaluate urinary biomarkers consistent with persistent UC. Clinical trial information: NCT02710734.

Mutational patterns in chemotherapy resistant muscle-invasive bladder cancer

Despite continued widespread use, the genomic effects of cisplatin-based chemotherapy and implications for subsequent treatment are incompletely characterized. Here, we analyze whole exome sequencing of matched pre- and post-neoadjuvant cisplatin-based chemotherapy primary bladder tumor samples from 30 muscle-invasive bladder cancer patients. We observe no overall increase in tumor mutational burden post-chemotherapy, though a significant proportion of subclonal mutations are unique to the matched pre- or post-treatment tumor, suggesting chemotherapy-induced and/or spatial heterogeneity. We subsequently identify and validate a novel mutational signature in post-treatment tumors consistent with known characteristics of cisplatin damage and repair. We find that post-treatment tumor heterogeneity predicts worse overall survival, and further observe alterations in cell-cycle and immune checkpoint regulation genes in post-treatment tumors. These results provide insight into the clinical and genomic dynamics of tumor evolution with cisplatin-based chemotherapy, suggest mechanisms of clinical resistance, and inform development of clinically relevant biomarkers and trials of combination therapies.

The impact of cisplatin-based chemotherapy on tumor genomes is complex. Here, the authors study matched pre- and post-chemotherapy primary samples in muscle-invasive bladder cancer, finding a cisplatin-based mutational signature, and highlighting the impact of intratumor heterogeneity on survival.

Circulating tumor cells: silent predictors of metastasis

Circulating tumor cells (CTCs) were added to the arsenal of clinical testing in 2004 for three cancer types: metastatic breast, prostate, and colorectal cancer. CTCs were found to be an independent prognostic indicator of survival for these three diseases. Multiple enrichment/isolation strategies have been developed and numerous assay applications have been performed using both single and pooled captured/enriched CTCs. We have reviewed the isolation techniques and touched on many analyses. The true utility of a CTC is that it acts as a “silent” predictor of metastatic disease. The mere presence of a single CTC is an indication that disease has spread from the primary site. Comments and suggestions have been set forth for CTCs and cell-free DNA to be used as a screening panel for the early detection of disease recurrence and metastatic spread, providing the opportunity for early intervention with curative intent to treat metastatic disease.

Abstract 3798: Multiplex phenotyping of circulating cancer associated macrophage-like cells in patients with solid tumors

Background: Circulating cancer associated macrophage-like cells (CAMLs) are cancer specific giant cells circulating in the blood of patients with solid tumors. Since their discovery, few studies have been done to elucidate their lineage or phenotypic identity. The difficulty in classifying CAMLs is exemplified by their expression of multiple heterogeneous markers that defy conventional identification. Recently, we described a restaining method (QUAS-R) to screen individual cells using an array of up to 15 biomarkers. We used this method to screen CAMLs isolated from 152 cancer patient samples in 4 types of solid tumors to classify CAMLs by phenotypic immunostaining. These data suggest that CAMLs are a morphologically diverse and phenotypically heterogeneous population of cancer specific giant cells with overlapping myeloid, epithelial, and endothelial phenotypes.

Methods: This multi-institutional study used peripheral blood samples from 152 cancer patients (stage I-IV) from breast (n=42), lung (n=39), renal cell carcinoma (36) and prostate (n=35). Blood was processed by the CellSieve™ microfiltration technique at 5 institutions and stained for cytokeratin 8, 18 & 19, EpCAM, and CD45. After identification/imaging, the QUAS-R (Quench, Underivatize, Amine-Strip and Restain) technique was used to quench fluorescence signal of cells and then restain with vimentin/CD146/CD144, CD14/CD11b/CD41, CD11c/CD68/TIE2, or CD34/CD41/CD61. After staining, QUAS-R was again used to remove the fluorescence and samples restained with a third panel. Each patient sample was stained, quenched and restained with the above mentioned panels.

Results: In agreement with a number of studies, CAMLs were found in 86% of cancer patients (n=131/152), with increased detection from stage 1 (71%), followed by stage 2 (94%), stage 3 (88%) to stage 4 (88%). Breast cancer had the most CAMLs per sample (14.1 cells/7.5mL), followed by prostate (6.8), renal cell carcinoma (4.9) and lung (3.2). CD34 was most prevalent, found on 88% of CAMLs, followed by cytokeratin (81%), CD41 (79%), CD61 (78%), CD45 (75%), CD14 (72%), vimentin (63%), EpCAM (56%), CD146 (53%), CD68 (44%), CD11c (38%), TIE-2 (25%) and CD11b (0%). Based on our results, CAMLs seem to express overlapping phenotypes from a variety of lineages i.e. macrophage (CD14/CD68/CD11c), epithelial (cytokeratin/EpCAM), endothelial (CD146/TIE-2) and megakaryocyte (CD41/CD61).

Conclusions: Although identification of CAMLs is straightforward by morphological criteria (size and nuclear profile), their identification and lineage remains undetermined. We report the first mass screening of CAMLs to determine phenotypic expression. These data suggest that CAMLs cannot be grouped into any known cell subtype based on their expression profiles and represent a heterogeneous and variably differentiated population whose biological consequences in cancer remain under investigation.

Citation Format: Daniel L. Adams, R Katherine Alpaugh, Thai H. Ho, Steven H. Lin, Jeffrey R. Marks, Raymond Bergan, Stuart S. Martin, Saranya Chumsri, Cha-Mei Tang, Massimo Cristofanilli. Multiplex phenotyping of circulating cancer associated macrophage-like cells in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3798. doi:10.1158/1538-7445.AM2017-3798

Abstract 778: Identifying, subtyping and classifying tumor associated circulating endothelial cells in patients with solid tumors

Background: Tumor endothelial cells (ECs) are a population of stromal cells required for tumor growth that cooperate with tumors to form angiogenic structures. In blood, circulating ECs (CECs) are normal constituents of healthy individuals, although a Cancer Associated Vascular Endothelial cell (CAVE) subtype has been observed in cancer patients. The CAVE population has been isolated and identified using their large size or multicellular clustering and a pooled mixture of classical EC markers (i.e. CD31 and CD146). However, there has been no attempt to differentiate CAVEs from the many EC subtypes. This is not surprising as in-depth phenotyping of ECs requires an array of biomarkers that until recently has not been feasible. A multi-phenotypic screening of EC markers was tested on CAVEs from 116 blood samples in 3 types of solid tumors. This data suggests that CAVEs exist as a common and diverse subtype of tumor derived CECs that may express cytokeratin (CK) and various EC biomarkers, correlating to disease stage.

Methods: Peripheral blood samples from 116 cancer patients (stage I-IV) were drawn from 2012-2014 including breast (n=42), lung (n=39) and prostate (n=35), as well as blood from 34 healthy controls. Blood was processed by an established filtration approach, i.e. the CellSieveTM microfiltration technique (Creatv MicroTech), filtering blood by size exclusion and staining cells for CK 8, 18 & 19, EpCAM and CD45. After identification and imaging, the QUAS-R (Quench, Underivatize, Amine-Strip and Restain) technique was used to remove fluorescence signal and restain all cells with CD31, CD146, CD144, & DAPI. After reimaging, QUAS-R was again used to remove fluorescence and restain the cells for CD14, CD105, CD34, & DAPI.

Results: Out of 116 patient samples, we identified CAVEs in 63 patients (54%) based on positivity of CD31, CD144 or CD146, but none were found in healthy controls. CAVEs per 7.5mL sample in patients averaged 5.1 (breast), 5.6 (prostate) and 7.9 (lung). Presence of CAVEs appeared related to stage with 26% in stage 1, 61% in stage 2, 68% in stage 3, and 74% in stage 4 patients. No CAVEs were positive for CD14 or CD45. CD31 was the most present marker, found on 93% of CAVEs, followed by CD144 (85%), CD34 (64%), CD146 (45%), & CD105 (4%). In contrast with the previous study on this topic, CK was found in 67% of CAVEs, but was not a universal marker.

Conclusions: It has been reported that CK+ and CD45- CECs are isolated from the blood of cancer patients in colon and lung cancers, prompting some to classify them as circulating tumor cells. However, subtyping these CECs is incomplete when characterized with only 3-4 biomarkers. A multi-phenotypic subtyping technique was used to properly identify and subtype these CECs in cancer patients. This data suggest that a subset of CECs, e.g. CAVEs, are found in circulation as CK+/CD45-, but exist as a heterogeneous population of cancer specific circulating cells that require further study.

Citation Format: Daniel L. Adams, R. Katherine Alpaugh, Steven H. Lin, Jeffrey R. Marks, Raymond Bergan, Stuart S. Martin, Sarany Chumsri, Massimo Cristofanilli, Cha-Mei Tang, Steingrimur Stefansson. Identifying, subtyping and classifying tumor associated circulating endothelial cells in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 778. doi:10.1158/1538-7445.AM2017-778

Combining chemotherapy and programmed death 1 (PD-1) blockade to induce a T-cell response in patients with metastatic triple negative breast cancer (mTNBC)

11563

Background: Correlative studies to determine the effect of combining chemotherapy (CT) simultaneously with checkpoint inhibition on the peripheral immune response are planned as part of a clinical trial in MTNB. The trial design is a Safety run-in, into a randomized phase II trial of combination pembrolizumab (P) with carboplatin (C) and gemcitabine (G) in patients with mTNBC. One key concern is that CT may suppress immune cell function, thereby diminishing the efficacy of PD-1 blockade. Methods: Patients with a diagnosis of mTNBC are recruited to this trial with a Safety Run-in (N = 6-12 subjects), followed by a randomized design of C + G with/without P (2:1 randomization, N = 75). Safety run-in consists of P 200 mg on day 1 of each 21-day cycle, and C (AUC2) + G (800mg/m2) on days 1 and 8. Patients are consented for a peripheral blood (PB) collection pre-cycle 1 and on day 1 of cycle 3, in order to phenotype immune system changes by flow-cytometry. Results: Six patients have been recruited as of this interim analysis. Data from PB analysis of 3 on-treatment patients is available. In 2 subjects, the activation marker CD69 increased on CD4+ and CD8+ T cells from baseline, indicating enhanced T cell function. Also the ratio of CD8+ T cells to regulatory T cells (CD25high CD127low) has increased. Both patients expressed PD-1 on T cells at baseline. The 2 subjects with evidence for enhanced immune response have a continued clinical benefit (12 cycles subject 1, 8 cycles subject 2). In contrast, subject 3 (who discontinued P and received corticosteroids for grade a 2 immune-related hepatitis during cycle 2) lacked expression of PD-1 on T cells and did not exhibit these immune changes, and her disease clinically progressed after 4 cycles of CT. Conclusions: Although comprising a very limited number of patients, early analysis from our correlative studies of combining CT with the PD-1 blockade revealed evidence for effective immune stimulation in two subjects. Furthermore, immune changes accompanied a lasting clinical response. Although early, we conclude that combining CT with checkpoint blockade can achieve its goal of unleashing an anti-tumor immune response in mTNBC patients. Clinical trial information: NCT02755272.

Cancer-associated macrophage-like cells as prognostic indicators of overall survival in a variety of solid malignancies

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Background: Cancer Associated Macrophage-Like cells (CAMLs) are a recently described circulating stromal cell subtype commonly found in the peripheral blood of patients in all stages of solid malignancies and in a variety of cancer subtypes. However, while their biological association to cancer is being studied, their clinical utilization as it relates to cancer prognosis has not been evaluated. Methods: A two year prospective study was undertaken to evaluate the relationship of CAMLs and overall survival (OS) in 6 solid tumor types. The single blind multi-institutional study consisted of 269 stage I-IV patients; breast (n = 57), esophageal (n = 21), prostate (n = 43), pancreatic (n = 59), lung (n = 54), and renal cell (n = 35), in treatment (n = 134) and untreated baseline (n = 135). 7.5mL of whole blood was filtered by CellSieve microfiltration assay and CAMLs enumerated, as previously described. Patients were grouped by CAML number ( < 6 or ≥6) and by size ( < 49 or ≥50 µm) to evaluate hazard ratios (HR) by censored univariate & multivariate analysis. Results: CAMLs were identified in 93% of samples, averaging 8.2 CAMLs/7.5mL blood sample, and found in all 6 cancers at baseline and during treatment. Average CAML number was associated with disease stage and CAML positivity was 4.4 & 80% (Stage I), 4.7 & 93% (Stage II), 9.3 & 98% (Stage 3), 12.1 & 97% (Stage IV). Univariate analysis of patients (n = 269) stratified by ≥6 CAMLs had reduced OS (HR = 1.8, 95%CI 1.1-2.9, p = 0.03). Further, CAML size also had reduced OS in patients with ≥50 µm CAMLs (HR = 2.7, 95%CI 1.8-4.0, p < 0.0001). Conclusions: Our data suggests that in solid malignancies, CAML number and size appear to clinically correlate with OS in early and late stage disease. Given these results relating CAMLs with OS, further analysis is warranted to determine if CAMLs can serve as a clinically-relevant blood-based marker.

NK cell dysfunction in chronic lymphocytic leukemia is associated with loss of the mature cells expressing inhibitory killer cell Ig-like receptors

A prospective analysis of natural killer (NK) cell phenotype and function was performed on fresh peripheral blood samples from untreated patients with B-cell chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). Compared to healthy controls, CD56^dim NK cells in CLL patients displayed reduced expression of the NKG2D activating receptor and increased CD27 expression, which indicates declines in mature cells. In addition, NK cells from CLL patients showed reduced degranulation responses toward transformed B cells alone or with rituximab and were more sensitive to activation-induced cell death. We further noted a striking reduction in the frequency and viability of NK cells expressing the inhibitory killer cell Ig-like receptors (KIR)2DL1 and/or KIR3DL1, which progressed over time in most patients. Comparisons between a CLL patient and healthy monozygotic twin were consistent with our results in the larger cohorts. Functional and biomarker alterations were less pronounced on NK cells from SLL patients, which have lower tumor burden in peripheral blood than CLL, but significant reduction in degranulation under ADCC conditions and lower frequency and viability of KIR-expressing NK cells were still evident in SLL. We conclude that mature KIR-expressing NK cells respond to the high circulating B cell tumor burden in CLL, but undergo activation-induced apoptosis. Consequently, CLL patients may benefit from therapies that augment NK cell survival and function.

Effect of exogenous interferon-gamma (IFN-gamma) on peripheral blood immune markers as part of a phase I clinical trial of combined IFN-gamma with nivolumab (Nivo) in patients (pts) with select solid tumors

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Background: IFN-gamma is a known activator of PD-L1 expression and plays a key role in immune activation. We present initial correlative peripheral blood findings after the first 2 cohorts of pts enrolled in a phase I trial of combined IFN-gamma/Nivo in pts with various solid tumors. Methods: Pts with advanced solid tumors who had progressed after at least 1 prior therapy were recruited. An induction phase of IFN-gamma (50 or 75 mcg/m2 subq every other day for 1 week) preceded the combination of Nivo (3 mg/kg IV every 2 weeks) with continuation of IFN-gamma at same dose and schedule for 3 months. Pts with clinical benefit could remain on Nivo alone for up to 1 year. Peripheral blood was analyzed via flow cytometry at baseline, after IFN-gamma induction (prior to Nivo start), and after 6 weeks of combo treatment. Results: 13 pts have been accrued. Pre and post induction samples were collected on all pts. Nine pts had available on-treatment samples at time of data analysis. Comparing blood collections from baseline to post-IFN-gamma induction revealed a substantial expansion of the CD14high, CD16+ monocyte population (p=0.001) and a statistically significant increase in MHC class II expression on all monocyte populations (p≤ 0.002 for all types). Natural killer (NK) cells demonstrated greater numbers of cells per ml of blood (p=0.03) and increased NKp30 expression, an important receptor mediating tumor cell lysis (p= 0.005 for CD56dim; p= 0.03 for CD56bright). With the addition of Nivo, evidence for activation of CD56dim NK cells was detected as increased CD69 expression compared to post-induction (p=0.02). PD-1 expression on T-cells showed reduced expression in most comparators after initiation of Nivo (p=0.055 CD8+; p=0.008 CD4+). Conclusions: Early correlative peripheral blood data demonstrate expected systemic IFN-gamma effect as measured by monocyte activation and increased MHC II expression. Evidence of NK cell activation and proliferation was also observed. Decreased PD-1 expression on T-cells may reflect down-regulation in response to PD-1 blockade. Correlations with biopsy specimens and clinical response are planned. Clinical trial information: NCT02614456.

Matrix-regulated integrin αvβ5 maintains α5β1-dependent desmoplastic traits prognostic of neoplastic recurrence

Desmoplasia, a fibrotic mass including cancer-associated fibroblasts (CAFs) and self-sustaining extracellular matrix (D-ECM), is a puzzling feature of pancreatic ductal adenocarcinoma (PDACs). Conflicting studies have identified tumor-restricting and tumor-promoting roles of PDAC-associated desmoplasia, suggesting that individual CAF/D-ECM protein constituents have distinguishable tumorigenic and tumor-repressive functions. Using 3D culture of normal pancreatic versus PDAC-associated human fibroblasts, we identified a CAF/D-ECM phenotype that correlates with improved patient outcomes, and that includes CAFs enriched in plasma membrane-localized, active α₅β₁-integrin. Mechanistically, we established that TGFβ is required for D-ECM production but dispensable for D-ECM-induced naïve fibroblast-to-CAF activation, which depends on α_vβ₅-integrin redistribution of pFAK-independent active α₅β₁-integrin to assorted endosomes. Importantly, the development of a simultaneous multi-channel immunofluorescence approach and new algorithms for computational batch-analysis and their application to a human PDAC panel, indicated that stromal localization and levels of active SMAD2/3 and α₅β₁-integrin distinguish patient-protective from patient-detrimental desmoplasia and foretell tumor recurrences, suggesting a useful new prognostic tool.

DOI:http://dx.doi.org/10.7554/eLife.20600.001

Tumors are not entirely made out of cancerous cells. They contain many other components – referred to as tumor stroma – that may either encourage or hinder the tumor’s growth. Tumor stroma includes non-cancerous cells and a framework of fibrous sugary proteins, called the extracellular matrix, which surround and signal to cells while providing physical support.

In the most common and aggressive form of pancreatic cancer, the stroma often makes up the majority of the tumor’s mass. Sometimes the stroma of these pancreatic tumors can protect the cancer cells from anti-cancer drugs. Researchers have therefore been interested in finding out exactly which aspects of the tumor stroma shield and support cancer cells, and which impede their growth and progression. Answering these questions could make it possible to develop new drugs that will change a tumor-supporting stroma into one that hinders the tumor’s growth and spread.

The most abundant cells in the stroma of pancreatic tumors are called cancer-associated fibroblasts. Healthy specialized fibroblasts – known as pancreatic stellate cells – help to build and maintain the ‘normal’ extracellular matrix and so these cells normally restrict a tumor’s development. However, cancer cells can adapt healthy fibroblasts into cancer-associated fibroblasts, which produce an altered extracellular matrix that could allow the tumor to grow.

Franco-Barraza et al. have now compared healthy and cancer-associated fibroblasts from patients’ pancreatic tumors. One of the main differences between these two cell types was the location of the activated form of a molecule called α₅β₁-integrin. Healthy fibroblasts, in a normal extracellular matrix, have active α₅β₁-integrin on the surface of the cell. However, a number of tumor-promoting signals, including some from the altered extracellular matrix, could force the active α₅β₁-integrins to relocate inside the fibroblasts instead. In further experiments, where the activated integrin was retained at the cell surface, the fibroblasts were able to resist the influence of the cancer-associated extracellular matrix. Then again, if the active α₅β₁-integrins were directed inside the cells, healthy cells turned into cancer-associated fibroblasts.

With this information in hand, Franco-Barraza et al. examined tumor samples from over a hundred pancreatic cancer patients using a new microscopy-based technique that distinguishes cancer cells from stroma cells. The analysis confirmed the pattern observed in the laboratory: those patients who appeared to produce more normal extracellular matrix and have active α₅β₁-integrin localized mostly to the surface of the cells survived longer without the cancer returning than those patients who lacked these stroma traits. Samples from patients with kidney cancer also showed similar results and, as before, an altered extracellular matrix was linked to a worse outcome of the disease.

Together these findings suggest that if future studies uncover ways to relocate or maintain active α₅β₁-integrin to the cell surface of fibroblasts they could lead to new treatments to restrict the growth of tumors in cancer patients.

DOI:http://dx.doi.org/10.7554/eLife.20600.002

Circulating Cancer-Associated Macrophage-Like Cells Differentiate Malignant Breast Cancer and Benign Breast Conditions

BACKGROUND

Blood-based testing can be used as a noninvasive method to recover and analyze circulating tumor-derived cells for clinical use. Circulating cancer-associated macrophage-like cells (CAML) are specialized myeloid cells found in peripheral blood and associated with the presence of solid malignancies. We measured CAMLs prospectively in peripheral blood to ascertain their prevalence, specificity, and sensitivity in relation to breast disease status at clinical presentation.

METHODS

We report on two related but separate studies: 1) CellSieve microfilters were used to isolate CAMLs from blood samples of patients with known malignant disease (n = 41). Prevalence and specificity was compared against healthy volunteers (n = 16). 2) A follow-up double-blind pilot study was conducted on women (n = 41) undergoing core-needle biopsy to diagnose suspicious breast masses.

RESULTS

CAMLs were found in 93% of known malignant patients (n = 38/41), averaging 19.4 cells per sample, but none in the healthy controls. In subjects undergoing core biopsy for initial diagnosis, CAMLs were found in 88% of subjects with invasive carcinoma (n = 15/17) and 26% with benign breast conditions (n = 5/19).

CONCLUSION

These preliminary pilot studies suggest that the presence of CAMLs may differentiate patients with malignant disease, benign breast conditions, and healthy individuals.

IMPACT

We supply evidence that this previously unidentified circulating stromal cell may have utility as a screening tool to detect breast cancer in various malignancies, irrespective of disease stage. Cancer Epidemiol Biomarkers Prev; 25(7); 1037-42. ©2016 AACR.

Mitosis in circulating tumor cells stratifies highly aggressive breast carcinomas

Background

Enumeration of circulating tumor cells (CTCs) isolated from the peripheral blood of breast cancer patients holds promise as a clinically relevant, minimally invasive diagnostic test. However, CTC utility has been limited as a prognostic indicator of survival by the inability to stratify patients beyond general enumeration. In comparison, histological biopsy examinations remain the standard method for confirming malignancy and grading malignant cells, allowing for cancer identification and then assessing patient cohorts for prognostic and predictive value. Typically, CTC identification relies on immunofluorescent staining assessed as absent/present, which is somewhat subjective and limited in its ability to characterize these cells. In contrast, the physical features used in histological cytology comprise the gold standard method used to identify and preliminarily characterize the cancer cells. Here, we superimpose the methods, cytologically subtyping CTCs labeled with immunohistochemical fluorescence stains to improve their prognostic value in relation to survival.

Methods

In this single-blind prospective pilot study, we tracked 36 patients with late-stage breast cancer over 24 months to compare overall survival between simple CTC enumeration and subtyping mitotic CTCs. A power analysis (1-β = 0. 9, α = 0.05) determined that a pilot size of 30 patients was sufficient to stratify this patient cohort; 36 in total were enrolled.

Results

Our results confirmed that CTC number is a prognostic indicator of patient survival, with a hazard ratio 5.2, p = 0.005 (95 % CI 1.6–16.5). However, by simply subtyping the same population based on CTCs in cytological mitosis, the hazard ratio increased dramatically to 11.1, p < 0.001 (95 % CI 3.1–39.7).

Conclusions

Our data suggest that (1) mitotic CTCs are relativity common in aggressive late-stage breast cancer, (2) mitotic CTCs may significantly correlate with shortened overall survival, and (3) larger and more defined patient cohort studies are clearly called for based on this initial pilot study.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0706-4) contains supplementary material, which is available to authorized users.

Precision Microfilters as an all in one System for Multiplex Analysis of Circulating Tumor Cells

Enumeration of circulating tumor cells (CTCs) from cancer patient blood is an established diagnostic assay used to evaluate patient status as a singleplex test. However, in the coming age of personalized medicine, multiplex analysis of patient CTCs, including proteomic and genomic techniques, will have to be integrated with CTC isolation platform technologies. Advancements in microfabrication have demonstrated that CTCs can be isolated and analyzed using microfluidic lab-on-a-chip devices. However, to date, most microfluidic devices are either still in the development phase, not applicable to all clinical tests, or are not commercially available. To overcome these discrepancies, we describe an all-in-one device for the isolation and multiplexing of clinically applicable CTC assays. Microfilters present an ideal lab-on-a-chip platform for analysis of CTCs as non-toxic and inert materials allow for a multitude of tests from cell growth through clinical staining techniques, all without background interference. Lithographically fabricated microfilters, can be made with high porosity, precise pore dimensions, arrayed pore distribution, and optimized for CTC size-based isolation. In this study we describe microfilter use in isolation and in situ analysis of CTCs using multiple sequential techniques including culture, FISH, histopathological analysis, H&E staining, photobleaching and re-staining. Further, as a proof of principle, we then describe the ability to quantitatively release patient derived CTCS from the microfilters for potential use in downstream genomic/proteomic analysis.

Abstract C22: A phase Ib study of the CXCR1/2 inhibitor Reparixin in combination with weekly paclitaxel in metastatic HER2 negative breast cancer - final analysis

Background. Cancer Stem Cells (CSC) have the ability to self-renew and generate the full range of cells that make up a bulk tumor. Experimental models and retrospective clinical observations point to CSC as responsible for tumor recurrence and metastasis. An ideal CSC targeting agent should be a non toxic molecule that can be safely administered also in combination with chemotherapy to improve disease control. CXCR1, one of the receptors for CXCL8, has been identified on breast cancer CSC. Reparixin, an allosteric inhibitor of CXCR1, reduced CSC in breast cancer (BC) xenografts (Ginestier C et al., JCI 2010) both as single agent and in combination with taxane chemotherapy.

Methods. Patients were female aged ≥ 18 years with HER-2 negative metastatic BC, non taxane-refractory, who had received up to 3 prior chemotherapy (CT) lines for advanced BC (not including neo/adjuvant CT), had measurable disease according to RECIST 1.1, ECOG PS of 0-1, adequate organ function, and no brain metastases. Patients received a 3-day run-in with reparixin oral tablets 3 times daily (tid) followed by paclitaxel 80 mg/m2 (days 1, 8, and 15 for 28-day cycle) + reparixin oral tablets tid for 21 days. Three dose levels of 3-6 subjects were explored: 400 mg, 800 mg and 1200 mg oral reparixin tid. The highest safe dose level was expanded twice to gain additional safety and activity data. Treatment continued until disease progression, unacceptable toxicity or withdrawal of consent. Primary endpoints were safety and tolerability, and pharmacokinetic (PK) profile of the combination treatment. Among secondary endpoints, assessment of disease response every 2 cycles for indication of efficacy and correlative evaluations on peripheral blood samples were conducted. First analysis (i.e., 60 days post last patient in, LPI) of the results from this trial was reported earlier (Schott AF et al., SABC 2014).

Results. Herein we report data at 6 months post LPI. From 02/2012 to 04/2014, 33 patients entered the study (4 in cohort 1, 3 in cohort 2 and 26 in cohort 3). 30 patients were evaluable for safety. Neither grade 4 adverse events (AE) nor Serious AE related to reparixin were reported. 9/23 patients at the highest dose level reported Grade 3 AE among which granulocytopenia (3 patients) and peripheral neuropathy (2 patients) that are commonly seen with paclitaxel alone. Overall, 8 confirmed responses (2 CR, 6 PR) were observed among 26 patients who underwent at least 1 tumor assessment (every 8 weeks). Response duration (days) was 645+, 466+ (for CR) and 280+, 169, 141, 113, 113+, 47 (for PR). Two additional patients experienced SD &gt; 6 months (318 and 288 days, respectively). Of responding patients, all but one was from cohort 3. Median TTP (days) in the safety population was 58, 67 and 170 in cohorts 1, 2 and 3, respectively.

Conclusions. Combination treatment demonstrated good tolerability with low incidence and severity of adverse reactions. The recommended dose of reparixin for the combination was established at 1200 mg tid. A sizeable response rate and mTTP was recorded, with some interesting long term responders. A randomized phase II study of the combination versus single agent weekly paclitaxel in frontline treatment of patients with metastatic triple-negative BC is ongoing (NCT02370238).

Citation Format: Anne F. Schott, Max S. Wicha, Raymond P. Perez, Giraldo Kato, Tiffany Avery, Massimo Cristofanilli, James M. Reuben, R. Katherine Alpaugh, Pier Adelchi Ruffini, Susan Mccanna, Lori J. Goldstein. A phase Ib study of the CXCR1/2 inhibitor Reparixin in combination with weekly paclitaxel in metastatic HER2 negative breast cancer - final analysis. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C22.

Abstract 1277: Tumor-specific human monoclonal antibodies isolated from cancer patients that bind antigens expressed on the outer plasma membrane of cancer cells

Introduction: Cancer cells express novel antigens that reflect their transformed state and may engender an antibody response. We hypothesize that some of these auto-antibodies detect neo-antigens that are shared by diverse tumor types and that a subset of these are expressed on the outer plasma membrane (PM) of cancer cells, but not normal cells. Here, we describe two human mAbs, isolated from lymph node B-cells of breast cancer patients, that bind antigens expressed only on the surface of cancer cells.

Methods: We have optimized a hybridoma method for cloning human IgG monoclonal antibodies (mAbs) by screening for those that bind to live, heterologous cancer cell lines. We use whole cell immunofluorescence binding assays with human cancer cell lines, detecting cell-reactive human IgG with the Operetta. We use B-cells from lymph nodes obtained at surgery from stage I, ER+PR+ breast cancer patients and Stage I or II lung cancer patients, as well as peripheral blood B-cells from lung cancer patients responsive to PD-1 inhibitors. We used cDNA library expression methods to identify the tumor antigens and characterized the tumor-specific activities of two mAbs using immunohistochemistry (IHC), gene transfection, flow cytometry, immunoblotting, and invasion assays.

Results: Two of the mAbs isolated from lymph nodes of patients with breast cancer bind to antigens that are only expressed on the outer PM of cancer cells. The antigen recognized by mAb 9H2 is known to be expressed on the outer PM of metastatic cells, while the antigen recognized by mAb 2B9 is a cytoplasmic protein not previously recognized to exist on the outer PM. IHC demonstrates that the 9H2 antigen is expressed only rarely on normal cells, but is commonly on breast and colon cancers (3 of 4 samples tested for each tumor type). Binding was also seen on 2 of 4 small cell lung cancers samples and 1 of 3 pancreatic cancers. The existence of the 2B9 antigen on the outer PM was confirmed by study of 293T cells transiently transfected with MYC-tagged antigen expression constructs and analyzed by flow cytometry with the mAb 2B9 and an anti-myc mAb. Treatment of MDA-MB-231 cells with the mAb 2B9 substantially reduced invasion in the transwell migration assay. An additional panel of 12 mAbs exhibited internalizing activity and is being evaluated for efficacy as antibody-drug conjugates

Conclusion: Our panel of mAbs from cancer patients supports the hypothesis that patients with malignancies make antibodies that bind novel cancer-specific antigens. Two mAbs bind antigens expressed only on the surface of malignant cells; one has not previously been detected on the outer PM. The ability of mAb 2B9 to inhibit breast cancer cell invasion suggests that the anti-tumor immune response may be functional. Studying the anti-cancer antibody repertoire may identify new targets for mAb-based cancer diagnostics and therapeutics.

Citation Format: Baron Heimbach, Cezary Swider, Huiwu Zhao, Paul Simon, R. Katherine Alpaugh, Michael Walker, David Krag, David Knight, Tung Chan, Hossein Borghaei, Scott Dessain. Tumor-specific human monoclonal antibodies isolated from cancer patients that bind antigens expressed on the outer plasma membrane of cancer cells. [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 1277. doi:10.1158/1538-7445.AM2015-1277

Biodistribution and radiation dosimetry of the carbonic anhydrase IX imaging agent [(18) F]VM4-037 determined from PET/CT scans in healthy volunteers

PURPOSE

[(18) F]VM4-037 has been developed as a positron emission tomography (PET) imaging marker to detect carbonic anhydrase IX (CA-IX) overexpression and is being investigated for use as a surrogate marker for tissue hypoxia. The purpose of this study was to determine the biodistribution and estimate the radiation dose from [(18) F]VM4-037 using whole-body PET/CT scans in healthy human volunteers.

PROCEDURES

Successive whole-body PET/CT scans were performed after intravenous injection of [(18) F]VM4-037 in four healthy humans. The radiotracer uptakes in different organs were determined from the analysis of the PET scans. Human radiation doses were estimated using OLINDA/EXM software.

RESULTS

High uptake of [(18) F]VM4-037 was observed in the liver and kidneys, with little clearance of activity during the study period, with mean standardized uptake values of ~35 in liver and ~22 in kidneys at ~1 h after injection. The estimated effective dose was 28 ± 1 μSv/MBq and the absorbed doses for the kidneys and liver were 273 ± 31 and 240 ± 68 μGy/MBq, respectively, for the adult male phantom. Hence, the effective dose would be 10 ± 0.5 mSv for the anticipated injected activity of 370 MBq, and the kidney and liver doses would be 101 ± 11 and 89 ± 25 mGy, respectively.

CONCLUSIONS

[(18) F]VM4-037 displayed very high uptake in the liver and kidneys with little clearance of activity during the study period, resulting in these organs receiving the highest radiation doses among all bodily organs. Though the effective dose and the organ doses are within the limits considered as safe, the enhanced uptake of [(18) F]VM4-037 in the kidneys and liver will make the compound unsuitable for imaging overexpression of CA-IX in those two organs. However, the tracer may be suitable for imaging overexpression of CA-IX in lesions in other regions of the body such as in the lungs or head and neck region.

Cytometric characterization of circulating tumor cells captured by microfiltration and their correlation to the CellSearch(®) CTC test

Recent studies reporting hundreds, to thousands, of circulating tumor cells (CTCs) in the blood of cancer patients have raised questions regarding the prevalence of CTCs, as enumerated by the CellSearch(®) CTC Test. Although CellSearch has been shown to consistently detect clinically relevant CTCs; the ability to only capture EpCAM positive cells has led to speculation that it captures limited subsets of CTCs. In contrast, alternative approaches to CTC isolation are often cited as capturing large numbers of CTCs from patient blood. Not surprisingly the number of cells isolated by alternative approaches show poor correlations when compared to CellSearch, even when accounting for EpCAM presence or absence. In an effort to address this discrepancy, we ran an exploratory method comparison study to characterize and compare the CTC subgroups captured from duplicate blood samples from 30 breast and prostate cancer patients using a microfiltration system (CellSieve™) and CellSearch. We then categorized the CellSieve Cytokeratin(CK)+/CD45-/DAPI+ cells into five morphologically distinct subpopulations for correlative analysis. Like other filtration techniques, CellSieve isolated greater numbers of CK+/CD45- cells than CellSearch. Furthermore, analysis showed low correlation between the total CK+/CD45- cells captured by these two assays, regardless of EpCAM presence. However, subgrouping of CK+/CD45-/DAPI+ cells based on distinct cytokeratin staining patterns and nuclear morphologies elucidated a subpopulation correlative to CellSearch. Using method comparison analyses, we identified a specific CTC morphology which is highly correlative between two distinct capture methods. These data suggests that although various morphologic CTCs with similar phenotypic expressions are present in the blood of cancer patients, the clinically relevant cells isolated by CellSearch can potentially be identified using non-EpCAM dependent isolation. © 2014 The Authors. Published by Wiley Periodicals, Inc.

A phase I-II study of the histone deacetylase inhibitor vorinostat plus sequential weekly paclitaxel and doxorubicin-cyclophosphamide in locally advanced breast cancer

Histone deacetylases (HDACs) are a family of enzymes that regulate chromatin remodeling and gene transcription. Vorinostat is a panHDAC inhibitor that sensitizes breast cancer cells to taxanes and trastuzumab by suppressing HDAC6 and Hsp90 client proteins. Fifty-five patients with clinical stage IIA-IIIC breast cancer received 12 weekly doses of paclitaxel (80 mg/m(2)) plus vorinostat (200-300 mg PO BID) on days 1-3 of each paclitaxel dose plus trastuzumab (for Her2/neu positive disease only), followed by doxorubicin/cyclophosphamide (60/600 mg/m(2) every 2 weeks plus pegfilgrastim). The primary study endpoint was pathologic complete response (pCR). pCR occurred in 13 of 24 evaluable patients with Her2-positive disease (54, 95 % confidence intervals [CI] 35-72 %), which met the prespecified study endpoint. pCR occurred in 4 of 15 patients with triple negative disease (27, 95 % CI 11-52 %) and none of 12 patients with ER-positive, Her2/neu negative disease (0, 95 % CI 0-24 %), which did not meet the prespecified endpoint. ER-positive tumors exhibited lower Ki67 and higher Hsp70 expression, and HDAC6, Hsp70, p21, and p27 expression were not predictive of response. Vorinostat increased acetylation of Hsp90 and alpha tubulin, and reduced expression of Hsp90 client proteins and HDAC6 in the primary tumor. Combination of vorinostat with weekly paclitaxel plus trastuzumab followed by doxorubicin-cyclophosphamide is associated with a high pCR rate in locally advanced Her2/neu positive breast cancer. Consistent with cell line and xenograft data, vorinostat increased acetylation of Hsp90 and alpha tubulin, and decreased Hsp90 client protein and HDAC6 expression in human breast cancers in vivo.

Phase II trial of vorinostat in advanced melanoma

INTRODUCTION

Vorinostat is a small molecule inhibitor of class I and II histone deacetylases with preclinical activity in melanoma.

METHODS

We evaluated 32 patients with advanced primary cutaneous or ocular melanoma in a multi-institutional setting (PMH Phase II Consortium) with continuous daily oral vorinostat 400 mg. The primary endpoint was response rate by RECIST, with time to progression as a secondary endpoint. The study was designed to distinguish a response rate of 20 % from a RR of 5 % and to distinguish a 2 month median progression-free survival (PFS), from one of 3.1 months. The study proceeded to stage 2 following 2 of 16 responses.. We also assessed VEGF, FGF levels, P52 polymorphisms and chromatin-associated proteins as potential biomarkers.

RESULTS

Therapy was associated with significant side effects, including fatigue, nausea, lymphopenia, and hyperglycemia. Eleven patients experienced at least one grade 3 or higher adverse event. There were two confirmed PRs in patients with cutaneous melanoma. Sixteen patients had stable disease and 14 patients had progressive disease for best response. In addition, two patients with cutaneous melanoma scored as stable disease had early unconfirmed partial responses with subsequent progression. Patients with stable disease or partial response (n = 18) had a median progression free survival of 5 months. (range 2-12 months).

CONCLUSIONS

Vorinostat demonstrated some early responses and a high proportion of patients with stable disease, but did not meet its primary endpoint of response. Different schedules of this agent with BRAF mutation status and markers of histone acetylation could be explored in melanoma.