Hillman, David W.

Abstract Introduction: Stromal tumor-infiltrating lymphocytes (sTILs) have established prognostic and predictive significance in triple-negative breast cancer (TNBC). However, the roles of other immune cells in TNBC are less well-established. We performed high-plex quantitative spatial profiling in a cohort of early-stage TNBC to 1) apply spatial context to tumoral immune landscapes and 2) identify immune proteins associated with clinical outcomes, independently of TILs and other established prognostic clinicopathologic variables, in patients (pts) treated with or without adjuvant chemotherapy (CTX). Methods: The Mayo TNBC cohort comprises pts with centrally-verified, CTX-naive tumors resected from 1985-2012. Using a cohort-based TMA, with Nanostring GeoMX DSP, we quantitated 58 proteins within spatially-distinct intra-epithelial, cytokeratin-positive tumor segments and adjacent cytokeratin-negative/nuclei-positive stromal segments. Differentially-expressed (DE) proteins were identified using a negative binomial generalized linear model (SNR>2, p< 0.05) and a target DE protein set was dichotomized (80th percentile). After adjusting for prognostic clinicopathologic variables, proteins associated with recurrence-free survival (RFS, defined as time from surgery to either local, regional, and distant recurrence, or death by any cause) were identified by performing variable selection using the Akaike Information Criterion (AIC) obtained from fitting all possible Cox proportional hazards regression models (performed separately for intra-epithelial/stromal segments, and in groups +/- adjuvant CTX. Results: From the TNBC TMA, DSP data (N=250 tumors) included 169 pts who received adjuvant CTX+ and 81 who did not (CTX-). Overall, 85/250 developed recurrent disease. In the CTX+ group, intra-epithelial tumor segments from pts without recurrent disease were enriched in 10 immune proteins, including CD8, markers involved in antigen presentation/dendritic cells (CD11c, CD40, HLA-DR) or NK cells (CD56) (FC: 1.4-2.1, p<0.05); CD14 was increased in stroma (FC: 1.5, p<0.05). In contrast, in the CTX- group, both the intra-epithelial tumor and stromal segments from pts without recurrences were enriched in immune proteins (N= 12 and 15 respectively; FC 1.6-5.5, p< 0.05) most markedly CD40, IDO1 and HLA-DR (FC: 3.2-5.5, p< 0.05). Overall, CD3, CD4, CD27, CD44, and ICOS among others were enriched only in the CTX- group; CD14 and CD56 were enriched only in the CTX+ group. Based on these spatial data, biologic function and DSP data from another set of TNBC (FinXX trial), CD11c, CD14, CD27, CD40, CD56, and IDO1 were selected for RFS analysis. After applying our model selection criterion and adjusting for pt age at surgery, tumor size, lymph node status, and sTILs, intra-epithelial CD56 was independently associated with improved RFS in the CTX+ group (HR: 0.31[0.12, 0.81]). In the CTX- group, intra-epithelial CD11c was independently associated with improved RFS (0.10 [0.01, 0.81]). Conclusion: In this early-stage TNBC cohort, spatially-distinct tumor immune landscapes were associated with RFS but differed according to receipt of CTX after surgical resection. In the patients who received CTX, the intra-epithelial compartment, rather than stromal compartment, was immune-enriched in pts without recurrences. Among a targeted protein set, intra-epithelial CD56 remained associated with improved outcomes, independent of sTILs and other clinicopathologic features. In the CTX- group, spatial landscapes were more balanced, and intra-epithelial CD11c was independently associated with improved outcomes. These data provide insight into the spatial context of intrinsic immune landscapes in TNBC, and identify candidate prognostic immune biomarkers which may inform therapeutic strategies. Citation Format: Jodi M Carter, Saranya Chumsri, David W Hillman, David M Zahrieh, Yaohua Ma, Xue Wang, Jennifer M Kachergus, Judy C Boughey, Minetta C Liu, Krishna R Kalari, JC Villasboas, Roberto A Leon Ferre, Fergus J Couch, Matthew P Goetz, E. Aubrey Thompson. Intra-epithelial tumor immune landscapes are associated with clinical outcomes in early-stage triple-negative breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS16-01.

PURPOSE CALGB 40601 assessed whether dual versus single human epidermal growth factor receptor 2 (HER2) –targeting drugs added to neoadjuvant chemotherapy increased pathologic complete response (pCR). Here, we report relapse-free survival (RFS), overall survival (OS), and gene expression signatures that predict pCR and survival. PATIENTS AND METHODS Three hundred five women with untreated stage II and III HER2-positive breast cancer were randomly assigned to receive weekly paclitaxel combined with trastuzumab plus lapatinib (THL), trastuzumab (TH), or lapatinib (TL). The primary end point was pCR, and secondary end points included RFS, OS, and gene expression analyses. mRNA sequencing was performed on 264 pretreatment samples. RESULTS One hundred eighteen patients were randomly allocated to THL, 120 to TH, and 67 to TL. At more than 7 years of follow-up, THL had significantly better RFS and OS than did TH (RFS hazard ratio, 0.32; 95% CI, 0.14 to 0.71; P = .005; OS hazard ratio, 0.34; 95% CI, 0.12 to 0.94; P = .037), with no difference between TH and TL. Of 688 previously described gene expression signatures, significant associations were found in 215 with pCR, 45 with RFS, and only 22 with both pCR and RFS (3.2%). Specifically, eight immune signatures were significantly correlated with a higher pCR rate and better RFS. Among patients with residual disease, the immunoglobulin G signature was an independent, good prognostic factor, whereas the HER2-enriched signature, which was associated with a higher pCR rate, showed a significantly shorter RFS. CONCLUSION In CALGB 40601, dual HER2-targeting resulted in significant RFS and OS benefits. Integration of intrinsic subtype and immune signatures allowed for the prediction of pCR and RFS, both overall and within the residual disease group. These approaches may provide means for rational escalation and de-escalation treatment strategies in HER2-positive breast cancer.

539 Background: An increased baseline sHER-2 concentration is an indicator of poor prognosis in the metastatic and adjuvant settings of HER-2+BC. This study evaluated the levels of sHER-2 during treatment and at time of recurrence in N9831. Methods: Aims were to describe sHER-2 levels during treatment and at time of recurrence in patients (pts) randomized to Arms A (standard chemotherapy) and C (standard chemotherapy with concurrent trastuzumab). Baseline serum samples of 1506 pts from both arms along with 86 recurrence serum samples were analyzed for sHER-2 (ng/mL). In addition, 556 serial samples were obtained in 148 patients over the treatment period. Median follow up was 4.5 years. Statistical methods included repeated measures linear models, Wilcoxon rank sum tests, and Cox regression models. Results: Analyzing serial sHER-2 levels during treatment, mean log sHER-2 remained constant in Arm C (estimated slope = 0.004, p = 0.44) while the estimated increase per month was 0.026 (on log e scale) for Arm A (p = 0.0003). Based on the linear model at 18 months, the mean log sHER-2 was 2.98 (95% CI: 2.87–3.09) and 2.55 (95% CI: 2.40–2.70) for Arms A and C, respectively. Among pts with disease recurrence, sHER-2 levels increased in Arm A from baseline to time of recurrence (mean = 72.9, median = 1.7, p =0.005) while sHER-2 levels remained unchanged in Arm C (mean = 9.2, median = -0.9, p = 0.65). While all 86 recurrence patients had baseline sHER2 levels <50, 24% (15/63) of Arm A patients had very high recurrence sHER-2 levels (≥50) as compared to 9% (2/23) on Arm C (p=0.10). Patients with recurrence sHER-2 levels ≥15 had shorter survival time following recurrence with 3 year overall survival of 51% compared to 76% for the <15 sHER-2 group (HR = 2.77; 95% CI: 1.20–6.43, p = 0.02). Conclusions: Based on serial specimens during treatment, the concurrent trastuzumab arm (C) had constant sHER-2 levels, whereas the standard chemotherapy arm (A) had increasing sHER-2 levels. In arm A, recurrence sHER-2 levels increased significantly from baseline while recurrence sHER-2 levels did not change in arm C. Additionally, pts with high sHER-2 levels at recurrence had shorter overall survival following recurrence. Partial support: CA25224, CA114740 , Genentech, Siemens, and the BCRF. [Table: see text]

PURPOSE Radical prostatectomy (RP) alone is often inadequate in curing men with clinically localized, high-risk prostate cancer (PC). We hypothesized that chemohormonal therapy (CHT) with androgen-deprivation therapy plus docetaxel before RP would improve biochemical progression–free survival (BPFS) over RP alone. PATIENTS AND METHODS Men with clinically localized, high-risk PC were assigned to RP alone or neoadjuvant CHT with androgen deprivation plus docetaxel (75 mg/m 2 body surface area every 3 weeks for 6 cycles) and RP. The primary end point was 3-year BPFS. Biochemical failure was defined as a serum prostate-specific antigen level > 0.2 ng/mL that increased on 2 consecutive occasions that were at least 3 months apart. Secondary end points included 5-year BPFS, overall BPFS, local recurrence, metastasis-free survival (MFS), PC-specific mortality, and overall survival (OS). RESULTS In total, 788 men were randomly assigned. Median follow-up time was 6.1 years. The overall rates of grade 3 and 4 adverse events during chemotherapy were 26% and 19%, respectively. No difference was seen in 3-year BPFS between neoadjuvant CHT plus RP and RP alone (0.89 v 0.84, respectively; 95% CI for the difference, −0.01 to 0.11; P = .11). Neoadjuvant CHT was associated with improved overall BPFS (hazard ratio [HR], 0.69; 95% CI, 0.48 to 0.99), improved MFS (HR, 0.70; 95% CI, 0.51 to 0.95), and improved OS (HR, 0.61; 95% CI, 0.40 to 0.94) compared with RP alone. CONCLUSION The primary study end point, 3-year BPFS, was not met. Although some improvement was seen in secondary end points, any potential benefit must be weighed against toxicity. Our data do not support the routine use of neoadjuvant CHT and RP in patients with clinically localized, high-risk PC at this time.

1016 Background: The ph III EMBRACE trial of E vs physician’s choice of tx led to FDA approval of E as ≥3rd-line tx for MBC pts with prior exposure to anthracyclines/taxanes. The ph III BOLD 301 trial of E vs capecitabine in advanced BC treated with anthracyclines/taxanes showed a nonsignificant trend to improved median OS for all pts; pre-planned analysis by HER2 status revealed a nominally significant benefit for HER2- pts. Methods: RU011201I is an investigator initiated ph III trial with 1:1 randomization to E (1.4 mg/m2 D1,8 q21days) vs P (90 mg/m2 D1,8,15 q28days) within strata defined by (neo)adjuvant taxanes (yes/no), HR status (+/-), and line of tx (1st/2nd). Pts had measurable or non-measurable disease by RECIST v1.1; new or progressive mets; peripheral neuropathy (PN) gr<2; ≤1 prior chemotx regimens for advanced or MBC. Asymptomatic brain mets with stable MRIs for >3 mos were allowed. (Neo)adjuvant taxanes were allowed if >12 mos between tx completion and disease recurrence. Radiographic studies occur q12wks. Survival data are collected q12wks after the Off-Tx Visit. Pts reported side effects weekly; post-baseline symptomatic AE rates worse than baseline were compared between arms using Fisher’s exact tests. We report clinical outcomes and the primary objective related to PRO-CTCAE use. Results: 201 pts enrolled 3/2014 - 5/2018 with 33.8 mos median f/u; 3 are on tx as of 2/20/20 (1E, 2P). Pt characteristics were the same between E vs P: median age 62 yrs (range 27-85); 42% prior taxane; 78% ER+; 70% starting 1st line tx. Baseline lesion distribution was similar except for lung mets (37E, 53P). No difference was seen between E vs P in PFS (5.7 vs 5.9 mos; P=0.72), OS (18.1 vs 16.4 mos; P=0.75), TTF (5.3 vs 4.9 mos; P=0.82), DOR (10.8 vs 12.3 mos; P=0.84), or number of metastatic events (55 vs 54). 37E and 36P pts required ≥1 dose reduction. Hematologic toxicities ≥ gr 3 were higher with E (40 vs 22%). PN events were similar: 56 vs 58 total, 4 vs 7 motor, 52 vs 51 sensory. Median duration of PN and median time to 1st PN event were 74 vs 140 and 56 vs 41 days. Worsened numbness/tingling severity and other pt-reported AE rates were similar, but worsened numbness/tingling interference (63% vs 78%, P=0.04) and vomiting frequency (35% vs 57%, P=0.005) were lower with E. Conclusions: Clinical outcomes were equivalent with E vs P as 1st/2nd line tx for HER2- advanced BC. The nature and severity of PN were similar between arms, but time of onset, duration, and interference with daily living favor E. E may be a suitable treatment option in this setting. Clinical trial information: NCT02037529 .

510 Background: Several studies have established the critical role of preexisting immune response in triple negative breast cancer (TNBC). Most studies evaluated the tumor infiltrating lymphocytes in stroma. However, limited data are available with regards to the importance of specific subtypes and spatial distribution of these immune infiltrates. Methods: NanoString IO360 gene expression analysis and Digital Spatial Profiling (DSP) were used. DSP was used to quantify 39 immune-related proteins in stromal and tumor-enriched segments from 44 TNBC samples from the FinXX trial (NCT00114816) and 335 samples from the Mayo Clinic (MC) cohort of centrally reviewed TNBC (Leon-Ferre BCRT 2018). In FinXX trial, 22 patients with recurrence and 22 patients without recurrence were included. In MC cohort, 217/335 patients received adjuvant chemotherapy while 118 patients had surgery only without adjuvant chemotherapy. Regions were segmented based on pancytokeratin staining. The general linear model was used for statistical analysis of differential expression with recurrence free survival (RFS) as a categorical variable (recur yes or no). Kaplan-Meier estimates and Cox regression models were also used for analysis. Results: In the FinXX trial, using global gene expression analysis with IO360, there was no signature significantly associated with RFS. However, using DSP, high protein expression of CD56 in the tumor-enriched segments was associated with significant improvement in RFS (HR 0.26, 95%CI 0.09-0.78, p 0.01). Nevertheless, CD56 expression in the stroma (HR 0.66, 95%CI 0.29-1.53, p 0.33) and all segments (HR 0.53, 95%CI 0.23-1.25, p 0.14) was not significantly associated with improved outcome. We further validated these findings in the MC TNBC cohort where intratumoral CD56 expression was associated with a significant improvement in RFS (HR 0.23, p 0.002) but not stromal CD56 (p 0.79). Interestingly, when evaluating the MC TNBC cohort according to receipt of chemotherapy, intratumoral CD56 was associated with improved outcome only in patients who received chemotherapy (p 0.02 vs. 0.07). In both cohorts, higher expressions of intratumoral PD-L1, HLA-DR, and CD8 were associated with improved outcome. Conclusions: Using an in-depth analysis with spatially defined context, we identify that intratumoral CD56-positive NK cells are associated with improved outcome in TNBC. Our study highlights the potential role of NK cells in TNBC and future implications for biomarkers and therapeutic targets.Support: W81XWH-15-1-0292, P50CA116201-9, P50CA015083. Clinical trial information: NCT00114816 .

1059 Background: Relapsed TNBC is characterized by its poor prognosis. B is a synthetic DNA minor groove binding non-cross resistant agent that is fully active against DNA-mismatch repair deficient tumor cells. C increases GSH/GST in which enhances the efficacy of B. Methods: Phase II study in pts with mTNBC. C Day 1 followed by B Day 2, repeated every 21 days. Aim: Efficacy of C + B in mTNBC. Primary endpoint: PFS at 3 mo. Secondary endpoints include ORR, duration of response (DOR), 6-mo PFS, OS and AE profile. Tertiary endpoints include assessment of baseline GSH levels, prevalence of BCRA1 mutation and pERK, and correlations with outcome. Results: Closed 3/2012. 48 pts accrued (1 ineligible pt). Median f/u 11.4 mo (6.6-14.8); 2 pts still on treatment. 47 pts evaluable for the PFS endpoint and AEs. 49% received therapy as 3rd-5th line. Median number of cycles = 4 (range 1-15). There are currently 9 confirmed responses (8 PR and 1 CR); DOR = 2.6-14.5 mo. The 3-mo PFS = 51%; 6-mo PFS = 28%; the median TTP is 3.2 mo. AE data: 75% G3/4 hematologic AE: febrile neutropenia 19%. Non-hematologic AEs included G3 (47%) and G4 (15%): G3 fatigue 17%; and no G5 non-heme AE. No correlation of GSH/GST levels with outcome was found. Among 35 pts with evaluable data, no association between BRCA1 expression and outcomes was found. pERK expression was negatively associated with 3-mo PFS, but not 6-mo PFS. Cytoplasmic pERK expression was negatively associated with tumor response (p=0.03). No significant effect of BRCA-1 or pERK expression was found on OS. Conclusions: This trial showed B + C is an active regimen, especially in heavily pretreated mTNBC pts. Correlative data demonstrated a negative association between pERK expression and outcomes. A randomized phase II trial is in development. Clinical trial information: NCT01091454.

17505 Background: A previous trial of 2-CDA as a single agent for therapy of mantle cell lymphoma demonstrated this agent to be efficacious with an overall response rate of 81% (31% complete responses) (Blood 1999 Nov 15; 94:660a). A phase II study of the addition of rituximab to 2-CDA was conducted by the North Central Cancer Treatment Group based on improved outcomes achieved by the addition of rituximab to other regimens active in MCL. Methods: This one-stage phase II study was designed to determine the complete response (CR) or complete response/unconfirmed (CRu) rate. Central pathology confirmation of cyclin D1 positive mantle cell lymphoma was required. No previous therapy for lymphoma was allowed, with the exception of splenectomy. The shedule was rituximab 375 mg/m2 IV day 1; 2-CDA 5 mg/m2/d IV days 1–5 of a 4-week cycle. After 2 of the first 6 patients developed grade 4 neutropenia, subsequent patients received either pegfilgrastim or filgrastim support. Patients received 2–6 cycles of therapy, depending on response. Patients were required to achieve at least a PR after 2 cycles of therapy to continue on protocol therapy. Results: Patient characteristics of all 29 eligible pts: median age: 70 (range: 41–86); 21 male, 8 female; PS 0 (55.2%), PS 1 (41.4%), PS 2 (3.5%); stage II (6.9%), stage III (3.5%), stage IV (89.7%); prior splenectomy (20.7%). The only grade 4 adverse event occurring more than once was neutropenia (20.7%). One patient died of cerebral ischemia in the setting of pneumonia without neutropenia. Response has been determined in 26 pts with 50.0% (95% CI: 30.0–70.0%) achieving a CR, none of whom have relapsed to date. Three patients progressed early at 17, 45, and 46 days, two of whom have died, and a fourth relapsed day 222. 10 pts (34.0%) went on to receive further therapy off study, 5 in less than a PR after 2 cycles, 2 in PR after study therapy, and 1 who went off study for a rash. At last contact, 26 (89.7%) were alive (median follow-up 10.7 months; range: 1–28). Conclusions: Rituximab and cladribine were well tolerated for the treatment of MCL in a group including elderly patients. The response rate may have been underestimated due to the study design, which required at least a PR after 2 cycles to continue therapy. Despite this, 50% achieved a complete remission. [Table: see text]

577 Background: BAY 43–9006 targets the ras/raf signaling pathway and inhibits VEGFR-2, VEGFR-3 and or PDGFR-β growth factors. A study was conducted to assess anti-tumor activity and the toxicity profile in patients (pts) with metastatic breast cancer (MBC). Methods: A two-stage phase II study was conducted with pts with MBC who had measurable disease and were candidates for 1 st or 2 nd line chemotherapy and had previously received an anthracycline and/or a taxane in the neoadjuvant, adjuvant, or metastatic setting. Pts started with a dose of 400 mg twice daily on days 1–28 of each 4 week cycle. Based on interval adverse events (AEs), a dose reduction was considered as 400 mg given one time daily. Primary endpoint was tumor response defined as a complete or partial response (PR) according to RESIST. The study required 40 pts, but was to be terminated if 0 or 1 responses occurred among 1 st 20 eligible pts. Results: 23 pts enrolled with a median age of 54 (range 37–70) but 3 were declared ineligible. All 23 pts were included in all analyses except efficacy analysis as stated per protocol. Fifteen (65%) had visceral metastasis; 22 (96%) had prior anthracycline treatment (tx); 16 (70%) had prior taxane tx.; 10 (44%) had received prior chemotherapy for metastatic disease and 14 (61%) had a prior relapse free interval of 12 months (mos) or more. Pts received tx for a median of 2 cycles (range 1–8) with a median follow-up of 7.2 mos. Dose reductions were due to dermatitis/skin rash (3), hand/foot skin reaction (2), hypertension (1) and cramping hands/feet (1). No grade 4 AEs occurred and grade 3 AEs included acne (2), hand/foot skin reaction (1), neutropenia (1), cough (1), wound infection (1), and prolonged PTT (1). Among the 20 pts eligible for efficacy analysis one pt (5%; 95% CI 0.5–20.5%) achieved a PR with duration of 3.6 mos and one pt achieved stable disease for at least 6 mos. The 6-month overall survival rate was 81% and the progression-free survival rates were 53% at 2 mos, 24% at 4 mos and 6% at 6 mos. Median time to progression was 2 mos. Based on the lack of sufficient response, we did not proceed with the 2nd stage of this study. Conclusion: Treatment with oral BAY 43–9006, while well tolerated, does not have sufficient activity to warrant further testing as a single agent in this disease setting. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech Genentech

15553 Background: 17-Allylamino-17-Demethoxygeldanamycin (17-AAG) is a benzoquinone ansamycin antibiotic with anti- proliferative activity in several mouse xenograft models including prostate cancer models. Serum IL-6, IL-8, and maspin are potentially important markers of prostate cancer biology. Methods: Patients (pts) with metastatic, hormone-refractory prostate cancer progressing on at least one prior systemic therapy with rising PSA were eligible. All pts received 17-AAG at a dose of 300 mg/m2 IV weekly for three out of four weeks. Primary objective was to assess the PSA response (50% decrease in PSA). Secondary objectives included Adverse Events (AEs) and correlative serum markers including IL-6, IL-8 and maspin levels. A Simon two-stage design required a total of 25 pts with early termination if < 2 responses occurred among the 1st 16 eligible patients. Results: Seventeen pts were enrolled of which 15 were deemed eligible. Median age was 68 and median PSA was 252 ng/mL. Pts received 17-AAG for a median number of 2 cycles. No pt had a PSA response. No grade 4/5 AEs occurred. Grade 3 AEs included fatigue (4 pts), lymphopenia (2 pts) and back pain (2 pts). The median PSA progression free survival was 1.8 months (95% CI: 1.3–3.4 months). The six-month overall survival was 61% (95% CI: 37%-100%). Due to the lack of PSA response, accrual was stopped per study design. At day 15, the median IL-6 and IL-8 increase from baseline was 0.4 pg/ml (p=0.57) and 3 pg/ml (p=0.73), respectively. Maspin levels had day 15 increase of 6-fold (p=0.44). At treatment failure (TF), the median IL-6 increase from baseline was 4.47 pg/ml (p=0.03) and IL-8 decrease was 1.8 pg/ml (p=0.31). Maspin levels had a 29-fold increase at TF (p=0.09). Conclusions: 17-AAG did not show any activity with regards to PSA response. Serum IL-6 was significantly increased at the time of TF. Further evaluation of 17-AAG at a dose of 300 mg/m2 IV weekly in this patient population is not warranted. No significant financial relationships to disclose.