A Phase 2 Study of In Situ Oncolytic Virus Therapy and Stereotactic Body Radiation Therapy Followed by Pembrolizumab in Metastatic Non-Small Cell Lung Cancer

PURPOSE

A phase 2 study of stereotactic body radiation therapy (SBRT) and in situ oncolytic virus therapy in metastatic non-small cell lung cancer (mNSCLC) followed by pembrolizumab (STOMP) was designed to explore the dual approach in enhancing single pembrolizumab with ADV/HSV-tk plus valacyclovir gene therapy and SBRT in mNSCLC.

METHODS AND MATERIALS

STOMP is a single-arm, open-label phase 2 study. Patients with mNSCLC received intratumoral injections of ADV/HSV-tk (5 × 1011 vp) and SBRT (30 Gy in 5 fractions) followed by pembrolizumab 200 mg IV every 3 weeks until disease progression or intolerable toxicity. The primary endpoint was overall response rate (ORR) (complete response [CR] and partial response [PR]). Secondary endpoints included clinical benefit rate (CBR) (CR, PR and stable disease [SD]), progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

28 patients were enrolled, of whom 27 were evaluated for response. The ORR was 33.3%, including 2 CR (7.4%) and 7 PR (25.9%). CBR was 70.4%. Six of eight (75.0%) patients who were immune checkpoint inhibitor (ICI) refractory derived clinical benefits. Responders had durable responses with median PFS, and OS not reached. The entire cohort had a median PFS of 7.4 months (95% CI, 5.1-9.6 months), and median OS of 18.1 months (95% CI, 15.4-20.9 months). The combination was well tolerated, with grade 3 or higher toxicity in 6 (21.4%) patients.

CONCLUSIONS

The dual approach of in situ ADV/HSV-tk plus valacyclovir gene therapy and SBRT as a chemotherapy-sparing strategy to enhance the antitumor effect of pembrolizumab is a well-tolerated encouraging treatment in patients with mNSCLC.

The impact of nitric oxide on HER family post-translational modification and downstream signaling in cancer

The human epidermal growth factor receptor (HER) family consists of four members, activated by two families of ligands. They are known for mediating cell-cell interactions in organogenesis, and their deregulation has been associated with various cancers, including breast and esophageal cancers. In particular, aberrant epidermal growth factor receptor (EGFR) and HER2 signaling drive disease progression and result in poorer patient outcomes. Nitric oxide (NO) has been proposed as an alternative activator of the HER family and may play a role in this aberrant activation due to its ability to induce s-nitrosation and phosphorylation of the EGFR. This review discusses the potential impact of NO on HER family activation and downstream signaling, along with its role in the efficacy of therapeutics targeting the family.

NOS2 and COX2 Provide Key Spatial Targets that Determine Outcome in ER- Breast Cancer

Estrogen receptor-negative (ER-) breast cancer is an aggressive breast cancer subtype with limited therapeutic options. Upregulated expression of both inducible nitric oxide synthase (NOS2) and cyclo-oxygenase (COX2) in breast tumors predicts poor clinical outcomes. Signaling molecules released by these enzymes activate oncogenic pathways, driving cancer stemness, metastasis, and immune suppression. The influence of tumor NOS2/COX2 expression on the landscape of immune markers using multiplex fluorescence imaging of 21 ER- breast tumors were stratified for survival. A powerful relationship between tumor NOS2/COX2 expression and distinct CD8+ T cell phenotypes was observed at 5 years post-diagnosis. These results were confirmed in a validation cohort using gene expression data showing that ratios of NOS2 to CD8 and COX2 to CD8 are strongly associated with poor outcomes in high NOS2/COX2-expressing tumors. Importantly, multiplex imaging identified distinct CD8+ T cell phenotypes relative to tumor NOS2/COX2 expression in Deceased vs Alive patient tumors at 5-year survival. CD8+NOS2-COX2- phenotypes defined fully inflamed tumors with significantly elevated CD8+ T cell infiltration in Alive tumors expressing low NOS2/COX2. In contrast, two distinct phenotypes including inflamed CD8+NOS2+COX2+ regions with stroma-restricted CD8+ T cells and CD8-NOS2-COX2+ immune desert regions with abated CD8+ T cell penetration, were significantly elevated in Deceased tumors with high NOS2/COX2 expression. These results were supported by applying an unsupervised nonlinear dimensionality-reduction technique, UMAP, correlating specific spatial CD8/NOS2/COX2 expression patterns with patient survival. Moreover, spatial analysis of the CD44v6 and EpCAM cancer stem cell (CSC) markers within the CD8/NOS2/COX2 expression landscape revealed positive correlations between EpCAM and inflamed stroma-restricted CD8+NOS2+COX2+ phenotypes at the tumor/stroma interface in deceased patients. Also, positive correlations between CD44v6 and COX2 were identified in immune desert regions in deceased patients. Furthermore, migrating tumor cells were shown to occur only in the CD8-NOS2+COX2+ regions, identifying a metastatic hot spot. Taken together, this study shows the strength of spatial localization analyses of the CD8/NOS2/COX2 landscape, how it shapes the tumor immune microenvironment and the selection of aggressive tumor phenotypes in distinct regions that lead to poor clinical outcomes. This technique could be beneficial for describing tumor niches with increased aggressiveness that may respond to clinically available NOS2/COX2 inhibitors or immune-modulatory agents.

Spatial analysis of NOS2 and COX2 interaction with T-effector cells reveals immunosuppressive landscapes associated with poor outcome in ER- breast cancer patients

Multiple immunosuppressive mechanisms exist in the tumor microenvironment that drive poor outcomes and decrease treatment efficacy. The co-expression of NOS2 and COX2 is a strong predictor of poor prognosis in ER- breast cancer and other malignancies. Together, they generate pro-oncogenic signals that drive metastasis, drug resistance, cancer stemness, and immune suppression. Using an ER- breast cancer patient cohort, we found that the spatial expression patterns of NOS2 and COX2 with CD3+CD8+PD1- T effector (Teff) cells formed a tumor immune landscape that correlated with poor outcome. NOS2 was primarily associated with the tumor-immune interface, whereas COX2 was associated with immune desert regions of the tumor lacking Teff cells. A higher ratio of NOS2 or COX2 to Teff was highly correlated with poor outcomes. Spatial analysis revealed that regional clustering of NOS2 and COX2 was associated with stromal-restricted Teff, while only COX2 was predominant in immune deserts. Examination of other immunosuppressive elements, such as PDL1/PD1, Treg, B7H4, and IDO1, revealed that PDL1/PD1, Treg, and IDO1 were primarily associated with restricted Teff, whereas B7H4 and COX2 were found in tumor immune deserts. Regardless of the survival outcome, other leukocytes, such as CD4 T cells and macrophages, were primarily in stromal lymphoid aggregates. Finally, in a 4T1 model, COX2 inhibition led to a massive cell infiltration, thus validating the hypothesis that COX2 is an essential component of the Teff exclusion process and, thus, tumor evasion. Our study indicates that NOS2/COX2 expression plays a central role in tumor immunosuppression. Our findings indicate that new strategies combining clinically available NOS2/COX2 inhibitors with various forms of immune therapy may open a new avenue for the treatment of aggressive ER-breast cancers.

A Deep Learning Decision Support Tool to Improve Risk Stratification and Reduce Unnecessary Biopsies in BI-RADS 4 Mammograms

Purpose

To evaluate the performance of a biopsy decision support algorithmic model, the intelligent-augmented breast cancer risk calculator (iBRISK), on a multicenter patient dataset.

Materials and Methods

iBRISK was previously developed by applying deep learning to clinical risk factors and mammographic descriptors from 9700 patient records at the primary institution and validated using another 1078 patients. All patients were seen from March 2006 to December 2016. In this multicenter study, iBRISK was further assessed on an independent, retrospective dataset (January 2015-June 2019) from three major health care institutions in Texas, with Breast Imaging Reporting and Data System (BI-RADS) category 4 lesions. Data were dichotomized and trichotomized to measure precision in risk stratification and probability of malignancy (POM) estimation. iBRISK score was also evaluated as a continuous predictor of malignancy, and cost savings analysis was performed.

Results

The iBRISK model's accuracy was 89.5%, area under the receiver operating characteristic curve (AUC) was 0.93 (95% CI: 0.92, 0.95), sensitivity was 100%, and specificity was 81%. A total of 4209 women (median age, 56 years [IQR, 45-65 years]) were included in the multicenter dataset. Only two of 1228 patients (0.16%) in the "low" POM group had malignant lesions, while in the "high" POM group, the malignancy rate was 85.9%. iBRISK score as a continuous predictor of malignancy yielded an AUC of 0.97 (95% CI: 0.97, 0.98). Estimated potential cost savings were more than $420 million.

Conclusion

iBRISK demonstrated high sensitivity in the malignancy prediction of BI-RADS 4 lesions. iBRISK may safely obviate biopsies in up to 50% of patients in low or moderate POM groups and reduce biopsy-associated costs.Keywords: Mammography, Breast, Oncology, Biopsy/Needle Aspiration, Radiomics, Precision Mammography, AI-augmented Biopsy Decision Support Tool, Breast Cancer Risk Calculator, BI-RADS 4 Mammography Risk Stratification, Overbiopsy Reduction, Probability of Malignancy (POM) Assessment, Biopsy-based Positive Predictive Value (PPV3) Supplemental material is available for this article. Published under a CC BY 4.0 license.See also the commentary by McDonald and Conant in this issue.

Targeting Nitric Oxide: Say NO to Metastasis

Utilizing targeted therapies capable of reducing cancer metastasis, targeting chemoresistant and self-renewing cancer stem cells, and augmenting the efficacy of systemic chemo/radiotherapies is vital to minimize cancer-associated mortality. Targeting nitric oxide synthase (NOS), a protein within the tumor microenvironment, has gained interest as a promising therapeutic strategy to reduce metastatic capacity and augment the efficacy of chemo/radiotherapies in various solid malignancies. Our review highlights the influence of nitric oxide (NO) in tumor progression and cancer metastasis, as well as promising preclinical studies that evaluated NOS inhibitors as anticancer therapies. Lastly, we highlight the prospects and outstanding challenges of using NOS inhibitors in the clinical setting.

Interferon-gamma is quintessential for NOS2 and COX2 expression in ER- breast tumors that lead to poor outcome

A strong correlation between NOS2 and COX2 tumor expression and poor clinical outcomes in ER breast cancer has been established. However, the mechanisms of tumor induction of these enzymes are unclear. Analysis of The Cancer Genome Atlas (TCGA) revealed correlations between NOS2 and COX2 expression and Th1 cytokines. Herein, single-cell RNAseq analysis of TNBC cells shows potent NOS2 and COX2 induction by IFNγ combined with IL1β or TNFα. Given that IFNγ is secreted by cytolytic lymphocytes, which improve clinical outcomes, this role of IFNγ presents a dichotomy. To explore this conundrum, tumor NOS2, COX2, and CD8⁺ T cells were spatially analyzed in aggressive ER-, TNBC, and HER2 + breast tumors. High expression and clustering of NOS2-expressing tumor cells occurred at the tumor/stroma interface in the presence of stroma-restricted CD8⁺ T cells. High expression and clustering of COX2-expressing tumor cells extended into immune desert regions in the tumor core where CD8⁺ T cell penetration was limited or absent. Moreover, high NOS2-expressing tumor cells were proximal to areas with increased satellitosis, suggestive of cell clusters with a higher metastatic potential. Further in vitro experiments revealed that IFNγ + IL1β/TNFα increased the elongation and migration of treated tumor cells. This spatial analysis of the tumor microenvironment provides important insight into distinct neighborhoods where stroma-restricted CD8⁺ T cells exist proximal to NOS2-expressing tumor niches that could have increased metastatic potential.

Interferon-gamma is Quintessential for NOS2 and COX2 Expression in ER - Breast Tumors that Lead to Poor Outcome

A strong correlation between NOS2 and COX2 tumor expression and poor clinical outcomes in ER-breast cancer has been established. However, mechanisms of tumor induction of these enzymes are unclear. Analysis of The Cancer Genome Atlas (TCGA) revealed correlations between NOS2 and COX2 expression and Th1 cytokines. Herein, single cell RNAseq analysis of TNBC cells shows potent NOS2 and COX2 induction by IFNγ combined with IL1β or TNFα. Given that IFNγ is secreted by cytolytic lymphocytes, which improve clinical outcomes, this role of IFNγpresents a dichotomy. To explore this conundrum, tumor NOS2, COX2, and CD8 ⁺ T cells were spatially analyzed in aggressive ER-, TNBC, and HER2+ breast tumors. High expression and clustering of NOS2-expressing tumor cells occurred at the tumor/stroma interface in the presence of stroma-restricted CD8 ⁺ T cells. High expression and clustering of COX2-expressing tumor cells extended into immune desert regions in the tumor core where CD8 ⁺ T cell penetration was limited or absent. Moreover, high NOS2-expressing tumor cells were proximal to areas with increased satellitosis suggestive of cell clusters with a higher metastatic potential. Further in vitro experiments revealed that IFNγ+IL1β/TNFα increased elongation and migration of treated tumor cells. This spatial analysis of the tumor microenvironment provides important insight of distinct neighborhoods where stroma-restricted CD8 ⁺ T cells exist proximal to NOS2-expressing tumor niches that could have increased metastatic potential.

Abstract 2709: Leukosome-based siRNA strategy for targeting ribosomal protein L39 (RPL39) in metaplastic breast cancer

Metaplastic breast cancer (MpBC) is a rare and highly aggressive subset accounting for <5% of all BCs. Clinically, MpBCs exhibit the most dismal prognosis of all BC subtypes, with a median survival rate of 8 months in patients with metastatic disease. The main therapeutic option for MpBC remains standard chemotherapy, despite known resistance to most cytotoxic drugs. We recently reported that ~40% of MpBC patient samples display a gain-of-function oncogenic mutation (A14V) in ribosomal protein RPL39, which is responsible for treatment resistance, cancer stem cell self-renewal, and lung metastases. We also showed that high RPL39 levels were associated with worse survival in patients with MpBC. Collectively, these findings support the rationale of targeting this ubiquitous genetic marker in MpBC. This study was aimed to design an innovative targeted therapy against RPL39 by combining a small interfering RNA (siRNA) strategy (siRPL39) with biomimetic lipid nanoparticle (LNP) technology for in vivo delivery to MpBC cells. These LNPs referred to as “leukosomes” incorporate membrane proteins from circulating leukocytes to facilitate evasion of immune clearance, enhance tropism towards inflamed endothelium such as the tumor-associated one, and improve siRNA internalization into the tumor mass. For leukosomes synthesis, we adapted a microfluidic device to incorporate membrane proteins from leukocytes within lipid bilayers. This technique retained all the physical and biological features of leukosomes, combined with high siRNA loading efficiency. We evaluated in vitro uptake and efficacy of siRPL39-loaded leukosomes in MpBC cell lines. We found that fluorescently labeled siRPL39 was rapidly internalized by leukosomes into MpBC cells demonstrating efficient and uniform uptake without inducing cytotoxicity. Treatment of MpBC cells with siRPL39-loaded leukosomes exhibited significantly knockdown of RPL39 mRNA, further supporting that the observed siRNA internalization results in potent and specific gene silencing. Notably, siRPL39-loaded leukosomes inhibited in vitro cell proliferation as compared with control siRNA leukosomes, indicating a key role of RPL39 in MpBC growth. Next, we sought to evaluate functional gene silencing of siRPL39-loaded leukosomes in vivo. We established MpBC patient-derived xenografts (PDXs) in the mammary fat pad of humanized NSG mice. We revealed that leukosomes formulation enables siRPL39 accumulation and functional gene silencing in MpBC tumors after local administration, without causing overt toxicity. Overall, our findings highlight RPL39 as a novel therapeutic target in MpBC and provide proof of principle for the development of leukosome-based siRNA drugs to improve delivery to cancer cells. Ongoing studies are directed to evaluate biodistribution, in vivo silencing and therapeutic effects of siRPL39-leukosomes after systemic administration.

Citation Format: Maria Florencia Chervo, Chiara Mancino, Federica Giordano, Tejaswini P. Reddy, Wei Qian, Jianying Zhou, Liliana Guzman-Rojas, Roberto R. Rosato, Francesca Taraballi, Jenny C. Chang. Leukosome-based siRNA strategy for targeting ribosomal protein L39 (RPL39) in metaplastic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2709.

Abstract 5698: A multicenter study validated an integrated deep learning model for precision malignancy risk assessment and reducing unnecessary biopsies in BI-RADS 4 cases

Introduction: BI-RADS category 4 is associated with a wide variability in probability of malignancy, ranging from 2 to 95% while biopsy-derived positive predictive value (PPV3) for this category’s lesions remains low at 21.1% in the US. A major fallout of these facts is that we have way very high false positive rate leading to too many unnecessary biopsies and their associated costs and emotional burden. We improved our in-house intelligent-augmented Breast cancer RISK calculator (iBRISK), an integrated deep learning (DL) based decision support app and assessed its performance in a multicenter IRB-approved study.

Methods: We improved iBRISK by retraining the DL model with an expanded dataset of 9,700 patient records of clinical risk-factors and mammographic descriptors from Houston Methodist Hospital (HMH) and validated using another 1,078 patient records. These patients were all seen between March 2006 and December 2016. We assessed the model using blinded, independent retrospective BI-RADS 4 patients who had biopsies subsequently after mammography and seen January 2015 - June 2019 at three major healthcare institutions in Texas, USA: MD Anderson Cancer Center, the University of Texas Health Sciences Center at San Antonio, and HMH. We dichotomized and trichotomized the data to evaluate precision of risk stratification and probability of malignancy (POM) estimation translated into biopsy decision augmentation. The iBRISK score as a continuous predictor of malignancy and possible cost savings was also analyzed.

Results: The multicenter validation dataset had 4,209 women, median age (interquartile) was 56 (45, 65) years. The use of iBRISK score as a continuous predictor of malignancy yielded an AUC of 0.97. Among “low” and “moderate” POM patients, only two out of 1,228 patients (0.16%) and 118 out of 1788 (6.6%) were malignant respectively. This translates to an even better precision when compared to newly introduced BI-RADS 4 subcategories 4A and 4B, with associated PPV3s of 7.6% and 22%, respectively. The “high” POM group had a malignancy rate of 85.9% (1,025/1,193). Estimated potential cost savings in the US was over $260 million.

Conclusion: The iBRISK app demonstrated high sensitivity in malignancy prediction and can potentially be used to safely obviate biopsies in up to 50% of patients in low/moderate POM-groups. This would result in significant healthcare quality improvement, cost savings, and help reduce patient anxiety.

Citation Format: Chika F. Ezeana, Tiancheng He, Tejal A. Patel, Virginia Kaklamani, Maryam Elmi, Erica Ibarra, Pamela M. Otto, Kenneth A. Kist, Heather Speck, Lin Wang, Joe Ensor, Ya-Chen T. Shih, Bumyang Kim, I-Wen Pan, David Spak, Wei T. Yang, Jenny C. Chang, Stephen T. Wong. A multicenter study validated an integrated deep learning model for precision malignancy risk assessment and reducing unnecessary biopsies in BI-RADS 4 cases. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5698.

A Phase 2 Trial of Enhancing Immune Checkpoint Blockade by Stereotactic Radiation and In Situ Virus Gene Therapy in Metastatic Triple-Negative Breast Cancer

PURPOSE

A Phase 2 trial of stereotactic radiotherapy and in situ cytotoxic virus therapy in patients with metastatic triple-negative breast cancer (mTNBC) followed by pembrolizumab (STOMP) was designed to evaluate dual approach of enhancing single-agent immune checkpoint blockade with adenovirus-mediated expression of herpes-simplex-virus thymidine-kinase (ADV/HSV-tk) plus valacyclovir gene therapy and stereotactic body radiotherapy (SBRT) in patients with mTNBC.

PATIENTS AND METHODS

In this single-arm, open-label Phase 2 trial, patients with mTNBC were treated with ADV/HSV-tk [5 × 1011 virus particles (vp)] intratumoral injection, followed by SBRT to the injected tumor site, then pembrolizumab (200 mg, every 3 weeks). The primary endpoint was clinical benefit rate [CBR; complete response (CR), partial response (PR), or stable disease (SD) ≥ 24 weeks per RECIST version1.1 at non-irradiated site]. Secondary endpoints included duration on treatment (DoT), overall survival (OS), and safety. Exploratory endpoints included immune response to treatment assessed by correlative tissue and blood-based biomarkers.

RESULTS

Twenty-eight patients were enrolled and treated. CBR was seen in 6 patients (21.4%), including 2 CR (7.1%), 1 PR (3.6%), and 3 SD (10.7%). Patients with clinical benefit had durable responses, with median DoT of 9.6 months and OS of 14.7 months. The median OS was 6.6 months in the total population. The combination was well tolerated. Correlative studies with Cytometry by Time of Flight (CyTOF) and imaging mass cytometry (IMC) revealed a significant increase of CD8 T cells in responders and of myeloid cells in non-responders.

CONCLUSIONS

The median OS increased by more than 2-fold in patients with clinical benefit. The therapy is a well-tolerated treatment in heavily pretreated patients with mTNBC. Early detection of increased effector and effector memory CD8 T cells and myeloids correlate with response and non-response, respectively.

Vitamin E Enhances Cancer Immunotherapy by Reinvigorating Dendritic Cells via Targeting Checkpoint SHP1

Despite the popular use of dietary supplements during conventional cancer treatments, their impacts on the efficacies of prevalent immunotherapies, including immune-checkpoint therapy (ICT), are unknown. Surprisingly, our analyses of electronic health records revealed that ICT-treated patients with cancer who took vitamin E (VitE) had significantly improved survival. In mouse models, VitE increased ICT antitumor efficacy, which depended on dendritic cells (DC). VitE entered DCs via the SCARB1 receptor and restored tumor-associated DC functionality by directly binding to and inhibiting protein tyrosine phosphatase SHP1, a DC-intrinsic checkpoint. SHP1 inhibition, genetically or by VitE treatment, enhanced tumor antigen cross-presentation by DCs and DC-derived extracellular vesicles (DC-EV), triggering systemic antigen-specific T-cell antitumor immunity. Combining VitE with DC-recruiting cancer vaccines or immunogenic chemotherapies greatly boosted ICT efficacy in animals. Therefore, combining VitE supplement or SHP1-inhibited DCs/DC-EVs with DC-enrichment therapies could substantially augment T-cell antitumor immunity and enhance the efficacy of cancer immunotherapies.

SIGNIFICANCE

The impacts of nutritional supplements on responses to immunotherapies remain unexplored. Our study revealed that dietary vitamin E binds to and inhibits DC checkpoint SHP1 to increase antigen presentation, prime antitumor T-cell immunity, and enhance immunotherapy efficacy. VitE-treated or SHP1-silenced DCs/DC-EVs could be developed as potent immunotherapies. This article is highlighted in the In This Issue feature, p. 1599.

Abstract 2658: NOS inhibition augments PI3K inhibitor-induced DNA damage and mesenchymal-to-epithelial transition in metaplastic breast cancer

Purpose: Metaplastic breast cancer (MpBC) is a highly chemoresistant and aggressive breast cancer variant with limited therapeutic options. Most MpBCs harbor a triple-negative breast cancer (TNBC) phenotype, yet have a worse prognosis compared to TNBC. We and others discovered two key molecular alterations in MpBC associated with poor overall survival: 1) hyperactivation of the phosphoinositide 3-kinase (PI3K) signaling pathway and 2) enhanced inducible nitric oxide synthase (iNOS) signaling. Nitric oxide produced from iNOS is able to activate various oncogenic pathways, such as PI3K signaling. In MpBC, both PI3K and NOS signaling pathways may synergistically work to enhance chemoresistance. We propose to evaluate whether pan-NOS inhibitor NG-monomethyl-l-arginine (L-NMMA) augments the efficacy of alpha isoform-specific PI3K inhibitor alpelisib in MpBC in vitro and in vivo models.

Methods: MpBC cell lines (Hs578T, BT549, SUM159) and MpBC Patient-Derived Xenograft (PDX) models were used in this study. Cell viability was determined with SRB Assay and the combination index was evaluated using Chou-Talalay Method. Flow cytometry was conducted to evaluate cellular apoptosis and cell cycle distribution analysis. In vivo efficacy of NOS and PI3K inhibition was assessed using MpBC PDX models. Transcriptional analysis of PDX tumors treated with vehicle control, single-agent (L-NMMA or alpelisib), or combination therapy (L-NMMA+alpelisib) was conducted to reveal top enriched pathways. Immunoblotting and immunofluorescence analyses of treated MpBC cell lines and PDX tissues were performed.

Results: Combination of L-NMMA and alpelisib synergistically reduced cellular proliferation (CI<1), enhanced apoptosis, depleted nucleotide pools, and arrested MpBC cell lines in G2/M phase of cell cycle relative to single-agent treatment. Furthermore, NOS+PI3K inhibition significantly suppressed tumor volume in MpBC PDX models with PIK3CA mutations, although less significantly in MpBC PIK3CA-wild type PDX models, augmented efficacy of taxane chemotherapy, and improved overall survival. Transcriptional analysis of MpBC PDX tumors treated with combination therapy versus vehicle control revealed that epithelial-to-mesenchymal transition, DNA repair, and E2F targets were among the top enriched pathways, suggesting their plausible involvement in the mechanism of response. Immunoblotting/immunofluorescence analyses of cell lines/PDX models confirmed that combination therapy enhances DNA damage, reduces expression of homologous recombination-mediated DNA repair proteins, and induces mesenchymal-to-epithelial transition, rendering MpBC cells potentially more chemosensitive.

Conclusion: Combined NOS and PI3K inhibition is a novel therapeutic strategy that may improve the efficacy of chemotherapy in patients with MpBC.

Citation Format: Tejaswini P. Reddy, Akshjot Puri, Liliana Guzman-Rojas, Bijan Mahboubi, Wei Qian, Jianying Zhou, Baek Kim, Stacy Moulder, Helen Piwnica-Worms, Roberto Rosato, Jenny C. Chang. NOS inhibition augments PI3K inhibitor-induced DNA damage and mesenchymal-to-epithelial transition in metaplastic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2658.

Clinical factors and association with treatment modalities in patients with breast cancer and brain metastases who develop leptomeningeal metastases

PURPOSE

Leptomeningeal metastases (LM) are an aggressive complication of metastatic breast cancer (MBC) with brain metastases (BM), with a short survival of weeks to months. Studies suggest that surgical resection of BM may increase the risk of LM, especially in infratentorial metastases. In this retrospective study, we examine this and other factors which may be associated with increased risk of LM.

METHODS

A database search at a single institution identified 178 patients with MBC and treated BM between 2007 and 2020. We collected demographic, clinical, radiographic, and other treatment data. LM was diagnosed by cerebrospinal fluid (CSF) cytology, neuroimaging, or both. Cox proportional hazards model was used.

RESULTS

After a median follow-up of 8.5 months, 41 out of 178 patients (23%) with BM developed LM. Median time to develop LM was 130 days. Mean age was 51.3 years. The number and size of the BM, hemorrhagic/cystic lesions, progressive/stable systemic disease, and extracranial metastases sites other than liver did not pose a higher risk of LM. Infratentorial lesions (HR = 5.41) and liver metastases (HR = 2.28) had a higher risk of LM. Patients who had any surgery did not have a higher risk for LM (HR 1.13). The LM group had a worse overall survival as compared to the non-LM group.

CONCLUSION

Among MBC patients with BM, infratentorial BM and visceral liver lesions increase the risk of LM, whereas local treatment modalities such as surgery and radiation do not. These data imply that local treatment strategy should not differ based on potential risk for LM.

Utilization of Immunotherapy for the Treatment of Hepatocellular Carcinoma in the Peri-Transplant Setting: Transplant Oncology View

Simple Summary

Hepatocellular carcinoma is the second most common cause of cancer-related deaths and accounts for over eighty percent of primary liver cancers worldwide. Regarding the Milan Criteria, only a small portion of HCC patients are eligible for liver transplantation due to advanced-stage disease and large tumor size preventing/delaying organ allocation. Recently, the use of anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-1 and PD-L1) checkpoint inhibitors in the treatment of cancers have evolved rapidly and these therapies have been approved for the treatment of HCC, however, the main concerns about organ rejection in liver transplant patients who will be treated with ICPIs are still the same in both pre-and post-transplant setting. To alleviate those concerns, more global collaborations to explore the safety and efficacy of ICPIs in both the pre-and post-organ transplantation settings are required. The decision to administer ICPI treatment in liver transplant patients should be made on a case-by-case basis according to the goal of care and the availability and efficacy of other treatment options.

Abstract

Hepatocellular carcinoma (HCC) represents the second most common cause of cancer-related deaths and accounts for over eighty percent of primary liver cancers worldwide. Surgical resection and radiofrequency ablation in small tumors are included in the treatment options for HCC patients with good liver function profiles. According to the Milan Criteria, only a small portion of HCC patients are eligible for liver transplantation due to advanced-stage disease and large tumor size preventing/delaying organ allocation. Recently, the use of anti-programmed cell death protein 1 and programmed cell death ligand 1 (PD-1 and PD-L1) checkpoint inhibitors in the treatment of cancers have evolved rapidly and these therapies have been approved for the treatment of HCC. Immune checkpoint inhibitors have resulted in good clinical outcomes in pre-and post-transplant HCC patients, although, some reports showed that certain recipients may face rejection and graft loss. In this review, we aim to illustrate and summarize the utilization of immune checkpoint inhibitor therapies in pre-and post-liver transplants for HCC patients and discuss the assessment of immune checkpoint inhibitor regulators that might determine liver transplant outcomes.

Abstract P5-17-04: Combined PI3K and NOS inhibition enhances efficacy of taxane-based chemotherapy in metaplastic breast cancer

Background: Metaplastic breast cancer (MpBC) is a therapeutically chemoresistant, aggressive, and heterogeneous breast cancer variant accounting for <5% of all breast cancers. Most MpBCs harbor a triple-negative breast cancer (TNBC) phenotype, yet have a worse prognosis and decreased survival compared to TNBC. Despite its chemorefractory nature, the current mainstay of treatment for MpBC is surgery and systemic chemotherapy. Common molecular alterations found in MpBC associated with poor prognosis and worse overall survival include 1) hyperactivation of the phosphoinositide 3-kinase (PI3K) signaling pathway and 2) enhanced production of nitric oxide via inducible nitric oxide synthase (iNOS). In MpBC, both the PI3K and NOS signaling pathways may synergistically work together to enhance chemoresistance. We propose that combined inhibition of PI3K and iNOS will enhance the efficacy of taxane-based chemotherapy in MpBC. Methods: For in vitro and in vivo studies, we used MpBC cell lines (Hs578T and BT549) and TNBC/MpBC Patient-Derived Xenograft (PDX) models, respectively. For all studies, we used pan-NOS inhibitor NG-monomethyl-l-arginine (L-NMMA, L), PI3K inhibitor alpelisib (A), and docetaxel (D). Immunohistochemistry (IHC), Western Blotting (WB), Cell Proliferation Assays, Flow Cytometry (to evaluate cell death and cell cycle distribution analysis), and HIV reverse transcriptase-based dNTP assay to quantify dNTPs were performed. For in vivo studies, five MpBC PDX models were implanted into the mammary fat pad of NSG mice and they received single therapy (vehicle control, L, A, D), dual therapy (D+A, D+L), or triple combination therapy (D+A+L). Tumor volumes were recorded twice weekly. Results: 66% (4/6) MpBC and 33% (7/21) TNBC PDX models had double-positive IHC staining of both iNOS and p-Akt (Ser473), supporting the concept that both signaling pathways are typically activated in MpBC tumors, relative to non-metaplastic TNBC tumors. Apoptosis and cell proliferation analysis found that MpBC cell lines treated with triple-combination (D+A+L) had an increased number of apoptotic cells and decreased cell proliferation relative to MpBC cells treated with dual combination (L+A), or single treatment (vehicle, D, A, or L). Cell cycle distribution analysis of treated MpBC cells found that in a time-dependent manner, there was a substantial decrease in the % of MpBC cells in S-phase and an increase in the % cells in G2/M cell cycle arrest due to dual and triple combination. This result was supported by dNTP quantification analysis revealing that combined PI3K and NOS inhibition induced greater nucleotide depletion within 8 hours of treatment relative to single treatment in MpBC cells. WB analysis revealed that dual/triple combination therapy in MpBC cells resulted in an enhanced DNA damage response signaling relative to single treatment, as indicated with increased expression of γ-H2AX, p-Chk1, p-Chk2, p-P53 (Ser15 and 20), and p21. Pro-survival PI3K signaling pathway was activated in response to docetaxel treatment alone in MpBC cells, but its activation was significantly reduced when docetaxel was coupled with PI3K and NOS inhibition. In vivo studies revealed that triple combination therapy significantly reduced tumor volume and improved survival proportions compared to dual/single therapy and vehicle control. Conclusions: The present data suggest that combined PI3K and NOS inhibition enhances docetaxel-mediated DNA damage by depleting nucleotide pools, leading to enhanced DNA damage response, growth arrest, and apoptosis. Ongoing studies are investigating how docetaxel coupled with PI3K and NOS inhibition influences DNA repair signaling and MpBC metastatic capacity. The addition of PI3K and NOS inhibitors to taxane-based chemotherapy may be a novel therapeutic strategy for aggressive MpBCs.

Citation Format: Tejaswini P Reddy, Bijan Mahboubi, Roberto R. Rosato, Liliana Guzman-Rojas, Wei Qian, Jianying Zhou, Baek Kim, Stacy Moulder, Helen Piwnica-Worms, Jenny C. Chang. Combined PI3K and NOS inhibition enhances efficacy of taxane-based chemotherapy in metaplastic breast cancer [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 P5-17-04.

Abstract PD3-01: Inducible nitric oxide synthase activates PI3K/Akt signaling via PTEN S-nitrosylation in triple-negative breast cancer

Our previous findings have shown that increased inducible nitric oxide synthase (iNOS) expression is a poor prognostic indicator and associated with worse overall survival in TNBC patients. Growing evidence has also suggested that hyperactivation of the phosphoinositide-3-kinase (PI3K) survival signaling pathway is one of the most common oncogenic aberrations in TNBC. Nitric oxide (NO) is a unique molecule in its ability to target multiple oncogenic pathways in a spatial and temporal manner, such as PI3K, extracellular signal-regulated kinase (ERK), β-catenin pathway, transforming growth factor beta (TGFβ) signaling, and hypoxia-inducible factor (HIF). This study investigates the role of NO in PI3K-Akt pathway activation in human TNBC cells, in conditions with extracellular NO donor exposure and increased intracellular iNOS (NOS2) expression. TNBC cell lines BT549, HCC1937, Hs578T, SUM159, MDA-MB-231, and BT-20 were exposed to the NO donor DETA NONOate at increasing concentrations (0-500 µM) for 12 hours. Significant elevation in phosphorylation of Akt (Ser473 and Thr308) in response to increase NO donor concentration was found only in cell lines with wild-type PTEN and PIK3R1, such as SUM159, MDA-MB-231, and BT20. To evaluate whether NO-induced activation of Akt was PI3K-dependent, SUM159 (wild-type PTEN) and HCC1937 (PTEN mutant) cells were also pre-treated with PI3K inhibitor alpelisib before NO exposure. PI3K inhibition was only able to eliminate basal phospho-Akt and prevent NO-induced Akt activation in the SUM159 cell line. Furthermore, compared to vehicle control treated cells, we found that NO donor-induced activation enhanced phosphorylation in 15/18 Akt signaling proteins in SUM159 cells (PTEN intact) and 3/18 Akt signaling proteins in HCC1937 cells (PTEN loss). In Hs578T cells in which NOS2 was either overexpressed or knocked down via lentiviral transduction, we found that enhanced expression of NOS2 was associated with increased p-Akt expression and knock-down of NOS2 led to reduced p-Akt. This result suggests that iNOS, as opposed to other NOS isoforms, is more associated with modulating PI3K signaling in TNBC.We also analyzed TNBC data from The Cancer Genome Atlas and found that patients with positive iNOS mRNA expression had significantly higher phospho-Akt (Ser473 and Thr308) [p≤0.0001] expression compared to patients with no iNOS expression. When we stratified this patient cohort based on both iNOS and PTEN expression, we only found significantly higher phospho-Akt (Ser473 and Thr308) [p≤0.01] expression in patients with positive iNOS and PTEN expression, supporting the hypothesis that NO may impair PTEN’s function as a PI3K antagonist. Ongoing studies are directed to investigate mechanisms of iNOS-PTEN physical interactions, iNOS-dependent post-translational modifications to PTEN, and whether iNOS and PTEN are dual prognostic markers in TNBC patients.

Citation Format: Tejaswini P. Reddy, Liliana Guzman-Rojas, Roberto R. Rosato, Wei Qian, Hong Zhao, Jenny C. Chang. Inducible nitric oxide synthase activates PI3K/Akt signaling via PTEN S-nitrosylation in triple-negative breast cancer [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 PD3-01.

Abstract P5-17-07: Phase 1B/2 clinical trial targeting nitric oxide in the treatment of chemo-refractory metaplastic triple-negative breast cancer patients

BACKGROUND Metaplastic breast cancer (MpBC) is an extremely rare, therapeutically recalcitrant and aggressive variant of triple negative breast cancer (TNBC). We have previously shown molecular alterations in inducible nitric oxide (iNOS) signaling in MpBC is associated with worse overall survival. Preclinical models have shown pan-NOS inhibitor NG-monomethyl-L-arginine (L-NMMA) reduces tumor growth and epithelial to mesenchymal transition in mesenchymal cell lines. We have also previously shown in TNBC patients treated with LNMMA and docetaxel, the non-responders have a higher expression of M2 macrophage vs the responders have decreased pro-tumor N2 neutrophils at the end of therapy. Here, we report the results of L-NMMA plus taxane in a cohort of MpBC patients. METHODS We conducted a phase 1B/2 trial, with L-NMMA (starting dose of 7.5 mg/kg which was escalated to recommended phase 2 dose of 20 mg/kg) and docetaxel (100 mg/m2) every 3 weeks. Daily amlodipine was given to prevent hypertension from L-NMMA. Primary objective was to assess clinical benefit rate (CBR), as assessed by the Response Evaluation Criteria in solid tumors (RECIST). Secondary objectives were to study overall response rate (ORR), progression free survival (PFS), overall survival (OS), dose limiting toxicities (DLT), response correlation with type of MpBC, body mass index (BMI) and ethnicity. Exploratory analysis included immune correlates for clinical response; staining for iNOS, M2 macrophages (CD 68, CD 163), N2 neutrophils (CD 15, arginase), immune infiltration (PD-L1, CD 8) and fibrosis marker (α- SMA). Fisher’s exact test was used to find the association between different patient’s characteristics and the main outcome. A p-value of 0.05 was considered statistically significant and all analyses were conducted using Stata V16.1 (StataCorp, College Station, Texas 77845 USA) RESULTS Of the total 35 TNBC patients recruited, 15 patients had MpBC (Phase 1B, n= 4; Phase 2, n=11); 86.6% (13/15) patients had metastatic breast cancer (MBC), with a median of 2 prior lines of therapy (range 0-5) and 13.3% (2/15) had anthracycline-refractory locally advanced breast cancer (LABC). The CBR was 40% (6/15); the ORR was 20% (3/15) with 1 PR in MBC , 1 pathological CR and 1 PR in LABC. Grade 3 or more toxicity was seen in 13.3% (2/15) patients; however, none was attributed to L-NMMA. The mPFS and mOS for MBC patients were 4.5 months (range 3-7m) and 12.8 months, respectively. The response was more likely to be in women of Caucasian ethnicity, BMI> 25 and non-spindle pathological features such as squamous differentiation, keratinized and myxo-chondroid tumors; albeit these were not statistically significant (Table 1). CONCLUSIONS Inhibition of iNOS pathway in MpBC is a promising and novel therapeutic option in this very challenging breast cancer subtype. The small study size is an impediment in identifying clinical factors which can predict a response. This warrants further evaluation of treatment with L-NMMA in chemo-refractory MpBC patients in a larger clinical trial.

Table 1.Association between ethnicity, BMI and pathological characteristics with responseTotalNo responderResponderp-valueN=13N=7N=6Ethnicity0.19Caucasian10 (76.92%)4 (57.14%)6 (100.00%)Other3 (23.08%)3 (42.86%)0 (0.00%)Obesity1.00<25 BMI3 (23.08%)2 (28.57%)1 (16.67%)>=25 BMI10 (76.92%)5 (71.43%)5 (83.33%)Pathological features0.27Spindle5 (38.46%)4 (57.14%)1 (16.67%)Other8 (61.54%)3 (42.86%)5 (83.33%)Data are presented as n (%). *P-value from Fisher’s exact test. The 2 patients with adverse events were excluded from the analysis.

Citation Format: Akshjot Puri, Adriana Ordonez, Ann C. Anselme, Liliana Guzman, Polly Niravath, Jenny C. Chang. Phase 1B/2 clinical trial targeting nitric oxide in the treatment of chemo-refractory metaplastic triple-negative breast cancer patients [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 P5-17-07.

Utility of Cell-Free DNA Detection in Transplant Oncology

Simple Summary

Transplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-liver transplant stages, and evaluate transplant rejection. The use of ctDNA to evaluate transplant rejection has been extensively studied in non-hepatocellular carcinoma (HCC) diseases. Emerging studies have also investigated the use of ctDNA detection in evaluating HCC tumor burden pre-and post-surgery as well as transplant rejection. However, extensive studies still need to be conducted to evaluate the role of ctDNA detection in the medical management of transplant oncology patients.

Abstract

Transplant oncology is an emerging field in cancer treatment that applies transplant medicine, surgery, and oncology to improve cancer patient survival and quality of life. A critical concept that must be addressed to ensure the successful application of transplant oncology to patient care is efficient monitoring of tumor burden pre-and post-transplant and transplant rejection. Cell-free DNA (cfDNA) detection has emerged as a vital tool in revolutionizing the management of cancer patients who undergo organ transplantation. The advances in cfDNA technology have provided options to perform a pre-transplant evaluation of minimal residual disease (MRD) and post-transplant evaluation of cancer recurrence and transplant rejection. This review aims to provide a comprehensive overview of the history and emergence of cfDNA technology, its applications to specifically monitor tumor burden at pre-and post-transplant stages, and evaluate transplant rejection.

A targetable LIFR-NF-κB-LCN2 axis controls liver tumorigenesis and vulnerability to ferroptosis

The growing knowledge of ferroptosis has suggested the role and therapeutic potential of ferroptosis in cancer, but has not been translated into effective therapy. Liver cancer, primarily hepatocellular carcinoma (HCC), is highly lethal with limited treatment options. LIFR is frequently downregulated in HCC. Here, by studying hepatocyte-specific and inducible Lifr-knockout mice, we show that loss of Lifr promotes liver tumorigenesis and confers resistance to drug-induced ferroptosis. Mechanistically, loss of LIFR activates NF-κB signaling through SHP1, leading to upregulation of the iron-sequestering cytokine LCN2, which depletes iron and renders insensitivity to ferroptosis inducers. Notably, an LCN2-neutralizing antibody enhances the ferroptosis-inducing and anticancer effects of sorafenib on HCC patient-derived xenograft tumors with low LIFR expression and high LCN2 expression. Thus, anti-LCN2 therapy is a promising way to improve liver cancer treatment by targeting ferroptosis.

A phase 1/2 clinical trial of the nitric oxide synthase inhibitor L-NMMA and taxane for treating chemoresistant triple-negative breast cancer

[Figure: see text].

P-321 The impact of endometrioma and ovarian cystectomy in patients with major indications for IVF/ICSI with endometriosis

Study question

Does presence of endometrioma has worse IVF/ICSI outcome than endometriosis per se? What about the impact of cystectomy of endometrioma on IVF/ICSI outcomes?

Summary answer

IVF/ICSI outcome of patients with endometrioma is comparable than with endometriosis. Cystectomy for endometrioma did not alter IVF/ICSI outcomes if ovarian reserve is comparable.

What is known already

Previous studies revealed women with endometrioma undergoing IVF/ICSI had similar reproductive outcomes compared with those without. Most of the comparisons are between women with endometrioma and women without endometriosis. However, endometrioma per se, different from endometriosis may have specific impact on IVF/ICSI outcomes. There is now molecular, histological and morphological evidence to suggest endometrioma is detrimental to the ovaries. Studies comparing IVF/ICSI outcomes between women with endometrioma and women with endometriosis are few.

Cystectomy of endometrioma may worse ovarian reserve, and subsequently adversely affect IVF/ICSI outcomes. But there are possible complications associated with the persistence of endometrioma during IVF/ICSI.

Study design, size, duration

Retrospective analysis of 2153 IVF/ICSI cases during Jan/01/2014 to Dec/31/2018 in VGHTC. We included women who received ART due to endometriosis(n = 208). Exclusion criteria including patients >40 years-old, simulation day < 5 days, severe male factor, uterine factor (including adenomyosis) and immunological factors. Patients whose embryos were not completely transferred back or who received embryo transfer from different OPU cycles are excluded. We followed up these patients till 2020/6. The primary outcome is cumulative LBR

Participants/materials, setting, methods

For first analysis, we divided 208 cases to patients with endometrioma during IVF/ICSI(n = 89), and patients only diagnosed of endometriosis (n = 119). Second analysis on the effect of cystectomy of endometrioma on IVF/ICSI outcomes. Patients with endometrioma (n = 89) during IVF/ICSI were further divided to patients with primary endometrioma (n = 70) and patients with recurrent endometrioma (n = 19, ever received cystectomy for endometrioma). Another group is patients without endometrioma during IVF/ICSI, but ever received cystectomy before (n = 40)

Main results and the role of chance

For the first analysis, age, BMI and AMH were comparable in endometrioma (n = 89) and endometriosis group(n = 119). The usage gonadotropin dose was significantly higher in the endometrioma group (FSH 3619IU vs 3471IU, p = 0.001. LH 1224 IU vs 941 IU, p = 0.009). The Blastocyst formation rate is lower in the endometrioma group (49.4% vs. 57.7% p = 0.005). The OPU number, LBR and cumulative LBR were comparable in both groups (10.3 vs 12.4 p = 0.131, 33.3% vs 37%, p = 0.687, 49.4% vs 60.5%, endometrioma vs endometriosis). For the second analysis, when comparing cystectomy before IVF/ICSI group with primary endometrioma group, cystectomy group were younger (32.8 vs 34.8 p = 0.006). AMH level were comparable. The BC formation rate was significantly higher in the cystectomy group (61.5% vs 50.4% 0= 0.007). The LBR and cumulative LBR were comparable in both groups (43.5% vs 28.1%, 60% vs 48% in cystectomy vs primary endometrioma group). As for the recurrent endometrioma group, the age and AMH level were comparable with cystectomy group, but the usage gonadotropin dose was significantly higher than other two groups. The BC formation rate was also lower than cystectomy group (47.8% vs 61.5% p = 0.042). The LBR and cumulative LBR were comparable with other two groups (55.6%, 57.9%).

Limitations, reasons for caution

This is a retrospective study, and the sample size is limit. We did not analysis the size of endometrioma nor the unilateral or bilateral endometrioma.

Wider implications of the findings

Cystectomy for endometrioma must be carefully selected since it did not alter IVF/ICSI outcome only if the ovarian reserve is not affected. Recurrent endometriomas do not have a worse impact on IVF/ICSI outcome than primary endometrioma. If there is recurrent endometrioma, IVF/ICSI may be the first priority.

Trial registration number

not applicable

P–321 The impact of endometrioma and ovarian cystectomy in patients with major indications for IVF/ICSI with endometriosis

Study question

Does presence of endometrioma has worse IVF/ICSI outcome than endometriosis per se? What about the impact of cystectomy of endometrioma on IVF/ICSI outcomes?

Summary answer

IVF/ICSI outcome of patients with endometrioma is comparable than with endometriosis. Cystectomy for endometrioma did not alter IVF/ICSI outcomes if ovarian reserve is comparable.

What is known already

Previous studies revealed women with endometrioma undergoing IVF/ICSI had similar reproductive outcomes compared with those without. Most of the comparisons are between women with endometrioma and women without endometriosis. However, endometrioma per se, different from endometriosis may have specific impact on IVF/ICSI outcomes. There is now molecular, histological and morphological evidence to suggest endometrioma is detrimental to the ovaries. Studies comparing IVF/ICSI outcomes between women with endometrioma and women with endometriosis are few.

Cystectomy of endometrioma may worse ovarian reserve, and subsequently adversely affect IVF/ICSI outcomes. But there are possible complications associated with the persistence of endometrioma during IVF/ICSI.

Study design, size, duration

Retrospective analysis of 2153 IVF/ICSI cases during Jan/01/2014 to Dec/31/2018 in VGHTC. We included women who received ART due to endometriosis(n = 208). Exclusion criteria including patients >40 years-old, simulation day < 5 days, severe male factor, uterine factor (including adenomyosis) and immunological factors. Patients whose embryos were not completely transferred back or who received embryo transfer from different OPU cycles are excluded. We followed up these patients till 2020/6. The primary outcome is cumulative LBR

Participants/materials, setting, methods

For first analysis, we divided 208 cases to patients with endometrioma during IVF/ICSI(n = 89), and patients only diagnosed of endometriosis (n = 119). Second analysis on the effect of cystectomy of endometrioma on IVF/ICSI outcomes. Patients with endometrioma (n = 89) during IVF/ICSI were further divided to patients with primary endometrioma (n = 70) and patients with recurrent endometrioma (n = 19, ever received cystectomy for endometrioma). Another group is patients without endometrioma during IVF/ICSI, but ever received cystectomy before (n = 40)

Main results and the role of chance

For the first analysis, age, BMI and AMH were comparable in endometrioma (n = 89) and endometriosis group(n = 119). The usage gonadotropin dose was significantly higher in the endometrioma group (FSH 3619IU vs 3471IU, p = 0.001. LH 1224 IU vs 941 IU, p = 0.009). The Blastocyst formation rate is lower in the endometrioma group (49.4% vs. 57.7% p = 0.005). The OPU number, LBR and cumulative LBR were comparable in both groups (10.3 vs 12.4 p = 0.131, 33.3% vs 37%, p = 0.687, 49.4% vs 60.5%, endometrioma vs endometriosis). For the second analysis, when comparing cystectomy before IVF/ICSI group with primary endometrioma group, cystectomy group were younger (32.8 vs 34.8 p = 0.006). AMH level were comparable. The BC formation rate was significantly higher in the cystectomy group (61.5% vs 50.4% 0= 0.007). The LBR and cumulative LBR were comparable in both groups (43.5% vs 28.1%, 60% vs 48% in cystectomy vs primary endometrioma group). As for the recurrent endometrioma group, the age and AMH level were comparable with cystectomy group, but the usage gonadotropin dose was significantly higher than other two groups. The BC formation rate was also lower than cystectomy group (47.8% vs 61.5% p = 0.042). The LBR and cumulative LBR were comparable with other two groups (55.6%, 57.9%).

Limitations, reasons for caution

This is a retrospective study, and the sample size is limit. We did not analysis the size of endometrioma nor the unilateral or bilateral endometrioma.

Wider implications of the findings: Cystectomy for endometrioma must be carefully selected since it did not alter IVF/ICSI outcome only if the ovarian reserve is not affected. Recurrent endometriomas do not have a worse impact on IVF/ICSI outcome than primary endometrioma. If there is recurrent endometrioma, IVF/ICSI may be the first priority.

Trial registration number

Not applicable

Abstract CT175: Targeting inducible nitric oxide in a first-in-class phase 1/2 trial in triple-negative breast cancer patients diminishes M2 macrophage polarization and led to a robust clinical response

Targeting inducible nitric oxide in a first-in-class phase 1/2 trial in triple-negative breast cancer patients diminishes M2 macrophage polarization and led to a robust clinical response. Andrew W. Chung*, Kartik Anand*, Polly Niravath* (co-first authors), Nakul Gupta, Luz A Venta, Mary R. Schwartz, Wei Qian, Yitian Xu, Licheng Zhang, Qiuying Chen, Nabeel Attarwala, John Kuhn, Tejal Patel, Angel Rodriguez, Anna Belcheva, Jorge Darcourt, Joe Ensor, Eric Bernicker, Ping-Ying Pan, Virginia Kaklamani, Shu Hsia Chen, Jenny C ChangIntroduction:The inducible nitric oxide signaling (iNOS) pathway has been associated with poor prognosis in triple-negative breast cancer (TNBC). Inhibition of iNOS pathway by using the pan-NOS inhibitor NG-monomethyl-L-arginine (L-NMMA) in patient-derived xenograft (PDX) models has shown reduced tumor growth and enhanced survival. Here, we report a first-in-class phase 1/2 trial of L-NMMA plus taxane for patients with chemorefractory locally advanced (LA) TNBC or metastatic TNBC and present findings on molecular immune correlates and metabolites of response/resistance. Methods:Women with chemorefractory LA or metastatic TNBC without uncontrollable hypertension or heart disease, age >18 years, and ECOG performance status ≤2 were eligible. A Bayesian model averaging continuous reassessment method was used to determine the recommended phase 2 L-NMMA dose (RP2D). In phase 1, two dose levels of docetaxel (75 and 100 mg/m2) and seven dose levels of L-NMMA (5,7.5, 10, 15,17.5, and 20 mg/kg) were studied. Patients in phase 2 received a maximum of six (q 3 weeks) cycles of L-NMMA given via IV on D1-D5. All patients also received amlodipine (6 days/cycle) and aspirin daily, as hypertensive and thromboembolic prophylaxis. Toxicity was measured as per CTCAE v4.03. Pharmacokinetics/Pharmacodynamics, 38 circulating cytokines, and 30 differential metabolites were also assayed. Tissue imaging mass cytometry (IMC) with 35 cell surface markers was performed on paired biopsies.

Results: From July 2016 to September 2020, a total of 35 patients were recruited (phase 1, n=15; phase 2, n= 24, including 4 RP2D patients from phase 1). RP2D dose was 20 mg/kg for L-NMMA and 100 mg/m2 for docetaxel. In phase 2, 54.2% had metastatic TNBC (with 5 median prior lines of chemotherapy) and 45.8% had LABC (anthracycline-refractory). Overall response rate (ORR) was 54.2% - 81.8% for LABC and 30.8% for metastatic TNBC. Radiologic complete response (CR) rate was 27.2% for LABC and 7.7% for metastatic TNBC. Among the LABC patients, 2 patients had pathological CR at surgery (18.2%). Grade ≥3 toxicity was noted in 21% of patients, however, none of grade ≥3 toxicity was attributed to L-NMMA. Compared to responder patients, correlative data showed that non-responders had a significant higher expression of biomarkers associated with M2 macrophage polarization including IL-10, adenosine and metabolite profile suggestive of aerobic glycolysis. In alignment, IMC analysis showed significant increase in intra-tumoral M2 macrophages in non-responders end of therapy biopsies.

Conclusion: L-NMMA combination with taxanes was well tolerated with a robust response rate. Further investigation is warranted to test this combination in larger studies along with biomarker evaluation.

Citation Format: Andrew W. Chung, Kartik Anand, Polly Niravath, Nakul Gupta, Luz A. Venta, Mary R. Schwartz, Wei Qian, Yitian Xu, Licheng Zhang, Qiuying Chen, Nabeel Attarwala, John Kuhn, Tejal A. Patel, Angel Rodriguez, Anna Belcheva, Jorge Darcourt, Joe E. Ensor, Eric Bernicker, Ping-Ying Pan, Virginia Kaklamani, Shu-Hsia Chen, Jenny C. Chang. Targeting inducible nitric oxide in a first-in-class phase 1/2 trial in triple-negative breast cancer patients diminishes M2 macrophage polarization and led to a robust clinical response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT175.

A Phase II Study of the Efficacy and Safety of Chloroquine in Combination With Taxanes in the Treatment of Patients With Advanced or Metastatic Anthracycline-refractory Breast Cancer

INTRODUCTION

Chemotherapy eliminates most of the cancer cells except those with potential for self-renewal and tumor initiation, called cancer stem cells (CSCs). Chloroquine, through bioinformatics, was found to be a potential agent to target CSCs. We designed a phase II trial to test the efficacy and safety of chloroquine in combination with taxane or taxane-like chemotherapy agents in patients with advanced or metastatic breast cancer who are refractory to anthracycline-based chemotherapy.

PATIENTS AND METHODS

Female patients ≥ 18 years of age who had received prior anthracycline chemotherapy were enrolled in this study. Chloroquine 250 mg was given daily orally with either docetaxel or paclitaxel or nab-paclitaxel or ixabepilone every 3 weeks. The maximum number of 3-week cycles allowed was 6. The primary efficacy endpoint was the objective response rate (ORR). The secondary efficacy endpoints included progression-free survival (PFS) and safety analysis.

RESULTS

Thirty-eight patients were enrolled in the study, and 31 patients were evaluated for response. The median age was 54.1 years (range, 31.7-78.1 years). The ORR was 45.16% (95% confidence interval [CI], 29.2%-62.2%), which was higher than the expected ORR of 30% (P = .03). Patients were followed for a median of 25.4 months and experienced a median PFS of 12.4 months (95% CI, 4.9-24.6 months) and a median OS of 25.4 months (95% CI, 13.7-83.5 months). The combination was well-tolerated, with only 13.15% of patients experiencing grade ≥ 3 adverse events.

CONCLUSION

A combination of chloroquine with taxane or taxane-like chemotherapy was efficacious in patients with locally advanced or metastatic breast cancer with prior anthracycline-based chemotherapy.

Sacituzumab govitecan, a Trop-2-directed antibody-drug conjugate, for patients with epithelial cancer: final safety and efficacy results from the phase I/II IMMU-132-01 basket trial

BACKGROUND

Sacituzumab govitecan (SG), a trophoblast cell surface antigen-2 (Trop-2)-directed antibody-drug conjugate, has demonstrated antitumor efficacy and acceptable tolerability in a phase I/II multicenter trial (NCT01631552) in patients with advanced epithelial cancers. This report summarizes the safety data from the overall safety population (OSP) and efficacy data, including additional disease cohorts not published previously.

PATIENTS AND METHODS

Patients with refractory metastatic epithelial cancers received intravenous SG (8, 10, 12, or 18 mg/kg) on days 1 and 8 of 21-day cycles until disease progression or unacceptable toxicity. Endpoints for the OSP included safety and pharmacokinetic parameters with investigator-evaluated objective response rate (ORR per RECIST 1.1), duration of response, clinical benefit rate, progression-free survival, and overall survival evaluated for cohorts (n > 10 patients) of small-cell lung, colorectal, esophageal, endometrial, pancreatic ductal adenocarcinoma, and castrate-resistant prostate cancer.

RESULTS

In the OSP (n = 495, median age 61 years, 68% female; UGT1A1∗28 homozygous, n = 46; 9.3%), 41 (8.3%) permanently discontinued treatment due to adverse events (AEs). Most common treatment-related AEs were nausea (62.6%), diarrhea (56.2%), fatigue (48.3%), alopecia (40.4%), and neutropenia (57.8%). Most common treatment-related serious AEs (n = 75; 15.2%) were febrile neutropenia (4.0%) and diarrhea (2.8%). Grade ≥3 neutropenia and febrile neutropenia occurred in 42.4% and 5.3% of patients, respectively. Neutropenia (all grades) was numerically more frequent in UGT1A1∗28 homozygotes (28/46; 60.9%) than heterozygotes (69/180; 38.3%) or UGT1A1∗1 wild type (59/177; 33.3%). There was one treatment-related death due to an AE of aspiration pneumonia. Partial responses were seen in endometrial cancer (4/18, 22.2% ORR) and small-cell lung cancer (11/62, 17.7% ORR), and one castrate-resistant prostate cancer patient had a complete response (n = 1/11; 9.1% ORR).

CONCLUSIONS

SG demonstrated a toxicity profile consistent with previous published reports. Efficacy was seen in several cancer cohorts, which validates Trop-2 as a broad target in solid tumors.

Abstract PS14-08: Clinical factors and association with treatment modalities in patients with breast cancer and brain metastases who develop leptomeningeal disease

BACKGROUNDImprovements in systemic therapies have led to significantly improved survival in patients with breast cancer and have created a challenge with regards to management of brain metastases (BM) and leptomeningeal disease (LMD). LMD is a highly aggressive condition, resulting in rapid neurological decline and a short survival of weeks to months. The purpose of this study is to identify clinical factors that can predict for LMD when a patient is diagnosed with BM, and to assess outcomes with various treatment modalities.METHODSA retrospective analysis was conducted using a clinical database at a single institution and included 178 patients with breast cancer and treated BM between 2007-2020. Demographic, clinical, radiographic, and dosimetric data were collected. LMD was diagnosed by cytology or neuroimaging. Chi-square and t-test were used.RESULTSOut of 178 patients with breast cancer and treated BM, 41 (23%) developed LMD. Median age for the study cohort was 51.3 +-13.4 years; those with LMD was 47.9 +-12.3 (p=0.057) years. One of the 178 patients was a male and all 41 with LMD were females. There were 58.5% Caucasian women in the LMD group followed by African-American being 24.4% (p=0.31). Characteristics like number of brain lesions (p=0.57), median size of the largest brain lesion (p=0.70), hemorrhagic/cystic lesions (p=0.68), systemic disease being progressive in 42.6%, stable in 19.3% and 26.1% with no evidence of systemic disease at the time of diagnosis of BM (p=0.34) did not pose a higher risk in developing LMD. For 29% patients the brain lesions were supratentorial, 23.7% were infratentorial and 47.4% patients had both and had a higher risk for LMD (p=0.025). Patients with liver (p=0.45) and bone (p=0.48) lesions did not have higher risk for LMD which was seen in those without lung metastases (p=0.03). In the LMD group, 39% had HR+, 31.7% HER2+, and 41.4% had triple negative breast cancer (TNBC). The higher incidence of HR+ patients could be attributed to the fact that the more aggressive HER2+ and TNBC patients may have not gotten treatment for their BM as they pursued comfort care status. In the LMD group, 13.1% received prior stereotactic radiation, 39.5% whole brain radiation, 10.5% had surgery alone and 36.8% had surgery with pre/post-op radiation. Patients who had any surgery did not have a higher risk for LMD (p=0.26). Surgery did not pose a higher risk for local recurrence, seen in 28% patients (p=0.42) and occurrence of BM at another site, seen in 36.5% patients (p=0.16). CONCLUSIONSAmong breast cancer patients with brain metastases those who develop LMD tend to be younger, with higher risk in Caucasians and African-American women; however, this was not statistically significant. The number, size, hemorrhagic/cystic character of brain lesions did not pose a higher risk whereas occurrence of synchronous lesions in supratentorial and infratentorial locations increased risk of LMD. There was no statistically significant difference in the rates of LMD, local recurrence, CNS recurrence at another site with surgery and/or radiation.

EthnicityBrain metastases (N=178)LMD group (N=41) (p=0.31)Caucasian58.4%58.5%Hispanic12.4%4.9%African-American19.1%24.2%Others10.1%12.2%

Clinical characteristicsBrain metastasesLMD groupP valueNumber of brain lesions (Median interquartile range)3 (1-8)2.5 (1-9)P=0.57Median size of the largest brain lesion (cm)2.4 1.42.53 1.69p=0.70Hemorrhagic lesions223P=0.68Cystic lesions163

Citation Format: Akshjot Puri, Charisma Mylavarapu, Jiagiong Xu, Tejal A Patel, Bin S Teh, Ivo Tremont-Lukats, Jenny C Chang, Polly Niravath. Clinical factors and association with treatment modalities in patients with breast cancer and brain metastases who develop leptomeningeal disease [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 PS14-08.

Abstract PS17-30: Trps1 disrupts angiogenesis in triple negative breast cancer by down regulating genes involved in angiogenesis pathways

Breast cancer is the second leading cause of cancer-related deaths in the United States. The Cancer Genome Atlas (TCGA) network has classified breast cancer into four main subtypes: luminal A, luminal B, HER2+, and Triple- negative breast cancer (TNBC). TNBC constitutes 10-20% of all breast cancer and has a higher rate of distal recurrence and a poorer prognosis than other breast cancer subtypes. Less than 30% of women with metastatic TNBC survive 5 years and almost all die from their disease despite adjuvant chemotherapy. Although all of the cancer genome-sequencing efforts, there is still an incomplete understanding of the genes and genetic networks driving TNBC. To better understand the genetic forces involved in TNBC, we performed a transposon mutagenesis screen in Pten mutant mice that identified several candidate trunk drivers and a much larger number of progression genes. A major finding of our screen was the discovery and functional validation of TRPS1 as a metastasis tumor suppressor in human TNBC. Consistent with these results, in SB-Pten tumors, Trsp1 was insertionally mutated only in TNBC. Remarkably, tumor cells from ER+ breast cancer patients after antihormone therapy have decreased TRPS1 expression and increased expression of mesenchymal markers, suggesting that breast tumors with low TRPS1 expression might be more resistant to chemotherapy and have a higher probability to metastasize. TRPS1 is a GATA-like transcription factor, which functions as a transcriptional repressor or activator, depending on cell type, stage of development, or pathological conditions. Based on this assumption, we explored additional roles of TRPS1 in tumor progression. ChIP-seq array studies indicated that TRPS1 modulates the expression of genes involved in the angiogenesis pathway. To validate the functional role of TRPS1 in angiogenesis, we perform tube formation and sprouting assays using MDA-MB-231 cells overexpressing TRPS1-ORF and inactivation of TRPS1 expression in HCC70 cells by different shRNAs. Interestingly, inactivation of TRPS1 expression accelerates tube formation structures compared to the vector control as well as cell branching in the sprouting assay. Overexpression of TRPS1 prevents tubing and branching formation in vitro assays. Moreover, immunohistochemistry staining of CD31 detected a reduced number of blood vessels in MDA-MB-231 tumor xenografts overexpressing TRPS1, and an increase of angiogenic vasculature in HCC70 TRPS1-shRNA tumor xenografts. In vitro and in vivo assays demonstrate the role of TRPS1 in tumor angiogenesis and ChIP-seq data suggest a direct interaction in the modulation of genes involved in pathological neovaculature mechanisms.

Citation Format: Liliana Guzman, Jessica Bronstad, Roberto Rangel, Roberto R Rosato, Wei Qian, Jianying Zhou, Jenny C Chang. Trps1 disrupts angiogenesis in triple negative breast cancer by down regulating genes involved in angiogenesis pathways [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 PS17-30.

Abstract PS13-28: Pre-treating TNBC with docetaxel and il-12 enhances anti-PD1 efficacy

Introduction: Amongst all breast cancers, Triple Negative Breast Cancer (TNBC) account for 15-20% of all the cases. TNBC affect younger patients, and is more prevalent in African-American women. The poor prognosis for this very aggressive tumor subtype is exacerbated by the lack of specific targeted therapy against the disease. Although TNBC initially respond very well to chemotherapy, paradoxically the disease-free survival is very short. It has been showed that TNBC have higher rates of CD8+ T-cells infiltration, and express high level of PD-L1. Together, these data provide a strong rationale for the combination of chemotherapy and immunotherapy to treat TNBC patients. In this study, we investigated the response to pre-priming the tumor with one round of docetaxel and IL-12, followed by anti-PD1 maintenance in mouse E0771 and 4T1 TNBC syngeneic models. We hypothesized that docetaxel will promote the release of neo-antigens, while IL-12 will activate immunity specific to these antigens and anti-PD1 therapy prevent the exhaustion of those T-cells. Materials/Methods: Mouse TNBC E0771 and 4T1 cell lines were injected in the mammary fat pad of C57BL/6, and Balb/c mice respectively. On day 1, the mice received a single dose (20mg/kg) of docetaxel and one intratumoral injection (1.25x109) of mAdv.IL-12, a replication defective adenoviral vector containing mIL-12 (mouse) cDNA under the transcriptional control of Rous sarcoma virus long terminal repeat (provided by Dr. Chen, HMRI). Anti-PD1 (InVivoMab anti-mouse PD-1 CD279) was administered 3 times a week (2 cycles) starting 5 days post docetaxel and Il-12 treatment. At the end of the study, IFN-gamma levels were measured from blood and tumor samples; tumor sizes were compared between treatment groups (Control/mAdv.IL-12/anti-PD1/and various Combination), as well as survival curves. The metastatic burden to the lungs (H&E), as well as the apoptosis in the tumor (TUNNEL) were assessed by IHC. Results: In both 4T1 and E0771 tumor models, triple combination of docetaxel + IL-12 followed by anti-PD1 significantly reduced tumor size compared to both single agents, and double combination. In the Triple Combo group, 1 mice had lung metastasis vs all of them in the other treatment groups. IHC data indicate a higher level of TILs in the treatment groups, with a statistically significant difference in the combination groups compared to single agents. There was more apoptosis in the triple combo group as indicated by TUNNEL. Conclusion:Our preliminary data strongly supports that treating TNBC models with docetaxel and mAdv.IL-12 followed by anti-PD1 significantly slows down tumor growth, and decrease lung metastasis incidence. We are actively investigating the mechanism through which the response is achieved.

Citation Format: Ann Cassany Anselme, Wei Qian, Jianying Zhou, Roberto R. Rosato, Jenny C. Chang. Pre-treating TNBC with docetaxel and il-12 enhances anti-PD1 efficacy [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 PS13-28.

A comprehensive overview of metaplastic breast cancer: clinical features and molecular aberrations

Metaplastic breast cancer (MpBC) is an exceedingly rare breast cancer variant that is therapeutically challenging and aggressive. MpBC is defined by the histological presence of at least two cellular types, typically epithelial and mesenchymal components. This variant harbors a triple-negative breast cancer (TNBC) phenotype, yet has a worse prognosis and decreased survival compared to TNBC. There are currently no standardized treatment guidelines specifically for MpBC. However, prior studies have found that MpBC typically has molecular alterations in epithelial-to-mesenchymal transition, amplification of epidermal growth factor receptor, PI3K/Akt signaling, nitric oxide signaling, Wnt/β-catenin signaling, altered immune response, and cell cycle dysregulation. Some of these molecular alterations have been studied as therapeutic targets, in both the preclinical and clinical setting. This current review discusses the histological organization and cellular origins of MpBC, molecular alterations, the role of radiation therapy, and current clinical trials for MpBC.

Analysis of the Implementation of Telehealth Visits for Care of Patients With Cancer in Houston During the COVID-19 Pandemic

PURPOSE

The purpose of this study was to evaluate the use of telemedicine amid the SARS-CoV-2 pandemic in patients with cancer and assess barriers to its implementation.

PATIENTS AND METHODS

Telehealth video visits, using the Houston Methodist MyChart platform, were offered to patients with cancer as an alternative to in-person visits. Reasons given by patients who declined to use video visits were documented, and demographic information was collected from all patients. Surveys were used to assess the levels of satisfaction of treating physicians and patients who agreed to video visits.

RESULTS

Of 1,762 patients with cancer who were offered telehealth video visits, 1,477 (83.8%) participated. The patients who declined participation were older (67.7 v 60.2 years; P < .0001), lived in significantly lower-income areas (P = .0021), and were less likely to have commercial insurance (P < .0001) than patients who participated. Most participating patients (92.6%) were satisfied with telehealth video visits. A majority of physicians (65.2%) were also satisfied with its use, and 74% indicated that they would likely use telemedicine in the future. Primary concerns that physicians had in using this technology were inadequate patient interactions and acquisition of medical data, increased potential for missing significant clinical findings, decreased quality of care, and potential medical liability.

CONCLUSION

Oncology/hematology patients and their physicians expressed high levels of satisfaction with the use of telehealth video visits. Despite recent advances in technology, there are still opportunities to improve the equal implementation of telemedicine for the medical care of vulnerable older, low-income, and underinsured patient populations.

Antihistamine Drug Ebastine Inhibits Cancer Growth by Targeting Polycomb Group Protein EZH2

Enhancer of zester homolog 2 (EZH2), a histone lysine methyltransferase and the catalytic component of polycomb repressive complex 2, has been extensively investigated as a chromatin regulator and a transcriptional suppressor by methylating H3 at lysine 27 (H3K27). EZH2 is upregulated or mutated in most cancers, and its expression levels are negatively associated with clinical outcomes. However, the current developed small-molecule inhibitors targeting EZH2 enzymatic activities could not inhibit the growth and progression of solid tumors. Here, we discovered an antihistamine drug, ebastine, as a novel EZH2 inhibitor by targeting EZH2 transcription and subsequently downregulating EZH2 protein level and H3K27 trimethylation in multiple cancer cell lines at concentrations below 10 μmol/L. The inhibition of EZH2 by ebastine further impaired the progression, migration, and invasiveness of these cancer cells. Overexpression of Ezh2 wild-type and its mutant, H689A (lacking methyltransferase activity), rescued the neoplastic properties of these cancer cells after ebastine treatment, suggesting that EZH2 targeted by ebastine is independent of its enzymatic function. Next-generation RNA-sequencing analysis also revealed that C4-2 cells treated with 8 μmol/L ebastine showed a gene profiling pattern similar to EZH2-knockdown C4-2 cells, which was distinctively different from cells treated with GSK126, an EZH2 enzyme inhibitor. In addition, ebastine treatment effectively reduced tumor growth and progression, and enhanced progression-free survival in triple-negative breast cancer and drug-resistant castration-resistant prostate cancer patient-derived xenograft mice. Our data demonstrated that ebastine is a novel, safe, and potent anticancer agent for patients with advanced cancer by targeting the oncoprotein EZH2.

Benchmarks for Academic Oncology Faculty

The role of clinical researchers is vital to cancer progress. The teaching, research, and leadership roles that academic oncologists hold need to be accounted for and appropriately compensated. National metrics are currently inexistent, but are necessary to move the oncology research field forward. Clinical research and routine clinical care must be harmoniously integrated without competing. This article reviews the national landscape of clinical cancer research and proposes a call for action.

MEK activation modulates glycolysis and supports suppressive myeloid cells in TNBC

Triple-negative breast cancers (TNBCs) are heterogeneous and aggressive, with high mortality rates. TNBCs frequently respond to chemotherapy, yet many patients develop chemoresistance. The molecular basis and roles for tumor cell-stromal crosstalk in establishing chemoresistance are complex and largely unclear. Here we report molecular studies of paired TNBC patient-derived xenografts (PDXs) established before and after the development of chemoresistance. Interestingly, the chemoresistant model acquired a distinct KRASQ61R mutation that activates K-Ras. The chemoresistant KRAS-mutant model showed gene expression and proteomic changes indicative of altered tumor cell metabolism. Specifically, KRAS-mutant PDXs exhibited increased redox ratios and decreased activation of AMPK, a protein involved in responding to metabolic homeostasis. Additionally, the chemoresistant model exhibited increased immunosuppression, including expression of CXCL1 and CXCL2, cytokines responsible for recruiting immunosuppressive leukocytes to tumors. Notably, chemoresistant KRAS-mutant tumors harbored increased numbers of granulocytic myeloid-derived suppressor cells (gMDSCs). Interestingly, previously established Ras/MAPK-associated gene expression signatures correlated with myeloid/neutrophil-recruiting CXCL1/2 expression and negatively with T cell-recruiting chemokines (CXCL9/10/11) across patients with TNBC, even in the absence of KRAS mutations. MEK inhibition induced tumor suppression in mice while reversing metabolic and immunosuppressive phenotypes, including chemokine production and gMDSC tumor recruitment in the chemoresistant KRAS-mutant tumors. These results suggest that Ras/MAPK pathway inhibitors may be effective in some breast cancer patients to reverse Ras/MAPK-driven tumor metabolism and immunosuppression, particularly in the setting of chemoresistance.

SNX27-retromer assembly recycles MT1-MMP to invadopodia and promotes breast cancer metastasis

Recycling of MT-MMPs to actin-rich membrane-protrusive structures promotes breast cancer invasion. This study shows that SNX27–retromer, an endosomal sorting and recycling machinery, interacts with MT1-MMP and regulates its transport to the cell surface, thus promoting matrix invasive activity of the breast cancer cells.

A variety of metastatic cancer cells use actin-rich membrane protrusions, known as invadopodia, for efficient ECM degradation, which involves trafficking of proteases from intracellular compartments to these structures. Here, we demonstrate that in the metastatic breast cancer cell line MDA-MB-231, retromer regulates the matrix invasion activity by recycling matrix metalloprotease, MT1-MMP. We further found that MT2-MMP, another abundantly expressed metalloprotease, is also invadopodia associated. MT1- and MT2-MMP showed a high degree of colocalization but were located on the distinct endosomal domains. Retromer and its associated sorting nexin, SNX27, phenocopied each other in matrix degradation via selectively recycling MT1-MMP but not MT2-MMP. ITC-based studies revealed that both SNX27 and retromer could directly interact with MT1-MMP. Analysis from a publicly available database showed SNX27 to be overexpressed or frequently altered in the patients having invasive breast cancer. In xenograft-based studies, SNX27-depleted cell lines showed prolonged survival of SCID mice, suggesting a possible implication for overexpression of the sorting nexin in tumor samples.

Metastatic triple-negative breast cancer: Established and emerging treatments

Metastatic triple-negative breast cancer (mTNBC) patients tend to have a poor overall survival. The primary goals of treatment focus on palliation of symptoms and improvement in overall survival (OS). Single-agent sequential chemotherapy with anthracycline or taxane has remained the cornerstone of treatment for many years. The FDA has approved newer agents such as poly-adenosine diphosphate-ribose polymerase (PARP) inhibitors upfront in germline BRCA (gBRCA) 1/2 mutation carriers; atezolizumab and nab-paclitaxel combination frontline in patients with PD-L1 expression > 1%; and sacituzumab govitecan (IMMU-132), an antibody-drug conjugate in heavily pretreated mTNBC patients.

Correction to: A window-of-opportunity trial of the CXCR1/2 inhibitor reparixin in operable HER-2-negative breast cancer

An amendment to this paper has been published and can be accessed via the original article.

Simultaneous targeting of HER family pro-survival signaling with Pan-HER antibody mixture is highly effective in TNBC: a preclinical trial with PDXs

BACKGROUND

The human epidermal growth factor receptor (HER) family, notably EGFR, is overexpressed in most triple-negative breast cancer (TNBC) cases and provides cancer cells with compensatory signals that greatly contribute to the survival and development of resistance in response to therapy. This study investigated the effects of Pan-HER (Symphogen, Ballerup, Denmark), a novel mixture of six monoclonal antibodies directed against members of the HER family EGFR, HER2, and HER3, in a preclinical trial of TNBC patient-derived xenografts (PDXs).

METHODS

Fifteen low passage TNBC PDX tumor samples were transferred into the right mammary fat pad of mice for engraftment. When tumors reached an average size of 100-200 mm3, mice were randomized (n ≥ 6 per group) and treated following three 1-week cycles consisting of three times/week intraperitoneal (IP) injection of either formulation buffer (vehicle control) or Pan-HER (50 mg/kg). At the end of treatment, tumors were collected for Western blot, RNA, and immunohistochemistry analyses.

RESULTS

All 15 TNBC PDXs were responsive to Pan-HER treatment, showing significant reductions in tumor growth consistent with Pan-HER-mediated tumor downmodulation of EGFR and HER3 protein levels and significantly decreased activation of associated HER family signaling pathways AKT and ERK. Tumor regression was observed in five of the models, which corresponded to those PDX tumor models with the highest level of HER family activation.

CONCLUSIONS

The marked effect of Pan-HER in numerous HER family-dependent TNBC PDX models justifies further studies of Pan-HER in TNBC clinical trials as a potential therapeutic option.

Clinical evaluation of germline polymorphisms associated with capecitabine toxicity in breast cancer: TBCRC-015

PURPOSE

Capecitabine is important in breast cancer treatment but causes diarrhea and hand-foot syndrome (HFS), affecting adherence and quality of life. We sought to identify pharmacogenomic predictors of capecitabine toxicity using a novel monitoring tool.

METHODS

Patients with metastatic breast cancer were prospectively treated with capecitabine (2000 mg/m²/day, 14 days on/7 off). Patients completed in-person toxicity questionnaires (day 1/cycle) and automated phone-in assessments (days 8, 15). Correlation of genotypes with early and overall toxicity was the primary endpoint.

RESULTS

Two hundred and fifty-nine patients were enrolled (14 institutions). Diarrhea and HFS occurred in 52% (17% grade 3) and 69% (9% grade 3), respectively. Only 29% of patients completed four cycles without dose reduction/interruption. In 39%, the highest toxicity grade was captured via phone. Three single nucleotide polymorphisms (SNPs) associated with diarrhea-DPYD*5 (odds ratio [OR] 4.9; P = 0.0005), a MTHFR missense SNP (OR 3.3; P = 0.02), and a SNP upstream of MTRR (OR 3.0; P = 0.03). GWAS elucidated a novel HFS SNP (OR 3.0; P = 0.0007) near TNFSF4 (OX40L), a gene implicated in autoimmunity including autoimmune skin diseases never before implicated in HFS. Genotype-gene expression analyses of skin tissues identified rs11158568 (associated with HFS via GWAS) with expression of CHURC1, a transcriptional activator controlling fibroblast growth factor (beta = - 0.74; P = 1.46 × 10^-23), representing a previously unidentified mechanism for HFS.

CONCLUSIONS

This is the first cancer pharmacogenomic study to use phone-in self-reporting, permitting augmented toxicity characterization. Three germline toxicity SNPs were replicated, and several novel SNPs/genes having strong functional relevance were discovered. If further validated, these markers could permit personalized capecitabine dosing.

Abstract ES11-2: Neoadjuvant Systemic Treatment (NST): Tailoring Response by Sub-type

Achieving a pathologic complete response (pCR) after neoadjuvant systemic treatment (NST) is clearly associated with improved survival in breast cancer patients, especially with HER2 and triple negative subtypes. In HER2-positive breast cancer patients, the neoadjuvant platform has allowed for the unprecedented accelerated approval for pertuzumab based on improved pCR rates. The KATHERINE trial, in patients who did not achieve pCR following standard trastuzumab/pertuzumab/chemotherapy, demonstrated for the first time that switching to trastuzumab-emtansine (TDM1) led to significant benefit, creating an interesting research paradigm for these high-risk patients with residual disease. For patients with residual disease, the CREATE-X trial demonstrated survival improvement with capecitabine, especially in patients with triple negative disease. New promising agents in the metastatic setting that are being incorporated into NST include immune-check-point inhibitors and cyclin-dependent kinase inhibitors. Evolving technologies like next generation sequencing and gene expression profiles have improved our knowledge regarding the biology of residual disease, and the mechanisms behind treatment resistance, and potentially, metastases. NST allows for testing of new promising treatment regimens - both escalation and de-escalation - depending on sub-types, before surgery. The management and strategies post-NST and the management of residual disease will be discussed.

Citation Format: JC Chang. Neoadjuvant Systemic Treatment (NST): Tailoring Response by Sub-type [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr ES11-2.

Abstract P3-03-05: Elucidating the synergistic relationship between the iNOS and PI3K/Akt pathways for treatment of metaplastic breast cancer

Metaplastic breast cancer (MBC) is a rare form of breast cancer characterized by histological presence of two or more cellular types, typically epithelial and mesenchymal components. MBC represents 0.2 to 5% of all breast cancers. Most MBC typically displays a triple-negative breast cancer phenotype in which they lack expression of ER, PR, and HER2 and they also exhibit basal-like or claudin-like molecular subtypes. The current treatment guidelines for MBC have yet to be established due to limited knowledge of its pathogenesis. Prior studies have shown that MBC harbor a subtype mutation in RPL39, which is correlated with higher levels of iNOS, and aberrations in the PI3K/Akt signaling pathway. Considering that aberrations in both of these pathways may play a role in disease pathogenesis, our goal is to further elucidate whether there is a synergistic relationship between the iNOS and PI3K/Akt pathways in MBC. Our hypothesis is that isoform-specific PIK3CA inhibitor Alpelisib, will interact synergistically with pan-NOS inhibitor L-NMMA, to act as an improved therapeutic combination against MBC. We used MBC cell lines Hs578t and BT549 and MBC PDX models RPL39-positive BCM 4664 and RPL39-negative BCM 3807 in our preliminary studies. Using flow cytometry to detect Annexin V+/DAPI+ cells, we found increased levels of cell death in MBC cell lines treated with LNMMA+Alpelisib combination treatment in comparison to single agent treatment. Western blot analysis of samples from single (LNMMA or Alpelisib) or combination treated cell lines and PDXs showed increased PARP degradation and cleaved caspase 3/9 with combination treatment. Pathway-focused RT-PCR analysis was performed using RNA collected from Hs578t cells treated for 48 hrs. with LNMMA, Alpelisib, or combination treatment. RT-PCR data were analyzed using Ingenuity Pathway Analysis (IPA; Qiagen) software which showed that insulin signaling and PI3K/AKT pathways were the most enriched pathways with single and combination treatment. In vivo data using PDX BCM 4664 showed that combination treatment of LNMMA+Alpelisib was most effective at reducing tumor volume in comparison to single treatment. Our preliminary results suggest that LNMMA and Alpelisib combination treatment have therapeutic potential in the treatment of MBC. Our results indicated that simultaneous inhibition of the NOS and PI3K/AKT pathways may represent a clinically relevant therapeutic concept against hard-to-treat MBC, and warrants further studies.

Citation Format: Tejaswini Parlapalle Reddy, Roberto Rosato, Liliana Guzman, Wei Qian, Jianying Zhou, Anthony J Kozielski, Jenny C Chang. Elucidating the synergistic relationship between the iNOS and PI3K/Akt pathways for treatment of metaplastic breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-03-05.

A randomized, controlled phase II trial of neoadjuvant ado-trastuzumab emtansine, lapatinib, and nab-paclitaxel versus trastuzumab, pertuzumab, and paclitaxel in HER2-positive breast cancer (TEAL study)

Background

Neoadjuvant dual human epidermal growth factor receptor (HER2) blockade with trastuzumab and pertuzumab plus paclitaxel leads to an overall pathologic complete response (pCR) rate of 46%. Dual HER2 blockade with ado-trastuzumab emtansine (T-DM1) and lapatinib plus nab-paclitaxel has shown efficacy in patients with metastatic HER2-positive breast cancer. To test neoadjuvant effectiveness of this regimen, an open-label, multicenter, randomized, phase II trial was conducted comparing T-DM1, lapatinib, and nab-paclitaxel with trastuzumab, pertuzumab, and paclitaxel in patients with early-stage HER2-positive breast cancer.

Methods

Stratification by estrogen receptor (ER) status occurred prior to randomization. Patients in the experimental arm received 6 weeks of targeted therapies (T-DM1 and lapatinib) followed by T-DM1 every 3 weeks, lapatinib daily, and nab-paclitaxel weekly for 12 weeks. In the standard arm, patients received 6 weeks of trastuzumab and pertuzumab followed by trastuzumab weekly, pertuzumab every 3 weeks, and paclitaxel weekly for 12 weeks. The primary objective was to evaluate the proportion of patients with residual cancer burden (RCB) 0 or I. Key secondary objectives included pCR rate, safety, and change in tumor size at 6 weeks. Hypothesis-generating correlative assessments were also performed.

Results

The 30 evaluable patients were well-balanced in patient and tumor characteristics. The proportion of patients with RCB 0 or I was higher in the experimental arm (100% vs. 62.5% in the standard arm, p = 0.0035). In the ER-positive subset, all patients in the experimental arm achieved RCB 0-I versus 25% in the standard arm (p = 0.0035). Adverse events were similar between the two arms.

Conclusion

In early-stage HER2-positive breast cancer, the neoadjuvant treatment with T-DM1, lapatinib, and nab-paclitaxel was more effective than the standard treatment, particularly in the ER-positive cohort.

Trial registration

Clinicaltrials.gov NCT02073487, February 27, 2014.

Autophagy inhibition elicits emergence from metastatic dormancy by inducing and stabilizing Pfkfb3 expression

Breast cancer stem cells (BCSCs) are unique in their ability to undergo unlimited self-renewal, an essential process in breast cancer recurrence following metastatic dormancy. Emergent metastatic lesions were subjected to microarray analysis, which identified 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (Pfkfb3) as a differentially expressed gene coupled to metastatic recurrence. Here, we report that elevated Pfkfb3 expression correlates with the appearance of aggressive breast cancers and reduces relapse-free survival, as well as enhances BCSC self-renewal and metastatic outgrowth. We observe an inverse relationship between Pfkfb3 expression and autophagy, which reduces Pfkfb3 expression and elicits cellular dormancy. Targeted depletion of Atg3, Atg7, or p62/sequestosome-1 to inactivate autophagy restores aberrant Pfkfb3 expression in dormant BCSCs, leading to their reactivation of proliferative programs and outgrowth. Moreover, Pfkfb3 interacts physically with autophagy machinery, specifically the UBA domain of p62/sequestosome-1. Importantly, disrupting autophagy and this event enables Pfkfb3 to drive dormant BCSCs and metastatic lesions to recur.

Detection of breast cancer stem cell gene mutations in circulating free DNA during the evolution of metastases

PURPOSE

Limited knowledge exists on the detection of breast cancer stem cell (BCSC)-related mutations in circulating free DNA (cfDNA) from patients with advanced cancers. Identification of new cancer biomarkers may allow for earlier detection of disease progression and treatment strategy modifications.

METHODS

We conducted a prospective study to determine the feasibility and prognostic utility of droplet digital polymerase chain reaction (ddPCR)-based BCSC gene mutation analysis of cfDNA in patients with breast cancer.

RESULTS

Detection of quantitative BCSC gene mutation in cfDNA by ddPCR mirrors disease progression and thus may represent a valuable and cost-effective measure of tumor burden. We have previously shown that hematological and neurological expressed 1-like (HN1L), ribosomal protein L39 (RPL39), and myeloid leukemia factor 2 (MLF2) are novel targets for BCSC self-renewal, and targeting these genetic alterations could be useful for personalized genomic-based therapy.

CONCLUSION

BCSC mutation detection in cfDNA may have important implications for diagnosis, prognosis, and serial monitoring.

The impact of molecular status on survival outcomes for invasive micropapillary carcinoma of the breast

Invasive micropapillary carcinoma (IMPC) is an uncommon variant of breast cancer. Previous studies demonstrated this subtype is often hormone receptor (HR)-positive, resulting in survival outcomes similar to invasive ductal carcinoma. However, many of these studies were conducted prior to HER2 testing availability. We aim to determine the impact of molecular marker status (including HER2 status) on IMPC survival outcomes. The National Cancer Data Base (NCDB) was used to retrieve patients with biopsy-proven IMPC from 2007 to 2012. Only patients with known HR and HER2 status were included. Cox multivariate regression was used to determine prognostic factors. In total, 865 patients were included; median follow-up was 2.5 years. Overall, 651 patients (75.3%) had HR + HER2- disease, 128 (14.8%) had HR + HER2+ disease, 41 (4.7%) had HR-HER2 + disease, and 45 (5.2%) had triple negative disease. Patients with triple negative disease were more likely to have poorly differentiated histology (66.7%), lymphovascular invasion (73.3%), stage 3 disease (37.8%), undergone mastectomy (68.9%), and positive surgical margins (15.6%). On Cox multivariate regression, those with triple negative disease had worse overall survival (hazard ratio [HR] 7.28, P < 0.001). Other adverse prognostic factors included African-American descent (HR 2.24, P = 0.018), comorbidity score of 1 (HR 2.50, P = 0.011), comorbidity score ≥2 (HR 3.27, P = 0.06), and ≥3 positive lymph nodes (HR 3.23, P = 0.007). Similar to invasive ductal carcinoma, triple negative disease in IMPC results in worse survival outcomes. This is the largest and first study to characterize molecular status (including HER2 status) in patients with IMPC and its impact on survival outcomes.

Abstract 1511: MEK activation modulates immunosuppressive MDSCs and metabolic phenotypes in TNBC

Triple-negative breast cancers (TNBCs) are highly heterogeneous and aggressive, with high mortality rates. Although TNBC is typically more responsive to chemotherapy than other breast cancer subtypes, many patients develop chemo-resistance. The molecular processes between tumor and stromal cells involved in developing chemo-resistance are under-explored. Here we report studies of paired TNBC patient-derived xenografts (PDX) established before and after chemo-resistance. Despite significant genetic similarities, the chemo-resistant PDX model harbored a rare constitutively-active KRASQ61R mutation which was not present in the chemo-naive PDX. Further analysis demonstrated that the chemo-resistant KRAS-mutant model exhibited altered gene expression changes including increased expression of CXCR2-ligands CXCL1 and CXCL2, which are responsible for recruiting immune cells to tumors. These expression patterns were largely inhibited in vivo by MEK inhibitor (MEKi) treatment. Moreover, in breast cancer cell lines, CXCL1, CXCL2, and granulocyte macrophage-colony stimulating factor (CSF2, stimulates granulocyte and macrophage differentiation from hematopoietic precursor cells, including immunosuppressive myeloid cells) transcripts were also downregulated by MEKi. Notably, chemo-resistant KRAS-mutant tumors harbored increased Gr1+ and Arginase-1+ cells, consistent with recruitment of immunosuppressive M2-like macrophages and/or myeloid-derived suppressor cells (MDSCs), which was inhibited by MEKi. Further experiments demonstrate that CD45+CD11b+Ly6G+ MDSC accumulation in tumors can be inhibited by MEKi treatment alone, or by CXCR2 inhibition, suggesting that the effects of MEK inhibition on MDSC recruitment are CXCL1/2-dependent. Confirming the translational relevance of these findings, in &gt;200 murine and &gt;1000 human breast tumors, Ras/MAPK transcriptional activity correlated with myeloid-recruiting CXCL1/2 expression and negatively with T-cell recruiting chemokines (CXCL9/10/11), even in the absence of activating KRAS mutations. The association with Ras/MAPK activity was also confirmed using immunofluorescence to quantify MHC-II-low myeloid cells in 80 post-chemotherapy TNBC tumors. Importantly, MEKi and chemotherapy combination treatment reversed immunosuppressive cell accumulation and metabolic phenotypes exemplified by altered optical redox ratios (NAD(P)H/FAD) in the chemo-resistant KRAS mutant tumors, resulting in tumor growth suppression in mice. MEKi treatment also reduced redox ratios in 3D cultures of breast cancer cell lines further suggesting that MEK inhibition targets multiple oncogenic processes in breast cancer. These results suggest that Ras/MAPK pathway inhibitors may be effective in some breast cancer patients to reverse Ras/MAPK-driven tumor metabolism and immunosuppression, particularly in the setting of chemo-resistant disease.

Citation Format: Derek A. Franklin, Joe T. Sharick, Paula I. Ericsson-Gonzalez, Violeta Sanchez, Phillip T. Dean, Susan R. Opalenik, Stefano Cairo, Jean-Gabriel Judde, Michael T. Lewis, Jenny C. Chang, Melinda E. Sanders, Rebecca S. Cook, Melissa C. Skala, Jennifer Bordeaux, Jehovana Orozco Bender, Christine Vaupel, Gary Geiss, Douglas Hinerfeld, Justin M. Balko. MEK activation modulates immunosuppressive MDSCs and metabolic phenotypes in TNBC [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 1511.

Abstract 2261: Understanding the mechanism underlying resistance to immunotherapy in TNBC

Triple Negative Breast Cancer (TNBC) accounts for 15-20% of all breast cancer cases. TNBC patients have the worst outcome amongst all breast cancers; and do not respond well to conventional therapies. Although TNBC patients have a high amount of tumor infiltrating lymphocytes, and express higher level of PD-L1 compared to other breast cancer subtypes, they do not all respond to PD-1 blockade therapy. IL-12 is a cytokine produced by dendritic cells (DCs), and other APCs, known to induce the activation of natural killer cells, cytotoxic T-cells, and induce a Th1 phenotype. Although the immune activating potential of Il-12 are known, its systemic uses have been limited due to high toxicity. Using three different tumor models (PDXs: BCM 4913, MC1 in humanized mice and E0771 syngeneic model C57/Bl), we are investigating the response of combining intratumoral injection of Adenovirus IL-12 (ad.Il-12) and anti-PD1 therapy.

Materials/Methods: E0771, a mice TNBC cell line was injected in the mammary fat pad of C57BL/6 mice. The same procedure was followed using MC1 and BCM 4913, in humanized NSG-MGM3 mice. The mice received weekly intratumoral injection of ad.IL-12; a replication defective adenoviral vector containing mIL-12 (mouse) and hIL-12 (PDX) cDNA under the transcriptional control of Rous sarcoma virus long terminal repeat (received from Dr. Chen). Anti-PD1 (InVivoMab anti-mouse PD-1 CD279) was administered 3 times a week, Pembrolizumab (once a week). Post treatment, INF-gamma level were measured from blood and tumor samples, in addition, tumor sizes were compared between treatment groups (Control/ad.IL-12/anti-PD1/ad.IL-12 + anti-PD1), as well as survival curves. Immunohistochemistry was used to assess levels on TILs in the tumors.

Results: Ad.Il-12 and PD-1 blockade therapy combination was more effective at reducing tumor growth in BCM4913, while in E00771 and MC1 combination treatment showed no difference compared to single agent. In all the models, levels of INF-gamma in the tumor were significantly upregulated in the combination group compared to control and single agents, while no difference was found between treatment groups from blood samples. Tumor growth in the combination group and the treated group were slower compared to the controls in BCM 4913. IHC data indicate a higher level of TILs in the treatment groups, with a statistically significant difference in the combination group compared to the others.

Conclusion: Our preliminary data suggest that intratumoral injection of IL-12 confine the release of INF-gamma in the tumor microenvironment, and mitigate the toxicity associated with systemic admission of ad.IL-12. Treatment response is not achieved in every model, suggesting an underlying mechanism which confers resistance to the treatment. We are currently investigating different models in the hope to identify markers of responders versus non responders.

Citation Format: Ann C. Anselme, Wei Qian, Anthony Kozielski, Roberto R. Rosato, Jenny C. Chang. Understanding the mechanism underlying resistance to immunotherapy in TNBC [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 2261.

Abstract CT052: A Phase Ib and II clinical trial investigating the efficacy of nitric oxide deprivation and docetaxel in triple negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive disease that currently lacks an efficacious form of therapy. Cancer relapse is thought to be initiated by chemotherapy-resistant breast cancer stem cells (BCSCs). Our previous studies revealed that BCSCs utilize inducible nitric oxide synthase (iNOS)-derived nitric oxide to promote their proliferation, migration, and self-renewal capacity. In an effort to target BCSCs, we found that iNOS inhibition with NG-monomethyl-L-arginine (L-NMMA) sensitized BCSCs to docetaxel in TNBC xenograft models, leading to decreased tumor burden. These findings suggest that BCSC resist conventional therapy in a nitric oxide-dependent manner and that combination of L-NMMA with docetaxel will effectively target BCSCs to prevent further relapse. A phase Ib/II clinical trial was conducted to determine the maximum tolerated dose, recommended phase 2 dose (R2PD), dose-limiting toxicities (DLTs), and efficacy of the L-NMMA and docetaxel combination in chemo-refractory Stage III and IV TNBC patients. For the phase Ib portion of the study, a standard Bayesian continual reassessment method is being used to investigate 7 dose levels of L-NMMA (5, 7.5, 10, 12.5, 15, 17.5, and 20 mg/kg) and two dose levels of docetaxel (75 and 100 mg/m2). Twenty patients have been recruited to date, and based on current pharmacokinetics, pharmacodynamics, and safety data, the RP2D is expected to be docetaxel 100 mg/m2 (Day 1) and L-NMMA 20 mg/kg (Days 1-5) every 3 weeks. At the RP2D, 87.5% of the patients experienced a decrease in total serum nitrates and nitrates at Day 2 (p = 0.0156, Wilcoxon Signed-Rank) as compared to baseline, and 75% experienced a decrease at Day 5 (p = 0.1484). Two and three patients received 15 mg/kg L-NMMA + 75 mg/m2 docetaxel and 17.5 mg/kg L-NMMA + 100 mg/m2 docetaxel, respectively. Of these 5 patients, one partial responder completed 8 cycles before discontinuing treatment due to taxane-associated neuropathy. Among the nine patients treated at the RP2D, only one taxane-associated DLT occurred. The overall response rate for patients treated at the higher doses was 33.3% as determined by RECIST 1.1. Early results of the phase Ib/II trial indicate the safety, tolerability, and promising activity of the first-in-class pan-NOS inhibitor L-NMMA in combination with chemotherapy in the treatment of chemo-refractory TNBC.

Citation Format: Andrew W. Chung, Joe E. Ensor, Jorge Darcourt, Anna Belcheva, Tejal Patel, Jenny C. Chang, Polly A. Niravath. A Phase Ib and II clinical trial investigating the efficacy of nitric oxide deprivation and docetaxel in triple negative breast cancer [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 CT052.

A combinatorial biomarker predicts pathologic complete response to neoadjuvant lapatinib and trastuzumab without chemotherapy in patients with HER2+ breast cancer

BACKGROUND

HER2-positive (+) breast cancers, defined by HER2 overexpression and/or amplification, are often addicted to HER2 to maintain their malignant phenotype. Yet, some HER2+ tumors do not benefit from anti-HER2 therapy. We hypothesize that HER2 amplification levels and PI3K pathway activation are key determinants of response to HER2-targeted treatments without chemotherapy.

PATIENTS AND METHODS

Baseline HER2+ tumors from patients treated with neoadjuvant lapatinib plus trastuzumab [with endocrine therapy for estrogen receptor (ER)+ tumors] in TBCRC006 (NCT00548184) were evaluated in a central laboratory for HER2 amplification by fluorescence in situ hybridization (FISH) (n = 56). HER2 copy number (CN) and FISH ratios, and PI3K pathway status, defined by PIK3CA mutations or PTEN levels by immunohistochemistry were available for 41 tumors. Results were correlated with pathologic complete response (pCR; no residual invasive tumor in breast).

RESULTS

Thirteen of the 56 patients (23%) achieved pCR. None of the 11 patients with HER2 ratio <4 and/or CN <10 achieved pCR, whereas 13/45 patients (29%) with HER2 ratio ≥4 and/or CN ≥10 attained pCR (P = 0.0513). Of the 18 patients with tumors expressing high PTEN or wild-type (WT) PIK3CA (intact PI3K pathway), 7 (39%) achieved pCR, compared with 1/23 (4%) with PI3K pathway alterations (P = 0.0133). Seven of the 16 patients (44%) with HER2 ratio ≥4 and intact PI3K pathway achieved pCR, whereas only 1/25 (4%) patients not meeting these criteria achieved pCR (P = 0.0031).

CONCLUSIONS

Our findings suggest that there is a clinical subtype in breast cancer with high HER2 amplification and intact PI3K pathway that is especially sensitive to HER2-targeted therapies without chemotherapy. A combination of HER2 FISH ratio and PI3K pathway status warrants validation to identify patients who may be treated with HER2-targeted therapy without chemotherapy.