Abstract 2142: Immune determinants of CAR-T expansion in solid tumor patients receiving GD2 CAR-T cell therapy

Chimeric antigen receptor T cells (CAR-Ts) have demonstrated remarkable efficacy in leukemia and lymphomas but limited responses in solid tumors. We conducted a phase I trial (NCT02107963) of GD2 CAR-Ts (GD2-CAR.OX40.28.z.ICD9), demonstrating feasibility and safety of administering GD2 CAR-Ts in children and young adults with neuroblastoma and, for the first time, osteosarcoma. 15 patients aged 8-28 years were enrolled on four dose levels, of which 13 patients were infused. No dose-limiting toxicities were observed, and administration of up to 1x107 GD2-CAR-T/kg was feasible and safe for children and young adults with neuroblastoma and osteosarcoma. At Day 28 following GD2 CAR-T infusion, 23.1% (3/13) of evaluable patients had progressive disease and 76.9% (10/13) had stable disease (SD). 3/10 SD patients remained stable at 60 days post-infusion of GD2 CAR-T, but all patients eventually progressed. Since a major barrier to CAR-T efficacy is inadequate CAR-T expansion, we evaluated CAR-T levels and found that patients stratified into good and poor expander groups, observed across dose levels and associated with pro-inflammatory cytokine signatures in patients. To understand the immune cell contributors to CAR-T expansion, patient pre-treatment apheresis, CAR-T product, and post-infusion samples were evaluated by high-dimensional proteomic (CyTOF), transcriptomic (RNAseq), and epigenetic (ATACseq) analyses. In patient apheresis, good CAR-T expansion associated with more open chromatin and with both proteomic and transcriptomic enrichment of naïve T cells, while poor CAR-T expansion associated with increased levels of T effector memory (TEMRA) cells and enrichment of myeloid derived suppressor cell (MDSC) transcriptomic signatures. CAR-T products across patients, regardless of CAR-T expansion, demonstrated increased T cell activation proteomic signatures, with enhanced exhaustion transcriptomic signatures in poor expanders compared to good. The most robust cellular correlate to good CAR-T expansion was a population of CXCR3-expressing monocytes in pre-treatment apheresis. Interestingly, this CXCR3+ monocyte population reduced in post-infusion timepoints of good expanders, resembling levels found in poor expanders. Our findings were validated in TARGET-OS patient data in The Cancer Genome Atlas, where high CXCR3 expression was found to be associated with survival benefit in osteosarcoma patients. CXCR3 has been extensively studied on T cells, but its function on myeloid populations is yet to be fully explored. These results are the first to demonstrate that the peripheral immune environment prior to CAR-T administration may effectively predict and modulate CAR-T expansion in patients.

Citation Format: Tara Murty, Sabina Kaczanowska, Ahmad Alimadadi, Cristina Contreras, Caroline Duault, Priyanka Balasubrahmanyan, Warren Reynolds, Norma Gutierrez, Reema Baskar, Catherine Wu, Franziska Michor, Jennifer Altreuter, Yang Liu, Aashna Jhaveri, Vandon Duong, Hima Anbunathan, Radim Moravec, Joyce Hong, Roshni Biswas, Stephen Van Nostrand, James Lindsay, Mina Pichavant, Elena Sotillo, Bita Sahaf, Sean Bendall, Holden Maecker, Steven Highfill, David Stroncek, Melinda Merchant, John Glod, Catherine Hedrick, Crystal Mackall, Sneha Ramakrishna, Rosandra Kaplan. Immune determinants of CAR-T expansion in solid tumor patients receiving GD2 CAR-T cell therapy [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 2142.

Disclosure of suicidal ideation and behaviours: A systematic review and meta-analysis of prevalence

Disclosure of suicidal ideation and behaviours, defined as thoughts, plans, or attempts, to other people provides opportunity for intervention and prevention. This study is the first to meta-analyze all available studies to estimate the prevalence of disclosure, to whom people disclose, and examine factors that influence disclosure. Databases were searched for studies reporting samples of people who had experienced suicidal ideation or behaviours (including those who had died by suicide) and whether they had disclosed this. Almost 100 studies (k = 94, N participants = 1,044,629) were included in the overall prevalance analysis. The results showed less than half of people disclosed suicidal ideation or behaviour: 45.9% (95%CI 41.9-49.9%, PI 12.3-81.8%; k = 94). High heterogeneity, common to prevalence studies, was found (Q[93] = 130,584, p < .001; I² = 99.9%). No publication bias was detected. Removing outliers did not change the prevalence estimate, but provided tighter prediction intervals: 45.6% (95%CI 43.4-47.9%, PI 35.8-55.7%; k = 33). Disclosure was related to higher prevalence of psychiatric disorders, female gender, and a longer timeframe of suicidal ideation or behaviour. Prevalence of disclosure was lower among people who died by suicide, relative to community samples, and lower when reported verbally rather than written online. Disclosure, and proportions of disclosures, to family members, was numerically higher than to friends or professionals, but could not be directly compared. In conclusion, between 50 and 60% of people do not disclose their suicidal ideation and behaviours to other people, and therefore remain unidentified and potentially untreated.

Abstract B017: Characterizing the key stromal and immune players in the microenvironment of primary and metastatic chordoma

Chordoma is a rare bone sarcoma of the skull and spine with notochordal origins and an incidence of approximately 1 in every 1,000,000 people. Most chordomas (95%) are pathologically classified as conventional type and generally affect adults. Other chordoma subtypes include dedifferentiated and poorly differentiated with the latter being more common in pediatric patients and both being more aggressive with higher propensity for metastasis than conventional chordomas. Depending on the subtype, local recurrence and metastasis occurs in ~40-80% and ~5-40% of patients, respectively. Due to the rarity of this cancer, the understanding of primary and metastatic chordoma and its microenvironment is poor. Consequently, there are currently no standard therapies for recurrent or metastatic chordomas and 10-year survival rates remain around 30%. The tumor microenvironment (TME), a cellular ecosystem composed of nonmalignant cells that can promote tumor development and progression, offers a promising perspective that could yield novel insights into metastatic chordoma. Stromal and immune cells play key roles in tumor initiation, dissemination, metastasis, and therapeutic response. We hypothesize that the progression of cancer is intimately linked to the characteristics of immune and myeloid populations within the TME. Despite significant advances in the understanding of the genomic landscape of chordoma, the complex cellular milieu of the chordoma TME and its contribution to tumor progression remains unclear. To understand the prevalence and diversity of stromal and immune cells within the chordoma TME, we are utilizing multiplex immunofluorescence on a tissue microarray of chordomas (n=~30). Our preliminary findings show that tumor cell (brachyury+) contribution to the TME is highly heterogenous ranging from 2-88% (SD = 20.0, avg = 30%). Further, stromal cells (aSMA+) are the predominant cell type, comprised ~40% of the TME (SD = 19, 8-78%) whereas CD11b+ myeloid cells were rare contributing only to ~0.15% (SD = 0.39, 0-1.6%) of the cellular milieu in the chordoma TME. These results indicate a high degree of heterogeneity in stromal and myeloid cell populations between chordoma tumors and further our understanding of the spatial relationship between TME populations and tumor cells. Ongoing studies will include stromal cell subtyping (pericytes, endothelial cells, etc) and investigation of other immune populations including T cells and macrophages by multiplex immunofluorescence. Additionally, these immune- and stromal-rich regions will serve as regions of interest for future spatial transcriptomics studies. Further analysis of stromal and immune subsets within the TME of chordoma could reveal insights into mechanisms of metastasis and tumor progression, with the hope for additional treatment options to effectively re-educate the TME to eliminate tumor cells as well as identify key tumorigenic cell populations.

Citation Format: Kailey Jackett, Miranda Sowder, Liny John, Ignatius Hazelwood, Rosandra Kaplan. Characterizing the key stromal and immune players in the microenvironment of primary and metastatic chordoma [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B017.

Abstract CT142: GD2.Ox40.CD28.z CAR T cell trial in neuroblastoma and osteosarcoma

Background: Chimeric antigen receptor T cells (CARTs) hold promising therapeutic potential for refractory tumors. GD2 is a tumor antigen expressed on neuroblastoma and osteosarcoma. In initial studies, T cells expressing 1st generation GD2-CARTs were shown to be safe and mediated modest antitumor activity in some patients with refractory neuroblastoma.

Methods: We developed a 3rd generation GD2-CART (GD2-CAR.OX40.28.z.ICD9) and conducted a phase I trial (NCT02107963) to determine the feasibility of producing and safety of administering escalating doses of GD2-CARTs in children and young adults with GD2+ solid tumors, including neuroblastoma and osteosarcoma, following cyclophosphamide-based lymphodepletion. Patient samples were evaluated for cytokine profile kinetics, immune phenotype analysis with mass cytometry (CyTOF), transcriptomic evaluation with RNA-sequencing (RNA-seq), epigenetic determination with Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq), and functional studies with flow cytometry.

Results: 15 patients aged 8-28 years were enrolled on four dose levels, of which 13 patients were infused. No dose-limiting toxicities were observed and administration of up to 1x107 GD2-CART/kg was feasible and safe for children and young adults with neuroblastoma and osteosarcoma. 15.4% (2/13) of patients experienced grade-1 cytokine release syndrome (CRS) and no neurological toxicity was observed. We measured the expansion and persistence of adoptively transferred GD2-CARTs in the peripheral blood. GD2-CARTs expanded in all patients receiving treatment, half of whom had expansion similar to that seen in clinically active CD19 and CD22 CARTs, but the GD2-CARTs had limited persistence. At Day 28 following GD2-CART infusion, 23.1% (3/13) of evaluable patients had progressive disease and 76.9% (10/13) had stable disease (SD). 3/10 SD patients remained stable at 60 days post-GD2-CART, but all patients eventually progressed. Since a major barrier to CART efficacy is inadequate CART expansion, we comprehensively evaluated for phenotypic, transcriptomic, and epigenetic immune profiles of patient apheresis, CART product, and post-treatment peripheral blood samples to identify determinants of CART expansion. GD2-CART expansion is significantly correlated with several T cell markers, and a larger baseline naïve and central memory T cell pool. Unique myeloid populations are associated with CART expansion. ATACseq identifies epigenetic differences in pre-treatment apheresis that may predict good CAR expansion in patients.

Conclusions: GD2-CART therapy following cyclophosphamide conditioning was well tolerated at all four dose levels in pediatric and young adult patients with neuroblastoma and osteosarcoma. Subsequent multi-dimensional analyses suggest key mechanisms underlying CART biology and function and highlight the potential of defining and applying molecular signatures in apheresis and CART product as biomarkers and prognostic indicators of CART expansion, with promise for advancing immunotherapies for solid tumor patients in the future.

Citation Format: Sneha Ramakrishna, Sabina Kaczanowska, Tara Murty, Cristina F. Contreras, Melinda Merchant, John Glod, Norma Gutierrez, Ahmad Alimadadi, David Stroncek, Steven Highfill, Caroline Duault, Priyanka B. Subrahmanyam, Tyson Holmes, Warren Reynolds, Reema Baskar, Antoine Barge, Hayley Lyon, Radim Moravec, Srinika Ranasinghe, Joyce Yu, Roshni Biswas, Samuel Pollack, Stephen Van Nostrand, James Lindsay, Mina Pichavant, Bita Sahaf, Sean C. Bendall, Andrew J. Gentles, Holden Maecker, Catherine C. Hedrick, Crystal Mackall, Rosandra Kaplan. GD2.Ox40.CD28.z CAR T cell trial in neuroblastoma and osteosarcoma [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 CT142.

209 Genetically engineered myeloid cells (GEMys) as a platform to enhance antitumor immunity

Background

Immune suppression is a major hurdle in cancer immunotherapy for solid tumors. Innate myeloid cells are key regulators of the immune system and can dampen the antitumor response against cancer. We have identified that bone marrow-derived myeloid cells play an immunosuppressive role in the metastatic microenvironment, limiting immune surveillance and facilitating the growth of tumor cells. We hypothesized that targeting the myeloid-mediated immune suppression program in the metastatic and primary tumor microenvironment could facilitate antitumor immune activation and be a successful immunotherapeutic approach.

Methods

To take advantage of the unique capability of myeloid cells to home to and infiltrate tumor and metastatic sites, we designed an immunotherapeutic approach in which we generate genetically engineered myeloid cells (GEMys) as a platform to locally deliver modulatory factors into the tumor and metastatic microenvironment.

Results

Mice treated with IL-12-secreting GEMys (IL12-GEMys) exhibited a robust IFNγ response associated with increased expression of antigen processing and presentation machinery as well as numbers of T and NK cells expressing markers associated with activation and cytotoxicity. These microenvironmental changes were associated with reduced metastasis, delayed tumor growth, and increased survival. When combined with chemotherapy pre-conditioning, IL12-GEMys cured mice of established tumors and generated long-lived T cell memory, as these mice were immune to subsequent tumor challenge. We are currently working on translating these exciting findings into the human setting.

Conclusions

This work demonstrates that IL12-GEMys can functionally modulate the core program of immune suppression in the pre-metastatic niche to successfully rebalance the dysregulated metastatic microenvironment in cancer. This approach holds promise to limit metastatic progression in patients with high risk and advanced cancers.

References

Kaczanowska S, Beury DW, Gopalan V, Tycko AK, Qin H, Clements ME, Drake J, Nwanze C, Murgai M, Rae Z, Ju W, Alexander KA, Kline J, Contreras CF, Wessel KM, Patel S, Hannenhalli S, Kelly M, Kaplan RN. Genetically engineered myeloid cells rebalance the core immune suppression program in metastasis. Cell 2021;184:1–20.

Genetically Engineered Myeloid Cells Rebalance the Core Regulatory Immune Suppression Program in Metastasis

Tumor metastasis is a critical step in the progression of solid tumors that is associated with patient mortality, yet we have limited knowledge of the metastatic microenvironment to effectively target this process. The pre-metastatic niche is the tumor-promoting microenvironment that is established at distant sites in response to primary tumor growth before detectable metastatic disease. We characterized immune populations in the lungs of tumor-bearing mice by flow cytometry and RNA sequencing approaches. We identified an immune suppression gene signature in pre-metastatic niche formation that is found predominantly within myeloid cells. In addition to the increase of myeloid cells and immunosuppressive pathways, we discovered that T cell populations are reduced in pre-metastatic lungs. We hypothesized that reversing this immunosuppressive environment would restore T cell function and antitumor immunity. We designed a novel approach in which we generated Genetically-Engineered Myeloid cells (GEMys) to deliver IL-12, a potent antitumor molecule, into the pre-metastatic microenvironment. We evaluated the lungs by flow cytometry and observed that IL12-GEMy-treated mice had increased numbers of T cells and enhanced expression of activation markers, resulting in reduced metastasis and increased survival. When combined with chemotherapy pre-conditioning, IL12-GEMys cured mice of established tumors and generated long-lived T cell memory, as these mice were immune to subsequent tumor challenge. These studies demonstrate that IL12-GEMys can functionally modulate the core program of immune suppression in the pre-metastatic niche to successfully rebalance the dysregulated metastatic microenvironment in cancer.

A feasibility study using time-driven activity-based costing as a management tool for provider cost estimation: lessons from the national TB control program in Zimbabwe in 2018

Background

Insufficient cost data and limited capacity constrains the understanding of the actual resources required for effective TB control. This study used process maps and time-driven activity-based costing to document TB service delivery processes. The analysis identified the resources required to sustain TB services in Zimbabwe, as well as several opportunities for more effective and efficient use of available resources.

Methods

A multi-disciplinary team applied time-driven activity-based costing (TDABC) to develop process maps and measure the cost of clinical pathways used for Drug Susceptible TB (DS-TB) at urban polyclinics, rural district and provincial hospitals, and community based targeted screening for TB (Tas4TB). The team performed interviews and observations to collect data on the time taken by health care worker-patient pairs at every stage of the treatment pathway. The personnel’s practical capacity and capacity cost rates were calculated on five cost domains. An MS Excel model calculated diagnostic and treatment costs.

Findings

Twenty-five stages were identified in the TB care pathway across all health facilities except for community targeted screening for TB. Considerable variations were observed among the facilities in how health care professionals performed client registration, taking of vital signs, treatment follow-up, dispensing medicines and processing samples.

The average cost per patient for the entire DS-TB care was USD324 with diagnosis costing USD69 and treatment costing USD255. The average cost for diagnosis and treatment was higher in clinics than in hospitals (USD392 versus USD256). Nurses in clinics were 1.6 time more expensive than in hospitals. The main cost components were personnel (USD130) and laboratory (USD119). Diagnostic cost in Tas4TB was twice that of health facility setting (USD153 vs USD69), with major cost drivers being demand creation (USD89) and sputum specimen transportation (USD5 vs USD3).

Conclusion

TDABC is a feasible and effective costing and management tool in low-resource settings. The TDABC process maps and treatment costs revealed several opportunities for innovative improvements in the NTP under public health programme settings. Re-engineering laboratory testing processes and synchronising TB treatment follow-up with antiretroviral treatments could produce better and more uniform TB treatments at significantly lower cost in Zimbabwe.

Immunotherapy for solid tumors: Chimeric antigen receptor (CAR) T-cells and the tumor microenvironment

Patients with solid tumors continue to experience decreased survival rates, with metastasis being the leading cause of mortality in these patients. This has prompted the development of novel immunotherapies, with cellular immunotherapy giving rise to the development of Chimeric Antigen Receptor (CAR) T-cells, an approach combining specificity for tumor antigens and cytotoxicity independent of major histocompatibility complex molecule co-stimulation. This modality has proven efficacious in Acute Lymphoblastic Leukemia and B-cell Lymphoma. However, progress has remained limited in solid tumors despite targeting of various antigens, one of such being disialoganglioside (GD2) which has proven a viable target in neuroblastoma. This study investigates the efficacy of GD2 as an antigen target for CAR T-cell therapy in osteosarcoma. Surface flow cytometric analysis revealed the presence of GD2 on human 143B and Hu09H3 osteosarcoma cell lines. Of note, the tumor microenvironment offers an additional potential therapeutic target, as we observed increases in myeloid-derived suppressor cells alongside decreases in CD4+ T cells in primary tumor and metastatic tissues. In summary, we report the utility of GD2 as a target for cellular immunotherapy in osteosarcoma and the role of the tumor microenvironment in anti-tumor therapeutic modalities, a therapeutic combination that could be applicable to optimizing potent therapeutic modalities for solid tumors.

Fasting and post-glucose load measures of insulin resistance and risk of incident atrial fibrillation: The Cardiovascular Health Study

BACKGROUND AND AIMS

Existing literature in individuals without diabetes has not demonstrated a relationship between IR and incident AF; however, data are limited and only fasting glucose measures of IR were assessed. We evaluated the relationship of both fasting and post-glucose load IR measures with the development of atrial fibrillation in nondiabetic older adults.

METHODS AND RESULTS

Among Cardiovascular Health Study participants, a population-based cohort of 5888 adults aged 65 years or older enrolled in two waves (1989-1990 and 1992-1993), those without prevalent AF or diabetes and with IR measures at baseline were followed for the development of AF, identified by follow-up visit electrocardiograms, hospital discharge diagnosis coding, or Medicare claims data, through 2014. Fasting IR was determined by the homeostatic model of insulin resistance (HOMA-IR) and post-glucose load IR was determined by the Gutt index. Cox proportional hazards models were used to determine the association of IR with risk of AF. Analyses included 3601 participants (41% men) with a mean age of 73 years. Over a median follow-up of 12.3 years, 1443 (40%) developed AF. After multivariate adjustment, neither HOMA-IR nor the Gutt index was associated with risk of developing AF [hazard ratios (95% confidence intervals): 0.96 (0.90, 1.03) for 1-SD increase in HOMA-IR and 1.03 (0.97, 1.10) for 1-SD decrease in the Gutt index].

CONCLUSIONS

We found no evidence of an association between either fasting or post-glucose load IR measures and incident AF.

Antitumor Activity Associated with Prolonged Persistence of Adoptively Transferred NY-ESO-1 c259T Cells in Synovial Sarcoma

We evaluated the safety and activity of autologous T cells expressing NY-ESO-1^c259, an affinity-enhanced T-cell receptor (TCR) recognizing an HLA-A2-restricted NY-ESO-1/LAGE1a-derived peptide, in patients with metastatic synovial sarcoma (NY-ESO-1^c259T cells). Confirmed antitumor responses occurred in 50% of patients (6/12) and were characterized by tumor shrinkage over several months. Circulating NY-ESO-1^c259T cells were present postinfusion in all patients and persisted for at least 6 months in all responders. Most of the infused NY-ESO-1^c259T cells exhibited an effector memory phenotype following ex vivo expansion, but the persisting pools comprised largely central memory and stem-cell memory subsets, which remained polyfunctional and showed no evidence of T-cell exhaustion despite persistent tumor burdens. Next-generation sequencing of endogenous TCRs in CD8⁺ NY-ESO-1^c259T cells revealed clonal diversity without contraction over time. These data suggest that regenerative pools of NY-ESO-1^c259T cells produced a continuing supply of effector cells to mediate sustained, clinically meaningful antitumor effects.Significance: Metastatic synovial sarcoma is incurable with standard therapy. We employed engineered T cells targeting NY-ESO-1, and the data suggest that robust, self-regenerating pools of CD8⁺ NY-ESO-1^c259T cells produce a continuing supply of effector cells over several months that mediate clinically meaningful antitumor effects despite prolonged exposure to antigen. Cancer Discov; 8(8); 944-57. ©2018 AACR.See related commentary by Keung and Tawbi, p. 914This article is highlighted in the In This Issue feature, p. 899.

An integrated community TB-HIV adherence model provides an alternative to DOT for tuberculosis patients in Cape Town

SETTING

Cape Town, South Africa.

OBJECTIVE

To evaluate anti-tuberculosis treatment outcomes and rate of antiretroviral therapy (ART) initiation using weekly community-based adherence support compared to daily directly observed therapy (DOT).

METHODS

This was a retrospective analysis comparing two cohorts treated for tuberculosis (TB) in 70 TB clinics during 6-month periods before and after the introduction of a new adherence model comprising treatment literacy sessions during 2 weeks of DOT, followed by weekly home visits by community care workers to eligible patients managing their own treatment. Odds ratios (ORs) of treatment success and ART initiation were calculated using multivariable random effects logistic regression models. Hazard ratios (HRs) of default and death were calculated using multivariable random effects Cox regression models.

RESULTS

The pre-intervention cohort comprised 11 896 patients with TB and the post-intervention cohort 11 314. There was no difference in pre- and post-intervention anti-tuberculosis treatment success rates (respectively 82.8% and 82.5%, adjusted OR [aOR] 1.02, 95%CI 0.89-1.17, P = 0.76) nor an increased hazard of death (adjusted HR [aHR] 0.98, 95%CI 0.80-1.21, P = 0.87) or default (aHR 0.97, 95%CI 0.81-1.15, P = 0.69). The ART initiation rate increased from 67% to 74% (aOR 1.43; 95%CI 1.01-1.85, P < 0.01).

CONCLUSION

Weekly community-based adherence support was a viable alternative to daily DOT, with no deterioration in anti-tuberculosis treatment outcomes and an increase in ART initiation.

Patients' preferences for adjuvant sorafenib after resection of renal cell carcinoma in the SORCE trial: what makes it worthwhile?

Background

We sought to determine the survival benefits that patients judged sufficient to warrant adjuvant therapy with sorafenib for 1 year, or for 3 years after resection of renal cell carcinoma in the SORCE trial.

Methods

SORCE participants from all sites in Australia and New Zealand, and selected sites in the UK, completed a validated preferences questionnaire at months 0, 3, 15, and 42 to elicit the minimum survival benefits they judged sufficient to warrant adjuvant sorafenib for 1 year (versus observation), or for 3 years (versus 1 year). The questionnaires used reference survival times of 5 and 15 years; and reference survival rates at 5 years of 65% and 85%.

Results

The 233 participants had a median age of 57 years (range 29-78) and 71% were male. For 1 year of sorafenib versus no adjuvant therapy, the median benefits in survival times judged sufficient to warrant treatment were an extra 9 months beyond 5 years and an extra 1 year beyond 15 years; the median benefit in survival rates were an extra 4% beyond 65% and an extra 3% beyond 85% at 5 years. For 3 years of sorafenib versus 1 year of sorafenib, the median benefit in survival time judged sufficient to warrant extended treatment was an extra 1 year beyond both 5 and 15 years. Participants randomly allocated to treatment with sorafenib judged larger benefits necessary than those allocated to placebo. Participants' preferences were not associated with their baseline characteristics or the interval from randomisation.

Conclusion

Most participants judged an extra year of survival necessary to warrant 1 year of adjuvant sorafenib worthwhile, and an additional year of survival to warrant extending the duration of sorafenib from 1 to 3 years. Patients' preferences are important in shared decision making.

SORCE trial clinical trials number

NCT00492258.

Physiological, Tumor, and Metastatic Niches: Opportunities and Challenges for Targeting the Tumor Microenvironment

The primary tumor niche and the related but distinct premetastatic/metastatic niche comprise a number of essential players, including immune cells, stromal cells, and extracellular matrix. The cross-talk between these components is key to tumor progression. Many of these cell types and signaling pathways in the tumor microenvironment also are found in physiological and stem cell niches, such as the bone marrow, colonic crypt, and skin bulge. Here they play tightly regulated roles in wound healing and tissue homeostasis. Understanding the similarities and differences between these distinct niches may better inform our ability to therapeutically target the tumor microenvironment. In this review we discuss a number of tumor and metastatic niche components as they relate to stem cell niches and highlight potential therapeutic strategies in pediatric cancers.

Mycobacterium bovis hip bursitis in a lung transplant recipient

We present a report of extrapulmonary Mycobacterium bovis infection in a lung transplant recipient. M. bovis is acquired predominantly by zoonotic transmission, particularly from consumption of unpasteurized foods. We discuss epidemiologic exposure, especially as relates to the Mexico-US border, clinical characteristics, resistance profile, and treatment.

Abstract 4725: Hematopoietic stem cell niche activation and progenitor mobilization mediate cancer-associated immunosuppression and metastasis

Metastatic tumors have been shown to establish microenvironments in distant tissues that are permissive to disseminated tumor cells. Hematopoietic cells are essential components of this microenvironment, yet the events that initiate the hematopoietic response remain unclear. Further, the functional contribution of hematopoietic stem and progenitor cells (HSPCs) to metastatic progression has not been addressed. Here, we utilized two highly metastatic C57bl/6 murine cell lines capable of spontaneous metastasis following orthotopic injection to study how the hematopoietic response is initiated and can function to promote metastatic progression in immune competent tumor-bearing mice. In both the E0771 breast carcinoma model and M3-9-M rhabdomyosarcoma model we found that a primary tumor drove expansion of HSPCs within the bone marrow prior to establishment of metastatic lesions. To detect changes within the bone marrow microenvironment that accounted for the observed HSPC expansion in tumor-bearing mice, we performed qPCR analysis of whole femur lysate from control or pre-metastatic tumor-bearing mice. We found the bone marrow microenvironment of tumor-bearing mice expressed a transcriptional program of hematopoietic niche activation that promoted expansion as well as mobilization of hematopoietic progenitors, including downregulation of the HSPC homing cytokine CXCR4. Consistent with this, we detected elevated HSPCs in the circulation of newly diagnosed cancer patients as well as pre-metastatic tumor-bearing mice. By using a pharmacological antagonist of CXCR4 to mobilize HSPCs as seen in the tumor bearing setting, we demonstrated that circulating HSPCs were functionally capable of significantly enhancing metastasis in mice. To determine the mechanisms by which circulating HSPCs can promote metastatic progression, we tracked the developmental fate of flow cytometry-sorted HSPCs injected into the circulation of control or tumor-bearing pre-metastatic mice. We found that HSPCs localized within pre-metastatic tissues preferentially differentiated into the myeloid lineage. Further, depletion of these myeloid cells abrogated the metastasis-promoting effects of HSPC mobilization. Together, these data establish bone marrow niche activation as one of the earliest steps of the metastatic process and identify circulating HSPCs as a potential indicator of metastatic niche initiation.

Citation Format: Amber J. Giles, Meera Murgai, Yorleny Vicioso, Steven Highfill, Miki Kasai, Linda Vahdat, Leonard Wexler, Crystal Mackall, David Lyden, Rosandra Kaplan. Hematopoietic stem cell niche activation and progenitor mobilization mediate cancer-associated immunosuppression and metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4725. doi:10.1158/1538-7445.AM2015-4725

Abstract 4126: CSF-1R inhibition blocks rhabdomyoscarcoma metastasis by polarizing macrophage differentiation

Colony Stimulating Factor 1 (CSF-1) is overexpressed by many tumors and predicts poor clinical outcome. CSF-1 expression results in the recruitment of CSF-1R (Fms)-expressing cells, which have been shown to suppress tumor immunity, thereby promoting cancer progression. PLX3397 is a novel, orally active small molecule inhibitor that selectively targets CSF-1R, KIT, and oncogenic FIT3. CSF-1R and KIT regulate the tumor, tumor microenvironment, and the pre-metastatic niche. However, it is unknown if targeting the myeloid CSF-1R expressing component of the tumor microenvironment regulates metastasis of pediatric tumors, such as rhabdomyosarcoma. Using the M3-9-M murine syngeneic orthotopic rhabdomyosarcoma model, we evaluated the effects of PLX3397 on primary tumor growth and metastatic progression. This highly metastatic rhabdomyosarcoma model has high infiltration of CSF-1R-expressing bone marrow-derived cells, which includes inflammatory monocytes, M2 macrophages, and myeloid-derived suppressor cells. Therefore, we hypothesized PLX3397 would have a direct effect on CSF-1R expressing M2 macrophages and inflammatory monocytes, resulting in decreased metastasis. Using both in vitro and in vivo models, we found that PLX3397 treatment decreased tumor-infiltrating M2 macrophages and skewed the differentiation of inflammatory monocytes toward M1 macrophages and development of immunocompetent mature dendritic cells. This resulted in impairment of spontaneous M3-9-M metastasis to secondary sites. In addition, we have found that the polarization of inflammatory monocytes reversed the T cell suppressive capability of tumor-derived myeloid cells. In conclusion, CSF-1R blockage with PLX3397 inhibited metastatic progression by decreasing the infiltration of M2 macrophages in the primary tumor and pre-metastatic niche. The polarization of inflammatory monocytes to dendritic cells restored the immune recognition and decreased metastasis. This data supports our rationale for testing PLX3397 in patients with high M2 infiltration and suggests value in this agent as an adjuvant setting for metastasis prevention in high-risk patients.

Note: This abstract was not presented at the meeting.

Citation Format: Justin Evans, Amber Giles, Caitlin Reid, Rosandra Kaplan. CSF-1R inhibition blocks rhabdomyoscarcoma metastasis by polarizing macrophage differentiation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4126. doi:10.1158/1538-7445.AM2015-4126

PROMIS--Prostate MR imaging study: A paired validating cohort study evaluating the role of multi-parametric MRI in men with clinical suspicion of prostate cancer

BACKGROUND

Transrectal ultrasound-guided prostate biopsies are prone to detection errors. Multi-parametric MRI (MP-MRI) may improve the diagnostic pathway.

METHODS

PROMIS is a prospective validating paired-cohort study that meets criteria for level 1 evidence in diagnostic test evaluation. PROMIS will investigate whether multi-parametric (MP)-MRI can discriminate between men with and without clinically-significant prostate cancer who are at risk prior to first biopsy. Up to 714 men will have MP-MRI (index), 10-12 core TRUS-biopsy (standard) and 5mm transperineal template mapping (TPM) biopsies (reference). The conduct and reporting of each test will be blinded to the others.

RESULTS

PROMIS will measure and compare sensitivity, specificity, and positive and negative predictive values of both MP-MRI and TRUS-biopsy against TPM biopsies. The MP-MRI results will be used to determine the proportion of men who could safely avoid biopsy without compromising detection of clinically-significant cancers. For the primary outcome, significant cancer on TPM is defined as Gleason grade >/= 4+3 and/or maximum cancer core length of ≥ 6 mm. PROMIS will also assess inter-observer variability among radiologists among other secondary outcomes. Cost-effectiveness of MP-MRI prior to biopsy will also be evaluated.

CONCLUSIONS

PROMIS will determine whether MP-MRI of the prostate prior to first biopsy improves the detection accuracy of clinically-significant cancer.

Abstract 2074: Metastasis prevention using fibroblast activation protein-targeting prodrugs at the pre-metastatic niche

Metastasis is the major cause of cancer death, and therapies that effectively target this process are required in order to improve patient survival. Previous work by Kaplan et al demonstrated that activated resident stromal cells and recruited bone marrow derived cells (BMDCs) form an altered microenvironment at distant sites in response to the primary tumor, termed the pre-metastatic niche, that promotes metastatic progression. Current on-going studies in the laboratory focus on in-depth investigations of the role, composition and mechanism of action by which each cell population including the bone marrow-derived hematopoietic cells and the activated stromal cells within the pre-metastatic niche contribute to metastatic progression. Fibroblast activation protein (FAP) is a serine protease that is overexpressed by tumor associated stromal cells, including cancer-associated fibroblasts (CAFs) and is implicated in the suppression of tumor immunity. Using a mouse model that expresses FAP promoter-driven mCherry and luciferase, we demonstrate that FAP gene expression is up-regulated in both tumor-bearing mice in pre-metastatic tissue at pre-metastatic time-points and in non-tumor-bearing mice injected with tumor-conditioned media, suggesting that metastatic tumors secrete factors that increases the number of FAP-expressing cells at the pre-metastatic niche. The studies described herein investigate the hypothesis that FAP-expressing cells at the pre-metastatic niche promote metastasis, and FAP-targeted cytotoxic drug delivery will aid in targeting tumor colonization and inhibiting metastatic progression.

Citation Format: Meera Murgai, Amber Giles, Miki Kasai, Yorleny Vicioso, Crystal Mackall, Rosandra Kaplan. Metastasis prevention using fibroblast activation protein-targeting prodrugs at the pre-metastatic niche. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2074. doi:10.1158/1538-7445.AM2014-2074

Toward a drug development path that targets metastatic progression in osteosarcoma

Despite successful primary tumor treatment, the development of pulmonary metastasis continues to be the most common cause of mortality in patients with osteosarcoma. A conventional drug development path requiring drugs to induce regression of established lesions has not led to improvements for patients with osteosarcoma in more than 30 years. On the basis of our growing understanding of metastasis biology, it is now reasonable and essential that we focus on developing therapeutics that target metastatic progression. To advance this agenda, a meeting of key opinion leaders and experts in the metastasis and osteosarcoma communities was convened in Bethesda, Maryland. The goal of this meeting was to provide a "Perspective" that would establish a preclinical translational path that could support the early evaluation of potential therapeutic agents that uniquely target the metastatic phenotype. Although focused on osteosarcoma, the need for this perspective is shared among many cancer types. The consensus achieved from the meeting included the following: the biology of metastatic progression is associated with metastasis-specific targets/processes that may not influence grossly detectable lesions; targeting of metastasis-specific processes is feasible; rigorous preclinical data are needed to support translation of metastasis-specific agents into human trials where regression of measurable disease is not an expected outcome; preclinical data should include an understanding of mechanism of action, validation of pharmacodynamic markers of effective exposure and response, the use of several murine models of effectiveness, and where feasible the inclusion of the dog with naturally occurring osteosarcoma to define the activity of new drugs in the micrometastatic disease setting.

A feasibility study testing four hypotheses with phase II outcomes in advanced colorectal cancer (MRC FOCUS3): a model for randomised controlled trials in the era of personalised medicine?

BACKGROUND

Molecular characteristics of cancer vary between individuals. In future, most trials will require assessment of biomarkers to allocate patients into enriched populations in which targeted therapies are more likely to be effective. The MRC FOCUS3 trial is a feasibility study to assess key elements in the planning of such studies.

PATIENTS AND METHODS

Patients with advanced colorectal cancer were registered from 24 centres between February 2010 and April 2011. With their consent, patients' tumour samples were analysed for KRAS/BRAF oncogene mutation status and topoisomerase 1 (topo-1) immunohistochemistry. Patients were then classified into one of four molecular strata; within each strata patients were randomised to one of two hypothesis-driven experimental therapies or a common control arm (FOLFIRI chemotherapy). A 4-stage suite of patient information sheets (PISs) was developed to avoid patient overload.

RESULTS

A total of 332 patients were registered, 244 randomised. Among randomised patients, biomarker results were provided within 10 working days (w.d.) in 71%, 15 w.d. in 91% and 20 w.d. in 99%. DNA mutation analysis was 100% concordant between two laboratories. Over 90% of participants reported excellent understanding of all aspects of the trial. In this randomised phase II setting, omission of irinotecan in the low topo-1 group was associated with increased response rate and addition of cetuximab in the KRAS, BRAF wild-type cohort was associated with longer progression-free survival.

CONCLUSIONS

Patient samples can be collected and analysed within workable time frames and with reproducible mutation results. Complex multi-arm designs are acceptable to patients with good PIS. Randomisation within each cohort provides outcome data that can inform clinical practice.

Impact of human immunodeficiency virus and CD4 count on tuberculosis diagnosis: analysis of city-wide data from Cape Town, South Africa

BACKGROUND

The impact of human immunodeficiency virus (HIV) infection and CD4 count on the diagnosis of tuberculosis (TB) at population level is incompletely defined.

OBJECTIVE

To determine how HIV infection and CD4 count affect disease site, sputum smear status and overall rate of laboratory confirmation (sputum smear microscopy or culture) of TB cases under routine programme conditions.

DESIGN

Retrospective analysis of the 2009 electronic TB register for Cape Town, South Africa.

RESULTS

Of 29,478 TB cases notified in 2009, HIV status was known for 25,744 (87.3%) cases, of whom 13,237 (51.4%) were HIV-positive. Of these, 61.2% had CD4 cell counts of <200 cells/μl and 82.7% had counts of <350 cells/μl. Laboratory confirmation of TB (by smear or culture) was obtained less frequently in HIV-infected than non-HIV-infected adult cases (53.9% vs. 74.3%, P< 0.001). HIV infection was associated with a higher proportion of sputum smear-negative and extra-pulmonary TB and lower grades of sputum smear positivity even among those with CD4 counts of ≥ 500 cells/μl. However, the relationship between the proportion of smear-positive cases and CD4 count was non-linear.

CONCLUSION

Much TB is not laboratory-confirmed in this setting despite good laboratory services. HIV-associated TB is more difficult to diagnose even at high CD4 cell counts of >500 cells/μl, suggesting early impact after HIV seroconversion.

Abstract LB-284: Bone marrow-derived progenitor cells develop into myeloid-derived suppressor cells at metastatic sites

The ability of tumor cells to metastasize to distant tissues is the most lethal aspect of cancer. Prior to detectable metastasis tumors elicit distant changes within the bone marrow and future sites of metastasis, including formation of the pre-metastatic niche. We have found that prior to detectable spontaneous metastasis, a primary tumor causes enhanced production and mobilization of progenitor cells from the bone marrow into the blood. We find in cancer patients that increased circulating progenitors are associated with metastatic disease progression. By utilizing bone marrow transplant models and a novel ex vivo lung culture, we demonstrate that bone marrow-derived progenitor cells accumulate at the primary tumor as well as metastatic lesions. As our cancer models approach detectable spontaneous metastases, we observe a loss of progenitor cells in pre-metastatic sites and an increase in myeloid-derived suppressor cells (MDSCs). We further traced adoptively transferred bone marrow-derived progenitors in tumor-bearing mice and demonstrate that these cells contribute to the MDSC population. Together, these data suggest that circulating progenitor cells provide a prognostic tool to predict metastatic dissemination. Furthermore, these cells likely contribute to metastatic progression by developing into MDSCs within the primary tumor and at metastatic sites.

Citation Format: Amber Giles, Yorleny Vicioso, Christianne Persenaire, Miki Kasai, Steven Highfill, Arnulfo Mendoza, Rosandra Kaplan. Bone marrow-derived progenitor cells develop into myeloid-derived suppressor cells at metastatic sites. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-284. doi:10.1158/1538-7445.AM2013-LB-284

Fatal case of sorafenib-associated idiosyncratic hepatotoxicity in the adjuvant treatment of a patient with renal cell carcinoma

Background

Sorafenib is an orally available kinase inhibitor with activity at Raf, PDGFβ and VEGF receptors that is licensed for the treatment of advanced renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC). Current evidence-based post-nephrectomy management of individuals with localized RCC consists of surveillance-based follow up. The SORCE trial is designed to investigate whether treatment with adjuvant sorafenib can reduce recurrence rates in this cohort.

Case presentation

Here we report an idiosyncratic reaction to sorafenib resulting in fatal hepatotoxicity and associated renal failure in a 62 year-old man treated with sorafenib within the SORCE trial.

Conclusion

This is the first reported case of sorafenib exposure associated fatal toxicity in the adjuvant setting and highlights the unpredictable adverse effects of novel adjuvant therapies.

Oxaliplatin/capecitabine vs oxaliplatin/infusional 5-FU in advanced colorectal cancer: the MRC COIN trial

Background:

COIN compared first-line continuous chemotherapy with the same chemotherapy given intermittently or with cetuximab in advanced colorectal cancer (aCRC).

Methods:

Choice between oxaliplatin/capecitabine (OxCap) and oxaliplatin/leucovorin (LV)/infusional 5-FU (OxFU) was by physician and patient choice and switching regimen was allowed. We compared OxCap with OxFU and OxCap+cetuximab with OxFU+cetuximab retrospectively in patients and examined efficacy, toxicity profiles and the effect of mild renal impairment.

Results:

In total, 64% of 2397 patients received OxCap(±cetuximab). Overall survival, progression free survival and overall response rate were similar between OxCap and OxFU but rate of radical surgeries was higher for OxFU. Progression free survival was longer for OxFU+cetuximab compared with OxCap+cetuximab but other efficacy measures were similar. Oxaliplatin/LV/infusional 5-FU (±cetuximab) was associated with more mucositis and infection whereas OxCap(±cetuximab) caused more gastrointestinal toxicities and palmar-plantar erythema. In total, 118 patients switched regimen, mainly due to toxicity; only 16% came off their second regimen due to intolerance. Patients with creatinine clearance (CrCl) 50–80 ml min⁻¹ on OxCap(±cetuximab) or OxFU+cetuximab had more dose modifications than those with better renal function.

Conclusions:

Overall, OxFU and OxCap are equally effective in treating aCRC. However, the toxicity profiles differ and switching from one regimen to the other for poor tolerance is a reasonable option. Patients with CrCl 50–80 ml min⁻¹ on both regimens require close toxicity monitoring.

How may clinical research improve healthcare outcomes?

Healthcare outcomes such as overall survival or quality of life are the end results of a complex interaction between the patient, treatment and the healthcare system. Research may identify superior interventions but their dissemination and changing the behaviour of healthcare providers is challenging. Demonstrating and measuring the benefits of clinical research on healthcare outcomes is an important issue but there is remarkably little empiric work to date in this area. In this chapter we explore benefits that may arise in healthcare from contributing to clinical research, and consider the mechanisms which may be relevant. Improvements in infrastructure, the processes of care and workforces are important. Complex adaptive systems theory provides a framework for considering the many feedback loops that relate research, health outcomes and the behaviour of healthcare providers. Given the costs of research, additional studies to examine the impact of research on healthcare outcomes and to explore the mechanisms are justified and highly desirable.

Extending the clinical research network approach to all of healthcare

The development of Clinical Research Networks (CRN) has been central to the work conducted by Health Departments and research funders to promote and support clinical research within the NHS in the UK. In England, the National Institute for Health Research has supported the delivery of clinical research within the NHS primarily through CRN. CRN provide the essential infrastructure within the NHS for the set up and delivery of clinical research within a high-quality peer-reviewed portfolio of studies. The success of the National Cancer Research Network is summarized in Chapter 5. In this chapter progress in five other topics, and more recently in primary care and comprehensively across the NHS, is summarized. In each of the 'topic-specific' networks (Dementias and Neurodegenerative Diseases, Diabetes, Medicines for Children, Mental Health, Stroke) there has been a rapid and substantial increase in portfolios and in the recruitment of patients into studies in these portfolios. The processes and the key success factors are described. The CRN have worked to support research supported by pharmaceutical, biotechnology and medical device companies and there has been substantial progress in improving the speed, cost and delivery of these 'industry' studies. In particular, work to support the increased speed of set up and delivery of industry studies, and to embed this firmly in the NHS, was explored in the North West of England in an Exemplar Programme which showed substantial reductions in study set-up times and improved recruitment into studies and showed how healthcare (NHS) organizations can overcome delays in set up times when they actively manage the process. Seven out of 20 international studies reported that the first patient to be entered anywhere in the world was from the UK. In addition, the CRN have supported research management and governance, workforce development and clinical trials unit collaboration and coordination. International peer reviews of all of the CRN have been positive and resulted in the continuation of the system for a further 5 years in all cases.

Research-intensive cancer care in the NHS in the UK

In the late 1990 s, in response to poor national cancer survival figures, government monies were invested to enhance recruitment to clinical cancer research. Commencing with England in 2001 and then rolling out across all four countries, a network of clinical cancer research infrastructure was created, the new staff being linked to existing clinical care structures including multi-disciplinary teams. In parallel, a UK-wide co-ordination of cancer research funders driven by the 'virtual' National Cancer Research Institute, combined to create a 'whole-system approach' linking research funders, researchers and NHS clinicians all working to the same ends. Over the next 10 years, recruitment to clinical trials and other well-designed studies, increased 4-fold, reaching 17% of the incident cancer population, the highest national rate world-wide. The additional resources led to more studies opened, and more patients recruited across the country, for all types of cancers and irrespective of additional clinical research staff in some hospitals. In 2006, a co-ordinated decision was made to increasingly focus on randomized trials, leading to increased recruitment, without any fall-off in accrual to non-randomized and observational studies. The National Cancer Research Network has supported large successful trials which are changing clinical practice in many cancers.