Comparing Barriers and Facilitators to Adolescent and Young Adult Clinical Trial Enrollment Across High- and Low-Enrolling Community-Based Clinics

BACKGROUND

Adolescent and young adult (AYA) patients with cancer are underrepresented on cancer clinical trials (CCTs), and most AYAs are treated in the community setting. Past research has focused on individual academic institutions, but factors impacting enrollment vary across institutions. Therefore, we examined the patterns of barriers and facilitators between high- and low-AYA enrolling community-based clinics to identify targets for intervention.

MATERIALS AND METHODS

We conducted 34 semi-structured interviews with stakeholders employed used at National Cancer Institute Community Oncology Research Program (NCORP) affiliate sites ("clinics"). Stakeholders (eg, clinical research associates, patient advocates) were recruited from high- and low-AYA enrolling clinics. We conducted a content analysis and calculated the percentage of stakeholders from each clinic type that reported the barrier or facilitator. A 10% gap between high- and low-enrollers was considered the threshold for differences.

RESULTS

Both high- and low-enrollers highlighted insufficient resources as a barrier and the presence of a patient eligibility screening process as a facilitator to AYA enrollment. High-enrolling clinics reported physician gatekeeping as a barrier and the improvement of departmental collaboration as a facilitator. Low-enrollers reported AYAs' uncertainty regarding the CCT process as a barrier and the need for increased physician endorsement of CCTs as a facilitator.

CONCLUSIONS

High-enrolling clinics reported more barriers downstream in the enrollment process, such as physician gatekeeping. In contrast, low-enrolling clinics struggled with the earlier steps in the CCT enrollment process, such as identifying eligible trials. These findings highlight the need for multi-level, tailored interventions rather than a "one-size-fits-all" approach to improve AYA enrollment in the community setting.

Brentuximab vedotin with chemotherapy in adolescents and young adults (AYAs) with stage III or IV Hodgkin lymphoma: A subgroup analysis from the phase 3 Echelon-1 study

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Background: Hodgkin lymphoma (HL) is a rare disease that commonly occurs in adolescents and young adults (AYAs) which is typically defined as 15 to 39 years. Given their young age at presentation, key factors in treatment selection include a high cure rate and limiting long-term toxicities. Brentuximab vedotin (Adcetris®; A) is a CD30-directed ADC approved in combination with doxorubicin, vinblastine, and dacarbazine chemotherapy (A+AVD) for adults with previously untreated stage III/IV cHL based on results from the phase 3 ECHELON-1 trial. Recent 5-year data demonstrated a significantly improved PFS per investigator (INV) vs doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) (HR, 0.69; 95% CI, 0.54–0.9; P = 0.003) (Straus 2020). Here we describe key efficacy and safety results for AYA pts enrolled in ECHELON-1. Methods: ECHELON-1 (N = 1334) is a global, open-label, multicenter, randomized trial of pts with previously untreated stage III/IV cHL. A total of 771 AYAs (57.8%) received either A+AVD (n = 396) or ABVD (n = 375) with a PET scan after cycle 2 (PET2). An analysis of PFS (time from randomization to progression or death from any cause) per INV was conducted. Results: After a median follow-up of 60.7 months (95% CI, 60.4-61.0), there was a 36% reduction in the risk of progression or death in AYAs receiving A+AVD vs ABVD (HR 0.64; 95% CI, 0.45-0.92; P = 0.013) with a 5-year PFS of 86.3% vs 79.4%, respectively, similar to the ITT population. The PFS benefit of A+AVD vs ABVD was independent of PET2 status; PET2 positivity (Deauville 4-5) was 6% and 8%, respectively. On the A+AVD arm, 81 AYAs (20%) had at least 1 subsequent anticancer therapy vs 96 AYAs (26%) on the ABVD arm; 26 AYAs (7%) received subsequent high dose chemotherapy and autologous stem cell transplant vs 32 AYAs (9%) on the A+AVD and ABVD arms, respectively. Resolution or improvement of peripheral neuropathy (PN) were similar in both arms; 224 AYAs (88%) on the A+AVD had resolution or improvement of PN vs 133 AYAs (89%) on the ABVD arm. Ongoing PN was predominantly Gr 1 (62%) and Gr 2 (26%), with 8 AYAs (13%) on the A+AVD arm and 1 AYA (5%) on the ABVD arm reporting ongoing Gr 3 PN. Finally, 7 AYAs (1.8%) and 5 AYAs (1.4%) on the A+AVD and ABVD arms, respectively, reported a secondary malignancy. Subsequent pregnancies were reported in female pts (44 A+AVD; 26 ABVD) and partners of male pts (31 A+AVD; 30 ABVD). No stillbirths were reported. All but 1 pt in each arm was < 40. Conclusions: Consistent with the ITT population, AYAs treated with A+AVD compared to ABVD had a durable PFS benefit at this significant 5-year milestone. No impact on the rate of secondary malignancies and a numerically greater number of pregnancies were observed, outcomes of interest to AYAs. Additionally, the majority of PN events improved or resolved over time. A+AVD should be considered a treatment option for AYAs with stage III/IV cHL. Clinical trial information: NCT01712490.

Prospective prediction of clinical drug response in high-grade gliomas using an ex vivo 3D cell culture assay

Background

Clinical outcomes in high-grade glioma (HGG) have remained relatively unchanged over the last 3 decades with only modest increases in overall survival. Despite the validation of biomarkers to classify treatment response, most newly diagnosed (ND) patients receive the same treatment regimen. This study aimed to determine whether a prospective functional assay that provides a direct, live tumor cell-based drug response prediction specific for each patient could accurately predict clinical drug response prior to treatment.

Methods

A modified 3D cell culture assay was validated to establish baseline parameters including drug concentrations, timing, and reproducibility. Live tumor tissue from HGG patients were tested in the assay to establish response parameters. Clinical correlation was determined between prospective ex vivo response and clinical response in ND HGG patients enrolled in 3D-PREDICT (ClinicalTrials.gov Identifier: NCT03561207). Clinical case studies were examined for relapsed HGG patients enrolled on 3D-PREDICT, prospectively assayed for ex vivo drug response, and monitored for follow-up.

Results

Absent biomarker stratification, the test accurately predicted clinical response/nonresponse to temozolomide in 17/20 (85%, P = .007) ND patients within 7 days of their surgery, prior to treatment initiation. Test-predicted responders had a median overall survival post-surgery of 11.6 months compared to 5.9 months for test-predicted nonresponders (P = .0376). Case studies provided examples of the clinical utility of the assay predictions and their impact upon treatment decisions resulting in positive clinical outcomes.

Conclusion

This study both validates the developed assay analytically and clinically and provides case studies of its implementation in clinical practice.

Barriers and Facilitators to Adolescent and Young Adult Cancer Trial Enrollment: NCORP Site Perspectives

Background

Although it is well documented that adolescents and young adults (AYAs) with cancer have low participation in cancer clinical trials (CCTs), the underlying reasons are not well understood. We used the National Cancer Institute Community Oncology Research Program (NCORP) network to identify barriers and facilitators to AYA CCT enrollment, and strategies to improve enrollment at community-based and minority and/or underserved sites.

Methods

We performed one-on-one semistructured qualitative interviews with stakeholders (NCORP site principle investigators, NCORP administrators, physicians involved in enrollment, lead clinical research associates or clinical research nurses, nurse navigators, regulatory research associates, patient advocates) in the AYA CCT enrollment process. NCORP sites that included high and low AYA–enrolling affiliate sites and were diverse in geography and department representation (eg, pediatrics, medical oncology) were invited to participate. All interviews were recorded and transcribed. Themes related to barriers and facilitators and strategies to improve enrollment were identified.

Results

We conducted 43 interviews across 10 NCORP sites. Eleven barriers and 13 facilitators to AYA enrollment were identified. Main barriers included perceived limited trial availability and eligibility, physician gatekeeping, lack of provider and research staff time, and financial constraints. Main facilitators and strategies to improve AYA enrollment included having a patient screening process, physician endorsement of trials, an “AYA champion” on site, and strong communication between medical and pediatric oncology.

Conclusions

Stakeholders identified several opportunities to address barriers contributing to low AYA CCT enrollment at community-based and minority and/or underserved sites. Results of this study will inform development and implementation of targeted interventions to increase AYA CCT enrollment.

Entospletinib in Combination with Induction Chemotherapy in Previously Untreated Acute Myeloid Leukemia: Response and Predictive Significance of HOXA9 and MEIS1 Expression

PURPOSE

Spleen tyrosine kinase (SYK) signaling is a proposed target in acute myeloid leukemia (AML). Sensitivity to SYK inhibition has been linked to HOXA9 and MEIS1 overexpression in preclinical studies. This trial evaluated the safety and efficacy of entospletinib, a selective inhibitor of SYK, in combination with chemotherapy in untreated AML.

PATIENTS AND METHODS

This was an international multicenter phase Ib/II study, entospletinib dose escalation (standard 3+3 design between 200 and 400 mg twice daily) + 7+3 (cytarabine + daunorubicin) in phase Ib and entospletinib dose expansion (400 mg twice daily) + 7+3 in phase II.

RESULTS

Fifty-three patients (n = 12, phase Ib and n = 41, phase II) with previously untreated de novo (n = 39) or secondary (n = 14) AML were enrolled (58% male; median age, 60 years) in this study. The composite complete response with entospletinib + 7+3 was 70%. Patients with baseline HOXA9 and MEIS1 expression higher than the median had improved overall survival compared with patients with below median HOXA9 and MEIS1 expression. Common adverse events were cytopenias, febrile neutropenia, and infection. There were no dose-limiting toxicities. Entospletinib-related skin rash and hyperbilirubinemia were also observed.

CONCLUSIONS

Entospletinib with intensive chemotherapy was well-tolerated in patients with AML. Improved survival was observed in patients with HOXA9/MEIS1 overexpression, contrasting published data demonstrating poor survival in such patients. A randomized study will be necessary to determine whether entospletinib was a mediator this observation.

Complete Response to Dual Immunotherapy in a Young Adult with Metastatic Alveolar Soft Part Sarcoma Enabled by a Drug Recovery Program in a Community Practice

Alveolar soft part sarcoma (ASPS) is an extremely rare tumor that frequently occurs in adolescent and young adults (AYA). Survival is poor for patients with metastatic and/or relapsed disease not amenable to local control, and limited therapeutic options are available. A major barrier to cancer care in the United States AYA population is lack of access to coordinated care and appropriate therapies for those who lack insurance or who are underinsured. We report a 25-year-old unemployed, uninsured, single mother who presented with a 12.8 × 21 cm soft tissue thigh mass with heterogeneous avidity, max standardized uptake value of 9, with metastatic disease to the ipsilateral inguinal lymph nodes and to the bilateral lungs. After local control of the primary mass was obtained, a recently developed, comprehensive drug replacement program (DRP) was used to gain access to nivolumab, and after frank progression was noted, ipilimumab was added every 6 weeks. No biomarkers associated with response to immunotherapy were identified. After four cycles, a complete response was observed and patient remains disease free 36 months after beginning dual immunotherapy treatment. We obtained immunotherapy agents through a DRP and describe the development and the utility of this program in the community setting. Our report highlights both first documented sustained complete response to sequenced immunotherapy in an AYA with ASPS as well as a comprehensive DRP, which enabled access to therapy for our patient.

Prospective Validation of an Ex Vivo, Patient-Derived 3D Spheroid Model for Response Predictions in Newly Diagnosed Ovarian Cancer

Although 70–80% of newly diagnosed ovarian cancer patients respond to first-line therapy, almost all relapse and five-year survival remains below 50%. One strategy to increase five-year survival is prolonging time to relapse by improving first-line therapy response. However, no biomarker today can accurately predict individual response to therapy. In this study, we present analytical and prospective clinical validation of a new test that utilizes primary patient tissue in 3D cell culture to make patient-specific response predictions prior to initiation of treatment in the clinic. Test results were generated within seven days of tissue receipt from newly diagnosed ovarian cancer patients obtained at standard surgical debulking or laparoscopic biopsy. Patients were followed for clinical response to chemotherapy. In a study population of 44, the 32 test-predicted Responders had a clinical response rate of 100% across both adjuvant and neoadjuvant treated populations with an overall prediction accuracy of 89% (39 of 44, p < 0.0001). The test also functioned as a prognostic readout with test-predicted Responders having a significantly increased progression-free survival compared to test-predicted Non-Responders, p = 0.01. This correlative accuracy establishes the test’s potential to benefit ovarian cancer patients through accurate prediction of patient-specific response before treatment.

Abstract 53: Ex vivo models of glioblastoma: a comparison of 3D tissues and patient-derived xenografts to clinical response

Standard first-line treatment of newly diagnosed Glioblastoma (GBM) is primarily radiotherapy and Temozolomide (TMZ) with a strong NCCN recommendation of enrollment in clinical trials. The only biomarker that can currently provide a stratification of strong and poor responders to standard of care is methylation of MGMT which indicates a median PFS of 10.3 months for methylated patients and 5.3 months for unmethylated patients. Development of patient-specific in vitro models of GBM for rapid testing of therapeutic options may yield more efficacious therapies and faster, more accurate assignation of therapies to each patient. To that end, we have developed a multi-faceted, patient-based 3D GBM model with modularity that facilitates increasing levels of model complexity such as the inclusion of immune cell components. Stable populations of glioma stem cells (GSC) from 24 of 41 patient samples have been successfully established, verified for stemness through limited dilution in in vitro and in vivo studies, and cultured long-term with minimal molecular changes, as determined from genetic analyses including RT-PCR arrays and MGMT methylation status, flow cytometry, and IHC. These cell populations have been used to establish and validate our 3D model system as well as generate comparable patient-derived xenografts (PDX). KIYATEC’s 3D microtumor in our 3DKUBE™ perfusion system provides a moderate throughput, dynamic system that is easily controlled to establish complex microtumors. GSC cell populations were cultured in monoculture only, co-cultured with human brain endothelial cells (HBEC), and tri-cultured with HBEC and CD14+ peripheral blood mononuclear cells (PBMC). Three microtumors were characterized by drug response to TMZ and axitinib, IHC, and molecular profiling including RNA expression and MGMT methylation status. Interestingly, increasing the complexity of the microtumor was capable of reestablishing the primary tumor MGMT methylation status if it were lost during culturing. We also generated PDX models from the same 3 patient tumor tissues as the above 3D models. PDX are a low throughput, time consuming, and expensive model that are still utilized for many systemic drug response studies and therefore a good comparator to the 3D tissue models we established. In vitro drug response in the 3D tissue models has been compared to both the matched PDX in vivo drug response and the patient’s clinical response to TMZ and MGMT methylation. Our data supports that KIYATEC’s complex patient-derived GBM model can be successfully used to identify, screen, and characterize novel treatments of GBM.

Citation Format: Ashley M. Smith, Lillia Holmes, Lacey E. Dobrolecki, Charles Kanos, Stephen Gardner, Philip Hodge, Michael Lynn, Jeff Edenfield, Michael T. Lewis, Howland E. Crosswell, Teresa M. DesRochers. Ex vivo models of glioblastoma: a comparison of 3D tissues and patient-derived xenografts to clinical response [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 53.

Abstract 2240: Redefining personalized medicine by drug response profiling of patient-derived spheroids

Personalized medicine in cancer typically refers to the use of genetics and/or biomarkers to direct the use of targeted therapy or predict overall prognosis based on statistical probability. Therapy selection and predictions are not based on any physical interaction between a patient’s tumor cells to clinically relevant therapies based on their disease indication. We have developed an assay using 3D cell culture that exposes a patient’s tumor cells to standard of care chemotherapies for the purpose of predicting their clinical response to potential treatment options prior to treatment. We have analytically validated this assay enabling its performance under CLIA regulations as a Laboratory Developed Test (LDT) and prospectively validated it against clinical patient outcome in ovarian cancer. The test utilizes excess fresh patient tissue acquired during standard of care surgical debulking or biopsy and returns results within 7 business days of tissue receipt, typically well before the start of chemotherapy. Previously, we have shown in newly diagnosed ovarian cancer, the test has an accuracy of 87% with a specificity of 100% and a sensitivity of 84% in the prediction of standard first-line carboplatin/taxol combination therapy using the biomarker CA-125 and CT imaging as clinical readouts. We have similar results for the prediction of response to neoadjuvant therapy following laparoscopic biopsy using RECIST criteria. We have now analytically validated the assay in glioblastoma (GBM) and rare tumors. Preliminary clinical validation in GBM has shown the ability of the test to accurately predict response to standard first-line temozolomide using RANO criteria as the clinical readout. Rare tumor validation has included a panel of 12 drugs covering those used as standard of care for most rare tumors. Aspects of validation have included examining inter- and intra-assay variability and drug panel response in a defined number of rare tumors including sarcomas, neuroendocrine, and other tumors such as Sertoli-Leydig. In breast cancer, we have validated the assay for the use of a single diagnostic biopsy core as the tissue source and established preliminary clinical validation against standard of care such as doxorubicin and paclitaxel with pathologic complete response (pCR) as the clinical readout. We are further validating the predictive ability of the test in newly diagnosed and relapsed ovarian cancer and GBM patients (clinical trial NCT03561207). With demonstrated accurate prediction of patient specific response, the transition to cancer therapy selection based on physical evidence vs statistical probability would significantly improve patient outcomes and benefit economic stakeholders.

Citation Format: Stephen Shuford, Christine Wilhelm, Ashley M. Smith, Melissa Rayner, Jeremy Stuart, Lillia Holmes, Matt Gevaert, Howland E. Crosswell, Teresa M. DesRochers. Redefining personalized medicine by drug response profiling of patient-derived spheroids [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 2240.

Drug Recovery and Copay Assistance Program in a Community Cancer Center: Charity and Challenges

PURPOSE

The cost of cancer care is escalating dramatically, in part because of the rising expense of systemic cancer therapy. This creates financial dilemmas for patients and insurers and potential economic disruption for institutions attempting to provide cancer care to the underserved. Our institution initiated a drug recovery and copay assistance program (DRCAP) to mitigate the impact of the rising cost of parenteral medications.

METHODS

We performed a 3-year review of our strategies to mitigate financial burden of parenteral therapeutics and supportive care medicines. Financial metrics were established and analyzed before and after implementing DRCAP. Medication encounters and associated costs were stratified by adolescents and young adults (15 to 39 years of age), and adults 40 years of age and older and were annualized from 2016 to 2018.

RESULTS

The DRCAP resulted in a total of nearly $3.5 million worth of drugs replaced or copay assistance yearly in 2017 and 2018. This accounted for approximately 10% of our pharmacy budget for parenteral medications in each of these years. The vast majority was received in the form of drug replacement. The DRCAP resulted in assistance to 173 and 256 patients in 2017 and 2018, respectively.

CONCLUSION

A DRCAP increased availability of otherwise unaffordable parenteral oncolytics and resulted in cost savings for our institution. Adolescents and young adults were disproportionately represented because of inadequate or no insurance. Despite the salutary benefits, such programs likely inflate the overall cost of cancer care. Cancer care providers participating in a DRCAP will remain in this conundrum until market forces can affect the cost of oncology therapeutics.

Abstract 1121: Profiling patient-specific glioblastoma drug response in vitro using complex 3D microtumors

Glioblastoma (GBM) has a median survival of less than 2 years due to intra-tumoral heterogeneity, diffuse infiltrations of adjacent brain tissue, and a lack of effective therapies. Development of more efficacious therapies will require better GBM models for the testing and identification of novel agents. Towards this end, we have successfully developed a GBM 3D tissue model that can provide in vitro, patient-specific compound screening. Stable populations of glioma stem cells (GSC) from 24 of 41 patient samples have been successfully established and cultured long-term with minimal changes. To confirm stemness of the GSC population, we have successfully established a limiting-dilution series within SCID/Bg mice and characterized the resultant tumors. 4 of these lines have been used to establish patient-derived xenograft (PDX) models in mice. The original, primary patient tissue established GSC populations, and the resultant PDX tissues have been characterized by flow cytometry, IHC, RNA expression, NGS, and MGMT methylation status. With the goal of better modeling the patient tumor tissue in vitro, our GSC populations have also been used to establish complex microtumors within the KIYATEC 3DKUBE™ perfusion system, consisting of monoculture GSCs, GSCs co-cultured with human brain endothelial cells (HBECs), and GSCs co-cultured with HBECs and CD14+ peripheral blood mononuclear cells. Our monoculture microtumors consisting of only GSCs show a maintenance of GSC markers Nestin and Sox2 by both IHC and mRNA. Interestingly, when these cells are used to produce PDX, they up-regulate GFAP as a marker of differentiation that is not observed in the neurosphere or monoculture microtumor cultures. We have shown these 3D models to be viable for more than 1 month in perfusion and to be effective models for drug compound screening by dosing the microtumors on a weekly basis with temozolomide (TMZ). We have correlated TMZ response to MGMT methylation as reported both clinically and measured in vitro. Finally, In vitro drug response has been compared to both matched PDX in vivo drug response and the patient's clinical response to TMZ and MGMT methylation. Our data supports that this complex, 3D, patient-derived GBM model can be used to effectively screen, identify and characterize novel treatments of GBM.

Citation Format: Ashley M. Smith, Melissa Millard, Lillia Holmes, Michael T. Lewis, Lacey E. Dobrolecki, Charles Kanos, Stephen Gardner, Philip Hodge, Fred Nelson, Michael Lynn, Jeff Edenfield, Christopher Corless, David Schammel, Howland E. Crosswell, Teresa M. DesRochers. Profiling patient-specific glioblastoma drug response in vitro using complex 3D microtumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1121.

Abstract 819: High response rates with entospletinib in patients with t(v;11q23.3);KMT2A rearranged acute myeloid leukemia and acute lymphoblastic leukemia

Introduction: Targeted therapy for KMT2A (mixed lineage leukemia [MLL]) rearranged acute leukemia (AL) is lacking. KMT2A regulates leukemic stem cell transcription factors HOXA9 and MEIS1. Spleen tyrosine kinase (SYK) signaling induces MEIS1 in conjunction with HOXA9. We hypothesize that this regulatory loop may be sensitive to SYK inhibition with Entospletinib (ENTO) a highly selective, oral SYK inhibitor. In this analysis, we evaluate the efficacy of ENTO in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) with t(v;11q23.3) KMT2A/MLL gene rearrangements.

Methods: Patients with KMT2A rearranged AL in two different clinical trials were included. AML patients (NCT02343939) received ENTO 400mg BID monotherapy for up to 14 days prior to and with induction chemotherapy (cytarabine 100 mg/m2 for 7 days plus daunorubicin 60 mg/m2 for 3 days) if previously untreated, or ENTO monotherapy alone if relapsed/refractory (R/R). R/R B-ALL patients received ENTO monotherapy for 7 days prior to and with vincristine and dexamethasone in a phase 1 study (NCT02404220).

Results: 18 patients with KMT2A rearranged AL were treated. Untreated AML (n=10) patients had a median age of 49 years. One patient was in a morphologic leukemia-free state after ENTO monotherapy (before chemotherapy). After induction chemotherapy plus ENTO, seven patients had morphologic (CR) and cytogenetic (CRc) remission, but two of them had incomplete count recovery (CRi). The composite CR rate (CR/CRi/CRc) was 90%: 5 CRc, 3 CRi (CR/CRc with incomplete count recovery), and 1 CR. Six patients underwent allogeneic stem cell transplantation (SCT) in CR1. After median follow-up of 9.9 months one patient who achieved CR relapsed, with persistence of t (6;11) and an NRAS mutation. Median overall survival and event-free survival have not been reached. In R/R AML (n=6), patients had a median age of 48 years, with 2 median prior therapies. One had CR and one had CRi (but normal cytogenetics) and both received SCT. In all, 3 AML patients (1 newly diagnosed, 2 R/R) responded to ENTO monotherapy alone. In R/R ALL (n=2), median age was 59 years. Both patients had t (4;11) along with other cytogenetic abnormalities with 2 prior therapies. Both patients achieved CR with loss of KMT2A on cytogenetic testing, and one patient received SCT. Overall, ENTO was safe and well tolerated, even in combination with chemotherapy.

Conclusions: KMT2A rearranged AL is sensitive to ENTO with CR observed on monotherapy in AML and high response rates in AL patients treated with combination therapy. This represents the first documentation of CR with small molecule monotherapy (n=3) in this genetic subgroup, which typically portends a poor prognosis. Correlative biomarker studies evaluating HOXA9/MEIS1 in patients with t(v;11q23.3) KMT2A rearranged leukemia treated with ENTO are pending.

Citation Format: Alison R. Walker, John C. Byrd, William Blum, Tara Lin, Howland E. Crosswell, Danjie Zhang, Jie Gao, Arati V. Rao, Mark D. Minden, Wendy Stock. High response rates with entospletinib in patients with t(v;11q23.3);KMT2A rearranged acute myeloid leukemia and acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 819.

Abstract 5673: Complex, patient-derived, multi-cell type, 3D models of breast cancer for personalized prediction of therapeutic response

Breast cancer survival has drastically improved over the past decades; however, drug resistance and subsequent disease progression is responsible for the incurability of advanced disease. While the focus of many drug response studies is the transformed tumor cells, there is increasing evidence suggesting a role for stromal cells in tumorigenesis and drug resistance. Microenvironmental components, including extracellular matrix, fibroblasts, leukocytes, and adipocytes, all contribute to physiological mammary gland biogenesis. Accordingly, these stromal elements contribute to disease progression and resistance. However, many in vitro drug response studies still utilize 2D monolayer cultures with purified breast tumor cells. In vivo studies remain the gold standard for drug development, even though they are performed with immune-compromised mice that may not reflect the physiological tumor microenvironment and have been repeatedly shown to be a poor representation of clinical outcomes. Thus, there is a need for more complex in vitro models to test drug response effectively and accurately. We have previously demonstrated the benefits of using a patient-derived, tri-culture (3x), 3D perfusion microtumor (3DpMT) system. To further replicate the complex tumor microenvironment, we have expanded to a penta-culture (5x) model by incorporating macrophages and lymphocytes alongside the tumor cells, fibroblasts, and adipocytes of the 3x model. We have accrued over 207 primary tumor samples, including both resected tumor and core biopsies, from which we have generated 12 stable PDX models (~50% ER+) and &gt;20 3x, 4x, and 5x 3DpMT with a focus on triple negative (TNBC). The 5x patient-derived 3DpMT tissues represent our most complex breast cancer in vitro model and have been cultured successfully for up to 5 weeks allowing for high-throughput, long term drug response testing with different dosing strategies. They have been characterized by flow cytometry, IHC, RNA expression, NGS, DNA methylation patterns, and cytokine/chemokine secretion. When possible, marker expression has been compared to the primary tumor. Furthermore, the accuracy of our models to replicate clinical tissue is evident in the similar toxicities of chemotherapies observed in clinical use. With these models we can replicate physiological processes including cell migration, polarization of macrophages, activation of lymphocytes, and changes in molecular profiles throughout the duration of our 5x culture assays. Our model has the potential to test a myriad of drugs, from conventional chemotherapies to novel immunotherapies over extended time periods with different dosing strategies in order to provide a more accurate prediction of patient-specific clinical response.

Citation Format: Qi Guo, Melissa Millard, Christine Wilhelm, Ashley Elrod, Nick Erdman, Lacey E. Dobrolecki, Brian McKinley, Mary Rippon, Wendy Cornett, John Rinkliff, Amanda Scopteuolo, Linda Gray, James Epling, Barbara Garner, Jeff Hanna, Eric McGill, C. David Williams, David Schammel, David L. Kaplan, Christopher Corless, Jeff Edenfield, Michael T. Lewis, Howland E. Crosswell, Teresa M. DesRochers. Complex, patient-derived, multi-cell type, 3D models of breast cancer for personalized prediction of therapeutic response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5673.

Abstract 320: Perfused 3D tri-culture breast cancer microtumors for accurate prediction of drug response

Background: Breast cancer (BC) occurs in 1 of 8 women, often requiring debilitating surgery, chemotherapy or radiation for long term survival. Histologic and molecular biomarkers are used to classify BC according to defined subtypes which dictate the choice of targeted therapy or of non-targeted cytotoxic therapy. Despite high initial response rates, relapses are common for more aggressive tumors, and choosing the right therapy for each patient remains challenging. In vitro 3D BC models maintain biologic features that more closely resemble clinical disease than 2D models. However, many 3D models do not contain multiple cell types, are maintained in static culture conditions and rely on immortalized cell lines previously propagated in 2D culture conditions. To address these issues, we developed long term, 3D heterotypic BC microtumors, which recapitulate the dynamic interaction between stromal and epithelial components, retain subtype-specific biomarkers and demonstrate clinically-relevant drug response. We further demonstrated the value of developing non-lytic, label-free in situ analysis to monitor morphology and function of complex 3D microtumors over time. Materials & Methods: Er+, Her2+ or triple negative (TNBC) cell lines (MCF7, SKBR3, MDA-MB-231) or patient derived xenograft (PDX) cells were embedded with human mammary fibroblasts and adipose cells within a hydrogel encapsulated by a silk fibroin scaffold. Microtumors were maintained at least 4 weeks under perfusion flow utilizing the 3DKUBE™ and were characterized for cell morphology and phenotype (IHC), proliferation (PrestoBlue and PicoGreen), gene expression (qRT-PCR), redox ratio (multiphoton microscopy), and biomarker secretion (xMAP® multiplex immunoassay). Drug response profiling (DRP) was performed with tamoxifen, lapatinib and cisplatin. Results: 3D microtumors successfully recapitulated the morphology of primary BC predicted by molecular subtype and gene expression. Perfusion promoted cell proliferation and impacted redox ratio, gene expression, and biomarker secretion in comparison to static culture. Relative redox ratios of 3D microtumors were significantly different from those of cell lines in 2D (p&lt;0.05). Perfusion, 3D conditions, Her2+ and TNBCs were independently associated with increased biomarker secretion, and both cell line and PDX microtumors had unique secretome signatures. PDX microtumors more accurately predicted drug response. Conclusions: Long-term, 3D heterotypic breast microtumors have unique metabolic and secretome signatures which are different than cells in 2D, and the microtumor morphology, metabolism and drug response can be monitored non-destructively in situ. Our ultimate goal is to develop these microtumors using primary human breast tumors for real time drug response profiling in the preclinical, co-clinical and clinical settings to improve outcomes for women with breast cancer.

Citation Format: Tessa M. DesRochers, Stephen Shuford, Christina Mattingly, Terri Bruce, Zhiyi Liu, Kyle Quinn, Irene Georgakoudi, David L. Kaplan, David Orr, Howland E. Crosswell. Perfused 3D tri-culture breast cancer microtumors for accurate prediction of drug response. [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 320. doi:10.1158/1538-7445.AM2015-320

Abstract A40: Development of a perfusion-based 3D human tri-culture breast microtumor

Background: The tumor microenvironment (TME) is a 3D, dynamic interaction between tumor and stromal cells, extracellular matrix, and soluble factors which can promote tumor progression and resistance to therapy. Significant efforts are being made to develop long-term in vitro TME models to study cancer biology, improve drug development, and guide clinical decisions. We have developed a cost-effective micro-bioreactor culture device which enables a wide variety of dynamic cellular and TME interactions that can be monitored with in situ, label free, and non-lytic microscopic analysis. Using the 3DKUBE™, we developed a 3D breast cancer model composed of MCF-7 cells and fibroblasts in segregated co-culture and identified a highly active PI3K inhibitor that had limited activity in 2D monoculture. Based on a more complex morphologic and functional 3D mammary gland model that incorporates multiple human primary cells including epithelial cells (HuMEC), mammary fibroblasts, and adipocytes, our long-term 3D perfused tri-culture breast cancer model is designed to evaluate drug response continuously using non-lytic analysis. We theorize that different breast cancer epithelial cells will be supported in a standard 3D stromal platform which supports mammary gland function. Herein, we describe the 3DKUBE™ modifications and early optimization of a defined stromal TME which supports HuMECs in 3D perfusion. Materials & Methods: Primary human cells were used to optimize seeding conditions for silk fibroin scaffolds containing Matrigel™/collagen hydrogels, including, media composition, cellular ratios, flow rates, and analytical methods for the 3DKUBE™. Destructive analytical methods included morphology (H&E), phenotype (histology), viability & survival (CyQuant, TUNEL, Ki-67), and ER, PR, and casein expression (RT-PCR). Non-lytic assays included metabolism (resazurin reduction), cytotoxicity (LDH release), soluble biomarker expression (xMAP™), and two-photon emission fluorescence via multiphoton microscopy (MPM). Results: The 3DKUBE™ imaging window (1.25 mm thick with a refractive index of 1.590, transmittance (~90%) at wavelengths &gt;290 nm) was replaced with a No. 1.5 glass, high resolution window allowing non-destructive, in situ microscopic imaging. MPM images obtained provided cellular detail (granularity, nuclear-cytoplasmic ratio, size). Optimization of the media conditions and cell numbers revealed that a tri-culture ratio of 1:1:1 was stable in the silk-Matrigel-collagen scaffold during prolonged static and perfusion culture in mixed media. Differentiation of adipocytes had to be performed separately from the tri-culture due to the cytotoxicity of the differentiation media to the epithelial cells. This was achieved via a serial seeding and differentiation method. Our initial drug studies revealed that cytotoxicity could be monitored over the course of a week by multiple methods, including LDH secretion, Presto blue, and CyQuant. Though non-specific drug binding (CPT-11) was seen in the complex 3D matrix, it did not materially impact total drug concentrations. Conclusions: Our current optimization results indicate our ability to grow a bioengineered 3D human breast tri-culture model under perfusion using the 3DKUBE™ while monitoring tissue structure, function, and drug response through both lytic and non-lytic methods. Future Development: The optimized perfused stroma will be used to develop ex vivo breast microtumors of clinically relevant subtypes (ER+, Her+, triple negative) validated against targeted agents. If validated, these 3D microtumors may be applied as predictive phenotypic screens to improve preclinical and clinical breast cancer drug development.

Citation Format: Teresa M. DesRochers, Stephen Shuford, Terri F. Bruce, Matthew R. Gevaert, Chaitra Cheluvaraju, Irene Georgakoudi, David L. Kaplan, Davie E. Orr, Howland E. Crosswell. Development of a perfusion-based 3D human tri-culture breast microtumor. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr A40. doi:10.1158/1538-7445.CHTME14-A40

Successful treatment with modified CHOP-rituximab in pediatric AIDS-related advanced stage Burkitt lymphoma

Burkitt lymphoma is the most common AIDS-related lymphoma (ARL) in childhood. The major issues in adult and pediatric ARL include identifying the optimal chemotherapy regimen and the concurrent treatment of both rituximab and highly active anti-retroviral therapy (HAART). We present a case of advanced stage Burkitt lymphoma in an 8-year-old female with acquired immunodeficiency syndrome (AIDS), who was successfully treated with a 3 month course of modified CHOP-R (cyclophosphamide, daunorubicin, vincristine, prednisone, and rituximab) and HAART therapy. The combination of rituximab and chemotherapy with HAART therapy may be well-tolerated and effective in HIV/AIDS patients with Burkitt lymphoma.