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David Barbie



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    MA12 - New Frontiers from Pathology to Genomics (ID 138)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Mesothelioma
    • Presentations: 1
    • Now Available
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      MA12.06 - Patient-Derived Organotypic Tumor Spheroids (PDOTS) Facilitate Therapeutic Screening for Malignant Pleural Mesothelioma (Now Available) (ID 2561)

      14:00 - 15:30  |  Author(s): David Barbie

      • Abstract
      • Presentation
      • Slides

      Background

      While genotype directed therapies are an essential aspect of personalized medicine in non-small cell lung cancer (NSCLC), this modality is not currently an option in mesothelioma. Instead there is a need for improved functional testing via predictive platforms that can help identify the susceptibility of patient tumors to drug therapies. Here, we demonstrate the use of a novel ex vivo functional system utilizing 3D microfluidic culture and patient-derived organotypic tumor spheroids (PDOTS) as a platform to study the tumor microenvironment and predict tumor responses to treatment in mesothelioma.

      Method

      We evaluated 31 mesothelioma patient specimens under an IRB approved protocol. PDOTS of mesothelioma were generated as previously described (Larios et al. AACR. 2017; Jenkins et al. Cancer Discovery. 2017). Samples were treated with standard chemotherapy (pemetrexed and cisplatin combined) as well as immunotherapy (ipilimumab and pembrolizumab combined) and live/dead quantification was conducted using dual labeling de-convolution fluorescence microscopy. Positive responses ex vivo included samples with significant cell death to control while positive in vivo responses were based on radiologic lack of tumor recurrence using the response evaluation criteria in solid tumors (RECIST, version 1.1) to assess for disease progression.

      Result

      We found that in treatment naïve specimens prolonged ischemic times were associated with decreased tissue viability (ischemia >25 minutes resulted in decrease of live cells from an average of 81% to 56%), lower tumor yield (< 50% tumor content), and decreased generation of spheroids (< 20 spheroids/well). Specimens with prior treatment were consistently associated with low tissue viability irrespective of ischemic times. Of the 31 specimens studied, 10 samples met viability and tumor content standards to undergo further treatment with standard chemotherapy and immunotherapy, and 5 of those samples were tracked to available patient-treatment response data. Ultimately, comparison of ex vivo and in vivo treatment responses demonstrated that 4 of 5 samples treated with standard chemotherapy had concordant responses to those of patients who received the same or similar post-operative therapy. Notably, our discordant sample exhibited large variation in standard deviations due to technical variability.

      Conclusion

      Here we demonstrate that analysis of ex vivo mesothelioma tissue correlates to in vivo responses. These results suggest that PDOTS can serve as a predictive platform for therapies. Further work streamlining human tissue collection and optimizing factors that affect formation of PDOTS prior to ex vivo treatment analysis should be further investigated.

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    OA15 - Targeted Agents and Immunotherapy for Small Cell Lung Cancer (ID 152)

    • Event: WCLC 2019
    • Type: Oral Session
    • Track: Small Cell Lung Cancer/NET
    • Presentations: 1
    • Now Available
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      OA15.01 - Combination Olaparib and Temozolomide in Relapsed Small Cell Lung Cancer: Updated Results from Phase 1/2 Clinical Trial (Now Available) (ID 1394)

      14:30 - 16:00  |  Author(s): David Barbie

      • Abstract
      • Presentation
      • Slides

      Background

      DNA damage repair inhibition is an emerging strategy for treating small cell lung cancer (SCLC). Combining poly(ADP-ribose) polymerase (PARP) inhibition with the DNA alkylating agent temozolomide has shown activity in both preclinical models and early phase clinical trials.

      Method

      This is a single-arm phase 1/2 study combining the PARP inhibitior olaparib (tablet formulation) with temozolomide in patients with SCLC. Key eligibility criteria include histologically or cytologically confirmed incurable SCLC which progressed following ≥ 1 platinum-based chemotherapy. In cohort 1, olaparib and temozolomide are administered orally on days 1-7 of 21-day cycles. After cohort 1 completed enrollment, cohort 2 was added in a protocol amendment, in which olaparib is administered continuously days 1-21 and temozolomide is administered days 1-7 of 21-day cycles. For each cohort, the phase 1 portion is a conventional 3+3 design, with the primary objective to determine the maximum tolerated dose (MTD) or recommended phase 2 dose (RP2D). The primary objective of the phase 2 dose expansion portion is to determine the objective response rate (ORR). Response assessments are performed every 6 weeks, with treatment continued until progression, unacceptable toxicity, or investigator’s discretion. Treatment post-progression is allowed for patients with ongoing clinical benefit.

      Result

      Between October 2015 and April 2018, 50 patients were enrolled to cohort 1. The median age was 63 (range 39-85), median number of prior therapies was 2 (range 1-7), and 72% were platinum sensitive. The RP2D was olaparib 200 mg PO BID d1-7 and T 75 mg/m2 QD d1-7. The confirmed ORR was 41.7%. After a median follow-up of 7.1 months among 22 surviving patients, the median progression-free survival (mPFS) was 4.2 months, median overall survival (mOS) was 8.5 months, and median duration of response (mDoR) was 4.3 months. The ORR among platinum-sensitive and platinum-resistant patients was 47.1% and 28.6%, respectively, with no significant differences in mPFS, mOS or mDOR. The most common grade 3/4 treatment related adverse events were neutropenia (38%), anemia (28%) and thrombocytopenia (26%). Among 41 pts treated at the RP2D, dose reductions occurred in 44% overall and 64% of those who received at least 3 cycles. Enrollment to the phase 1 portion of cohort 2 began in November 2018 and is ongoing. Updated results from cohorts 1 and 2 will be presented at the meeting.

      Conclusion

      Combination olaparib and temozolomide has an acceptable tolerability profile and shows promising clinical activity in relapsed SCLC. Clinical trials identifier NCT02446704.

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    P2.04 - Immuno-oncology (ID 167)

    • Event: WCLC 2019
    • Type: Poster Viewing in the Exhibit Hall
    • Track: Immuno-oncology
    • Presentations: 1
    • Now Available
    • Moderators:
    • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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      P2.04-23 - Tumor-Stroma Interactions Promote cGAS-STING Driven Inflammation in Lung Tumor Microenvironment (Now Available) (ID 2351)

      10:15 - 18:15  |  Author(s): David Barbie

      • Abstract
      • Slides

      Background

      The tumor stroma is an essential component of the tumor microenvironment (TME) and has critical roles in promoting resistance to immunotherapies. Most anticancer therapies target cancer cells specifically, however, it is important to also study signaling contributions from the TME. The recruitment of immune cells following intratumoral administration of Stimulation of Interferon Genes (STING) agonists in the TME is a critical event in the cGAS-STING-driven antitumor immune response, a pathway with great relevance in the context of cancer immunotherapy. Towards this, the infiltration of immune cells rely on functional vasculature to infiltrate into the tumor tissue. We have previously demonstrated that LKB1 mutation is associated with suppression of tumor cell STING levels due to mitochondrial dysfunction and reduced production of T-cell chemoattractants such as CXCL10 in KRAS-driven non-small cell lung cancer (NSCLC). Consistently, immunohistochemical staining of patient samples showed poor infiltration of CD3, CD4, and CD8 T cells into LKB1 negative versus LKB1 intact cancer epithelium, and instead, retention of T-cells in stroma.

      Method

      3-D microfluidic device was fabricated using cyclic olefin polymer (COP) at AIM BIOTECH. NCI-H1355 cells were cultured for 24h in ultra low-attachment culture plates for spheroid formation. To form the 3D tumor microvascular model, cancer spheroids, human lung fibroblasts (hLFBs) and human umbilical vein endothelial cells (HUVECs) were resuspended in an extracellular matrix-like fibrin/collagen gel and loaded into the central channel and cultured for 7 days and hydrated with culture medium (Vasculife, lifeline). Cytokine profiling (Human Cytokine 40-plex panel) was performed with media collected from 3D culture.

      Result

      To examine how LKB1 alters immune cell recruitment, we used a 3-D microfluidic co-culture system to study interactions between vasculature and tumor spheroids derived from a KRAS/LKB1 mutated (KL) cell line with LKB1 reconstitution +/- STING deletion. Co-culturing tumor spheroids and vasculature, we identified changes in morphology, cytokine production, and gene expression that occur during the co-culture. We found that co-culture induced cooperative production of multiple immune cell chemo-attractants such as CXCL10, CCL2, CCL5, and G-CSF (Fig.1b,c). Interestingly, this more physiologic ex vivo tumor model of LKB1 reconstitution revealed particularly strong cooperative production of STING-dependent cytokines such as CXCL10 in the vasculature. Moreover, knocking down STING in the LKB1-reconstituted cancer cells did not significantly attenuate production of CXCL10 and other cytokines in co-culture, suggesting that tumor/vasculature interaction may promote STING activation in the vasculature regardless of cancer cell-intrinsic STING function. Furthermore, although there was no appreciable response after treatment of KL cancer cells with cGAMP based STING agonists, treatment of isolated 3-D vascular networks with cGAMP enhanced vascular permeability and increased production of CXCL10 and CCL5, possibly contributing to defective chemokine gradients that retain T cells near the vasculature.

      Conclusion

      Developing these more complex models that incorporate 3-dimensional tumor and self-assembled microvasculature may elucidate important aspects of cGAS-STING biology in KL lung cancer microenvironment, and may ultimately aid further development of effective immunotherapies targeting this signaling pathway.

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