Pancreatic cancer is the most lethal common solid malignancy. Systemic therapies are often ineffective, and predictive biomarkers to guide treatment are urgently needed. We generated a pancreatic cancer patient-derived organoid (PDO) library that recapitulates the mutational spectrum and transcriptional subtypes of primary pancreatic cancer. New driver oncogenes were nominated and transcriptomic analyses revealed unique clusters. PDOs exhibited heterogeneous responses to standard-of-care chemotherapeutics and investigational agents. In a case study manner, we found that PDO therapeutic profiles paralleled patient outcomes and that PDOs enabled longitudinal assessment of chemosensitivity and evaluation of synchronous metastases. We derived organoid-based gene expression signatures of chemosensitivity that predicted improved responses for many patients to chemotherapy in both the adjuvant and advanced disease settings. Finally, we nominated alternative treatment strategies for chemorefractory PDOs using targeted agent therapeutic profiling. We propose that combined molecular and therapeutic profiling of PDOs may predict clinical response and enable prospective therapeutic selection. New approaches to prioritize treatment strategies are urgently needed to improve survival and quality of life for patients with pancreatic cancer. Combined genomic, transcriptomic, and therapeutic profiling of PDOs can identify molecular and functional subtypes of pancreatic cancer, predict therapeutic responses, and facilitate precision medicine for patients with pancreatic cancer. .

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The Hedgehog (Hh) pathway is a developmental signaling pathway involved in numerous developmental processes, including determination of cell fate, patterning, proliferation, survival, and differentiation. While this pathway is silenced in most adult tissues, aberrant activation of it has been documented in a variety of malignancies. In cancers such as basal cell carcinoma (BCC), ligand-independent mechanisms lead to constitutive Hh pathway activation through mutations in components of the pathway, including patched-1 (PTCH1) or smoothened (SMO). On the contrary, numerous other solid and hematologic tumors have been shown to harbor ligand-dependent activation of the Hh pathway by autocrine or paracrine mechanisms. Given that aberrant Hh pathway signaling has been seen in a number of malignancies, this pathway has been an attractive target for drug development. While the best-characterized approach is to target the SMO receptor, other rational approaches for inhibiting the Hh pathway include inhibiting downstream components or directly binding Hh ligands. In January of 2012, vismodegib, a SMO antagonist, became the first agent to target the Hh pathway to receive approval by the United States Food and Drug Administration (FDA) after this agent showed remarkable activity in phase I and II trials for the treatment of BCC. Despite promising preclinical studies with Hh pathway inhibitors in other malignancies that have suggested a potential role for these agents, attempts to translate this potential to clinical benefit has been disappointing. Future efforts will require further careful interpretation and analysis to determine the potential determinants and predictors of efficacy. Currently, several phase I and II trials evaluating Hh inhibitors in a variety of tumor settings are underway.

BACKGROUND. MEK inhibitors have limited activity in biliary tract cancers (BTCs) as monotherapy but are hypothesized to enhance responses to programmed death ligand 1 (PD-L1) inhibition. METHODS.This open-label phase II study randomized patients with BTC to atezolizumab (anti-PD-L1) as monotherapy or in combination with cobimetinib (MEK inhibitor). Eligible patients had unresectable BTC with 1 to 2 lines of prior therapy in the metastatic setting, measurable disease, and Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 1. The primary endpoint was progression-free survival (PFS). RESULTS.Seventy-seven patients were randomized and received study therapy. The trial met its primary endpoint, with a median PFS of 3.65 months in the combination arm versus 1.87 months in the monotherapy arm (HR 0.58, 90% CI 0.35-0.93, 1-tail P = 0.027). One patient in the combination arm (3.3%) and 1 patient in the monotherapy arm (2.8%) had a partial response. Combination therapy was associated with more rash, gastrointestinal events, CPK elevations, and thrombocytopenia. Exploratory analysis of tumor biopsies revealed enhanced expression of antigen processing and presentation genes and an increase in CD8/FoxP3 ratios with combination treatment. Patients with higher baseline or lower fold changes in expression of certain inhibitory ligands (LAG3, BTLA, VISTA) on circulating T cells had evidence of greater clinical benefit from the combination. CONCLUSION.The combination of atezolizumab plus cobimetinib prolonged PFS as compared with atezolizumab monotherapy, but the low response rate in both arms highlights the immune-resistant nature of BTCs. TRIAL REGISTRATION. ClinicalTrials.gov NCT03201458.

298 Background: The treatment landscape for pts with uHCC has recently expanded. However, there is an unmet need for effective treatment options in CPB pts. LEN is approved first-line in uHCC based on the REFLECT study (Child-Pugh A [CPA] pts were allowed, per inclusion criteria). In a prior analysis of REFLECT, pts treated with LEN benefited irrespective of baseline liver function (ALBI grade 1 or 2; Child-Pugh score 5 or 6). To determine outcomes in pts with reduced liver function, we report a post hoc analysis of key efficacy and safety results in LEN-treated pts from REFLECT who progressed to CPB and those who did not within the first 8 weeks of treatment. Methods: In REFLECT, pts with uHCC were randomized 1:1 to LEN (per bodyweight: 12 mg/day for ≥60 kg; 8 mg/day for < 60 kg) or sorafenib (400 mg twice daily) in 28-day cycles. This analysis assessed ORR. Landmark analyses (starting at week 8) of PFS, time-to-progression (TTP), and OS in CPB pts and in pts who remained CPA at 8 weeks post-randomization were also conducted. Tumors were assessed by mRECIST by independent imaging review. Safety was also assessed from baseline. Results: This subgroup analysis included LEN-treated pts (n = 60) who progressed to CPB within the first 8 weeks of treatment (CPB pts) and 413 pts who did not (CPA pts). At baseline, 26.7% and 73.1% of pts had an ALBI grade of 1 and 73.3% and 26.9% of pts had an ALBI grade of 2 in CPB and CPA pts, respectively. ORR was 28.3% (95% CI 16.9–39.7) for CPB pts and 42.9% (95% CI 38.1–47.6) for CPA pts. A landmark analysis showed a median PFS of 3.7 mos (95% CI 1.8–7.4) for CPB pts and 6.5 mos (95% CI 5.6–7.4) for CPA pts from the week 8 timepoint. Landmark analyses at week 8 also showed that the median TTP was 5.6 mos (95% CI 3.5–9.3) for CPB pts and 7.3 mos (95% CI 5.6–7.4) for CPA pts; the median OS was 6.8 mos (95% CI 2.6–10.3) for CPB pts and 13.3 mos (95% CI 11.6–16.1) for CPA pts per week 8 landmark analyses. As expected, efficacy appeared to be greater in CPA pts versus CPB pts; however, OS of 6.8 months in CPB pts after the week 8 landmark is notable. Moreover, median duration of treatment was 3.2 mos for CPB pts and 6.9 mos for CPA pts, thereby suggesting CPB pts can remain on LEN. The incidence of grade ≥3 treatment-related AEs (TRAEs) was 71.7% in CPB pts and 54.7% in CPA pts. TRAEs leading to discontinuation occurred in 18.3% of CPB pts and 7.5% of CPA pts. Conclusions: In this post hoc analysis of pts in REFLECT, we examine the key efficacy and safety results for LEN-treated pts who progressed to CPB by week 8. This post hoc analysis is limited by its descriptive nature; however, the results indicate that further study of LEN in CPB pts with uHCC is warranted. Clinical trial information: NCT01761266.