First-in-human Phase I Trial of TPST-1120, an Inhibitor of PPARα, as Monotherapy or in Combination with Nivolumab, in Patients with Advanced Solid Tumors

PURPOSE

TPST-1120 is a first-in-class oral inhibitor of peroxisome proliferator-activated receptor α (PPARα), a fatty acid ligand-activated transcription factor that regulates genes involved in fatty acid oxidation, angiogenesis, and inflammation, and is a novel target for cancer therapy. TPST-1120 displayed antitumor activity in xenograft models and synergistic tumor reduction in syngeneic tumor models when combined with anti-PD-1 agents.

EXPERIMENTAL DESIGN

This phase I, open-label, dose-escalation study (NCT03829436) evaluated TPST-1120 as monotherapy in patients with advanced solid tumors and in combination with nivolumab in patients with renal cell carcinoma (RCC), cholangiocarcinoma (CCA), or hepatocellular carcinoma. Objectives included evaluation of safety, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity (RECIST v1.1).

RESULTS

A total of 39 patients enrolled with 38 treated (20 monotherapy, 18 combination; median 3 prior lines of therapy). The most common treatment-related adverse events (TRAE) were grade 1-2 nausea, fatigue, and diarrhea. No grade 4-5 TRAEs or dose-limiting toxicities were reported. In the monotherapy group, 53% (10/19) of evaluable patients had a best objective response of stable disease. In the combination group, 3 patients had partial responses, for an objective response rate of 20% (3/15) across all doses and 30% (3/10) at TPST-1120 ≥400 mg twice daily. Responses occurred in 2 patients with RCC, both of whom had previously progressed on anti-PD-1 therapy, and 1 patient with late-line CCA.

CONCLUSIONS

TPST-1120 was well tolerated as monotherapy and in combination with nivolumab and the combination showed preliminary evidence of clinical activity in PD-1 inhibitor refractory and immune compromised cancers.

SIGNIFICANCE

TPST-1120 is a first-in-class oral inhibitor of PPARα, whose roles in metabolic and immune regulation are implicated in tumor proliferation/survival and inhibition of anticancer immunity. This first-in-human study of TPST-1120 alone and in combination with nivolumab supports proof-of-concept of PPARα inhibition as a target of therapeutic intervention in solid tumors.

Oral Carbon Monoxide Enhances Autophagy Modulation in Prostate, Pancreatic, and Lung Cancers

Modulation of autophagy, specifically its inhibition, stands to transform the capacity to effectively treat a broad range of cancers. However, the clinical efficacy of autophagy inhibitors has been inconsistent. To delineate clinical and epidemiological features associated with autophagy inhibition and a positive oncological clinical response, a retrospective analysis of patients is conducted treated with hydroxychloroquine, a known autophagy inhibitor. A direct correlation between smoking status and inhibition of autophagy with hydroxychloroquine is identified. Recognizing that smoking is associated with elevated circulating levels of carbon monoxide (CO), it is hypothesized that supplemental CO can amplify autophagy inhibition. A novel, gas-entrapping material containing CO in a pre-clinical model is applied and demonstrated that CO can dramatically increase the cytotoxicity of autophagy inhibitors and significantly inhibit the growth of tumors when used in combination. These data support the notion that safe, therapeutic levels of CO can markedly enhance the efficacy of autophagy inhibitors, opening a promising new frontier in the quest to improve cancer therapies.

The Clinical Implications of Reversions in Patients with Advanced Pancreatic Cancer and Pathogenic Variants in BRCA1, BRCA2, or PALB2 after Progression on Rucaparib

PURPOSE

PARP inhibitors (PARPi) provide an effective maintenance option for patients with BRCA- or PALB2-mutated pancreatic cancer. However, mechanisms of PARPi resistance and optimal post-PARPi therapeutic strategies are poorly characterized.

EXPERIMENTAL DESIGN

We collected paired cell-free DNA samples and post-PARPi clinical data on 42 patients with advanced, platinum-sensitive pancreatic cancer who were treated with maintenance rucaparib on NCT03140670, of whom 32 developed progressive disease.

RESULTS

Peripherally detected, acquired BRCA or PALB2 reversion variants were uncommon (5/30; 16.6%) in patients who progressed on rucaparib. Reversions were significantly associated with rapid resistance to PARPi treatment (median PFS, 3.7 vs. 12.5 months; P = 0.001) and poor overall survival (median OS, 6.2 vs. 23.0 months; P < 0.0001). All patients with reversions received rechallenge with platinum-based chemotherapy following PARPi progression and experienced faster progression on this therapy than those without reversion variants (real-world time-to-treatment discontinuation, 2.4 vs. 5.8 months; P = 0.004). Of the patients who progressed on PARPi and received further chemotherapy, the OS from initiation of second-line therapy was significantly lower in those with reversion variants than in those without (5.5 vs. 12.0 months, P = 0.002). Finally, high levels of tumor shedding were independently associated with poor outcomes in patients who received rucaparib.

CONCLUSIONS

Acquired reversion variants were uncommon but detrimental in a population of patients with advanced BRCA- or PALB2-related pancreatic ductal adenocarcinoma who received maintenance rucaparib. Reversion variants led to rapid progression on PARPi, rapid failure of subsequent platinum-based treatment, and poor OS of patients. The identification of such variants in the blood may have both predictive and prognostic value. See related commentary by Tsang and Gallinger, p. 5005.

Abstract 1043: Liquid biopsy signature combining copy number instability and mutant KRAS detection is associated with survival for patients with metastatic pancreatic cancer

Introduction: In the setting of metastatic pancreatic adenocarcinoma (mPDAC), lower baseline plasma KRAS mutation levels have been associated with improved survival. While tissue-agnostic, plasma-based copy number instability (CNI) has been demonstrated as an early indicator of response to immunotherapy for some solid tumors, it has not been assessed for patients with mPDAC, nor in combination with KRAS mutations for patients receiving standard of care chemo/radiotherapy. Here we evaluate the combination of mutant KRAS (mKRAS) and CNI detection in plasma as a predictor of overall and progression-free survival (OS/PFS) in mPDAC patients who received standard of care therapy.

Methods: Cell-free DNA was extracted from plasma and libraries prepared at baseline (Week 0) and weeks 8, 16 and 24 on therapy, and analyzed by next-generation sequencing (CNI) and droplet digital PCR (mKRAS). Descriptive statistics were computed for variables including CNI (score is a measure of circulating tumor DNA) and mKRAS variant allele fraction. Detection was defined as above the limit of detection (mKRAS=0.13%) and above the 95th percentile of the value in normal individuals (CNI=24). Therapy response was assessed by OS and PFS.

Results: 196 plasma samples from 64 mPDAC patients were analyzed. When dichotomized as detectable vs undetectable, CNI alone was significantly associated with OS at all on-therapy timepoints but not baseline, whereas mKRAS was significantly associated with OS for all 4 timepoints (Table 1). Detection of both CNI and mKRAS in combination was strongly associated with worse OS at all timepoints, yielding the highest HR. Similar results were obtained when mKRAS and CNI were dichotomized at their respective median values or with PFS as the clinical endpoint.

Conclusions: Combined CNI and mKRAS detection at baseline and on-therapy may provide a strong and early indication of worse prognosis for patients with mPDAC.

Table 1. Association of CNI and mKRAS with Overall Survival (HazardRatio [95% CI], log-rank p-value) Timepoint CNI mKRAS CNI and KRAS Baseline/Week 0 1.54 [0.89-2.68], 0.1 2.05 [1.12-3.78], 0.02 2.50 [1.46-4.28], 0.0006 Week 8 1.78 [0.99-3.18], 0.05 2.21 [1.19-4.08], 0.01 9.81 [3.40-28.28], &lt;0.0001 Week 16 1.91 [1.03-3.53], 0.04 3.26 [1.60-6.62], 0.0006 11.11 [4.28-28.83], &lt;0.0001 Week 24 2.55 [1.28-5.09], 0.006 4.55 [2.03-10.23], &lt;0.0001 6.42 [2.61-15.84], &lt;0.0001

Citation Format: Samuele Cannas, Jacob E. Till, Kristine Kim, Michael J. LaRiviere, Charles M. Vollmer, Jennifer R. Eads, Thomas B. Karasic, Peter J. O'Dwyer, Charles J. Schneider, Ursina R. Teitelbaum, Kim A. Reiss Binder, Mark H. O'Hara, Douglas T. Ross, Kim McGregor, Kirsten Bornemann-Kolatzki, Ekkehard Schütz, Julia Beck, Erica L. Carpenter. Liquid biopsy signature combining copy number instability and mutant KRAS detection is associated with survival for patients with metastatic pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1043.

Futibatinib for FGFR2-Rearranged Intrahepatic Cholangiocarcinoma

BACKGROUND

Alterations in fibroblast growth factor receptor 2 (FGFR2) have emerged as promising drug targets for intrahepatic cholangiocarcinoma, a rare cancer with a poor prognosis. Futibatinib, a next-generation, covalently binding FGFR1-4 inhibitor, has been shown to have both antitumor activity in patients with FGFR-altered tumors and strong preclinical activity against acquired resistance mutations associated with ATP-competitive FGFR inhibitors.

METHODS

In this multinational, open-label, single-group, phase 2 study, we enrolled patients with unresectable or metastatic FGFR2 fusion-positive or FGFR2 rearrangement-positive intrahepatic cholangiocarcinoma and disease progression after one or more previous lines of systemic therapy (excluding FGFR inhibitors). The patients received oral futibatinib at a dose of 20 mg once daily in a continuous regimen. The primary end point was objective response (partial or complete response), as assessed by independent central review. Secondary end points included the response duration, progression-free and overall survival, safety, and patient-reported outcomes.

RESULTS

Between April 16, 2018, and November 29, 2019, a total of 103 patients were enrolled and received futibatinib. A total of 43 of 103 patients (42%; 95% confidence interval, 32 to 52) had a response, and the median duration of response was 9.7 months. Responses were consistent across patient subgroups, including patients with heavily pretreated disease, older adults, and patients who had co-occurring TP53 mutations. At a median follow-up of 17.1 months, the median progression-free survival was 9.0 months and overall survival was 21.7 months. Common treatment-related grade 3 adverse events were hyperphosphatemia (in 30% of the patients), an increased aspartate aminotransferase level (in 7%), stomatitis (in 6%), and fatigue (in 6%). Treatment-related adverse events led to permanent discontinuation of futibatinib in 2% of the patients. No treatment-related deaths occurred. Quality of life was maintained throughout treatment.

CONCLUSIONS

In previously treated patients with FGFR2 fusion or rearrangement-positive intrahepatic cholangiocarcinoma, the use of futibatinib, a covalent FGFR inhibitor, led to measurable clinical benefit. (Funded by Taiho Oncology and Taiho Pharmaceutical; FOENIX-CCA2 ClinicalTrials.gov number, NCT02052778.).

Abstract A016: Phase 1 study of hypofractionated radiation in combination with tremelimumab and durvalumab in refractory metastatic pancreatic adenocarcinoma

Immune checkpoint inhibitors have limited clinical activity in pancreatic cancer. Based on preclinical data, we hypothesized that hypofractionated radiation may cooperate with dual checkpoint inhibition in patients (Rech AJ, et al, Cancer Research, 2018). We therefore designed a phase 1 study to evaluate the safety and feasibility of two schedules of hypofractionated radiation with durvalumab (anti-PDL1) and tremelimumab (anti-CTLA-4) in patients with metastatic pancreatic, lung, and breast cancers and melanoma. Here, we present the data for pancreatic adenocarcinoma. Methods: Patients with metastatic pancreatic cancer treated with at least one prior line of therapy with measurable disease by RECIST in addition to an index lesion amenable to hypofractionated radiation were enrolled sequentially to two cohorts – cohort A evaluating 3 fractions of 8 Gy or cohort B evaluating 1 fraction of 17 Gy. Patients received 4 cycles of tremelimumab 1 mg/kg IV and durvalumab 20 mg/kg IV every 4 weeks for 4 doses followed by durvalumab 10 mg/kg IV every 2 weeks until progression. Radiation was given in week 2 of treatment. Patients were replaced if they did not receive week 5 of therapy on trial, but were included in safety/feasibility analysis. Blood and, when feasible, baseline and on-treatment biopsies were obtained for exploratory biomarker evaluation. Results: 10 patients were treated in cohort A and 21 patients in cohort B. All patients were included in the safety and feasibility assessment. Overall, treatment was well tolerated in both cohorts. The most common adverse events were grade 1 or 2 fatigue (A 30%, B 23.8%), diarrhea (A 10%, B 14.3%), pruritis (A 10%, B 14.3%), AST/ALT elevation and constipation (each A 10%, B 9.5%). Grade 3 diarrhea, elevated bilirubin, pneumonitis, and syncope were noted in 1 patient each, all in cohort B. Grade 5 pneumothorax occurred after baseline biopsy in 1 patient. Grade 2 hyperthyroidism (A) and pneumonitis (B) were noted each in 1 patient. 8 patients in cohort A and 13 patients in cohort B were evaluable for response. In cohort A, 50% of patients had stable disease as best response, and median overall survival was 4.9 months. In cohort B, 23.1% had PR and 30.8% had SD as best response and mOS was 5.2 months. Responses occurred more frequently when metastatic lung nodules were radiated – SD in 3/5 (60%) patients in cohort A, PR in 3/10 (30%) and SD in 4/10 (40%) patients in cohort B, compared to SD in 1/3 (33%) patients in cohort A and 0/3 (0%) patients in cohort B who underwent radiation to a liver lesion. Biomarker analysis will be presented. Conclusions: The combination of durvalumab, tremelimumab with hypofractionated radiation is safe and feasible in a refractory pancreatic adenocarcinoma patient population. Encouraging clinical activity warrants further evaluation, especially when hypofractionated radiation is delivered to lung nodules.

Citation Format: Mark H. O'Hara, Adham S. Bear, Max M. Wattenberg, Ursina R. Teitelbaum, Kim A. Reiss, Thomas B. Karasic, Charles J. Schneider, Peter J. O'Dwyer, Edgar H. Ben-Josef, Andrzej P. Wojcieszynski, Amit H. Maity, Rosemarie H. Mick, Robert H. Vonderheide. Phase 1 study of hypofractionated radiation in combination with tremelimumab and durvalumab in refractory metastatic pancreatic adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A016.

DWI Metrics Differentiating Benign Intraductal Papillary Mucinous Neoplasms from Invasive Pancreatic Cancer: A Study in GEM Models

KPC (KrasG12D:Trp53R172H:Pdx1-Cre) and CKS (KrasG12D:Smad4L/L:Ptf1a-Cre) mice are genetically engineered mouse (GEM) models that capture features of human pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasms (IPMN), respectively. We compared these autochthonous tumors using quantitative imaging metrics from diffusion-weighted MRI (DW-MRI) and dynamic contrast enhanced (DCE)-MRI in reference to quantitative histological metrics including cell density, fibrosis, and microvasculature density. Our results revealed distinct DW-MRI metrics between the KPC vs. CKS model (mimicking human PDAC vs. IPMN lesion): the apparent diffusion coefficient (ADC) of CKS tumors is significantly higher than that of KPC, with little overlap (mean ± SD 2.24±0.2 vs. 1.66±0.2, p<10−10) despite intratumor and intertumor variability. Kurtosis index (KI) is also distinctively separated in the two models. DW imaging metrics are consistent with growth pattern, cell density, and the cystic nature of the CKS tumors. Coregistration of ex vivo ADC maps with H&E-stained sections allowed for regional comparison and showed a correlation between local cell density and ADC value. In conclusion, studies in GEM models demonstrate the potential utility of diffusion-weighted MRI metrics for distinguishing pancreatic cancer from benign pancreatic cysts such as IPMN.

Multianalyte Prognostic Signature Including Circulating Tumor DNA and Circulating Tumor Cells in Patients With Advanced Pancreatic Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is associated with a poor prognosis. Multianalyte signatures, including liquid biopsy and traditional clinical variables, have shown promise for improving prognostication in other solid tumors but have not yet been rigorously assessed for PDAC.

MATERIALS AND METHODS

We performed a prospective cohort study of patients with newly diagnosed locally advanced pancreatic cancer (LAPC) or metastatic PDAC (mPDAC) who were planned to undergo systemic therapy. We collected peripheral blood before systemic therapy and assessed circulating tumor cells (CTCs), cell-free DNA concentration (cfDNA), and circulating tumor KRAS (ctKRAS)-variant allele fraction (VAF). Association of variables with overall survival (OS) was assessed in univariate and multivariate survival analysis, and comparisons were made between models containing liquid biopsy variables combined with traditional clinical prognostic variables versus models containing traditional clinical prognostic variables alone.

RESULTS

One hundred four patients, 40 with LAPC and 64 with mPDAC, were enrolled. CTCs, cfDNA concentration, and ctKRAS VAF were all significantly higher in patients with mPDAC than patients with LAPC. ctKRAS VAF (cube root; 0.05 unit increments; hazard ratio, 1.11; 95% CI, 1.03 to 1.21; P = .01), and CTCs ≥ 1/mL (hazard ratio, 2.22; 95% CI, 1.34 to 3.69; P = .002) were significantly associated with worse OS in multivariate analysis while cfDNA concentration was not. A model selected by backward selection containing traditional clinical variables plus liquid biopsy variables had better discrimination of OS compared with a model containing traditional clinical variables alone (optimism-corrected Harrell's C-statistic 0.725 v 0.681).

CONCLUSION

A multianalyte prognostic signature containing CTCs, ctKRAS, and cfDNA concentration outperformed a model containing traditional clinical variables alone suggesting that CTCs, ctKRAS, and cfDNA provide prognostic information complementary to traditional clinical variables in advanced PDAC.

Comparison of nivolumab and sorafenib for first systemic therapy in patients with hepatocellular carcinoma and Child-Pugh B cirrhosis

BACKGROUND

Patients with decompensated cirrhosis are excluded or underrepresented in clinical trials of systemic therapies for hepatocellular carcinoma (HCC) and comparisons of available therapies are lacking. We aimed to compare overall survival for patients with HCC and Child-Pugh B cirrhosis treated with nivolumab or sorafenib as first systemic treatment.

METHODS

We performed a retrospective cohort study in patients with HCC and Child-Pugh B cirrhosis treated at Veterans Affairs medical centers to compare overall survival, adverse events, and reason for discontinuation of therapy between patients treated with nivolumab or sorafenib as first systemic treatment. All statistical tests were 2-sided.

RESULTS

Of those meeting inclusion criteria, 431 patients were treated with sorafenib and 79 with nivolumab. Median OS was 4.0 months (95% CI 3.5-4.8) in the sorafenib cohort and 5.0 months (95% CI 3.3-6.8) in the nivolumab cohort. In the multivariable Cox proportional hazards model, nivolumab was associated with a significantly reduced hazard of death compared to sorafenib (HR 0.69; 95% CI 0.52-0.91; p = 0.008). In a secondary analysis using propensity score methods, results did not reach statistical significance (HR 0.77; 95% CI 0.55-1.06; p = 0.11). Treatment was discontinued due to toxicity in 12% of patients receiving nivolumab compared to 36% receiving sorafenib (p = 0.001).

CONCLUSION

In patients with HCC and Child-Pugh B cirrhosis, nivolumab treatment may be associated with improved overall survival and improved tolerability compared to sorafenib and should be considered for the first systemic treatment in this population.

Trends of Clinical Outcomes of Patients with Advanced Hepatocellular Carcinoma Treated with First-Line Sorafenib in Randomized Controlled Trials

BACKGROUND

Sorafenib has consistently served as the control arm in multiple randomized clinical trials (RCTs) evaluating novel therapies for advanced hepatocellular carcinoma (HCC) for more than a decade. Analyzing trends in clinical outcomes of patients treated with sorafenib for the same indication over time offers the opportunity for unique insight into the evolution of clinical trial conduct and potential non-drug factors impacting outcomes.

METHODS

We identified RCTs in patients with treatment-naïve advanced HCC where sorafenib was compared to another systemic therapy or placebo. We extracted trial-level demographic, clinicopathologic, and outcome data (overall survival [OS], progression-free survival [PFS], objective response rate [ORR], and duration of therapy). Sample-weighted linear regression was used to identify temporal trends with significance set at p ≤ 0.05.

RESULTS

Sixteen RCTs (9 phase III and 7 phase II) enrolling 4,086 patients treated with sorafenib were included in the analysis. Included trials enrolled patients from 2005 to 2019. OS has significantly improved by 4.5 months from 2005 to 2019 (p = 0.048) over time. Thirteen studies provided data on PFS using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, with no significant change over time (p = 0.69). ORR assessed by RECIST 1.1 has significantly improved by 6.0% over time (p = 0.003). Median duration of therapy with sorafenib has decreased by 53% since the enrollment of the first clinical trial in 2005, from 23.1 weeks to 12.2 weeks (p = 0.0037). There was no significant change in patient demographics were identified over time to explain the OS findings.

CONCLUSION

The median OS of patients with advanced HCC treated with sorafenib has improved significantly over 15 years. At the same time, the median duration of therapy with sorafenib has decreased. The reason for these findings was not explained by changing demographics of patients enrolled in these trials and has implications for ongoing clinical trials.

OUP accepted manuscript

BACKGROUND

The antiangiogenic tyrosine kinase inhibitor regorafenib provides a survival benefit in patients with previously treated metastatic colorectal cancer (CRC). Antiangiogenic therapy causes hypoxic stress within tumor cells, which activates autophagy as a survival mechanism. The histone deacetylase inhibitor (HDAC) entinostat increases dependence on autophagy through epigenetic mechanisms. Hydroxychloroquine (HCQ) blocks autophagy by blunting lysosomal acidification. We hypothesized that HCQ and entinostat would be tolerable with regorafenib and potentiate the antitumor response.

METHODS

This was a 3+3 phase I trial of HCQ and entinostat with regorafenib in patients with metastatic CRC. The primary objective was safety, and the secondary objective was clinical efficacy.

RESULTS

Twenty patients received study therapy. Six evaluable patients were enrolled at each of the three planned dose levels, one patient at an intermediate dose level, and one additional patient withdrew consent after 4 days to receive treatment closer to home. One dose-limiting toxicity was noted in the study at dose level 2 (grade 3 fatigue). Seven patients discontinued therapy due to related toxicities; rapid weight loss was near universal, with a median weight loss of 4.4 kg (range 1.5-12.2 kg) in the first 2 weeks of treatment. No objective responses were observed.

CONCLUSION

The combination of regorafenib, HCQ, and entinostat was poorly tolerated without evident activity in metastatic CRC.

CLINICALTRIALS.GOV IDENTIFIER

NCT03215264.

Phase II Study of Maintenance Rucaparib in Patients With Platinum-Sensitive Advanced Pancreatic Cancer and a Pathogenic Germline or Somatic Variant in BRCA1, BRCA2, or PALB2

PURPOSE

Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi), is approved as maintenance therapy for patients with advanced pancreatic cancer (PC) and a germline BRCA1 or BRCA2 pathogenic variant (PV). This investigator-initiated, single-arm phase II study assessed the role of the PARPi rucaparib as maintenance therapy in advanced PC with germline or somatic PV in BRCA1, BRCA2, or PALB2.

PATIENTS AND METHODS

Eligible patients had advanced PC; germline (g) or somatic (s) PVs in BRCA1, BRCA2, or PALB2, and received at least 16 weeks of platinum-based chemotherapy without evidence of platinum resistance. Chemotherapy was discontinued and patients received rucaparib 600 mg orally twice a day until progression. The primary end point was the progression-free survival (PFS) rate at 6 months (PFS6). Secondary end points included safety, ORR, disease control rate, duration of response, and overall survival.

RESULTS

Of 46 enrolled patients, 42 were evaluable (27 gBRCA2, seven gBRCA1, six gPALB2, and two sBRCA2). PFS6 was 59.5% (95% CI, 44.6 to 74.4), median PFS was 13.1 months (95% CI, 4.4 to 21.8), and median overall survival was 23.5 months (95% CI, 20 to 27). The PFS at 12 months was 54.8%. ORR of the 36 patients with measurable disease was 41.7% (3 complete responses; 12 partial responses; 95% CI, 25.5 to 59.2), and disease control rate was 66.7% (95% CI, 49.0 to 81.4). Median duration of response was 17.3 months (95% CI, 8.8 to 25.8). Responses occurred in patients with gBRCA2 (41%, 11 out of 27), gPALB2 (50%, 3 out of 6), and sBRCA2 (50%, 1 out of 2). No new safety signals were noted.

CONCLUSION

Maintenance rucaparib is a safe and effective therapy for platinum-sensitive, advanced PC with a PV in BRCA1, BRCA2, or PALB2. The finding of efficacy in patients with gPALB2 and sBRCA2 PVs expands the population likely to benefit from PARPi beyond gBRCA1/2 PV carriers.

The efficacy and safety of definitive concurrent chemoradiotherapy for non-operable esophageal cancer

Objective

To report outcomes and toxicity in patients who received definitive concurrent chemoradiation (DCCRT) for non‐operable esophageal cancer (EC) in the modern era, and to identify markers of overall and disease‐free survival (OS/DFS).

Methods

We conducted a retrospective cohort study of patients with unresectable EC who received DCCRT at our institution between 1/2008 and 1/2019. Descriptive statistics were used to report disease‐control outcomes and CTCAE v4.0–5.0 toxicities. Univariable and multivariable Cox regression, and stepwise regression were used to identify associations with survival.

Results

At a median follow‐up of 19.5 months, 130 patients with adenocarcinoma (AC) (62%) or squamous cell carcinoma (SCC) (38%) were evaluable (Stage II‐III: 92%). Patients received carboplatin/paclitaxel (75%) or fluorouracil‐based (25%) concurrent chemotherapy. Median total RT dose was 50.4 Gy (range, 44.7–71.4 Gy) delivered in 28 fractions (24–35). Locoregional and distant recurrence occurred in 30% and 35% of AC, and 24% and 33% of SCC, respectively. Median OS and DFS were 22.9 and 10.7 months in AC, and 25.7 and 20.2 months in SCC, respectively. On stepwise regression, tumor stage, feeding tube during DCCRT, and change in primary tumor PET/CT SUVmax were significantly associated with OS and DFS. Most severe toxicities were acute grade 4 hematologic cytopenia (6%) and radiation dermatitis (1%). Most common acute grade 3 toxicities were hematologic cytopenia (35%), dysphagia (23%), and anorexia (19%).

Conclusions

Treatment of non‐operable EC with DCCRT has acceptable toxicity and can provide multi‐year disease control for some patients, even in AC. Continued follow‐up and investigation in large studies would be useful.

A Pilot Study of Galunisertib plus Stereotactic Body Radiotherapy in Patients with Advanced Hepatocellular Carcinoma

TGFβ is a pleiotropic cytokine with immunosuppressive activity. In preclinical models, blockade of TGFβ enhances the activity of radiation and invokes T-cell antitumor immunity. Here, we combined galunisertib, an oral TGFβ inhibitor, with stereotactic body radiotherapy (SBRT) in patients with advanced hepatocellular carcinoma (HCC) and assessed safety, efficacy, and immunologic correlatives. Patients (n = 15) with advanced HCC who progressed on, were intolerant of, or refused sorafenib were treated with galunisertib (150 mg orally twice a day) on days 1 to 14 of each 28-day cycle. A single dose of SBRT (18-Gy) was delivered between days 15 to 28 of cycle 1. Site of index lesions treated with SBRT included liver (9 patients), lymph node (4 patients), and lung (2 patients). Blood for high-dimensional single cell profiling was collected. The most common treatment-related adverse events were fatigue (53%), abdominal pain (46.6%), nausea (40%), and increased alkaline phosphatase (40%). There were two instances of grade 2 alkaline phosphatase increase and two instances of grade 2 bilirubin increase. One patient developed grade 3 achalasia, possibly related to treatment. Two patients achieved a partial response. Treatment with galunisertib was associated with a decrease in the frequency of activated T regulatory cells in the blood. Distinct peripheral blood leukocyte populations detected at baseline distinguished progressors from nonprogressors. Nonprogressors also had increased CD8⁺PD-1⁺TIGIT⁺ T cells in the blood after treatment. We found galunisertib combined with SBRT to be well tolerated and associated with antitumor activity in patients with HCC. Pre- and posttreatment immune profiling of the blood was able to distinguish patients with progression versus nonprogression.

A Phase I Study of GGTI-2418 (Geranylgeranyl Transferase I Inhibitor) in Patients with Advanced Solid Tumors

BACKGROUND

Geranylgeranyltransferase I (GGTase I) catalyzes geranylgeranylation, a modification required for the function of many oncogenic RAS-related proteins. GGTI-2418 is a peptidomimetic small molecule inhibitor of GGTase I.

OBJECTIVE

The aim of this study was to establish the maximum tolerated dose of GGTI-2418 in patients with advanced solid tumors.

PATIENTS AND METHODS

This was a phase I, open-label, dose-escalation study conducted in two US centers (University of Pennsylvania and Indiana University) in adults with treatment-refractory advanced solid tumors. An accelerated dose-escalation schema was used across eight dose levels, from 120 to 2060 mg/m², administered on days 1-5 of each 21-day cycle.

RESULTS

Fourteen patients were enrolled in the dose-escalation cohort. No dose-limiting toxicities were observed, and 2060 mg/m² was determined to be the maximum tolerated dose. The only potential drug-related grade 3 or 4 toxicities were elevated bilirubin and alkaline phosphatase in a single patient with concurrent malignant biliary obstruction. No objective responses were observed. Four of thirteen evaluable patients had stable disease for up to 6.7 months. The study was terminated prior to dose expansion based on a sponsor decision. Pharmacokinetic analysis demonstrated a mean terminal half-life of 1.1 h.

CONCLUSIONS

GGTI2418 was safe and tolerable at all tested dose levels with some evidence of disease stability. Due to rapid elimination, dosing of GGTI2418 in this study may have been inadequate to achieve optimal inhibition of its target, GGTase I.

Effect of Gemcitabine and nab-Paclitaxel With or Without Hydroxychloroquine on Patients With Advanced Pancreatic Cancer: A Phase 2 Randomized Clinical Trial

Importance

Autophagy is a mechanism of treatment resistance to chemotherapy that has a role in the maintenance of pancreatic cancer. Hydroxychloroquine sulfate (HCQ) is an inhibitor of autophagy that inhibits the fusion of the autophagosome to the lysosome.

Objective

To determine whether HCQ improves overall survival at 1 year in combination with gemcitabine hydrochloride and nab-paclitaxel (GA) among patients with metastatic pancreatic cancer.

Design, Setting, and Participants

Open-label, phase 2 randomized clinical trial conducted between March 18, 2013, and November 16, 2017, at the University of Pennsylvania, HonorHealth, and The Johns Hopkins University among 112 patients with previously untreated metastatic or advanced pancreatic ductal adenocarcinoma, Eastern Cooperative Oncology Group performance status of 0 or 1, and adequate marrow and organ function. All efficacy analyses were performed for the intention-to-treat population.

Interventions

Patients were randomized in a 1:1 ratio to receive GA with or without HCQ. All patients received standard doses of GA, and those randomized to receive HCQ were treated continuously with 600 mg orally twice daily.

Main Outcome and Measure

Overall survival at 1 year.

Results

A total of 112 patients (45 women and 67 men; median age, 65 years; range, 43-86 years) were enrolled; 55 were randomized to receive GA plus HCQ, and 57 to receive GA. Overall survival at 12 months was 41% (95% CI, 27%-53%) in the HCQ group and 49% (95% CI, 35%-61%) in the non-HCQ group. Median progression-free survival was 5.7 months (95% CI, 4.0-9.3 months) in the HCQ group and 6.4 months (95% CI, 4.5-7.6 months) in the non-HCQ group. Median overall survival was 11.1 months (95% CI, 9.0-14.2 months) in the HCQ group and 12.1 months (95% CI, 9.3-15.5 months) in the non-HCQ group. Overall response rate was 38.2% (n = 21) in the HCQ group and 21.1% (n = 12) in the non-HCQ group (P = .047). Treatment-related grade 3 or 4 adverse events that differed between the HCQ and non-HCQ groups were neutropenia (23 of 54 [42.6%] vs 12 of 53 [22.6%]), anemia (2 of 54 [3.7%] vs 9 of 53 [17.0%]), fatigue (4 of 54 [7.4%] vs 0), nausea (5 of 54 [9.3%] vs 0), peripheral neuropathy (7 of 54 [13.0%] vs 3 of 53 [5.7%]), visual changes (3 of 54 [5.6%] vs 0), and neuropsychiatric symptoms (3 of 54 [5.6%] vs 0).

Conclusions and Relevance

The addition of HCQ to block autophagy did not improve the primary end point of overall survival at 12 months. These data do not support the routine use of GA plus HCQ for metastatic pancreatic cancer in the absence of a biomarker. However, improvement seen in the overall response rate with HCQ may indicate a role for HCQ in the locally advanced setting, where tumor response may permit resection.

Trial Registration

ClinicalTrials.gov identifier: NCT01506973.

Abstract CT085: Randomized phase II trial of hydroxychloroquine in combination with gemcitabine/nab-paclitaxel to inhibit autophagy in pancreatic cancer: A SU2C-funded trial

Autophagy, a regulated metabolic process that enables energy conservation in adverse environmental circumstances, has been shown in animal models to confer resistance to chemotherapy, which can be reversed by hydroxychloroquine (HCQ). After establishing safety in a Phase I run-in, 112 patients were randomized to receive standard gemcitabine (1000mg/m2) and nab-paclitaxel (125 mg/m2) weekly x 3 every 4 weeks, with (n=55 evaluable) or without (n=55 evaluable) HCQ 600mg bid. Median age was 65 (range 43-86) of whom 47% were aged &gt; 65, 40% were female, 93% Caucasian, ECOG PS 0/1 51%/49%, and did not differ between the arms. Treatment-related side-effects were consistent with prior studies, and were balanced by arm, except for Grade 3/4 neutropenia (42 vs 23%), nausea (9 vs 0%), and fatigue (7 vs 0%), all higher with HCQ. Partial responses were observed in 21/46 (46%) with HCQ, and 8/48 (17%) without HCQ. The primary endpoint, overall survival at 12 months, was 41% (95% CI 27-53%) in the HCQ arm and 51% (95% CI 36-63%) in the non-HCQ arm. Median progression-free survival was 5.7 months (95% CI 4.0-9.3) in the HCQ arm and 6.4 months in the non-HCQ arm (95% CI 4.5-7.6). Median overall survival was 11.1 months (95% CI 9.0-14.2) in the HCQ arm and 14.4 months (95% CI 9.5-15.6) in the non-HCQ arm. Genomic testing was performed on a subset of the patients (41%), in whom outcomes did not differ by p53 mutational status. We conclude that based on the primary endpoint, the addition of the autophagy reversal agent HCQ did not improve the survival of patients with metastatic pancreatic cancer. Response rates in patients who received HCQ were higher, and toxicity was tolerable. Autophagy reversal might be explored in the management of locally-advanced disease.

Citation Format: Thomas B. Karasic, Mark H. O'Hara, Arturo Loaiza-Bonilla, Kim A. Reiss-Binder, Ursina R. Teitelbaum, Erkut Borazanci, Ana M. De Jesus-Acosta, Colleen Redlinger, Jessica A. Burrell, Daniel D. Von Hoff, Daniel A. Laheru, Ravi K. Amaravadi, Jeffrey A. Drebin, Peter J. O'Dwyer. Randomized phase II trial of hydroxychloroquine in combination with gemcitabine/nab-paclitaxel to inhibit autophagy in pancreatic cancer: A SU2C-funded trial [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 CT085.

Palbociclib (PD0332991)-a Selective and Potent Cyclin-Dependent Kinase Inhibitor: A Review of Pharmacodynamics and Clinical Development

IMPORTANCE

Palbociclib (PD0332991) is a newly developed drug that received breakthrough designation and recent US Food and Drug Administration approval in combination with endocrine therapy in the treatment of hormone receptor positive, ERBB2-negative (formerly HER2 or HER2/neu) breast cancer in the first-line metastatic setting.

OBJECTIVE

Herein we describe the preclinical and translational data and early- and late-phase clinical trials in which palbociclib has been investigated in a broad array of tumor types. We discuss the pharmacodynamics, pharmacokinetics, toxic effects, and clinical response rates.

EVIDENCE REVIEW

On March 1, 2015, we conducted a review of the literature describing the development of palbociclib. We used the PubMed search terms "PD0332991," "palbociclib," and "CDK4/6 inhibitor" to find all published articles of interest, without limitation as to publication date.

FINDINGS

Palbociclib is a potent and specific oral cyclin-dependent kinase (CDK) 4/6 inhibitor that has strong preclinical data to support its activity in retinoblastoma protein-expressing tumors. Phase 1 trials have demonstrated safety, and phase 2 trials have shown single-agent activity in mantle-cell lymphoma, breast cancer, liposarcoma, and teratoma with reversible neutropenia as the main toxic effect. Addition of palbociclib to endocrine therapy improves progression-free survival in endocrine therapy-naïve and endocrine therapy-resistant metastatic settings.

CONCLUSIONS AND RELEVANCE

Palbociclib is well tolerated and has therapeutic potential for multiple cancers, including breast cancer, where its efficacy has been demonstrated alone and in combination with endocrine therapy. Additional combinations of palbociclib with endocrine therapy, chemotherapy, and targeted therapy have potential in various tumors, and phase 3 trials are under way.

Radiation-induced bystander signaling pathways in human fibroblasts: a role for interleukin-33 in the signal transmission

The main goal of this study is to elucidate the mechanisms of the signal transmission for radiation-induced bystander response. The NF-kappaB-dependent gene expression of IL8, IL6, PTGS2/COX2, TNF and IL33 in directly irradiated human skin fibroblasts produced the cytokines and prostaglandin E2 (PGE2) with autocrine/paracrine functions, which further activated signaling pathways and induced NF-kappaB-dependent gene expression in bystander cells. As a result, bystander cells also started expression and production of interleukin-8, interleukin-6, COX-2-generated PGE2 and interleukin-33 (IL-33) followed by autocrine/paracrine stimulation of the NF-kappaB and MAPK pathways. A blockage of IL-33 transmitting functions with anti-IL-33 monoclonal antibody added into the culture media decreased NF-kappaB activation in directly irradiated and bystander cells. On the other hand, the IGF-1-Receptor kinase regulated the PI3K-AKT pathway in both directly irradiated and bystander fibroblasts. A pronounced and prolonged increase in AKT activity after irradiation was a characteristic feature of bystander cells. AKT positively regulated IL-33 protein expression levels. Suppression of the IGF-R1-AKT-IL-33 pathway substantially increased radiation-induced or TRAIL-induced apoptosis in fibroblasts. Taken together, our results demonstrated the early activation of NF-kappaB-dependent gene expression first in directly irradiated and then bystander fibroblasts, the further modulation of critical proteins, including IL-33, by AKT in bystander cells and late drastic changes in cell survival and in enhanced sensitivity to TRAIL-induced apoptosis after suppression of the IGF-1R-AKT-IL-33 signaling cascade in both directly irradiated and bystander cells.

Disruption of IGF-1R signaling increases TRAIL-induced apoptosis: a new potential therapy for the treatment of melanoma

Resistance of cancer cells to apoptosis is dependent on a balance of multiple genetic and epigenetic mechanisms, which up-regulate efficacy of the surviving growth factor-receptor signaling pathways and suppress death-receptor signaling pathways. The Insulin-like Growth Factor-1 Receptor (IGF-1R) signaling pathway is highly active in metastatic melanoma cells by mediating downstream activation of PI3K-AKT and MAPK pathways and controlling general cell survival and proliferation. In the present study, we used human melanoma lines with established genotypes that represented different phases of cancer development: radial-growth-phase WM35, vertical-growth-phase WM793, metastatic LU1205 and WM9 [1]. All these lines have normal NRAS. WM35, WM793, LU1205 and WM9 cells have mutated BRAF (V600E). WM35 and WM9 cells express normal PTEN, while in WM793 cells PTEN expression is down-regulated; finally, in LU1205 cells PTEN is inactivated by mutation. Cyclolignan picropodophyllin (PPP), a specific inhibitor of IGF-1R kinase activity, strongly down-regulated the basal levels of AKT activity in WM9 and in WM793 cells, modestly does so in LU1205, but has no effect on AKT activity in the early stage WM35 cells that are deficient in IGF-1R. In addition, PPP partially down-regulated the basal levels of active ERK1/2 in all lines used, highlighting the role of an alternative, non-BRAF pathway in MAPK activation. The final result of PPP treatment was an induction of apoptosis in WM793, WM9 and LU1205 melanoma cells. On the other hand, dose-dependent inhibition of IGF-1R kinase activity by PPP at a relatively narrow dose range (near 500 nM) has different effects on melanoma cells versus normal cells, inducing apoptosis in cancer cells and G2/M arrest of fibroblasts. To further enhance the pro-apoptotic effects of PPP on melanoma cells, we used a combined treatment of TNF-Related Apoptosis-Inducing Ligand (TRAIL) and PPP. This combination substantially increased death by apoptosis for WM793 and WM9 cells, but did so only modestly for LU1205 cells with very high basal activity of AKT. The ultimate goal of this direction of research is the discovery of a new treatment method for highly resistant human metastatic melanomas. Our findings provide the rationale for further preclinical evaluation of this novel treatment.