Oral Iloprost Research Articles

Phase Ib trial of inhaled iloprost for the prevention of lung cancer with predictive and response biomarker assessment.

Iloprost, a prostacyclin analog, has lung cancerpreventive activity in preclinical models and improved dysplasia in former smokers in a phase IIb trial. Oral iloprost is currently unavailable. We performed a phase Ib trial of inhaled iloprost in former smokers to assess tolerance and compliance. Participants self-administered nebulized iloprost (5ug) or placebo four (QID) or two (BID) times daily. As QID dose was well tolerated and due to expiration of the placebo, the BID dosing and placebo were eliminated early on in the trial. Bronchoscopy with biopsyat six standard sites was performed at treatment initiation and two months post-iloprost, with exploratory histological analysis. Bulk RNA sequencing, single cell RNA sequencing and an in vitro assay of epithelial progenitor cell iloprost response were performed on a subset of biopsies in an exploratory investigation of response mechanisms and predictive biomarkers. Thirty-four of a planned 48 participants were recruited to the trial.Inhaled iloprost was well tolerated with no adverse events > grade 2. Compliance was 67% in the QID group. The trial was not powered to detect histologic response and none was found. Bulk RNA sequencing of biopsies pre/post iloprost suggest that iloprost is immunomodulatory and downregulates cell proliferation pathways. Single cell RNA sequencing showed an increase in CD8-positive T cells with upregulation of genes in interferon γ signaling. In vitro iloprost response by epithelial progenitor cells correlated with histologic response with kappa coefficient of 0.81 (95% CI 0.47, 1.0). Inhaled iloprost was well tolerated with suboptimal compliance. Molecular analysis suggested that iloprosthas immunomodulatory and antiproliferative effects.The progenitor cell iloprost response assay may be a promising avenue to develop predictive biomarkers. https://clinicaltrials.gov/study/NCT02237183, identifier NCT02237183.

Abstract IA017: Iloprost for lung cancer prevention

Abstract Iloprost is a prostacyclin analogue with anti-metastatic, vasodilatory and anti-inflammatory properties. Increased prostacyclin is protective in pre-clinical murine models of adenocarcinoma and squamous cell carcinoma (SCC), including tobacco smoke. The chemoprotective properties are independent of the single cell surface prostacyclin receptor, as knockout animals are still protected. Clinical studies of iloprost have included both oral and inhaled preparations. Oral iloprost improves endobronchial dysplasia (pre-cursor lesions for invasive SCC) in former smokers. Dysplastic lesions are now being characterized beyond histology to better understand lesion evolution. Investigations into the mechanism of iloprost associated cancer prevention (including effects on basal progenitor cells, progenitor multi-potentiality, and differentiation) and biomarkers predicting response will be presented, along with an outline for an upcoming clinical trial in former smokers. Citation Format: Robert Keith. Iloprost for lung cancer prevention [abstract]. In: Proceedings of the Second Biennial NCI Meeting: Translational Advances in Cancer Prevention Agent Development (TACPAD); 2022 Sep 7-9. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_2): Abstract nr IA017.

Intranasal Iloprost Prevents Tumors in a Murine Lung Carcinogenesis Model.

Lung cancer chemoprevention with the prostacyclin analogue iloprost is the most promising approach to date for intercepting progression of premalignant lung lesions in former smokers. Previous preclinical studies of iloprost used oral delivery, but a study modeling delivery directly to the target organ was needed. In vivo and in vitro studies have identified gene expression changes following iloprost treatment, including increased e-cadherin and Ppargγ and decreased COX2 and vimentin. We used tumor counts and gene expression to demonstrate the effectiveness of intranasal delivery of iloprost in a murine model of premalignant adenomas. Intranasal delivery of iloprost reduced adenoma multiplicity 14 weeks after urethane exposure in FVB/N mice compared with untreated urethane controls. Intranasal iloprost reversed urethane-induced gene expression changes in tumors and whole lung. These results correspond to previous studies of oral iloprost and in vitro treatment of human bronchial epithelial cells. This study demonstrates that intranasal delivery of iloprost in a mouse model of lung premalignant lesions is effective chemoprevention. This will be an essential tool for exploring mechanisms and outcomes of iloprost chemoprevention, along with supporting ongoing clinical trials of inhaled iloprost chemoprevention. PREVENTION RELEVANCE: Iloprost is a promising chemoprevention agent for lung cancer and this work describes a new delivery approach in vivo.

Pharmacological treatment for Buerger's disease.

Buerger's disease (thromboangiitis obliterans) is a non-atherosclerotic, segmental inflammatory pathology that most commonly affects the small and medium sized arteries, veins, and nerves in the upper and lower extremities. The aetiology is unknown, but involves hereditary susceptibility, tobacco exposure, immune and coagulation responses. In many cases, there is no possibility of revascularisation to improve the condition. Pharmacological treatment is an option for patients with severe complications, such as ischaemic ulcers or rest pain.This is an update of the review first published in 2016. To assess the effectiveness of any pharmacological agent (intravenous or oral) compared with placebo or any other pharmacological agent in patients with Buerger's disease. The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, AMED, the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials register to 15 October 2019. The review authors searched LILACS, ISRCTN, Australian New Zealand Clinical Trials Registry, EU Clinical Trials Register, clincialtrials.gov and the OpenGrey Database to 5 January 2020. We included randomised controlled trials (RCTs) involving pharmacological agents used in the treatment of Buerger's disease. Two review authors, independently assessed the studies, extracted data and performed data analysis. No new studies were identified for this update. Five randomised controlled trials (total 602 participants) compared prostacyclin analogue with placebo, aspirin, or a prostaglandin analogue, and folic acid with placebo. No studies assessed other pharmacological agents such as cilostazol, clopidogrel and pentoxifylline or compared oral versus intravenous prostanoid. Compared with aspirin, intravenous prostacyclin analogue iloprost improved ulcer healing (risk ratio (RR) 2.65; 95% confidence interval (CI) 1.15 to 6.11; 98 participants; 1 study; moderate-certainty evidence), and helped to eradicate rest pain after 28 days (RR 2.28; 95% CI 1.48 to 3.52; 133 participants; 1 study; moderate-certainty evidence), although amputation rates were similar six months after treatment (RR 0.32; 95% CI 0.09 to 1.15; 95 participants; 1 study; moderate-certainty evidence). When comparing prostacyclin (iloprost and clinprost) with prostaglandin (alprostadil) analogues, ulcer healing was similar (RR 1.13; 95% CI 0.76 to 1.69; 89 participants; 2 studies; I² = 0%; very low-certainty evidence), as was the eradication of rest pain after 28 days (RR 1.57; 95% CI 0.72 to 3.44; 38 participants; 1 study; low-certainty evidence), while amputation rates were not measured. Compared with placebo, the effects of oral prostacyclin analogue iloprost were similar for: healing ischaemic ulcers (iloprost 200 mcg: RR 1.11; 95% CI 0.54 to 2.29; 133 participants; 1 study; moderate-certainty evidence, and iloprost 400 mcg: RR 0.90; 95% CI 0.42 to 1.93; 135 participants; 1 study; moderate-certainty evidence), eradication of rest pain after eight weeks (iloprost 200 mcg: RR 1.14; 95% CI 0.79 to 1.63; 207 participants; 1 study; moderate-certainty evidence, and iloprost 400 mcg: RR 1.11; 95% CI 0.77 to 1.59; 201 participants; 1 study; moderate-certainty evidence), and amputation rates after six months (iloprost 200 mcg: RR 0.54; 95% CI 0.19 to 1.56; 209 participants; 1 study, and iloprost 400 mcg: RR 0.42; 95% CI 0.13 to 1.31; 213 participants; 1 study). When comparing folic acid with placebo in patients with Buerger's disease and hyperhomocysteinaemia, pain scores were similar, there were no new cases of amputation in either group, and ulcer healing was not assessed (very low-certainty evidence). Treatment side effects such as headaches, flushing or nausea were not associated with treatment interruptions or more serious consequences. Outcomes such as amputation-free survival, walking distance or pain-free walking distance, and ankle brachial index were not assessed by any study. Overall, the certainty of the evidence was very low to moderate, with few studies, small numbers of participants, variation in severity of disease of participants between studies and missing information (for example regarding baseline tobacco exposure). Moderate-certainty evidence suggests that intravenous iloprost (prostacyclin analogue) is more effective than aspirin for eradicating rest pain and healing ischaemic ulcers in Buerger's disease, but oral iloprost is not more effective than placebo. Very low and low-certainty evidence suggests there is no clear difference between prostacyclin (iloprost and clinprost) and the prostaglandin analogue alprostadil for healing ulcers and relieving pain respectively in severe Buerger's disease. Very low-certainty evidence suggests there is no clear difference in pain scores and amputation rates between folic acid and placebo, in people with Buerger's disease and hyperhomocysteinaemia. Further well designed RCTs assessing the effectiveness of pharmacological agents (intravenous or oral) in people with Buerger's disease are needed.

Abstract B35: Biomarkers for precision application of prostacyclin lung cancer chemoprevention

Abstract Lung cancer remains the leading cause of cancer death in the United States, and chemoprevention offers an appealing area of investigation in the face of limited therapeutic success. Improvement in endobronchial histology was demonstrated in former smokers after oral iloprost chemoprevention in a phase II clinical trial. Of the 48 patients who received iloprost in the chemoprevention trial, 23 had regressive histology and 25 had stable or progressive histology. Identifying markers that predict which patients will respond to treatment will help refine target populations for future trials and clinical applications. Markers of drug activity will also facilitate clinical application by allowing monitoring during treatment. Preclinical studies indicate that iloprost, a prostacyclin analogue, acts through peroxisome proliferator activated receptor gamma (PPAR) to reduce transformed lung epithelial cell growth and markers of epithelial-to-mesenchymal transition (EMT). We hypothesize that PPAR expression status predicts response to prostacyclin chemoprevention and that expression changes in known downstream targets of PPAR and prostacyclin indicate response to prostacyclin treatment. Prostacyclin may also induce expression of PPAR, leading to increased antitumor signaling. We found that expression of PPAR and markers of prostacyclin signaling (15pgdh, CES1, and PTGS2) and EMT markers (Snail, Vimentin, Ecadherin, and CRB3) changed in cultured human bronchial epithelial cells (HBEC) in response to cigarette smoke condensate (CSC) and that iloprost reversed these changes. Expression in mice also changed in response to cigarette smoke carcinogens and prostacyclin. miR-34c is inversely correlated with bronchial histology grade and suppresses lung cancer progression. In our study, the level of miR-34c was lower in the NSCLC cell line H322 compared to HBEC. In H322, miR-34c increased with PPAR agonist treatment and decreased with PPAR antagonist treatment. In HBEC and mouse models of lung cancer chemoprevention, miR-34c increased with prostacyclin and decreased with cigarette smoke carcinogen exposure. In cultured primary progressive dysplastic bronchial epithelial cells, treatment with iloprost resulted in similar expression changes in Vimentin, Snail, Ecadherin, CRB3, CES1, and miR-34c. This study has the potential to improve iloprost lung cancer chemoprevention by allowing future trials to more effectively target high-risk patients, by providing a clinical biomarker for identification of chemoprevention candidates, and by identifying biomarkers for intermediate monitoring of response. Future studies will test expression of these markers in lung tissue biopsy and liquid biopsy samples from the oral and inhaled iloprost chemoprevention trials. Citation Format: Melissa New, Debbie McArthur, Lori Nield, Dan Merrick, Robert L. Keith, Meredith A. Tennis. Biomarkers for precision application of prostacyclin lung cancer chemoprevention [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr B35.

The Second-Generation PGI2 Analogue Treprostinil Fails to Chemoprevent Tumors in a Murine Lung Adenocarcinoma Model.

Prostacyclin (prostaglandin I2, PGI2) overproduction in FVB/N mice prevents the formation of carcinogen and tobacco smoke-induced adenomas, and administration of the oral prostacyclin analogue iloprost to wild-type mice also prevented carcinogen-induced mouse lung adenoma formation. Former smokers taking oral iloprost showed improved bronchial dysplasia histology compared with placebo. Next-generation oral prostacyclin analogues, like treprostinil, were developed for the treatment of pulmonary arterial hypertension (PAH). On the basis of our prior studies with iloprost, we performed preclinical studies examining the ability of treprostinil to chemoprevent urethane-induced murine lung adenocarcinoma. We determined the MTD in chow (prior studies had delivered treprostinil by gavage), and this dose produced serum levels in the experimental animals similar to those found in PAH patients treated with treprostinil. We then examined the chemopreventive efficacy of treprostinil exposure initiated both before (1 week) and after (6 weeks) urethane exposure to better model chemoprevention studies conducted in former smokers. Neither of these dosing strategies prevented murine lung cancer; however, we did detect changes in pulmonary inflammatory cell infiltrate and expression of CXCR4 (a chemokine receptor previously shown to increase in response to treprostinil exposure) in tumor-bearing, treprostinil-treated animals, indicating that the drug was bioavailable. One potential explanation stems from iloprost and treprostinil differentially activating cell surface prostaglandin receptors and intracellular peroxisome proliferator-activated receptors. When murine lung tumor cells were treated with treprostinil, their proliferation rate increased; in contrast, iloprost had no effect on proliferation. Future investigations comparing these two agents will provide insight into iloprost's chemopreventive mechanisms. Cancer Prev Res; 10(11); 671-9. ©2017 AACR.

Pharmacological treatment for Buerger's disease.

Buerger's disease (thromboangiitis obliterans) is a non-atherosclerotic, segmental inflammatory pathology that most commonly affects the small and medium sized arteries, veins, and nerves in the upper and lower extremities. The etiology is unknown, but involves hereditary susceptibility, tobacco exposure, immune and coagulation responses. In many cases, there is no possibility of revascularization to improve the condition. Pharmacological treatment is an option for patients with severe complications, such as ischaemic ulcers or rest pain. To assess the effectiveness of any pharmacological agent (intravenous or oral) compared with placebo or any other pharmacological agent in patients with Buerger's disease. The Cochrane Vascular Trials Search Co-ordinator searched their Specialised Register (last searched in April 2015) and the Cochrane Register of Studies (Issue 3, 2015). The review authors searched trial registers and the European grey literature; screened reference lists of relevant studies, and contacted study authors and major pharmaceutical companies. Randomised controlled trials (RCTs) involving pharmacological agents used in the treatment of Buerger's disease. Two review authors, independently assessed the studies, extracted data and performed data analysis. Five randomised controlled trials (total 602 participants) compared prostacyclin analogue with placebo, aspirin, or a prostaglandin analogue, and folic acid with placebo. No studies assessed other pharmacological agents such as cilostazol, clopidogrel and pentoxifylline or compared oral versus intravenous prostanoid.Compared with aspirin, intravenous prostacyclin analogue iloprost improved ulcer healing (risk ratio (RR) 2.65; 95% confidence interval (CI) 1.15 to 6.11; 98 participants; one study; moderate quality evidence), and helped to eradicate rest pain after 28 days (RR 2.28; 95% CI 1.48 to 3.52; 133 participants; one study; moderate quality evidence), although amputation rates were similar six months after treatment (RR 0.32; 95% CI 0.09 to 1.15; 95 participants; one study; moderate quality evidence). When comparing prostacyclin (iloprost and clinprost) with prostaglandin (alprostadil) analogues, ulcer healing was similar (RR 1.13; 95% CI 0.76 to 1.69; 89 participants; two studies; I² = 0%; very low quality evidence), as was the eradication of rest pain after 28 days (RR 1.57; 95% CI 0.72 to 3.44; 38 participants; one study; low quality evidence), while amputation rates were not measured. Compared with placebo, the effects of oral prostacyclin analogue iloprost were similar for: healing ischaemic ulcers (iloprost 200 mcg: RR 1.11; 95% CI 0.54 to 2.29; 133 participants; one study; moderate quality evidence, and iloprost 400 mcg: RR 0.90; 95% CI 0.42 to 1.93; 135 participants; one study; moderate quality evidence), eradication of rest pain after eight weeks (iloprost 200 mcg: RR 1.14; 95% CI 0.79 to 1.63; 207 participants; one study; moderate quality evidence, and iloprost 400 mcg: RR 1.11; 95% CI 0.77 to 1.59; 201 participants; one study; moderate quality evidence), and amputation rates after six months (iloprost 200 mcg: RR 0.54; 95% CI 0.19 to 1.56; 209 participants; one study, and iloprost 400 mcg: RR 0.42; 95% CI 0.13 to 1.31; 213 participants; one study). When comparing folic acid with placebo in patients with Buerger's disease and hyperhomocysteinaemia, pain scores were similar, there were no new cases of amputation in either group, and ulcer healing was not assessed (very low quality evidence).Treatment side effects such as headaches, flushing or nausea were not associated with treatment interruptions or more serious consequences. Outcomes such as amputation-free survival, walking distance or pain-free walking distance, and ankle brachial index were not assessed by any study.Overall, the quality of the evidence was very low to moderate, with few studies, small numbers of participants, variation in severity of disease of participants between studies and missing information regarding for example baseline tobacco exposure. Moderate quality evidence suggests that intravenous iloprost (prostacyclin analogue) is more effective than aspirin for eradicating rest pain and healing ischaemic ulcers in Buerger's disease, but oral iloprost is not more effective than placebo. Verylow and low quality evidence suggests there is no difference between prostacyclin (iloprost and clinprost) and the prostaglandin analogue alprostadil for healing ulcers and relieving pain respectively in severe Buerger's disease. Very-low quality evidence suggests there is no difference in pain scores and amputation rates between folic acid and placebo, in people with Buerger's disease and hyperhomocysteinaemia. High quality trials assessing the effectiveness of pharmacological agents (intravenous or oral) in people with Buerger's disease are needed.

Pharmacological treatment for Buerger's disease.

Buerger's disease (thromboangiitis obliterans) is a non-atherosclerotic, segmental inflammatory pathology that most commonly affects the small and medium sized arteries, veins, and nerves in the upper and lower extremities. The etiology is unknown, but involves hereditary susceptibility, tobacco exposure, immune and coagulation responses. In many cases, there is no possibility of revascularization to improve the condition. Pharmacological treatment is an option for patients with severe complications, such as ischaemic ulcers or rest pain. To assess the effectiveness of any pharmacological agent (intravenous or oral) compared with placebo or any other pharmacological agent in patients with Buerger's disease. The Cochrane Vascular Trials Search Co-ordinator searched their Specialised Register (last searched in April 2015) and the Cochrane Register of Studies (Issue 3, 2015). The review authors searched trial registers and the European grey literature; screened reference lists of relevant studies, and contacted study authors and major pharmaceutical companies. Randomised controlled trials (RCTs) involving pharmacological agents used in the treatment of Buerger's disease. Two review authors, independently assessed the studies, extracted data and performed data analysis. Five randomised controlled trials (total 602 participants) compared prostacyclin analogue with placebo, aspirin, or a prostaglandin analogue, and folic acid with placebo. No studies assessed other pharmacological agents such as cilostazol, clopidogrel and pentoxifylline or compared oral versus intravenous prostanoid.Compared with aspirin, intravenous prostacyclin analogue iloprost improved ulcer healing (risk ratio (RR) 2.65; 95% confidence interval (CI) 1.15 to 6.11; 98 participants; one study; moderate quality evidence), and helped to eradicate rest pain after 28 days (RR 2.28; 95% CI 1.48 to 3.52; 133 participants; one study; moderate quality evidence), although amputation rates were similar six months after treatment (RR 0.32; 95% CI 0.09 to 1.15; 95 participants; one study; moderate quality evidence). When comparing prostacyclin (iloprost and clinprost) with prostaglandin (alprostadil) analogues, ulcer healing was similar (RR 1.13; 95% CI 0.76 to 1.69; 89 participants; two studies; I² = 0%; very low quality evidence), as was the eradication of rest pain after 28 days (RR 1.57; 95% CI 0.72 to 3.44; 38 participants; one study; low quality evidence), while amputation rates were not measured. Compared with placebo, the effects of oral prostacyclin analogue iloprost were similar for: healing ischaemic ulcers (iloprost 200 mcg: RR 1.11; 95% CI 0.54 to 2.29; 133 participants; one study; moderate quality evidence, and iloprost 400 mcg: RR 0.90; 95% CI 0.42 to 1.93; 135 participants; one study; moderate quality evidence), eradication of rest pain after eight weeks (iloprost 200 mcg: RR 1.14; 95% CI 0.79 to 1.63; 207 participants; one study; moderate quality evidence, and iloprost 400 mcg: RR 1.11; 95% CI 0.77 to 1.59; 201 participants; one study; moderate quality evidence), and amputation rates after six months (iloprost 200 mcg: RR 0.54; 95% CI 0.19 to 1.56; 209 participants; one study, and iloprost 400 mcg: RR 0.42; 95% CI 0.13 to 1.31; 213 participants; one study). When comparing folic acid with placebo in patients with Buerger's disease and hyperhomocysteinaemia, pain scores were similar, there were no new cases of amputation in either group, and ulcer healing was not assessed (very low quality evidence).Treatment side effects such as headaches, flushing or nausea were not associated with treatment interruptions or more serious consequences. Outcomes such as amputation-free survival, walking distance or pain-free walking distance, and ankle brachial index were not assessed by any study.Overall, the quality of the evidence was very low to moderate, with few studies, small numbers of participants, variation in severity of disease of participants between studies and missing information regarding for example baseline tobacco exposure. Moderate quality evidence suggests that intravenous iloprost (prostacyclin analogue) is more effective than aspirin for eradicating rest pain and healing ischaemic ulcers in Buerger's disease, but oral iloprost is not more effective than placebo. Verylow and low quality evidence suggests there is no difference between prostacyclin (iloprost and clinprost) and the prostaglandin analogue alprostadil for healing ulcers and relieving pain respectively in severe Buerger's disease. Very-low quality evidence suggests there is no difference in pain scores and amputation rates between folic acid and placebo, in people with Buerger's disease and hyperhomocysteinaemia. High quality trials assessing the effectiveness of pharmacological agents (intravenous or oral) in people with Buerger's disease are needed.

Oral prostacycline analog and clopidogrel combination provides early maturation and long-term survival after arteriovenous fistula creation: A randomized controlled study.

Vascular access is used as a lifeline for hemodialysis in patients with end stage renal disease failure (ESRD). Failure of arteriovenous fistula (AVF) maturation is still high. The purpose of this study was to research the effects of clopidogrel in combination with oral iloprost, a synthetic analog of prostacyclin PGI2. Ninety-six diabetic ESRD patients were divided into two groups. In the first group (Group 1, N = 50), clopidogrel (75 mg daily dose) and an oral prostacycline analog (200 mg daily dose) were administered. In the second group (Group 2, N = 46), placebo was given. All patients took study medication 7–10 days prior to surgery. A Doppler ultrasound (USG) was performed for measurement of arterial and venous diameters, and peak systolic velocity of arterial flow based on subsequent fistula adequacy. Autogenous AVFs were constructed in forearm as distally as possible in all patients. Both groups were followed-up for a year. In the placebo group, early AVF thrombosis was detected in two patients (4.3%). AVF maturation failure was noted in 14 patients (30.4%) in placebo group and in four patients (8%) in clopidogrel plus oral prostacycline analog group in the early postoperative period (P = 0.001). The mean maturation time was 38 ± 6.5 and 53 ± 12.8 days in study and placebo groups, respectively (P = 0.023). The mean blood flow was 352 ± 94 mL/min in placebo group and 604 ± 125 mL/min in study group (P = 0.001). The arterial end diastolic velocity was 116 ± 14 cm/s in study group and 72 ± 21 cm/s in placebo group (P = 0.036) 1 year after the surgery. Our data indicated that clopidogrel and oral prostacycline analog combination is effective and safe for the prevention of primary AVF failure in hemodialysis patients and decreased acute and chronic thrombotic events.

Abstract 233: Prostacyclin analogs, iloprost and treprostinil, differentially influence proliferation of lung tumor cells

Abstract Lung cancer will kill approximately 160,000 Americans this year–more than the next four cancer subtypes (breast, prostate, colorectal, and pancreatic) combined. Even if lung cancer is diagnosed at an early stage, the 5 year survival rate is 52.2%. The poor survival rates for early stage disease suggests that chemopreventive interventions in high-risk populations are necessary. We found that prostacyclin (prostaglandin I2 or PGI2) synthase (PGIS) overexpression retards lung tumor growth in preclinical chemical carcinogen and smoking models, and treatment with iloprost (a PGI2 analog currently approved for treatment of pulmonary hypertension) inhibits lung adenocarcinoma formation in these same preclinical models. Oral iloprost also improves bronchial dysplasia (precursor lesions to squamous cell lung cancer) in former smokers. Mechanistic in vitro and in vivo studies using genetically modified mice showed that PGI2 and iloprost exert their chemopreventive effects through activation of the peroxisome proliferator-activated receptor γ (PPARγ) pathway rather than the classic PGI2 receptor, IP1, and that this activation requires frizzled 9 (Fzd9) activity. Treprostinil, a next generation PGI2 analog also approved to treat pulmonary hypertension, activates IP1 as well, but its ability to activate PPARγ/Fzd9 has yet to be fully characterized. In vitro studies show that in addition to binding to IP, iloprost and treprostinil differentially activate other prostaglandin (PG) receptors suggesting that they may have different chemopreventive efficacies. Molecular modeling of iloprost and treprostinil binding to PPARγ indicates these molecules may induce different PPARγ conformations which could affect binding of co-activators/repressors or interaction with the retinoic acid receptor (which is required for induction of gene transcription). While iloprost does not affect mouse lung tumor cell proliferation in vitro, treprostinil and prostaglandin E2 actually increase proliferation 2-5 fold in a dose dependent manner. Alveolar macrophage conditioned media also increases mouse lung tumor cell proliferation, and this increase is enhanced if macrophages are treated with treprostinil or PGE2 prior to media harvest. If macrophages are pretreated with iloprost, either alone or in combination with PGE2 or treprostinil, this increased proliferation is attenuated suggesting that iloprost may be exerting its chemopreventive effects directly on tumor cells and by modulating macrophage production of pro-growth factors. Macrophage IL-6 production decreased almost 80% with iloprost pre-treatment while little effect was seen with treprostinil pre-treatment. Comparisons between iloprost and treprostinil may indicate new agents/targets for lung cancer chemoprevention. Citation Format: Lori D. Dwyer-Nield, Gregory Hickey, Meredith A. Tennis, Kevin S. Choo, Donald S. Backos, Robert L. Keith. Prostacyclin analogs, iloprost and treprostinil, differentially influence proliferation of lung tumor cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 233. doi:10.1158/1538-7445.AM2014-233

Abstract PL01-02: Smoking, molecular markers, and the risk of second cancers in cancer patients

Abstract Chemoprevention entails the reversal, prevention, abrogation or delay of carcinogenic progression to cancer (1). A number of successful trials have been conducted in the reversal of premalignancy in breast (2,3), prostate (4,5), and colorectal (6,7) cancer. In tobacco-related cancers, compelling evidence has suggested that ongoing tobacco smoking is able to prevent the reversal of premalignant lesions (8-10). The first such evidence was demonstrated by Lee et al. who noted that only those patients who ceased smoking saw meaningful improvement in their premalignancy in a randomized trial of 13-cis-retinoic acid in reversal of premalignancy (11). This built on the seminal work by Hong et al. who were able to show that high doses of vitamin A derivatives, specifically, 13-cis-retinoic acid, were able to reverse premalignancy in head and neck cancer (12), and perhaps more importantly, prevent or delay the development of second primary tumors while patients were on high dose 13-cis-retinoic acid (13). Unfortunately, the vast majority of patients on high dose 13-CRA or isotretinoin failed to tolerate this dose and required dose reduction or dose interruption (12,13). Subsequent randomized trials of 13-CRA in prevention of second primary tumors of the lung (14) and head and neck failed (15) to show the same promise as the higher dose, but one message was clearly consistent. Those patients who stopped smoking had considerably lower rates of second primary tumors and a trend toward a lower rate of primary lung or head and neck tumor recurrence (14, 15). Similar data emerged from the selenium trial, where the agent itself was ineffective in preventing second primary tumors of the lung, but those patients who were able to cease smoking had consistently lower rates of development of second primary tumors (16). A series of recent studies have indicated that genomic testing of patients on the 13-CRA head and neck second primary tumor prevention trial can select those patients who appear to derive the greatest benefit from chemopreventive approaches with natural compounds and their derivatives (17,18). These data suggest that patients with activation of the PI3-kinase/mTOR pathway are more likely to develop second primary cancers (18), consistent with data implicating this pathway demonstrated by Spira et al (19). Similarly, the Retinoid Head and Neck Second Primary Prevention Trial has shown data that certain patient populations on the head and neck second primary trial were more likely to benefit than others, based on genomic background, and that of their tumor (17,18). Thus, a strategy emerges whereby specific molecular markers, which are likely to predict benefit from second primary tumors, will be used to select future populations who are placed on chemopreventive approaches (20). However, one lesson must remain clear, and it must impact the future of all chemoprevention trials. Since smoking cessation, generally initiated by the patient, was the single most important factor in reducing secondary primary tumor risk, on these trials (14, 15, 21), all future such trials will require active smoking cessation efforts in these patient populations in order to achieve effective and active chemoprevention approaches. Such trials are planned and are necessary to undertake. The next generation of chemoprevention trials will involve CT screening studies, now the standard for those patients deemed at high risk for developing lung cancer (22, 23), and whether using inhibitors targeting inflammation (8-10) or metabolism (24), the inclusion of effective smoking cessation strategies in these chemopreventive trials is now a must. The overwhelming weight of the evidence therefore shows that effective development of approaches that integrate smoking cessation into biomarker-based chemoprevention of tobacco-driven cancers is no longer optional.

Abstract PR03: Frizzled 9 expression is a potential marker of response to iloprost chemoprevention of lung cancer

Abstract Lung cancer remains the leading cause of cancer death in the United States and chemoprevention offers an appealing area of investigation in the face of limited therapeutic success. We recently demonstrated improvement in endobronchial histology in former smokers after oral iloprost treatment. Of the 48 patients who received iloprost in the chemoprevention trial, 23 had regressive histology and 25 had stable or progressive histology. Identifying markers that predict response to treatment will refine target populations for future trials and clinical applications. In vitro studies of NSCLC indicate that iloprost, a prostacyclin analogue, acts through the G-protein coupled receptor Frizzled 9 (Fzd9) instead of the prostacyclin receptor. We hypothesize that Fzd9 expression status predicts response to iloprost chemoprevention and that expression is modified by promoter hypermethylation. Patients who have lost Fzd9 expression will not respond to iloprost treatment. If Fzd9 is lost by methylation, a demethylating agent could restore Fzd9 expression and sensitivity to iloprost chemoprevention. In a urethane A/J mouse model of lung cancer, Fzd9 mRNA expression is reduced in lung tumors compared to matched, uninvolved lung tissue. Human lung tumors demonstrated reduced Fzd9 mRNA expression compared to matched normal lung tissue. Fzd9 expression is also decreased in human primary dysplastic cell lines, suggesting that loss of Fzd9 expression occurs early in lung tumorigenesis. Non-transforming lung epithelial cell lines (B2B or HBEC) were treated for four weeks with 1% cigarette smoke condensate. B2B cells were treated with the tobacco carcinogen NNK (10μM) for 2 hours. Both treatment conditions resulted in reduced Fzd9 mRNA expression measured by qPCR. Future work will assess Fzd9 expression in an in vitro chemoprevention and smoking model, in tissues from additional mouse models of lung cancer, and in tissues from chemoprevention trials. These initial studies suggest that Fzd9 expression is lost in early smoking-induced lesions. This study has the potential to improve iloprost lung cancer chemoprevention by allowing future trials to more effectively target high-risk patients and by providing a clinical biomarker for identification of chemoprevention candidates. This abstract is also presented as Poster A29. Citation Format: Meredith Tennis, Lori Nield, Dan Merrick, Robert Keith. Frizzled 9 expression is a potential marker of response to iloprost chemoprevention of lung cancer. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr PR03.

Abstract 1607: Airway gene expression alterations associated with lung cancer chemoprevention using green tea extract

Abstract Lung cancer is the leading cause of cancer death in the United States and in the world. Identifying an effective chemopreventive agent for lung cancer would reduce lung cancer mortality by reversing, preventing, or delaying carcinogenic progression. Several randomized, controlled lung cancer chemoprevention trials have produced neutral or harmful results; with the exception of oral iloprost that demonstrated a small, but significant improvement in histology after 6 months of treatment in former smokers. One of the challenges in lung cancer chemoprevention trials have been the lack of surrogate endpoints to establish drug efficacy. In this study we use molecular profiling to study alterations assoicated with changes in airway histology and treatment with a promising chemopreventative, green tea extract. Airway epithelial cells were collected from patients with bronchial dysplasia during bronchoscopy at baseline, on-treatment, and post-treatment with green tea extract or placebo ranging from 2 to 6 months (n=27 patients, n=63 samples). RNA from the samples was processed and hybridized to Affymetrix Human Gene 1.0 ST arrays. Gene-level expression data was obtained using the Robust Multiarray Average (RMA) algorithm and ANOVA and linear modeling strategies were used to identify gene expression alterations associated with dysplasia regression and green tea extract treatment. Cancer and smoking-related pathway gene expression signatures were used to predict the pathway activation of each sample using a binary regression model. Gene set enrichment analysis (GSEA) was used to identify important biological pathways. Airway gene expression alterations associated with dysplasia regression were identified and pathways such as p53 and mTOR signaling were enriched among genes up-regulated in airways with dysplasia. The E2F3 oncogenic pathway was also found to be significantly altered in airways with dysplasia (p<0.05). The effect of green tea extract on airway gene expression was more pronounced among former versus current smokers. As a result, the degree to which pathways were modulated by green tea extract varied with smoking status. Pathways related to metabolism of xenobiotics, and glutathione, and retinol were decreased among treated current smokers while genes related to oxidative phosphorylation and DNA repair were increased in treated former smokers (FDR q-value<0.05). Our studies suggest that airway gene expression is altered in high-risk smokers with premalignant airway lesions and that this airway “field of injury” can be modulated by treatment with green tea extract especially among former smokers. We are currently investigating whether airway gene-expression can serve as an intermediate biomarker of response to green tea extract and identify those smokers who are most likely to benefit from this type of chemopreventive strategy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1607. doi:1538-7445.AM2012-1607

Abstract ED01-03: Chemoprevention of lung cancer with prostacyclins or PPAR gamma agonists.

Abstract Introduction: Prostacyclin genetic overexpression or the oral prostacyclin analogue iloprost prevent development of lung cancer in a variety of murine models, including cigarette smoke exposure mice. The mechanism of action is through non-canonical PPARγ activation. PPARγ agonists also prevent development of lung cancer in experimental models. These observations have led to completed ongoing and planned phase II chemoprevention clinical trials using bronchial histology as the primary endpoint. Methods: In the completed randomized Phase II study comparing iloprost to placebo entry criteria included: current or former smoker (> 20 pack years); at least mild cytologic atypia on sputum cytology; no previous history of cancer. Autofluorescence and white light bronchoscopy was performed with 6 standard endobronchial sites biopsied, along with all other abnormally appearing areas. Subjects were then randomized to oral iloprost (in escalating doses) or placebo for 6 months and then a second bronchoscopy with repeat biopsy of all the central airway areas sampled during the first bronchoscopy, as well as any new areas suspicious for dysplasia. The predetermined primary endpoint for the study was average bronchial histologic score (based on the WHO classification of premalignant lesions) in all subjects, as well as in current and ex-smokers separately. In the ongoing study of the PPRAα agonist, pioglitazone, entry criteria, sample size and endpoints are similar. Results: For the iloprost study, 152 subjects were randomized and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure and baseline histology. Endobronchial histology was summarized within patients using three separate measures: worst biopsy score (Max), dysplasia index (DI - defined as the percentage of biopsies with a score of at least 4 (mild dysplasia) or worse), and average of all biopsy scores (Avg). 74% of subjects had at least one biopsy displaying mild dysplasia (score 4.0) or worse on the initial bronchoscopy. A reproducibility study with two independent pathologists demonstrated that 85% of readings were within one histologic grade. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). Former smokers receiving oral iloprost exhibited a significant improvement in Avg (0.41 better, p=0.010), Max (1.10 units, p=0.002), and an improvement in DI (12.45%, p=0.006). No histologic improvement occurred in current smokers. Proliferation by Ki-67 index was a secondary endpoint and demonstrated no change with iloprost administration. There were no differences in dropout rates or SAEs between treatment groups. In the ongoing pioglitazone study - patients have been enrolled and dropout rates are also very low. Conclusions and Future Directions: Oral iloprost significantly improved endobronchial dysplasia in former heavy smokers with sputum dysplasia. Unfortunately, the oral iloprost studied is no longer available commercially. Since the ultimate goal is to prevent lung cancer and the groups at highest risk and greatest numbers are resected stage I lung cancer and head and neck cancer patients. We are planning a randomized phase II trial in resected stage I NSCLC and SCCHN patients. The study drug will be a new oral prostacyclin or to placebo for one year with bronchial biopsies at times 0, 6 month and 12 months. CT scan will also be obtained at these times with bronchial histology as primary endpoint. When the pioglitazone study and this study are completed, a phase III randomized trial with prevention of secondary lung cancer as the primary endpoint in contemplated. Disclosures: RLK, YEM and MWG hold a patent for the use of prostacylin analogs for the prevention of cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr ED01-03.

Abstract PL04-02: Oral iloprost for the chemoprevention of lung cancer: A multicenter, SPORE-initiated trial

Abstract Background: Tissue microarray studies have shown that the majority of NSCLC have decreased expression of prostacyclin synthase (PGIS) and prostacyclin supplementation (genetic overexpression and the oral prostacyclin analogue iloprost) chemoprevent lung cancer in a variety of murine models, including cigarette smoke exposure. Based on these promising results, a multi-center, double-blind, placebo controlled, phase II trial of iloprost in subjects at increased risk for lung cancer conducted at SPORE in lung cancer sites. Methods: Subjects were selected for the trial if they meet the following criteria: current or former smoker (> 20 pack years); at least mild cytologic atypia on sputum cytology; no previous history of cancer. Fluorescent bronchoscopy was performed with 6 standard endobronchial sites biopsied, along with all other abnormally appearing areas. Subjects were then randomized to oral iloprost (in escalating doses) or placebo for 6 months and then a repeat bronchoscopy with biopsy of all the central airway areas sampled on the first bronchoscopy. The primary endpoints for the study are bronchial histology and Ki-67 labeling index. Results: For the iloprost study, 152 subjects were randomized and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure and baseline histology. Endobronchial histology was summarized within patients using three separate measures: worst biopsy score (Max), dysplasia index (DI - defined as the percentage of biopsies with a score of at least 4 (mild dysplasia) or worse), and average of all biopsy scores (Avg). 74% of subjects had at least one biopsy displaying mild dysplasia (score 4.0) or worse on the initial bronchoscopy. A reproducibility study with two independent pathologists demonstrated that 85% of readings were within one histologic grade. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). Former smokers receiving oral iloprost exhibited a significant improvement in Avg (0.41 better, p=0.010), Max (1.10 units, p=0.002), and an improvement in DI (12.45%, p=0.006). No histologic improvement occurred in current smokers. Proliferation by Ki-67 index was a secondary endpoint and demonstrated no change with iloprost administration. There were no differences in dropout rates or SAEs between treatment groups. Analyses for other biomarkers in iloprost samples (including urinary prostaglandin metabolites, miRNAs, and EMT markers) are in progress. Conclusions: Oral iloprost significantly improves endobronchial dysplasia in former smokers and deserves further study to determine if it can prevent the development of lung cancer. Citation Information: Cancer Prev Res 2011;4(10 Suppl):PL04-02.

The management of pregnancy and pregnancy-related medical conditions in pulmonary arterial hypertension patients

This is the case report of a pregnant woman who refused pregnancy termination when diagnosed with pulmonary arterial hypertension (PAH) functional class 2-3 at the 24th week of gestation and of her newborn. A pregnant woman with PAH functional class 2-3 was treated with inhaled prostacyclin analog (iloprost), oral sildenafil, oxygen, and low molecular weight heparin. She delivered at 32nd week by Cesarean section. The infant required oxygen up to 36th week postconceptional age and had a short steroid treatment. The mother needed close cardiovascular monitorization, intensive oxygen and pulmonary vasodilator therapy for 2 months and was discharged with oxygen and oral iloprost treatment. A multidisciplinary approach together with pulmonary vasodilator therapy may be succesful in such a high-risk pregnant woman.

Lung cancer a hot topic at AACR meeting

Lung cancer a hot topic at AACR meeting

Oral Iloprost Improves Endobronchial Dysplasia in Former Smokers

There are no established chemopreventive agents for lung cancer, the leading cause of cancer death in the United States. Prostacyclin levels are low in lung cancer and supplementation prevents lung cancer in preclinical models. We carried out a multicenter double-blind, randomized, phase II placebo-controlled trial of oral iloprost in current or former smokers with sputum cytologic atypia or endobronchial dysplasia. Bronchoscopy was performed at study entry and after completion of six months of therapy. Within each subject, the results were calculated by using the average score of all biopsies (Avg), the worst biopsy score (Max), and the dysplasia index (DI). Change in Avg was the primary end point, evaluated in all subjects, as well as in current and former smokers. The accrual goal of 152 subjects was reached and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure, and baseline histology. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). When compared with placebo, former smokers receiving oral iloprost exhibited a significantly greater improvement in Avg (0.41 units better, P = 0.010), in Max (1.10 units better, P = 0.002), and in DI (12.45%, P = 0.006). No histologic improvement occurred in current smokers. Oral iloprost significantly improves endobronchial histology in former smokers and deserves further study to determine if it can prevent the development of lung cancer.

Abstract LB-90: Oral iloprost improves endobronchial dysplasia in former smokers

Abstract Introduction: Prostacyclin supplementation by either genetic overexpression or the oral prostacyclin analogue iloprost prevents development of lung cancer in a variety of murine models, including cigarette smoke exposure. We conducted a multi-center, double-blind, placebo controlled, phase II trial of iloprost in subjects at increased risk for lung cancer. Methods: Entry criteria included: current or former smoker (> 20 pack years); at least mild cytologic atypia on sputum cytology; no previous history of cancer. Autofluorescence and white light bronchoscopy was performed with 6 standard endobronchial sites biopsied, along with all other abnormally appearing areas. Subjects were then randomized to oral iloprost (in escalating doses) or placebo for 6 months and then a second bronchoscopy with repeat biopsy of all the central airway areas sampled during the first bronchoscopy, as well as any new areas suspicious for dysplasia. The predetermined primary endpoint for the study was average bronchial histologic score (based on the WHO classification of premalignant lesions) in all subjects, as well as in current and ex-smokers separately. Results: The accrual goal of 152 subjects was reached and 125 completed both bronchoscopies (60/75 iloprost, 65/77 placebo). Treatment groups were well matched for age, tobacco exposure and baseline histology. Endobronchial histology was summarized within patients using three separate measures: worst biopsy score (Max), dysplasia index (DI – defined as the percentage of biopsies with a score of at least 4 (mild dysplasia) or worse), and average of all biopsy scores (Avg). 74% of subjects had at least one biopsy displaying mild dysplasia (score 4.0) or worse on the initial bronchoscopy. A reproducibility study with two independent pathologists demonstrated that 85% of readings were within one histologic grade. Baseline histology was significantly worse for current smokers (Avg 3.0) than former smokers (Avg 2.1). Former smokers receiving oral iloprost exhibited a significant improvement in Avg (0.41 better, p=0.010), Max (1.10 units, p=0.002), and an improvement in DI (12.45%, p=0.006). No histologic improvement occurred in current smokers. Proliferation by Ki-67 index was a secondary endpoint and demonstrated no change with iloprost administration. There were no differences in dropout rates or SAEs between treatment groups. Conclusions: Oral iloprost significantly improves endobronchial dysplasia in former smokers and deserves further study to determine if it can prevent the development of lung cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-90. doi:10.1158/1538-7445.AM2011-LB-90

MRI-Demonstrated Outcome of Subchondral Stress Fractures of the Knee After Treatment with Iloprost or Tramadol: Observations in 14 Patients

To investigate the outcome of subchondral stress fractures (SSF) of the knee after treatment with the prostacyclin analogue Iloprost or the opioid analgesic Tramadol. Case series/retrospective review. Tertiary care center. Fourteen patients with at least a single subchondral stress fracture of the knee, surrounded by bone marrow edema, visible on T1-weighted and short tau inversion recovery magnetic resonance images. Nine patients had been treated with oral Iloprost (group 1; 11 SSF) and 5 patients with Tramadol (group 2; 5 SSF) for 4 weeks in the course of a double-blind, randomized clinical trial. MR images were obtained at baseline (1 day before the start of treatment), after 3 months, and after 1 year. SSF volumes and their rates of change between baseline and follow-up examinations, as determined on T1-weighted images by computer-assisted quantification. After three months, the SSF volumes had decreased by a median of 42.2% in group 1 and increased by a median of 2.2% in group 2 (P = 0.008). After 1 year, the median decrease in SSF volumes was 100.0% in group 1 and 65.7% in group 2 (P = 0.017). This small case series suggests that healing of SSF is more pronounced after Iloprost treatment.