Phase II, double-blinded, randomized study of enzastaurin plus pemetrexed as second-line therapy in patients with advanced non-small cell lung cancer.

INTRODUCTION: We examined the efficacy of enzastaurin plus pemetrexed as second-line therapy in patients with advanced (stage IIIA/B or IV) non-small cell lung cancer in a double-blinded, randomized, phase II study. METHODS: Patients received pemetrexed 500 mg/m intravenously on day 1 of 21-day cycles (day 8 in cycle 1) plus oral enzastaurin (250 mg two times per day; combination arm) or placebo (pemetrexed arm). Both arms received supplementation with vitamin B12, folic acid, and dexamethasone. An interim analysis was conducted to determine whether efficacy would warrant a phase III study. RESULTS: The interim analysis showed no evidence of improved progression-free survival with enzastaurin. At final analysis (N = 160, 80 in each arm), baseline characteristics were well balanced. There was no significant difference in progression-free survival (3.0 months, p = 0.544) or overall survival (9.6 months in combination arm and 7.4 months in pemetrexed arm, p = 0.171). Drug-related serious adverse events included cerebrovascular accident, palpitations, and renal failure (n = 1, each) in combination arm and neutropenic sepsis, thrombocytopenia, and panniculitis (n = 1, each) in pemetrexed arm. Nonhematologic drug-related grade 3/4 toxicities were similar in both arms. Grade 3/4 hematologic toxicities were higher with the combination, specifically leukopenia (6.3% versus 0%), neutropenia (15.2% versus 5.0%), and thrombocytopenia (8.9% versus 1.3%). Of the 26 deaths reported on-study or within 30 days of discontinuation (10 in combination arm and 16 in pemetrexed arm), none were drug related. CONCLUSION: The combination regimen of enzastaurin and pemetrexed is well tolerated but does not improve efficacy over pemetrexed and placebo as second-line treatment of unselected patients with advanced non-small cell lung cancer.

Enzastaurin, a protein kinase Cbeta- selective inhibitor, and its potential application as an anticancer agent in lung cancer.

Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through protein kinase C (PKC)-beta and the phosphatidylinositol 3-kinase/AKT pathway to induce tumor cell apoptosis, reduce proliferation, and suppress tumor-induced angiogenesis. In contrast to previous PKC inhibitors, enzastaurin is very well tolerated with a favorable safety profile, allowing it to be dosed for extended durations. In the present review, we summarize the rationale for targeting PKC in cancer, the preclinical experience of enzastaurin, and the clinical findings of the current phase I and II studies. Based on the combined information, we present the rationale for its future assessment in the treatment of lung cancer.

High-resolution quantitative computed tomography demonstrating selective enhancement of medium-size collaterals by placental growth factor-1 in the mouse ischemic hindlimb.

BACKGROUND: The process of arteriogenesis after occlusion of a major artery is poorly understood. We have used high-resolution microcomputed tomography (mu-CT) imaging to define the arteriogenic response in the mouse model of hindlimb ischemia and to examine the effect of placental growth factor-1 (PlGF-1) on this process. METHODS AND RESULTS: After common femoral artery ligation, mu-CT imaging demonstrated formation of collateral vessels originating near the ligation site in the upper limb and connecting to the ischemic calf muscle region. Three-dimensional mu-CT and quantitative image analysis revealed changes in the number of segments and the segmental volume of vessels, ranging from 8 to 160 microm in diameter. The medium-size vessels (48 to 160 microm) comprising 85% of the vascular volume were the major contributor (188%) to the change in vascular volume in response to ischemia. Intramuscular injections of Ad-PlGF-1 significantly increased Sca1+ cells in the circulation, alpha-actin-stained vessels, and perfusion of the ischemic hindlimb. These effects were predominantly associated with an increase in vascular volume contributed by the medium-size (96 to 144 microm) vessels as determined by mu-CT. CONCLUSIONS: High-resolution mu-CT delineated the formation of medium-size collaterals representing a major vascular change that contributed to the restoration of vascular volume after ischemia. This effect is selectively potentiated by PlGF-1. Such selective enhancement of arteriogenesis by therapeutically administered PlGF-1 demonstrates a desirable biological activity for promoting the growth of functionally relevant vasculature.

Identification of a novel selective peroxisome proliferator-activated receptor alpha agonist, 2-methyl-2-(4-{3-[1-(4-methylbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]propyl}phenoxy)propanoic acid (LY518674), that produces marked changes in serum lipids and apolipoprotein A-1 expression.

Low high-density lipoprotein-cholesterol (HDL-c) is an important risk factor of coronary artery disease (CAD). Optimum therapy for raising HDL-c is still not available. Identification of novel HDL-raising agents would produce a major impact on CAD. In this study, we have identified a potent (IC50 approximately 24 nM) and selective peroxisome proliferator-activated receptor alpha (PPARalpha) agonist, 2-methyl-2-(4-{3-[1-(4-methylbenzyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]propyl}phenoxy)propanoic acid (LY518674). In human apolipoprotein A-1 (apoA-1) transgenic mice, LY518674 produced a dose-dependent increase in serum HDL-c, resulting in 208 +/- 15% elevation at optimum dose. A new synthesis of apoA-1 contributed to the increase in HDL-c. LY518674 increased apoA-1 mRNA levels in liver. Moreover, liver slices from animals treated with LY518674 secreted 3- to 6-fold more apoA-1 than control liver slices. In cultured hepatocytes, LY518674 produced 50% higher apoA-1 secretion, which was associated with increase in radiolabeled methionine incorporation in apoA-1. Thus, LY518674 is a potent and selective PPARalpha agonist that produced a much greater increase in serum HDL-c than the known fibrate drugs. The increase in HDL-c was associated with de novo synthesis of apoA-1.