Derenofylline

Ovarian cancer is the deadliest gynecologic cancer due to lack of early effective diagnosis and development of resistance to platinum-based chemotherapy. Several studies reported that adenosine concentrations are higher in tumor microenvironment than in non-tumor tissue. This finding inspired us to study the role of adenosine in ovarian cancer cells and to investigate if adenosine pathways offer new treatment options urgently needed to prevent or overcome chemoresistance. The ovarian cancer cell lines HEY, A2780, and its cisplatin-resistant subline A2780CisR were used in this study. Expression and functional activity of adenosine receptors were investigated by RT-PCR, Western blotting, and cAMP assay. A1 and A2B adenosine receptors were expressed and functionally active in all three cell lines. Adenosine showed moderate cytotoxicity (MTT-IC₅₀ values were between 700 and 900 μM) and induced apoptosis in a concentration-dependent manner by increasing levels of sub-G1 and cleaved PARP. Apoptosis was diminished by QVD-OPh, confirming caspase-dependent induction of apoptosis. Forty-eight hours pre-incubation of adenosine prior to cisplatin significantly enhanced cisplatin-induced cytotoxicity in a synergistic manner and increased apoptosis. SLV320 or PSB603, selective A1 and A2B antagonists, was not able to inhibit adenosine-induced increase in cisplatin cytotoxicity or apoptosis whereas dipyridamole, a nucleoside transporter inhibitor, completely abrogated both effects. Mechanistically, adenosine increased pAMPK and reduced pS6K which was prevented by dipyridamole. In conclusion, application of adenosine prior to cisplatin could be a new therapeutic option to increase the potency of cisplatin in a synergistic manner and thus overcome platinum resistance in ovarian cancer.

Baseline renal impairment as well as worsening renal function during hospitalization is associated with worse short- and long-term outcomes in patients hospitalized for acute heart failure (AHF). We hypothesized that selective A1 adenosine receptor blockade would induce natriuresis while preserving renal function in AHF patients with renal dysfunction.

A phase II, randomized, double-blind, placebo-controlled, parallel group, multicenter study to evaluate the efficacy and safety of 2.5, 7.5, 15, and 30 mg/d SLV320 (1 hour intravenous infusions of 1.25, 3.75, 7.5, and 15 mg SLV320, every 12 hours for 3 days [a total of 6 doses] in addition to standard therapy) in subjects hospitalized with AHF and renal impairment who meet all inclusion/exclusion criteria. The study planned to enroll 450 subjects, with 90 subjects allocated equally to each treatment arm.

The study was terminated early. The decision, which was unrelated to the study conduct or results, with a total of 46 subjects randomized. Of those randomized, 6:8:8:8 and 6 patients, respectively, completed the study in each of the dosing subgroups, with placebo as the fifth group. For the 1.25-mg study group, the mean age was 73 years; mean (SD) systolic blood pressure (SBP), 128.5 (16.2); heart rate, 80.8 (25.0); brain natriuretic peptide, 969.7 (571.28); creatinine (μmol/L), 149.7 (41.0); cystatin C, 1.468 (0.2777); estimated glomerular filtration rate, 33.8 (7.913); and blood urea nitrogen, 12.1 (2.9), with roughly similar values in each treatment arm. No seizures were reported during the study. Eight patients died during the study, none of whom were associated with the study drug per an independent, blinded, data safety monitoring board.

Because of the limited number of subjects and variability observed in the results, no definite conclusions can be made regarding the efficacy and safety of SLV320.