Phase I study of the antifolate pralatrexate given with vitamin B12 and folic acid supplementation in patients (pts) with advanced non-small cell lung cancer (NSCLC)

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Background: Pralatrexate is a novel antifolate that has shown promising activity in the treatment of pts with previously- treated NSCLC at doses of 135–150 mg/m2 IV every other week (q2w). [Krug, Clin Cancer Res 9(6), 2003; 6(9), 2000] The addition of vitamin B12 and folic acid supplementation may mitigate toxicity from pralatrexate and improve efficacy by allowing higher doses to be delivered. Methods: This study is designed to determine the maximum tolerated dose (MTD) of pralatrexate in combination with vitamin B12 and folic acid supplementation in pts with NSCLC. Key eligibility criteria include confirmed stage IIIB or IV NSCLC; at least 1 prior chemotherapy regimen; Karnofsky performance status (KPS) = 70%; and no other active concurrent malignancy. Using a rapid escalation design, pralatrexate was initially administered at a dose of 150 mg/m2 IV q2w, escalating by 40 mg/m2 increments in successive cohorts, with one patient per cohort if no dose limiting toxicity (DLT) is encountered. All pts receive vitamin B12 1 mg intramuscular q 8–10 weeks and folic acid 1 mg by mouth once a day beginning at least 7 days prior to pralatrexate. All patients undergo pharmacokinetic testing following their first and second dose of pralatrexate. Results: Between 1/05–12/06, a total of 9 pts have been treated at the following dose levels: 150 (n=1), 190 (n=1), 230 (n=1), and 270 (n=6). Patient characteristics include: 2 male/7 female; median age 63 (range 52–73); KPS 80–90%; all pts had stage 4 NSCLC; 5 pts received 1 prior regimen and 4 pts received 2 or more prior regimens. Grade 3 esophagitis was a DLT in one patient at the 270 mg/m2 dose. Three other patients experienced grade 1–2 mucositis at this dose level without limiting drug delivery. The trial is ongoing, and enrollment is planned at 310 mg/m2 q2w to determine the MTD. Conclusions: When given in combination with vitamin B12 and folic acid supplementation, pralatrexate has been well tolerated in this pt population, with an MTD at least twice as high as achieved in previous phase 1 testing without supplementation. We plan to conduct a phase 2 trial of pralatrexate with vitamin B12 and folic acid supplementation to see if a higher dose will improve efficacy.

No significant financial relationships to disclose.

A new cyclooxygenase-2 inhibitor, rofecoxib (VIOXX), did not alter the antiplatelet effects of low-dose aspirin in healthy volunteers

The present study examined whether rofecoxib (VIOXX), a new specific inhibitor of cyclooxygenase-2 (COX-2), would interfere with the desired antiplatelet effects of aspirin. Thus, the effects of rofecoxib on inhibition of ex vivo serum-generated thromboxane B2 (TXB2) and platelet aggregation by low doses (81 mg) of aspirin were examined in healthy volunteers. This was a double-blind, randomized, placebo-controlled, parallel study of two treatment groups (n = 12 per group) in which subjects received 50 mg of rofecoxib or placebo for 10 days in a blinded fashion. Subjects also received 81 mg aspirin once on each of days 4 through 10 in an open-label fashion. Blood for measurement of serum TXB2 production and platelet aggregation studies was collected on day 1 (prior to rofecoxib/placebo), on day 4 (prior to aspirin), and on day 10 (before and 4 hours following the seventh dose of aspirin). Platelet-derived serum TXB2 (COX-1 assay) was measured in blood clotted for 1 hour at 37 degrees C. Platelet aggregation was independently induced employing 1 mM arachidonic acid and 1 microgram/mL collagen as agonists. Rofecoxib administered alone had no significant effect on serum TXB2 production or platelet aggregation (day 4). TXB2 production was inhibited 98.4% by aspirin coadministered with either rofecoxib or placebo (day 10). Similarly, platelet aggregation induced by arachidonic acid was inhibited 93.7% and 93.5% by aspirin coadministered with either rofecoxib or placebo, respectively (day 10). The comparable values for inhibition of collagen-induced platelet aggregation were 86.8% and 90.8%, respectively. No important clinical or laboratory adverse experiences were observed. In conclusion, rofecoxib alone (50 mg QD for 4 days) did not inhibit serum TXB2 production or platelet aggregation. In addition, rofecoxib (50 mg QD for 10 days) did not alter the antiplatelet effects of low-dose aspirin (inhibition of platelet aggregation and TXB2 production). Rofecoxib was generally well tolerated when administered alone or in combination with low-dose aspirin.

Efficacy and tolerability of the specific cyclooxygenase-2 inhibitor DFP compared with naproxen sodium in patients with postoperative dental pain

DFP [3-(2-propyloxy)-(4-methyl-sulfonylphenyl)-(5,5-dimethyl)-fu ranone] is a highly specific cyclooxygenase-2 inhibitor (>2500-fold selective in transfected Chinese hamster ovary cell assays) that has demonstrated efficacy in preclinical models of pain and inflammation. The present single-dose, randomized, double-masked, double-dummy, placebo-controlled, parallel-group study was undertaken to compare DFP 5, 25, and 50 mg with naproxen sodium 550 mg and with placebo in 196 patients (mean age, 25.8 years; 187 [95.4%] males) who experienced moderate-to-severe pain after surgical removal of > or =2 third molars. Overall analgesic effect, duration of effect, time to onset of analgesic effect, peak analgesic effect, and tolerability were assessed over a 24-hour postdose period. Both DFP 25 and 50 mg, as well as the active comparator, naproxen sodium 550 mg, were significantly more effective than placebo. The onset of analgesic effect in the DFP 25-mg, DFP 50-mg, and naproxen sodium 550-mg groups did not differ significantly. DFP was generally well tolerated in single doses up to 50 mg. DFP 50 mg was efficacious in the treatment of postoperative dental pain and was indistinguishable from the active comparator, naproxen sodium 550 mg.

Coronary hypertension and diastolic compliance in isolated rabbit hearts

Acute pulmonary edema during hypertensive crisis has been attributed to acute left ventricular systolic failure secondary to increased afterload. We tested the hypothesis that the increase in coronary artery perfusion pressure associated with systemic hypertension could also contribute to increased left ventricular filling pressures by acutely increasing coronary intravascular volume and decreasing left ventricular diastolic compliance. Isolated isovolumic (balloon in left ventricle) normal rabbit hearts (n = 13) with pericardium removed and right ventricle vented were blood perfused at an initial coronary artery perfusion pressure of 100 mm Hg; left ventricular balloon volume was adjusted to produce an initial left ventricular end-diastolic pressure of 15 +/- 1 mm Hg; left ventricular systolic pressure was 102 +/- 3 mm Hg. When coronary perfusion pressure was increased to 130 +/- 1 mm Hg to simulate a hypertensive crisis, coronary flow increased from 2.0 +/- 0.2 to 3.0 +/- 0.2 ml/min/g left ventricle (p less than 0.001), left ventricular systolic pressure increased to 116 +/- 4 mm Hg, and isovolumic left ventricular end-diastolic pressure increased to 21 +/- 1 mm Hg (p less than 0.001), which indicated a decrease in left ventricular diastolic compliance. When coronary perfusion pressure was decreased to a physiological level of 70 mm Hg, coronary flow rate decreased to 1.4 +/- 0.1 ml/min/g left ventricle (p less than 0.001), left ventricular systolic pressure fell to 82 +/- 4 mm Hg, and left ventricular end-diastolic pressure fell to 14 +/- 1 mm Hg (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)