Triazole-polyene antagonism in experimental invasive pulmonary aspergillosis: in vitro and in vivo correlation.

Combination antifungal therapy is increasingly used in the treatment of invasive aspergillosis. Whether the interaction between amphotericin B and triazoles is antagonistic against invasive aspergillosis is a controversial issue that is not likely to be resolved through a randomized clinical trial. Here, we found both in vitro and in vivo antagonism between liposomal amphotericin B and ravuconazole in simultaneous treatment of experimental invasive pulmonary aspergillosis in persistently neutropenic rabbits. Bliss independence-based drug-interaction modeling showed significant antagonism in vitro and in vivo, with the observed drug effects being 20%-69% lower than would be expected if the drugs were acting independently. These in vitro and in vivo findings of antagonism were consistent with the findings from Loewe additivity-based drug-interaction modeling. No pharmacokinetic interaction was found. The combination of a triazole and polyene may be antagonistic in the treatment of invasive pulmonary aspergillosis.

A phase I pharmacologic and pharmacogenetic trial of sequential 24-hour infusion of irinotecan followed by leucovorin and a 48-hour infusion of fluorouracil in adult patients with solid tumors.

PURPOSE: In preclinical studies, sequential exposure to irinotecan (CPT-11) then fluorouracil (5-FU) is superior to concurrent exposure or the reverse sequence; a 24-hour infusion of CPT-11 may be better tolerated than shorter infusions. EXPERIMENTAL DESIGN: CPT-11 was first given at four levels (70-140 mg/m(2)/24 hours), followed by leucovorin 500 mg/m(2)/0.5 hours and 5-FU 2,000 mg/m(2)/48 hours on days 1 and 15 of a 4-week cycle. 5-FU was then increased in three cohorts up to 3,900 mg/m(2)/48 hours. RESULTS: Two patients had dose-limiting toxicity during cycle 1 at 140/3,900 of CPT-11/5-FU (2-week delay for neutrophil recovery; grade 3 nausea despite antiemetics); one of six patients at 140/3,120 had dose-limiting toxicity (grade 3 diarrhea, grade 4 neutropenia). Four of 22 patients with colorectal cancer had partial responses, two of which had prior bolus CPT-11/5-FU. The mean 5-FU plasma concentration was 5.1 micromol/L at 3,900 mg/m(2)/48 hours. The end of infusion CPT-11 plasma concentration averaged 519 nmol/L at 140 mg/m(2)/24 hours. Patients with UDP-glucuronosyltransferase (UGT1A1; TA)6/6 promoter genotype had a lower ratio of free to glucuronide form of SN-38 than in patients with >/=1 (TA)7 allele. Thymidylate synthase genotypes for the 28-base promoter repeat were 2/2 (13%), 2/3 (74%), 3/3 (13%); all four responders had a 2/3 genotype. CONCLUSIONS: Doses (mg/m(2)) of CPT-11 140/24 hours, leucovorin 500/0.5 hours and 5-FU 3,120/48 hours were well tolerated.

Efficacy and safety of generic amphotericin B in experimental pulmonary aspergillosis.

The recent shortage of the brand name drug Fungizone has necessitated a change to generic formulations of amphotericin B deoxycholate. Clinical trials cannot be conducted in a timely manner to provide data on the safety and efficacy of these formulations. We therefore compared generic amphotericin B and Fungizone for activity and safety in the treatment of experimental invasive pulmonary aspergillosis (IPA) in persistently neutropenic rabbits. Fungizone and generic amphotericin B are similar in efficacy, pharmacokinetics, and safety in the treatment of experimental IPA.

Local administration of vasoactive intestinal peptide after nerve transection accelerates early myelination and growth of regenerating axons.

Our goal was to determine whether local injections of vasoactive intestinal peptide (VIP) promote early stages of regeneration after nerve transection. Sciatic nerves were transected bilaterally in 2 groups of 10 adult mice. In the first group, 15 microg (20 microL) of VIP were injected twice daily into the gap between transected ends of the right sciatic nerve for 7 days (4 mice) or 14 days (6 mice). The same number of mice in the second group received placebo injections (20 microL of 0.9% sterile saline) in the same site, twice daily, for the same periods. After 7 days, axon sizes, relationships with Schwann cells and degree of myelination were compared in electron micrographs of transversely sectioned distal ends of proximal stumps. Fourteen days after transection, light and electron microscopy were used to compare and measure axons and myelin sheaths in the transection gap, 2-mm distal to the ends of proximal stumps. Distal ends of VIP-treated proximal stumps contained larger axons 7 days after transection. More axons were in 1:1 relationships with Schwann cells and some of them were surrounded by thin myelin sheaths. In placebo-treated proximal stumps, axons were smaller, few were in 1:1 relationships with Schwann cells and no myelin sheaths were observed. In VIP-treated transection gaps, measurements 14 days after transection showed that larger axons were more numerous and their myelin sheaths were thicker. Our results suggest that in this nerve transection model, local administration of VIP promotes and accelerates early myelination and growth of regenerating axons.