Safety, tolerability and pharmacokinetics of rilpivirine following administration of a long-acting formulation in healthy volunteers.

OBJECTIVES: This phase I healthy volunteer study (NCT01031589) was carried out to investigate the safety/tolerability and pharmacokinetics of a rilpivirine (RPV; TMC278) long-acting (LA) formulation after single and multiple intramuscular (i.m.) injections. METHODS: In the first part of the study, which had an open-label design, a single RPV LA i.m. injection (300 mg/mL) of 300 (n = 6) or 600 (n = 5) mg was given to the volunteers. In the second part of the study, which had a double-blind, randomized, placebo-controlled design, three RPV LA i.m. injections (one every 4 weeks) at 1200/600/600 mg (n = 6) or placebo (n = 2) were given. Safety and local tolerability were monitored. RPV plasma concentrations were analysed up to 28 days after injection or until they were < 20 ng/mL. RESULTS: Grade 1/2 RPV-related adverse events in the 300, 600 and 1200/600/600 mg groups were: rash (zero, one and one subject, respectively, the last of whom discontinued participation in the study); musculoskeletal stiffness (three, zero and zero subjects, respectively); injection site reactions (one, two and two subjects, respectively). After one injection of 300, 600 or 1200 mg RPV LA, the mean (standard deviation) maximum plasma concentration was 39 (25), 48 (13) and 140 (16) ng/mL, and the mean (standard deviation) area under the concentration-time curve (28 days) was 17,090 (8907), 25,240 (8184) and 55,350 (13,550) ng h/mL, respectively. RPV pharmacokinetics were largely comparable after the 1200 mg loading dose and both 600 mg injections of RPV LA. The mean (standard deviation) RPV plasma concentration across the 28-day dosing interval after the last injection in the 1200/600/600 mg group was 79 (19) ng/mL. CONCLUSIONS: Single and multiple i.m. injections of RPV LA demonstrated favourable local/systemic tolerability in healthy volunteers. RPV pharmacokinetics suggested that clinically relevant plasma concentrations can be achieved with this LA formulation.

Antiviral and lung protective activity of a novel respiratory syncytial virus fusion inhibitor in a mouse model.

Respiratory syncytial virus (RSV) causes bronchiolitis in young children and common colds in adults. There is no licensed vaccine, and prophylactic treatment with palivizumab is very expensive and limited to high-risk infants. Ribavirin is used as an antiviral treatment in infants and immunosuppressed patients, and its use is limited due to side-effects, toxicity to the recipient and staff, and evidence of marginal clinical efficacy. Therefore, we studied the in vivo kinetics, and the antiviral and protective properties of a novel candidate for RSV disease treatment. The drug is a small molecule (TMC353121) discovered by screening for fusion inhibitory properties against RSV in a cellular infection model. The pharmacokinetics of TMC353121 was studied in BALB/c mice and antiviral effects determined by testing viral loads in lung tissue by quantitative RT-PCR and plaque assay after intranasal RSV infection. At doses of 0.25-10 mg · kg(-1), TMC353121 significantly reduced viral load, bronchoalveolar lavage cell accumulation and the severity of lung histopathological change after infection. Treatment remained effective if started within 48 h of infection, but was ineffective thereafter. Therefore, TMC353121 is a novel potent antiviral drug, in vivo reducing RSV replication and inhibiting consequential lung inflammation, with a great potential for further clinical development.

ucb L059, a novel anti-convulsant drug: pharmacological profile in animals.

The anticonvulsant activity of ucb L059 ((S)-alpha-ethyl-2-oxo-pyrrolidine acetamide) was evaluated in a range of animal models. ucb L059 was active after oral and intraperitoneal administration in both rats and mice, with a unique profile of action incorporating features in common with several different types of antiepileptic drugs. The compound was active, with ED50 values generally within the range of 5.0-30.0 mg/kg, in inhibiting audiogenic seizures, electrically induced convulsions and convulsions induced chemically by pentylenetetrazole (PTZ), bicuculline, picrotoxin and N-methyl-D-aspartate (NMDA). ucb L059 retarded the development of PTZ-induced kindling in mice and reduced PTZ-induced EEG spike wave discharge in rats. The R enantiomer, ucb L060, had low intrinsic anticonvulsant activity, showing the stereospecificity of action of the molecule although the actual mechanism of action remains unknown. Neurotoxicity, evaluated with an Irwin-type observation test, the rotarod test and open-field exploration, was minimal, with only mild sedation being observed, even at doses 50-100 times higher than the anticonvulsant doses; at pharmacologically active doses, the animals appeared calm but slightly more active. ucb L059 thus presents as an orally active, safe, broad-spectrum anticonvulsant agent, with potential antiepileptogenic and anti-absence actions.

Facilitation of calcium-dependent cholinergic function by ucb L059, a new "second generation" nootropic agent.

We have investigated the effect of piracetam (PIR) and of its structural analogs, ucb L059 and ucb L060, the optical isomer of ucb L059, on cholinergic function in the guinea pig ileum in vitro. Only ucb L059 (10 microM-10 mM) caused contraction of the ileal preparation in a dose-dependent manner. This effect was inhibited by atropine (greater than or equal to 3.2 nM), by tetrodotoxin (10 nM) and by a combined treatment of veratridine (50 nM) and hemicholinium-3 (HC-3;0.5 mM), and was potentiated by physostigmine (50 nM). Electrically evoked contractions (EEC) of guinea pig ileal preparations subjected to HC-3 (0.5 mM) followed by veratridine (50 microM) were suppressed due to depletion of acetylcholine. Choline (greater than or equal to 3.2 10(-7)M) and ucb L059 (0.1-10 mM), but not ucb L060, facilitated recovery of EEC in a dose-dependent manner. This effect was abolished by HC-3. In addition, twitch recovery was inversely related to the concentration of Ca+2 in the medium. These results indicate that ucb L059, a close structural analog of piracetam, appears to facilitate cholinergic function in vitro through a stereospecific mechanism.

Effects of nootropic drugs in a scopolamine-induced amnesia model in mice.

Scopolamine (3 mg/kg IP) given before an acquisition trial, reduced the retention of a one-trial passive avoidance "step through" response in mice. A single administration of cholinergic agonists such as oxotremorine, BM-5, or arecoline, antagonized this amnesic effect of scopolamine. A significant anti-amnesic effect was also found with nootropic drugs such as piracetam and ucb L059, whereas ucb L060 (the enantiomer of ucb L059), oxiracetam and rolziracetam were shown to be ineffective. Moreover, ucb L059, administered twice daily for 3 days, counteracted the amnesic effects of scopolamine completely, whereas ucb L060 was again inactive. The results demonstrate that: (a) this model of impaired cognition by scopolamine is able to discriminate between closely related chemical substances and even stereoisomers; and (b) nootropic drugs, such as ucb L059, are more effective after repeated rather than after acute administration.

Successful immunotherapy with micrococcus, BCG or related polysaccharides on L1210 leukaemia after BCNU chemotherapy.

The experiments aimed at evaluating the optimal parameters in the chemo-immunotherapeutic treatment of the L1210 lymphoid leukaemia grafted to [female BALB/c (H2d) X male DBA/2 (H2d)]F1 hybrid mice, hereafter referred to as CDF1 mice. In vitro irradiation of leukaemic ascites cells by X- or gamma-rays and subsequent inoculation in mice showed that optimum immunogenicity is radiation dose-dependent. Grafting mice with 10(7) leukaemic ascites cells irradiated at optimum dose (80 GyX- or gamma-rays) delays mortality of the animals when challenged later with untreated L1210 cells, but is unable to cure mice. By contrast, specific immunoprophylaxis induced by Micrococcus, complement-triggering polysaccharides or BCG and irradiated leukaemic cells was able to protect mice against grafts of 10(4) L1210 cells. The i.p. route was notably superior to the i.v. route. When mice bearing advanced L1210 tumour were treated by chemotherapy (12 mg/kg of BCNU) on Day 6.5 after grafting 10(4) L1210 cells and subsequently treated by immunotherapy, a very high percentage (up to 90%) of mice with 10(8) leukaemic cells could be cured by repeated 1mg injections of bacterium or polysaccharide, and challenge with irradiated leukaemic cells was unnecessary. Because of the high cure rate obtained, the very regular response pattern and the non-pathogenicity, the bacterium Micrococcus lysodeikticus would seem a promising new candidate for chemo-immunotherapeutic antitumour strategies.

Influence of micrococcus, BCG and related polysaccharides on the proliferation of the L1210 leukaemia.

A comparative study of the effects of BCG, Micrococcus lysodeikticus, and a series of structurally related polysaccharides (complement triggers) on the non-specific and specific immune resistance against L1210 lymphoid leukaemia was carried out and commented on. In contrast with authors of earlier reports, we were unable to generate any effective non-specific or specific immunotherapy after the graft of 10(4) leukaemic cells to 8--10-week-old CDF1 mice. However, when mice were prevaccinated with irradiated (8 krad X-rays) cultured cells combined with 1 mg of bacterium or polysaccharide one month before grafting 10(4) cells, they were given an immunoprotection that was more pronounced with the i.p. than with the i.v. route. Prevaccinated mice were afforded a stronger immunoprotection when boosted repeatedly with 1mg injections of bacterium or polysaccharide after tumour challenge.