The efficacy and safety of oral desmopressin in children with primary nocturnal enuresis.

PURPOSE: We confirmed findings that oral desmopressin safely decreases the number of wet nights in children with enuresis and identified doses at which acceptable responses can be obtained. MATERIALS AND METHODS: We evaluated the safety and efficacy of oral desmopressin in a double-blind, placebo controlled, parallel group, randomized, multicenter trial of 193 children 6 to 16 years old with documented primary nocturnal enuresis. The study was conducted in 2 phases: 1) a 2-week dose ranging phase in which children received desmopressin (0.2, 0.4 or 0.6 mg.) or placebo at bedtime and 2) an 8-week dose titration phase that followed a 2-week placebo washout. Patients received 0.2 mg. desmopressin or placebo for the first 2 weeks and then the dose was increased in 0.2 mg. increments at 2-week intervals until the patient was completely dry or was receiving 0.6 mg. Patients were instructed to limit fluid intake. Mean decrease from baseline in the number of wet nights, percentage of responding patients and safety were assessed at 2-week intervals. RESULTS: There was a statistically significant linear response to oral desmopressin at doses from 0.2 to 0.6 mg. during the dose ranging phase (p < or =0.05). The decrease in wet nights after 2 weeks of treatment with desmopressin was 27%, 30% and 40% at 0.2, 0.4 and 0.6 mg. doses, respectively, compared to 10% with placebo. All doses were statistically significantly different from placebo (p < or =0.05). During the dose titration phase all placebo treated and 87% of desmopressin treated patients were receiving the maximum dose of 3 tablets nightly because they had not been completely dry in the previous 2 weeks. Nevertheless, 44% of desmopressin treated patients had achieved at least a 50% reduction from baseline in the number of wet nights per 2 weeks at the lower doses of 0.2 and 0.4 mg. Most adverse events (rhinitis, pharyngitis, headache and increased cough) were mild to moderate in severity, unrelated to treatment and resolved before the study was completed. CONCLUSIONS: Oral desmopressin administered at bedtime to children with primary nocturnal enuresis was significantly better than placebo for decreasing episodes of bed-wetting (p <0.05). A linear dose-response relationship was observed (p <0.05). An acceptable response to treatment (50% or greater reduction from baseline in wet nights per 2 weeks) was seen at all doses of desmopressin. Oral desmopressin, up to 0.6 mg. for 8 weeks, was well tolerated.

The Rilutek (riluzole) Global Early Access Programme: an open-label safety evaluation in the treatment of amyotrophic lateral sclerosis.

OBJECTIVES: This study had two main objectives: 1. To enable patients with amyotrophic lateral sclerosis (ALS) who had not participated in previous riluzole trials to receive riluzole therapy, and 2. To expand safety experience with the drug in a broad patient population. METHODS: This was a Phase IIIb multicentre, multinational, open-label, uncontrolled single treatment study of riluzole. Patients with diagnosed possible or probable ALS were administered 100 mg of riluzole/day (50 mg b.i.d.). Clinical and laboratory adverse events were recorded every month for the first 3 months and thereafter at 3-monthly intervals. RESULTS: 8383 patients from 44 countries were entered into the study; 7916 of these patients with recorded data were administered the study drug. The mean duration of riluzole treatment was 202.1 days, with a range of 1-630 days. The most frequently reported serious and non-serious adverse events were common symptoms of ALS (respiratory symptoms and dysphagia), and only 1.9% of serious adverse events were considered to be related to the study drug. CONCLUSIONS: The safety results with this broad population (over 10% of the estimated ALS population worldwide) were consistent with those previously reported from placebo-controlled trials. No increase in adverse events and no unexpected adverse events were observed.

In vivo recovery and survival of monoclonal-antibody-purified factor VIII concentrates.

In response to reports of discrepant in vitro assays of high-purity concentrates, a double-blind crossover study of in vivo recovery and half-life of two brands of monoclonal-antibody-purified factor VIII concentrates (Monoclate and Hemofil-M) was performed in 23 patients with hemophilia A. In vivo recoveries were close to values predicted from the labelled unitage when plasma samples were assayed by a one-stage method. When a two-stage assay was used, lower recoveries were calculated and the recovery with Hemofil-M was slightly but significantly lower than that with Monoclate. The concentrates were re-assayed in vitro by the two-stage method. Monoclate (which is assayed by the manufacturer using a two-stage method) contained 97% of the labelled potency and Hemofil-M (which is assayed by the manufacturer using a one-stage method) contained 81% of the labelled potency. Differences in in vitro and in vivo assay methods contribute to disparities between expected and observed factor VIII recovery. Clearance of Hemofil-M was significantly faster than that of Monoclate, but volume of distribution at the steady state, mean residence time, and plasma half-disappearance times of the two concentrates were not significantly different.

Lack of immune response to mouse IgG in hemophilia A patients treated chronically with Monoclate, a monoclonal antibody affinity purified factor VIII preparation.

Hemophilia A is caused by factor VIII deficiency that historically has been treated with either a cryoprecipitate fraction of serum or factor VIII concentrate. Recently, the availability of affinity isolated factor VIII (Monoclate) has allowed for a highly purified preparation for the chronic therapy of hemophilia A. This factor VIII preparation contains a trace quantity (less than 50 ng/100 I. U.) of mouse IgG. Immunoassays for the measurement of human IgG, IgM and IgE anti-mouse IgG antibody (HAMA) were developed and used to measure HAMA levels in hemophilia A patients undergoing chronic therapy with Monoclate in three different clinical studies. Natural antibodies to mouse IgG were observed in patient sera prior to Monoclate infusion. Data is presented demonstrating that induction of HAMA upon Monoclate treatment does not occur. The low level of mouse IgG contained in Monoclate appears to be below the threshold of immunogenicity. Most importantly, clinical symptoms related to hypersensitivity or anaphylaxis were never observed in any patient undergoing chronic therapy with Monoclate in these clinical studies.

Viral safety and inhibitor development associated with factor VIIIC ultra-purified from plasma in hemophiliacs previously unexposed to factor VIIIC concentrates. The Monoclate Study Group.

A multicenter study evaluated the potential for transmitting non-A/non-B hepatitis, as well as other viruses, with the use of the factor VIIIC product Monoclate. This product is purified from plasma via the monoclonal process that includes heat treatment for ultra-purification as a final step. Twenty different lots of Monoclate were used, and each patient received the assigned lot for the first 6 months of the trial. Nineteen of 38 patients adhered strictly to International Committee on Thrombosis and Hemostasis criteria in that they had normal liver enzymes, no evidence of hepatitis prestudy, and had no previous blood product use. Fourteen hemophilia centers from the United States, the United Kingdom, the Netherlands, and Israel participated in this study. Development of factor VIII inhibitor occurred in six of 38 patients, which was within the statistically expected range. Adverse events were mild, and Monoclate was well tolerated in this group. All 38 patients remained HIV seronegative.

Prostacyclin and thromboxane A2 synthesis by rabbit pulmonary artery.

Superfused spiral strips of rabbit intrapulmonary artery (i.p.a.) were contracted by arachidonic acid (AA) and by the following substances in order of potency: prostaglandin (PG) endoperoxide analog (U46619) > PGH2 > PGF2 alpha. Intrapulmonary artery strips were consistently relaxed by PGE2 and by the enzyme inhibitors, indomethacin, aspirin, meclofenamic acid and 1-pentylimidazole. These latter inhibitors of cyclooxygenase and thromboxane (TX) synthetase also blocked the AA-induced contraction of rabbit i.p.a. Prostacyclin had no effect on the i.p.a. or produced either a small contraction or relaxation. TXA2, formed by incubating horse platelet microsomes with PHG2, always contracted the tissue and was more potent than the parent endoperoxide. Incubations of [14C]AA with i.p.a. produced mainly [14C]-6-keto-PGF1 alpha (he breakdonw product of prostacyclin ) and [14C]TXB2 (the breakdown product of TXA2); the identities of these products were confirmed by radioimmunoassay and by gas chromatography-mass spectrometry. The synthesis of TXB2 by i.p.a. cannot be attributed to adhering lung tissue or platelets and appears to be produced by the vascular tissue itself. It is concluded that, although both prostacyclin and thromboxane may contribute to the resting tone of the rabbit i.p.a., the response to AA is mainly due to production of TXA2.

Poststimulation catecholamine synthesis and tyrosine hydroxylase activation in central noradrenergic neurons. I. In vivo stimulation of the locus coeruleus.

The ability of increased neuronal activity to accelerate catecholamine biosynthesis and tyrosine hydroxylase activity in the rat brain was tested. Noradrenergic neurons of the locus coeruleus (LC) were stimulated unilaterally at 20 Hz and the cortex and/or hippocampus from stimulated and contralateral (control) sides of the brain were analyzed and compared. Rats were injected with a dopa decarboxylase inhibitor and the accumulation of endogenously synthesized dopa used as an in vivo index of tyrosine hydroxylase activity. Thirty minutes after termination of 15 min of unilateral LC stimulation, dopa accumulation was 35% greater in the ipsilateral cortex + hippocampus. In untreated rats, at the end of 15 min of LC stimulation, there was an ipsilateral depletion of cortical norepinephrine (NE) which recovered within 30 min. When rats were injected with [3H]tyrosine (i.v.) during this half-hour recovery period, a poststimulation increase in [3H]catecholamine synthesis was observed in both the cortex (63%) and hippocampus (55%). In the cortex, there was more newly synthesized [3H]dopamine than [3H]NE, but LC stimulation preferentially increased the synthesis of [3H]NE. The hippocampus contained negligible amounts of [3H]dopamine and was used in subsequent studies. Tyrosine hydroxylase activity was assayed in vitro in supernatants derived from stimulated and control hippocampi. Ten minutes of LC stimulation (20 Hz) maximally activated hippocampal tyrosine hydroxylase and this activation was maintained for up to 20 min after stimulation was terminated. The results illustrate a stimulation-induced activation of NE biosynthesis and tyrosine hydroxylase activity in central NE neurons in vivo. This activation is maintained in the immediate poststimulation period and is not necessarily due to removal of end product inhibition by NE.

Poststimulation catecholamine synthesis and tyrosine hydroxylase activation in central noradrenergic neurons. II. Depolarized hippocampal slices.

The ability of neuronal depolarization to increase catecholamine biosynthesis in the poststimulation period was investigated in a preparation of central noradrenergic tissue, maintained in vitro. Rat hippocampal slices were superfused with oxygenated Krebs-Ringer phosphate saline (KRP) or depolarized with KRP containing 55 mM KCl. Slices were then transferred to fresh, nondepolarizing KRP containing [3H]tyrosine for further incubation. Ten minutes of K+ depolarization resulted in a 78% increase in [3H]catecholamine synthesis, measured in the poststimulation period, relative to nondepolarized, control slices. This activation of catecholamine synthesis was maintained for up to 10 min following termination of K+ depolarization. Depolarization in the presence of tetrodotoxin did not block the poststimulation increase in catecholamine synthesis. The increased catecholamine synthesis in the poststimulation period can be accounted for by increased tyrosine hydroxylation since: 1) the synthesis of [14C]catecholamines from [14C]dopa was not increased by K+ depolarization and 2) K+ depolarization led to a 71% increase in the accumulation of [3H]dopa newly synthesized from [3H]tyrosine in the presence of the decarboxylase inhibitor, brocresine. Under these conditions, no significant depletion of tissue norepinephrine could be detected. The depolarization-induced increase in catecholamine synthesis was independent of the presence of Ca++ in the superfusion and/or incubation media, suggesting its dissociation from Ca++-dependent transmitter release. The absence of enhanced [3H]catecholamine synthesis following depolarization of slices in a Ca++-free K+-KRP containing 1.0 mM ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) suggested that there is an absolute requirement for tissue Ca++ during the stimulation-induced synthesis activation process. There appears to be a depolarization-related phenomenon whose triggering is Ca++-independent, but which, in the presence of Ca++, is manifested as an increase in catecholamine biosynthesis (tyrosine hydroxylase activity).

Tyrosine hydroxylase: allosteric activation induced by stimulation of central noradrenergic neurons.

Electrical stimulation of the rat locus coeruleus cases about a 300% increase in the activity of the tyrosine hydroxylase prepared from the hippocampus on the stimulated side and assayed in the presence of subsaturating concentrations of tyrosine and pteridine cofactor. Addition of calcium or cAMP to soluble preparations of tyrosine hydroxylase isolated from the hippocampus produces a similar activation of tyrosine hydroxylase. The activation of tyrosine hydroxylase produced by calcium is reversed by addition of the calcium chelator, EGTA, while the activation produced by cAMP addition or by electrical stimulation of the locus coeruleus is unaffected by addition of EGTA to the assay medium. The activation of tyrosine hydroxylase produced by electrical stimulation or by addition of calcium or cAMP to the assay medium appears to be mediated in part by alterations in the kinetic properties of the enzyme. All treatment causes the enzyme to have an increased affinity for substrate and pteridine cofactor and a decreased affinity for the endproduct inhibitor, norepinephrine. These results are suggestive that the activation of tyrosine hydroxylase which occurs during periods of increased impulse flow in noradrenergic neurons may be initiated by alterations in calcium fluxes or by changes in the steady state levels of cAMP which accompany neuronal depolarization.