Real-World Clinical Experience With Idebenone in the Treatment of Leber Hereditary Optic Neuropathy

BACKGROUND

Leber hereditary optic neuropathy (LHON) leads to bilateral central vision loss. In a clinical trial setting, idebenone has been shown to be safe and to provide a trend toward improved visual acuity, but long-term evidence of effectiveness in real-world clinical practice is sparse.

METHODS

Open-label, multicenter, retrospective, noncontrolled analysis of long-term visual acuity and safety in 111 LHON patients treated with idebenone (900 mg/day) in an expanded access program. Eligible patients had a confirmed mitochondrial DNA mutation and had experienced the onset of symptoms (most recent eye) within 1 year before enrollment. Data on visual acuity and adverse events were collected as per normal clinical practice. Efficacy was assessed as the proportion of patients with either a clinically relevant recovery (CRR) or a clinically relevant stabilization (CRS) of visual acuity. In the case of CRR, time to and magnitude of recovery over the course of time were also assessed.

RESULTS

At time of analysis, 87 patients had provided longitudinal efficacy data. Average treatment duration was 25.6 months. CRR was observed in 46.0% of patients. Analysis of treatment effect by duration showed that the proportion of patients with recovery and the magnitude of recovery increased with treatment duration. Average gain in best-corrected visual acuity for responders was 0.72 logarithm of the minimal angle of resolution (logMAR), equivalent to more than 7 lines on the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Furthermore, 50% of patients who had a visual acuity below 1.0 logMAR in at least one eye at initiation of treatment successfully maintained their vision below this threshold by last observation. Idebenone was well tolerated, with most adverse events classified as minor.

CONCLUSIONS

These data demonstrate the benefit of idebenone treatment in recovering lost vision and maintaining good residual vision in a real-world setting. Together, these findings indicate that idebenone treatment should be initiated early and be maintained more than 24 months to maximize efficacy. Safety results were consistent with the known safety profile of idebenone.

[Evaluation of tear film stability by means of laser interferometry]

PURPOSE

The paper presents a new method for evaluation of the tear film stability on the human eye.

METHODS

The tear film distribution on the cornea is measured by the lateral shearing interference technique. The eye is kept open during approximately a two-minute recording, when the blinking has to be prevented. Continuous recording and viewing of interferograms enables registration of the changes in disturbances of interference fringes during elapsed time. The changes in fringes are caused by evaporation of tears from the ocular surface and appearance of the breakups.

CONCLUSIONS

The noninvasive tear breakup time (NITBUT) can be evaluated by comparing the recorded consecutive interferograms.

[Erection disorders after implantation of aorto-bifemoral prosthesis]

In this paper we present sexual complications occurring after implantation of vascular aorto-bifemoral prosthesis. We have sent an inquiry to 1236 men, who were operated in Vascular Department of Medical Academy in Wrocław in years 1983-1997. We received 659 answers. Additionally 302 patients were examined. We noticed disorders of erection after vascular operation in 350 cases. In 29 cases erection reappeared after operation. Only 112 patients declared correct ejaculation and 137 men have satisfied sexual life. This results present problem of postoperative ischaemia of minor pelvis and trauma to neural plexus of bifurcation of aorta. In cases of younger sexually active men, who need revascularisation of lower extremities by implantation of vascular aortobifemoral prosthesis we suggest endarterectomy of hypogastric artery and/or implantation this artery to prosthesis.

The Magill-Venturi attachment: studies in volunteers and patients

Including a venturi injector in a Magill breathing attachment reduces the requirement of compressed gases to 40% of that normally used: 100-120 ml x kg-1 x min-1. The entrainment of ambient air through the venturi injector enables the supply of an adequate flow of gas mixture to the patient. In 10 awake volunteers and 12 patients under N2O/halothane anaesthesia, it was demonstrated that a fresh gas flow from the anesthetic machine of 40 ml x kg-1 x min-1 is sufficient to prevent rebreathing during spontaneous respiration, when the venturi injector is included in the Magill attachment.

Distribution of expiratory gas and rebreathing in a T-piece modification combined with a PEEP valve

T-piece modifications with PEEP valves are often used in weaning from mechanical ventilation or for intubated patients not requiring ventilatory support. Distribution of expiratory gas and the extent of rebreathing in a T-piece modified with an inspiratory reservoir (ICR) and with a PEEP valve were studied in a model with various fresh gas flows (FGF), tidal volumes and frequencies at three valve settings: 0 cmH2O (ZEEP) and PEEP of 5 and 10 cmH2O (0.490-0.981 kPa). Two types of distribution of expiratory gas were delineated: type one with expiratory gas in the inspiratory limb (IL) and a high ratio of the maximum CO2 content and corresponding end-expiratory CO2 concentration in the expiratory limb (EL) (FmaxCO2/FECO2) and a type 2 with no detectable alveolar gas in the IL and a low ratio of FmaxCO2/FECO2. The use of PEEP did not increase the amount of alveolar gas in the system, and no increase occurred in the end-expiratory CO2 concentration. The investigated system is in fact a Mapleson A system. The ratio of FGF to minute ventilation just preventing rebreathing during spontaneous ventilation is approximately 1, in contrast to 3 in other modifications. These advantages minimize the risk of rebreathing, even when the minute ventilation rises to that of the fresh gas flow. The T-system with a compliant inspiratory reservoir and a PEEP valve can, in most clinical weaning situations, satisfy the inspiratory peak flow of different respiratory patterns with a standard FGF of 15 l X min-1.

Distribution of expiratory gas and rebreathing in T-piece modifications used in weaning

The simple T-piece is frequently used as a weaning system during respirator treatment. It is modified with an expiratory non-compliant reservoir (EnCR), an inspiratory compliant reservoir (ICR) and/or an expiratory one-way valve. The distribution of expiratory gases and rebreathing were studied in a model set-up in the corresponding systems at different fresh gas flows (FGF) and tidal volumes (VT). An EnCR produces no change, whereas an ICR causes the expiratory gas to flow into the inspiratory limb, an effect which is intensified by the presence of an expiratory valve. With a falling FGF and a rising VT, increasing amounts of expiratory gas are found in the inspiratory limb in the modifications with an ICR. However, this gives rise to rebreathing in the valve modification with a low FGF and high VT. The modification of the T-piece with an ICR but without a one-way valve is advantageous, as this system combines only slight dilution via the expiratory limb and a minimal risk of rebreathing.

Comparative study of the action of naloxone (Narcan) and nalorphine in man

The comparative study of 2 narcotic antagonists, naloxone and nalorphine, was performed in healthy volunteers. The influence of these drugs on the respiratory and cicularoty systems and on the psychical state was compared. The study was carried out in a double-blind, cross-over manner. Increasing doses of naloxone and placebo or nalorphine and placebo, were administered intravenously. Naloxone, even in very high doses, caused no changes in cardivascular system, acid-base balance, sensitivity of respiratory centre to carbon dioxide and psychical state of volunteers. After the administration of nalorphine, even in very small doses, changes in psychical state in all examined subjects were observed. Nalorphine caused the significant change in the ventilatory response to CO2. Based on their results, the authors conclude that naloxone has no agonist or intrinsic narcotic activity, as opposed to nalorphine possessing strong narcotic action.