Long-term treatment with eteplirsen in nonambulatory patients with Duchenne muscular dystrophy

This analysis aims to describe the outcomes of two nonambulatory patients with Duchenne muscular dystrophy (DMD) who participated in two clinical studies. The two consecutive trials of eteplirsen (studies 201 and 202) were conducted in patients with DMD (N = 12) and confirmed genetic mutations amenable to exon 51 skipping.In study 201, 12 patients were randomized to receive once-weekly, double-blind intravenous infusions of eteplirsen 30 or 50 mg/kg or placebo for 24 weeks; patients then received open-label eteplirsen during weeks 25 through 28. All 12 patients continued onto open-label extension study 202 and received long-term treatment with eteplirsen. We compared cardiac, pulmonary, and upper limb function and dystrophin production in the nonambulatory twin patients versus the 10 ambulatory patients through 240 combined treatment weeks.Ten study patients remained ambulatory through both studies, while the identical twin patients both experienced early, rapid loss of ambulation. The twin patients had greater disease severity at baseline (6-minute walk test [6MWT], 330 and 256 m) versus the other patients (n = 10; 6MWT range, 341-418 m). They maintained cardiac and upper limb function through combined week 240, with outcomes similar to those of the patients who remained ambulatory. Dystrophin production was confirmed following eteplirsen treatment.Despite the loss of ambulation, other markers of disease progression remained relatively stable in the eteplirsen-treated twin patients and were similar to those of the ambulatory patients.

Ophthalmic abnormalities in homocystinuria: the value of screening

PURPOSE

Homocystinuria, a genetic metabolic abnormality, eventually causes a variety of ocular and other pathologies if not treated. To evaluate the results of screening newborns for homocystinuria, we compared ophthalmic outcomes for two groups of homocystinuria patients who had been diagnosed either at birth or later than 6 weeks.

METHODS AND RESULTS

Nineteen patients had been screened and diagnosed shortly after birth, with treatment instigated before 6 weeks of age (mean follow-up and age 10.8 years; median 11 years). Eight of 17 were myopic; 13 of 15 had good vision in both eyes; one had lens subluxation. The second group of 17 patients were diagnosed later than 6 weeks, often (12 patients) because of ocular problems (mean follow-up 8.3 years; mean age 19.4 years; median age 16 years). Visual function varied from 6/6 (4 patients) to less than 6/36 (4 patients); 3 eyes had no perception of light. Thirteen patients had lens subluxation or dislocation.

CONCLUSION

Early diagnosis and treatment of homocystinuria is advantageous.

Molecular characterization of PKU allele prevalent in southern Europe and Ireland

A novel substitution has been characterized in the phenylalanine hydroxylase (PAH) gene that is linked exclusively to mutant haplotype 6, which is prevalent in southern Europe but rare in northern and eastern Europe. It is a G-to-A transition in intron 10, 11 bases from exon 11. This substitution creates an additional AG dinucleotide, which may serve as a cryptic splice acceptor site. Individuals who bear this substitution in the homozygous state have a severe PKU phenotype with pretreatment serum phenylalanine levels over 1200 mumol/liter. The frequency and distribution of this substitution among European populations suggests two possible founding populations, one being Middle Eastern and the other Roman. The use of this substitution as a marker to identify PKU chromosomes will be an invaluable aid to carrier screening and prenatal diagnosis in populations where mutant haplotype 6 is prevalent.