A framework for individualized splice-switching oligonucleotide therapy

Splice-switching antisense oligonucleotides (ASOs) could be used to treat a subset of individuals with genetic diseases1, but the systematic identification of such individuals remains a challenge. Here we performed whole-genome sequencing analyses to characterize genetic variation in 235 individuals (from 209 families) with ataxia-telangiectasia, a severely debilitating and life-threatening recessive genetic disorder2,3, yielding a complete molecular diagnosis in almost all individuals. We developed a predictive taxonomy to assess the amenability of each individual to splice-switching ASO intervention; 9% and 6% of the individuals had variants that were 'probably' or 'possibly' amenable to ASO splice modulation, respectively. Most amenable variants were in deep intronic regions that are inaccessible to exon-targeted sequencing. We developed ASOs that successfully rescued mis-splicing and ATM cellular signalling in patient fibroblasts for two recurrent variants. In a pilot clinical study, one of these ASOs was used to treat a child who had been diagnosed with ataxia-telangiectasia soon after birth, and showed good tolerability without serious adverse events for three years. Our study provides a framework for the prospective identification of individuals with genetic diseases who might benefit from a therapeutic approach involving splice-switching ASOs.

Brain glucose metabolism in adults with ataxia-telangiectasia and their asymptomatic relatives

Ataxia-telangiectasia is a recessive genetic disorder (ATM is the mutated gene) of childhood with severe motor impairments and whereas homozygotes manifest the disorder, heterozygotes are asymptomatic. Structural brain imaging and post-mortem studies in individuals with ataxia-telangiectasia have reported cerebellar atrophy; but abnormalities of motor control characteristic of extrapyramidal dysfunction suggest impairment of broader motor networks. Here, we investigated possible dysfunction in other brain areas in individuals with ataxia-telangiectasia and tested for brain changes in asymptomatic relatives to assess if heterozygocity affects brain function. We used positron emission tomography and (18)F-fluorodeoxyglucose to measure brain glucose metabolism (quantified as µmol/100 g/min), which serves as a marker of brain function, in 10 adults with ataxia-telangiectasia, 19 non-affected adult relatives (12 siblings, seven parents) and 29 age-matched healthy controls. Statistical parametric mapping and region of interest analyses were used to compare individuals with ataxia-telangiectasia, asymptomatic relatives, and unrelated controls. We found that participants with ataxia-telangiectasia had lower metabolism in cerebellar hemispheres (14%, P < 0.001), anterior vermis (40%, P < 0.001) and fusiform gyrus (20%, P < 0.001) compared with controls or siblings, and lower metabolism in hippocampus (12%, P = 0.05) compared with controls, and showed significant intersubject variability (decreases in vermis ranged from 18% to 60%). Participants with ataxia-telangiectasia also had higher metabolism in globus pallidus (16%, P = 0.05), which correlated negatively with motor performance. Asymptomatic relatives had lower metabolism in anterior vermis (12%; P = 0.01) and hippocampus (19%; P = 0.002) than controls. Our results indicate that, in addition to the expected decrease in cerebellar metabolism, participants with ataxia-telangiectasia had widespread changes in metabolic rates including hyperactivity in globus pallidus indicative of basal ganglia involvement. Changes in basal ganglia metabolism offer potential insight into targeting strategies for therapeutic deep brain stimulation. Our finding of decreased metabolism in vermis and hippocampus of asymptomatic relatives suggests that heterozygocity influences the function of these brain regions.

Budesonide foam versus budesonide enema in active ulcerative proctitis and proctosigmoiditis

BACKGROUND

Rectal budesonide is an effective treatment of active ulcerative proctitis or proctosigmoiditis.

AIM

To compare the therapeutic efficacy, tolerability and safety, and patient's preference of budesonide foam vs. budesonide enema.

METHODS

Patients with active ulcerative proctitis or proctosigmoiditis (clinical activity index > 4 and endoscopic index > or = 4) were eligible for this double-blind, double-dummy, randomized, multicentre study. They received 2 mg/25 mL budesonide foam and placebo enema (n = 265), or 2 mg/100 mL budesonide enema and placebo foam (n = 268) for 4 weeks. Primary endpoint was clinical remission (clinical activity index < or = 4) at the final/withdrawal visit (per protocol).

RESULTS

A total of 541 patients were randomized--533 were evaluable for intention-to-treat analysis and 449 for per protocol analysis. Clinical remission rates (per protocol) were 60% for budesonide foam and 66% for budesonide enema (P = 0.02362 for non-inferiority of foam vs. enema within a predefined non-inferiority margin of 15%). Both formulations were safe and no drug-related serious adverse events were observed. Because of better tolerability and easier application most patients preferred foam (84%).

CONCLUSION

Budesonide foam is as effective as budesonide enema in the treatment of active ulcerative proctitis or proctosigmoiditis. Both budesonide formulations are safe, and most patients prefer foam.

Efficacy and tolerability of mesalazine foam enema (Salofalk foam) for distal ulcerative colitis: a double-blind, randomized, placebo-controlled study

BACKGROUND

Rectal formulations of mesalazine are the treatment of choice in mildly to moderately active ulcerative colitis. A new foam formulation of mesalazine was developed to improve both drug delivery and patient acceptance.

METHODS

In this multicentre, randomized, double-blind, parallel-group study, 111 patients with mildly to moderately active proctitis, proctosigmoiditis, or left-sided ulcerative colitis received mesalazine foam enema or placebo enema (2 g mesalazine per day) for 6 weeks. Disease activity was monitored on the basis of the Clinical Activity Index, Endoscopic Index, Histological Index, and global efficacy assessment by the investigators. Safety assessments included the recording of adverse events, laboratory variables and vital signs.

RESULTS

Clinical remission was more frequent in the mesalazine group than the placebo group (65% vs. 40%; P=0.0082), particularly in patients with mild disease and patients with proctosigmoiditis. The frequency of patients with an endoscopic remission was higher in the mesalazine group (57%) than in the placebo group (37%). Similarly, 59% of patients receiving mesalazine but only 41% of those receiving placebo showed an improved Histological Index. The foam enemas were generally well-tolerated, and no treatment-related changes on laboratory variables and vital signs were noted.

CONCLUSIONS

Mesalazine foam enema was well-tolerated and was more effective than placebo in the treatment of patients with distal ulcerative colitis.