Improved patient-reported health impact of multiple sclerosis: The ENABLE study of PR-fampridine.

BACKGROUND: Multiple sclerosis (MS) is a debilitating disease that negatively impacts patients' lives. OBJECTIVE: ENABLE assessed the effect of long-term prolonged-release (PR) fampridine (dalfampridine extended release in the United States) treatment on patient-perceived health impact in patients with MS with walking impairment. METHODS: ENABLE was a 48-week, open-label, Phase 4 study of PR-fampridine 10 mg twice daily. Patients who showed any improvement in Timed 25-Foot Walk walking speed at weeks 2 and 4 and any improvement in 12-item MS Walking Scale score at week 4 remained on treatment. The primary endpoint was change from baseline in 36-Item Short-Form Health Survey (SF-36) physical component summary (PCS) score. RESULTS: At week 4, 707/901 (78.5%) patients met the criteria to remain on treatment. Patients on treatment demonstrated significant and clinically meaningful improvements in SF-36 PCS scores from baseline (mean change (95% confidence interval)) to week 12 (4.30 (3.83, 4.78); p < 0.0001), week 24 (3.75 (3.23, 4.27); p < 0.0001), week 36 (3.46 (2.95, 3.97); p < 0.0001), and week 48 (3.24 (2.72, 3.77); p < 0.0001). Significant improvements from baseline were also demonstrated in secondary health measures in patients on treatment. CONCLUSION: PR-fampridine improved patient-perceived physical and psychological health impact of MS measured in a real-life setting.

Prolonged-release fampridine and walking and balance in MS: randomised controlled MOBILE trial.

BACKGROUND: Mobility impairment is a common disability in MS and negatively impacts patients' lives. OBJECTIVE: Evaluate the effect of prolonged-release (PR) fampridine (extended-release dalfampridine in the United States) on self-assessed walking disability, dynamic/static balance and safety in patients with MS. METHODS: MOBILE was a randomised, double-blind, exploratory, placebo-controlled trial. Patients with progressive/relapsing-remitting MS and Expanded Disability Status Scale score of 4.0-7.0 were treated with PR-fampridine or placebo twice daily for 24 weeks. Efficacy endpoints included change from baseline in the 12-item MS Walking Scale (MSWS-12), Timed Up and Go (TUG) test and Berg Balance Scale (BBS). RESULTS: 132 patients were randomised at 24 sites in six countries. PR-fampridine therapy resulted in greater median improvements from baseline in MSWS-12 score, TUG speed and BBS total score versus placebo over 24 weeks. A higher proportion of patients receiving PR-fampridine versus placebo experienced significant improvements at MSWS-12 improvement thresholds ⩾7 (p = 0.0275), ⩾8 (p = 0.0153) and ⩾9 points (p = 0.0088) and TUG speed thresholds ⩾10% (p = 0.0021) and ⩾15% (p = 0.0262). PR-fampridine was well tolerated. CONCLUSIONS: PR-fampridine therapy resulted in early and sustained improvements in broad measures of walking and balance over six months.

IgG subclass and heavy chain domains contribute to binding and protection by mAbs to the poly γ-D-glutamic acid capsular antigen of Bacillus anthracis.

Bacterial capsules are common targets for antibody-mediated immunity. The capsule of Bacillus anthracis is unusual among capsules because it is composed of a polymer of poly-γ-d-glutamic acid (γdPGA). We previously generated murine IgG3 monoclonal antibodies (mAbs) to γdPGA that were protective in a murine model of pulmonary anthrax. IgG3 antibodies are characteristic of the murine response to polysaccharide antigens. The goal of the present study was to produce subclass switch variants of the γdPGA mAbs (IgG3 → IgG1 → IgG2b → IgG2a) and assess the contribution of subclass to antibody affinity and protection. Subclass switch antibodies had identical variable regions but differed in their heavy chains. The results showed that a switch from the protective IgG3 to IgG1, IgG2b or IgG2a was accompanied by i) a loss of protective activity ii) a change in mAb binding to the capsular matrix, and iii) a loss of affinity. These results identify a role for the heavy chain constant region in mAb binding. Hybrid mAbs were constructed in which the CH1, CH2 or CH3 heavy chain constant domains from a non-protective, low binding IgG2b mAb were swapped into the protective IgG3 mAb. The IgG3 mAb that contained the CH1 domain from IgG2b showed no loss of affinity or protection. In contrast, swapping the CH2 or CH3 domains from IgG2b into IgG3 produced a reduction in affinity and a loss of protection. These studies identify a role for the constant region of IgG heavy chains in affinity and protection against an encapsulated bacterial pathogen.