Safety of Switching Factor VIII Products in the Era of Evolving Concentrates: Myths and Facts.

Recent advances in the development of factor VIII (FVIII) concentrates offer patients with hemophilia the opportunity to switch to products considered safer or with improved properties. In some cases, product switch occurs due to side effects, convenience issues, or economic reasons affecting clinical choices. Reluctance to change FVIII concentrates is shown by patients and also by their physicians, because of concerns in particular about the risk of inhibitor development. A literature review was performed to retrieve the best evidence regarding safety issues of switching FVIII concentrate in patients with severe hemophilia A. Product switch was not associated with an increased inhibitor risk in four studies in patients during the first 50 to 75 exposure days, or in three studies reporting national switches in Canada and United Kingdom. The latter, the only available study comparing switcher and nonswitcher patients, showed an inhibitor incidence similar to that historically reported in the United Kingdom. In 16 phase III clinical trials and 6 postmarketing studies of FVIII concentrates, few de novo inhibitors were detected in previously treated patients, mostly transient and low-titer, with some additional recurrent inhibitors in patients with previous positive testing. On the whole, although rigorous controlled studies are lacking, literature data do not support increased risk of inhibitor development or other safety issues related to product switch. Therefore, in the presence of clinical needs, the advantages of switching FVIII products should not be missed because of perceived more than evidence-based challenges, in particular in this era of products with improved properties recently introduced or available in few years. Caution, however, is suggested in patients with high inhibitor risk, including in those in concomitance with surgery or intensive treatment. A careful inhibitor testing prior to and after product switch is always needed, to identify real de novo inhibitors and to gather further information in the current evolving scenario, in particular comparing switch and nonswitch patients.

Cyclic supplementation of 5-MTHF is effective for the correction of hyperhomocysteinemia.

Folic acid supplementation is the mainstay treatment of hyperhomocysteinemia (HHcy). However, no recommendations are currently available in regard to the optimal replacement therapy. Therefore, this prospective study hypothesized that a cyclic schedule (1 month of therapy followed by 2 months of withdrawal) of 5-methyltetrahydrofolate (5-MTHF) would reduce plasma levels of fasting total homocysteine (tHcy) in patients with mild/moderate HHcy. Patients with a new diagnosis of mild/moderate HHcy were evaluated for the methylenetetrahydrofolate reductase genotype and the presence of major features of metabolic syndrome. All enrolled subjects received a cyclic 5-MTHF oral supplementation and were reevaluated after each treatment cycle for a total of 2 years. In the 246 enrolled subjects, a significant reduction of tHcy levels occurred after the first cycle of treatment (from 31.6 ± 13.6 to 14.4 ± 5.77 µmol/L, P < .001) and during the whole 2-year follow-up (from 31.6 ± 13.6 to 12.18 ± 3.03 µmol/L, P < .001). The values of tHcy returned to reference range in 117 subjects (51.3%) after the first cycle and in 198 (86.8%) during the follow-up. The risk of failure in tHcy level normalization was increased in patients with metabolic syndrome (hazard ratio [HR], 3.49; 95% confidence interval [CI], 1.46-8.36), higher baseline tHcy levels (HR, 1.045; 95% CI, 1.018-1.073), or methylenetetrahydrofolate reductase homozygous mutation (HR, 6.59; 95% CI, 2.64-16.4). This study clearly shows that a cyclic schedule (1 month of therapy followed by 2 months of withdrawal) of 5-MTHF supplementation is able to significantly reduce tHcy levels in patients with mild/moderate HHcy.

Treatment of hemophilia: a review of current advances and ongoing issues.

Replacement of the congenitally deficient factor VIII or IX through plasma-derived or recombinant concentrates is the mainstay of treatment for hemophilia. Concentrate infusions when hemorrhages occur typically in joint and muscles (on-demand treatment) is able to resolve bleeding, but does not prevent the progressive joint deterioration leading to crippling hemophilic arthropathy. Therefore, primary prophylaxis, ie, regular infusion of concentrates started after the first joint bleed and/or before the age of two years, is now recognized as first-line treatment in children with severe hemophilia. Secondary prophylaxis, whenever started, aims to avoid (or delay) the progression of arthropathy and improve patient quality of life. Interestingly, recent data suggest a role for early prophylaxis also in preventing development of inhibitors, the most serious complication of treatment in hemophilia, in which multiple genetic and environmental factors may be involved. Treatment of bleeds in patients with inhibitors requires bypassing agents (activated prothrombin complex concentrates, recombinant factor VIIa). However, eradication of inhibitors by induction of immune tolerance should be the first choice for patients with recent onset inhibitors. The wide availability of safe factor concentrates and programs for comprehensive care has now resulted in highly satisfactory treatment of hemophilia patients in developed countries. Unfortunately, this is not true for more than two-thirds of persons with hemophilia, who live in developing countries.