Integrated analysis of safety data from 12 clinical interventional studies of plasma- and albumin-free recombinant factor VIII (rAHF-PFM) in haemophilia A.

INTRODUCTION: Antihaemophilic factor (recombinant), plasma/albumin-free method (rAHF-PFM) is a human recombinant full-length factor VIII (FVIII) approved worldwide for the control and prevention of bleeding episodes, routine prophylaxis and perioperative management in adults and children with haemophilia A. AIM: To evaluate rAHF-PFM safety [including adverse events (AEs) and inhibitor incidence] from 12 interventional studies spanning >10 years. METHODS: The study population comprised 418 treated patients (median age = 18.7 years) with FVIII levels ≤2% of normal, including 55 previously untreated or minimally treated patients (PUPs/MTPs) from all rAHF-PFM phase I-IV studies, excluding observational safety studies. RESULTS: Most AEs were non-serious; only 93 AEs in 45 patients (10.8%) were related to rAHF-PFM. A total of 106 serious AEs (SAEs) occurred in 69 patients (16.5%); the most common were FVIII inhibitors (4.1%), device-related infection (1.0%) and pyrexia (0.7%). The 17 SAEs considered related to treatment consisted of FVIII inhibitors in 1 previously treated patient (PTP) (≤5 Bethesda Units [BU]) and 16 PUPs/MTPs [7/55 high titre (>5 BU), 12.7%; 9/55 low titre (≤5 BU), 16.4%]. Overall, the incidence of FVIII inhibitors was 0.36% in PTPs and 29.1% in PUPs/MTPs. No deaths or cases of hypersensitivity related to rAHF-PFM occurred. CONCLUSION: This integrated safety analysis evaluated the safety and tolerability of rAHF-PFM in children and adults with moderately severe or severe haemophilia A in all interventional studies completed to date. It was important to review consolidated evidence as some AEs are rare. There were no new safety signals in a wide variety of clinical settings.

Patient data meta-analysis of Post-Authorization Safety Surveillance (PASS) studies of haemophilia A patients treated with rAHF-PFM.

UNLABELLED: A Post-Authorization Safety Study (PASS) global program was designed to assess safety and effectiveness of rAHF-PFM (ADVATE) use in haemophilia patients in routine clinical settings. The main aim of this project was to estimate the rate of inhibitors and other adverse events across ADVATE-PASS studies by meta-analysing individual patient data (IPD). Eligible Studies: PASS studies conducted in different countries, between 2003 and 2013, for which IPD were provided. Eligible patients: haemophilia A patients with baseline FVIII:C < 5%, with a known number of prior exposure days (EDs). PRIMARY OUTCOME: de novo inhibitors in severe, previously treated patients (PTPs) with > 150 EDs. SECONDARY OUTCOMES: de novo inhibitors according to prior exposure and disease severity; other adverse events; annualized bleeding rate (ABR). ANALYSIS: random-effects logistic regression. Five of seven registered ADVATE-PASS (Australia, Europe, Japan, Italy and USA) and 1188 patients were included (median follow-up 384 days). Among severe PTPs with > 150 EDs, 1/669 developed de novo inhibitors (1.5 per 1000; 95% confidence interval [CI] 0.2, 10.6 per 1000). Among all patients included in the PASS studies, 21 developed any type of inhibitors (2.0%, 95% CI: 0.8%, 4.7%). Less than 1% of patients presented with other serious adverse events possibly related to ADVATE. The overall median ABR was 3.83 bleeds/year (first, third quartiles: 0.60, 12.90); 1.66 (0, 4.78) in the 557 patients continuously on prophylaxis ≥ twice/week. Meta-analysing PASS data from different countries confirmed the overall favourable safety and effectiveness profile of ADVATE in routine clinical settings.

Constitutive and barbital-induced expression of the Cyp6a2 allele of a high producer strain of CYP6A2 in the genetic background of a low producer strain.

The levels of one or more cytochrome P450 (CYP) enzymes and the respective mRNAs are found to be higher in insecticide-resistant insects than in susceptible insects. To understand better how insects regulate the levels of CYPs, we examined the expression of the Cyp6a2 gene in various strains of Drosophila melanogaster. We also took a transgenic approach to understand the molecular mechanisms that are involved in strain variation of Cyp6a2 expression. RNA blot analysis showed that the constitutive expression of Cyp6a2 varies from strain to strain; the level of CYP6A2 mRNA is barely detectable in the underproducer ry506 strain, whereas it is very high in the overproducer 91-R and MHIII-D23 strains. The long terminal repeat (LTR) of mobile element 17.6 that is found in the 3' untranslated region (UTR) of the Cyp6a2 gene of some strains does not appear to have any role on the steady-state CYP6A2 mRNA level. We also found that the Cyp6a2 gene is inducible by barbital in 91-R, ry506 as well as 91-C, which carries an LTR insertion. To examine the genetic background of the underproducer ry506 strain with respect to Cyp6a2 expression, we transformed the ry506 strain with the Cyp6a2 allele of the overproducer 91-R strain (Cyp6a2-91 R) and measured the constitutive and barbital-induced expression of the Cyp6a2-91 R transgene in the transformed flies. The Cyp6a2-91 R transgene carrying 129 bp of DNA upstream of the ATG codon did not show any constitutive or barbital-induced expression in the ry506 host genome. However, transgenes with 1331 and 985 bp upstream DNA showed similar levels of constitutive expression that were higher than that of the endogenous Cyp6a2 gene of the ry506 host strain, but lower than the expression of the same gene in the 91-R strain. Both these transgenes, with 1331 and 985 bp upstream DNA, also showed induction with 0.1 M barbital. DNA sequence analysis revealed that in both 91-R and ry506, the upstream DNA between +1 and -985 bp contains a distal and a proximal group of three potential barbie boxes, i.e. cis-elements that are thought to be involved in barbiturate-mediated induction of CYP genes. Except for four bases located near the distal cluster of barbie boxes and two other bases, the base sequence of the upstream DNA is identical in ry506 and 91-R strains. These results suggest that the underproducer ry506 strain has the trans-regulatory factors to support constitutive and induced expression of the Cyp6a2-91 R allele carrying DNA between -129 and -1331 bp regions. Possible reasons for low constitutive expression of the endogenous Cyp6a2 gene and moderate level of expression of the Cyp6a2-91 R allele in the ry506 genetic background are discussed.