| Factor VIII inhibition The occurrence of neutralising antibodies (inhibitors) to factor VIII is well known in the treatment of patients with haemophilia A. As with all coagulation factor VIII products, patients are to be monitored for the development of inhibitors that are to be titrated in Bethesda Units (BUs) using the Nijmegen modification of the Bethesda assay. If such inhibitors occur, the condition may manifest itself as an insufficient clinical response. In such cases, it is recommended that a specialised haemophilia centre be contacted. In a clinical study with ReFacto AF in previously treated patients (PTPs), the incidence of factor VIII inhibitors was the primary safety endpoint. Two clinically silent, low-titre, transient inhibitors were observed in 94 patients with a median exposure of 76 exposure days (ED, range 1-92), corresponding to 2.2% of the 89 patients with at least 50 ED. In a supporting study of ReFacto AF, 1 de novo and 2 recurrent inhibitors (all low-titre, central laboratory determination) were observed in 110 patients; median exposure of 58 ED (range 5-140) and 98 patients had at least 50 ED to ReFacto AF. Ninety eight (98) of the original 110 patients continued treatment in a second supportive study and had subsequent extended exposure to ReFacto AF with a median of 169 additional ED (range 9-425). One (1) additional low-titre de novo inhibitor was observed. The frequency of inhibitors observed in these studies is within the expected range.In a clinical study with ReFacto in PTPs, 1 inhibitor was observed in 113 patients. Also, there have been spontaneous post-marketing reports of high titre inhibitors involving previously treated patients.There are no clinical data on previously untreated patients (PUPs) with ReFacto AF. However, clinical trials are planned in previously untreated patients (PUPs) with ReFacto AF. In a clinical trial, 32 out of 101 (32%) previously untreated patients (PUPs) treated with ReFacto developed inhibitors: 16 out of 101 (16%) with a titre> 5 BU and 16 out of 101 (16%) with a titre 5 BU. The median number of exposure days up to inhibitor development in these patients was 12 (range 3-49). Of the 16 patients with high titres, 15 received immune tolerance (IT) treatment. Of the 16 patients with low titres, IT treatment was started in 10. IT had an efficacy of 73% for patients with high titres and 90% for those with low titres. For all 101 treated PUPs, regardless of inhibitor development, the median number of exposure days is 197 (range 1-1299).Adverse reactions based on experience from clinical trials with ReFacto or ReFacto AF are presented in the table below by system organ class. These frequencies have been estimated on a per-patient basis and are described using the following categories: very common ( 1/10); common ( 1/100 to <1/10); and uncommon ( 1/1,000 to <1/100).Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness. System Organ Class | Frequency of Occurrence per Patient with ReFacto or ReFacto AF | Very common ( 1/10) | Common ( 1/100 to <1/10) | Uncommon ( 1/1,000 to <1/100) | Blood and lymphatic disorders | Factor VIII inhibitors - PUPs | Factor VIII inhibitors - PTPs | | Metabolism and nutrition disorders | | | Anorexia | Nervous system disorders | | Headache | Neuropathy, dizziness, somnolence, dysgeusia | Cardiac disorders | | | Angina pectoris, tachycardia, palpitations | Vascular disorders | | Haemorrhage/ Haematoma | Hypotension, thrombophlebitis, vasodilatation, flushing | Respiratory, thoracic and mediastinal disorders | | | Dyspnoea, cough | Gastrointestinal disorders | Vomiting | Nausea | Abdominal pain, diarrhoea | Skin and subcutaneous tissue disorders | | | Urticaria, pruritis, rash, hyperhidrosis | Musculoskeletal, connective tissue and bone disorders | | Arthralgia | Myalgia | General disorders and administration site conditions | | Asthenia, pyrexia | Chills/feeling cold, injection site inflammation, injection site reaction, injection site pain | Investigations | | | Aspartate aminotransferase increased, alanine aminotransferase increased, blood bilirubin increased, blood creatine phosphokinase increased | Surgical and medical procedures | | Vascular access complication | | One event of cyst in an 11-year old patient and one event described as confusion in a 13-year old patient have been reported as possibly related to ReFacto AF treatment. Safety of ReFacto AF was evaluated in previously treated children and adolescents (n=18, age 12 16 in a study and n=49, age 7 16 in a supporting study). Although a limited number of children have been studied, there is a tendency for higher frequencies of adverse events in children aged 7-16 as compared to adults. A clinical trial evaluating use of moroctocog alfa (AF CC) in children less than 6 years of age is on going.The following adverse events have also been reported for ReFacto: paraesthesia, fatigue, blurred vision, acne, gastritis, gastroenteritis, and pain. Hypersensitivity or allergic reactions (which may include angioedema, burning and stinging at the infusion site, chills, flushing, generalised urticaria, headache, hives, hypotension, lethargy, nausea, restlessness, tachycardia, tightness of the chest, tingling, vomiting, wheezing) have been observed infrequently for ReFacto, and may in some cases progress to severe anaphylaxis including shock (see section 4.4).Trace amounts of hamster protein may be present in ReFacto AF. Very rarely, development of antibodies to hamster protein has been observed, but there were no clinical sequelae. In a study of ReFacto, twenty of 113 (18%) PTPs had an increase in anti-CHO antibody titre, without any apparent clinical effect. If any reaction takes place that is thought to be related to the administration of ReFacto AF, the rate of infusion is to be decreased or the infusion stopped, as dictated by the response of the patient (see section 4.4). | |