XTEND-1 study design
XTEND-1 was an open-label, multicentre, Phase 3 study of ALTUVOCT in previously treated adult and adolescent patients (≥12 years old) with severe haemophilia A (N=159).4
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XTEND-ed study design
Participants who completed XTEND-1 were eligible to enrol into the ongoing XTEND-ed study (n=146).7
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A lower HJHS indicates better joint health. A target joint was defined as a major joint with at least three spontaneous bleeding episodes in a consecutive 6-month period before study entry. Target joint resolution was defined as no more than two episodes of bleeding into that joint during 12 months of continuous exposure to ALTUVOCT.4
*Prior FVIII prophylaxis group.4 †Only includes patients with at least 12 months of follow-up.4
In the ongoing XTEND-ed trial, ALTUVOCT has continued to provide joint protection in adults and adolescents on once-weekly prophylaxis:12
A lower HJHS indicates better joint health. A target joint was defined as a major joint with at least three spontaneous bleeding episodes in a consecutive 6-month period before study entry. Target joint resolution was defined as no more than two episodes of bleeding into that joint during 12 months of continuous exposure to ALTUVOCT.12
*The greatest improvements were in people aged 30–39 years and those with the worst joint health at XTEND-1 baseline.12
ALTUVOCT can be used as a monotherapy for the treatment of acute bleeds and in the surgical setting2,3
Over 52 weeks in the XTEND-1 trial, a single dose of ALTUVOCT resolved:2–4
With excellent or good haemostatic response in 95% (317/334) of first evaluable injections in adults and adolescents.4
*Of the 362 bleeding events that occurred in XTEND-1, 74% (268/362) occurred among patients in Arm B during the on-demand treatment period.4
In the perioperative setting (XTEND-1):15
11 patients underwent 12 major surgeries (on 50 IU/kg perioperative loading dose, plus 30 IU/kg or 50 IU/kg every 2–3 days, as needed).
One patient experienced three treatment-emergent AEs, all of which were unrelated to ALTUVOCT. No treatment-emergent serious AEs were reported during the surgical period.
*Decreased CD4 lymphocyte count in a patient with a history of HIV infection and combined tibia–fibula fracture in a patient who received treatment with another FVIII product, which was prohibited during the study.4
In the ongoing XTEND-ed study, ALTUVOCT continued to demonstrate a generally-well tolerated safety profile in adults and adolescents (n=146):9,10
Frequency of adverse reactions with ALTUVOCT
| MedDRA System organ class2,3 | Adverse reactions2,3 | Frequency2,3 |
| Blood and lymphatic system disorders | Factor VIII inhibition* | Very common (PUPs)†, Uncommon (PTPs)‡ |
| Immune system disorders | Hypersensitivity, anaphylactic reactions* | Not known |
| Nervous system disorders | Headache§ | Very common |
| Gastrointestinal disorders | Vomiting | Common |
| Skin and subcutaneous tissue disorders | Eczema Rash¶ Urticaria¥ | Common Common Common |
| Musculoskeletal and connective tissue disorders | Arthralgia Pain in extremity Back pain | Very common Common Common |
| General disorders & administration site conditions | Pyrexia Injection site reaction** | Common Uncommon |
Very common (≥1/10); common (≥1/100 to <1 /10); uncommon (≥1/1000 to <1/100); not known (cannot be estimated from the available data).2,3
No age-specific differences in adverse reactions were observed between paediatric and adult patients.2,3
For complete safety information, please refer to the SmPC.
*Reported in post-marketing setting.2,3 †Frequency is based on studies with other factor VIII products which included PUPs with severe haemophilia A.2,3 ‡Frequency is based on studies with all factor VIII products which included PTPs with severe haemophilia A.2,3 §Including migraine.2,3 ¶Including rash maculo papular.2,3 ¥Including urticaria papular.2,3 **Including injection site haematoma and injection site dermatitis.2,3
ALTUVOCT special warnings and precautions
| Hypersensitivity2,3 | Allergic type hypersensitivity reactions, including anaphylactic reactions have been observed with ALTUVOCT. If symptoms of hypersensitivity occur, patients should be advised to discontinue use of the medicinal product immediately and contact their physician. Patients should be informed of the early signs of hypersensitivity reactions including hives, generalised urticaria, itching, nausea, vomiting, tightness of the chest, wheezing, hypotension, and anaphylaxis. In case of shock, standard medical treatment for shock should be implemented. |
| Inhibitors2,3 | The formation of neutralising antibodies (inhibitors) to factor VIII is a known complication in the management of individuals with haemophilia A. These inhibitors are usually IgG immunoglobulins directed against the factor VIII pro-coagulant activity, which are quantified in Bethesda Units (BU) per mL of plasma using the modified assay. The risk of developing inhibitors is correlated to the severity of the disease as well as the exposure to factor VIII, this risk being highest within the first 50 exposure days but continues throughout life although the risk is uncommon. The clinical relevance of inhibitor development will depend on the titre of the inhibitor, with low titres posing less of a risk of insufficient clinical response than high titre inhibitors. In general, all patients treated with coagulation factor VIII products should be carefully monitored for the development of inhibitors by appropriate clinical observations and laboratory tests. If the expected factor VIII activity plasma levels are not attained, or if bleeding is not controlled with an appropriate dose, testing for factor VIII inhibitor presence should be performed. In patients with high levels of inhibitor, factor VIII therapy may not be effective and other therapeutic options should be considered. Management of such patients should be directed by physicians with experience in the care of haemophilia and factor VIII inhibitors. |
| Monitoring laboratory events2,3 | If the chromogenic assay or the one-stage clotting assay with Actin-FS reagent are used, divide the result by 2.5 to approximate the patient’s factor VIII activity level. Of note , this conversion factor only represents an estimate (mean chromogenic assay/one-stage clotting assay Actin-FSL ratio: 2.53; SD: 1.54; Q1: 1.98; Q3: 2.96; N= 3 353). |
| Cardiovascular events2,3 | In patients with existing cardiovascular risk factors, substitution therapy with factor VIII may increase the cardiovascular risk. |
| Catheter-related complications2,3 | If a central venous access device (CVAD) is required, risk of CVAD-related complications including local infections, bacteraemia and catheter site thrombosis should be considered. |
For complete safety information, please refer to the SmPC.
The listed warnings and precautions apply to both adults and children.2,3
There is limited experience in patients ≥65 years.2,3
ABR, annualised bleeding rate; AE, adverse reaction; CD4, cluster of differentiation 4; CI, confidence interval; ED, exposure day; FVIII, factor VIII; HIV, human immunodeficiency virus; HJHS, Haemophilia Joint Health Score; IQR, interquartile range; PK, pharmacokinetic; SD, standard deviation; TESAE, treatment-emergent serious adverse event.
1. Malec L, Matino D. Haemophilia. 2023;29(6):1419–1429. 2. ALTUVOCT UK Summary of Product Characteristics. 3. ALTUVOCT EU Summary of Product Characteristics. 4. von Drygalski A, et al. N Engl J Med. 2023;388(4):310–318. 5. Srivastava A, et al. Haemophilia. 2020;26(Suppl 6):1–158. 6. von Drygalski A, et al. N Engl J Med. 2023;388:310–318(Suppl). 7. Klamroth R, et al. ASH 2024. San Diego, USA. Oral presentation. 8. Malec L, et al. Blood. 2024;5495–5496. 9. Klamroth R, et al. Blood. 2024;717–718. 10. Susen S, et al. EAHAD 2026. Dublin, Ireland. Oral presentation. 11. Susen S, et al. ASH 2025. Orlando, FL, USA. Oral presentation. 12. Königs C, et al. ISTH 2025. Washington, D.C., USA. PB1425. 13. von Drygalski A, et al. Hamostaseologie. 2025;45(Suppl 1):S55–S563. 14. Oldenburg J, et al. EAHAD 2025. Milan, Italy. PO060. 15. Klamroth R, et al. Haemophilia. 2025;0:1–10.
In the UK, ALTUVOCT (efanesoctocog alfa) is indicated for the treatment and prophylaxis of bleeding in patients 2 years and above with severe or moderate haemophilia A (≤5% endogenous plasma factor VIII activity). There are limited data in paediatric patients <2 years of age.2
In Ireland, ALTUVOCT (efanesoctocog alfa) is indicated for the treatment and prophylaxis of bleeding in patients with haemophilia A (congenital factor VIII deficiency). ALTUVOCT can be used for all age groups.3
| ▼ This medicine is subject to additional monitoring. This will allow quick identification of new safety information. Healthcare professionals are asked to report any suspected adverse reactions. Adverse events should be reported. Reporting forms and information can be found, for United Kingdom: via the Yellow Card Scheme at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. For Ireland: via HPRA Pharmacovigilance, website www.hpra.ie. Adverse events should also be reported to Swedish Orphan Biovitrum Ltd by email at [email protected] or by calling +44 (0) 800 111 4754. |