A programmable mini-pump able to provide regular doses after surgery of FVIIa to hemophilia A patients with inhibitors — those resistant to standard FVIII replacement therapy — successfully maintained expected levels of blood clotting factors, a small study reports.
Attending surgical nurses also voiced satisfaction with the pump’s use, reporting a substantial time savings in patient care.
The study, “A novel protocol for accurate and reliable postoperative bolus administration of recombinant factor VIIa using an automated mini‐pump system,” was published in the journal Haemophilia.
Hemophilia A is caused by a missing or defective blood clotting factor VIII (FVIII). Standard of care treatment involves regular infusions of lab-made FVIII. However, patients can develop antibodies against this treatment over time — and among those with hemophilia A, about 1 in 5 do develop such inhibitors.
Resistance to FVIII treatment is particularly hazardous following surgery. Complementary therapies, called bypassing agents — like factor VIIa (FVIIa), marketed as NovoSeven RT by Novo Nordisk, and an anti-inhibitor coagulant complex, marketed as Feiba by Shire Pharmaceuticals (now part of Takeda) — have been successfully used as alternatives for controlling bleeding after surgery.
Current post-surgical guidelines recommend that nurses give small doses (bolus) of FVIIa — because of its short half-life — every two hours for the first 48 hours, then at increased dosing intervals until the bleeding has stabilized.
Alternatively, a pump that could deliver regular and measured doses of FVIIa at specified times may provide the same level of care and help reduce the burden on nurses.
A team of researchers based at the Université Lyon, in France, examined the efficacy and safety of the CADD‐Prizm Ambulatory Infusion Pump, made by Smiths Medical, to deliver regular doses of FVIIa after surgery to two adults with severe hemophilia A who were resistant to FVIII therapy.
The first was a 35-year-old man who regularly used FVIIa as an on‐demand home treatment. Due to complications from a previous knee surgery, he was required to have his leg amputated at the thigh.
This patient was manually given three doses of FVIIa, one before and two following surgery. The mini-pump was then programmed to deliver a series of 10 doses every two hours, followed by a total of eight doses over every three hours, and a series of nine doses every four hours. In total, he was given 27 doses by mini-pump over 78 hours.
Afterward, he was put on continuous infusion for six more days.
The patient’s blood clotting potential, as measured by the endogenous thrombin potential (ETP) — the amount of thrombin (primary clotting enzyme) generated by therapy — remained in the expected range for the first two days after surgery, then declined for two days before becoming stable upon continuous infusion. Blood levels of FVIIa followed a similar pattern as ETP.
No further medications were needed, no adverse events were reported, and the man’s clinical outcome was good. The attending hematologist rated the efficacy of FVIIa and the value of the pump as excellent.
The second patient was a 70-year-old man, also with severe hemophilia A and FVIII resistance, who was scheduled for cataract surgery. He, too, was given manual infusions before and directly after surgery, then connected to the mini-pump with a regular infusion at increasing dosing intervals over time. Continuous infusion was not given this patient.
His blood clotting potential also stabilized, with no need for additional medications, no reported adverse events, evidence of effective FVIIa levels in his blood, and an overall good clinical outcome.
In addition to checks of device effectiveness, nurses who used the mini-pump were given a questionnaire to assess their experiences. Each of the six nurses who worked the surgical wards during this postoperative period responded.
Overall, these nurses were satisfied with the pump and its impact on real-world practice. Primarily, they reported substantial time savings in the care of these patients, giving them more time for other responsibilities.
“All respondents noted that the mini‐pump allowed the administration schedule for rFVIIa to be followed correctly, without the need to resort to manual injections,” the researchers wrote.
Testing also showed that the FVIIa remained stable and sterile over its days of use.
“These two patients represent a pilot exercise, demonstrating the use and advantages of a mini‐pump protocol in accurately and reliably administering bolus injections of rFVIIa at specified time points in the postoperative setting,” the scientists concluded.
“Furthermore, the study has also shown that the use of an automated bolus dosing device was well accepted by nurses and placed a minimal burden on them in the delivery of care to patients recovering from surgery.”