Bona, Robert

Abstract Intracranial hemorrhage (ICH) and resulting neurologic disability are severe complications for a subset of infants with severe hemophilia A (HA). Although prophylactic factor replacement reduces bleeding risk, it is typically delayed until after age 1 year due to risks associated with central venous access placement. Emicizumab, a subcutaneous activated factor VIII (FVIII) mimetic, has demonstrated safety and efficacy in preventing ICH in infants aged <12 months in the HAVEN 7 trial. Despite its high cost, the cost-effectiveness of emicizumab prophylaxis initiated during the first year of life for infants with severe HA is not known. We developed a Markov cohort model to compare emicizumab prophylaxis to standard care (no prophylaxis) in infants aged 0 to 1 year with severe HA without FVIII inhibitors. The analysis was conducted from a US societal perspective over a lifetime horizon across all accepted willingness-to-pay (WTP) thresholds. The primary outcome was the incremental cost-effectiveness ratio (ICER) in US dollar per quality-adjusted life-year (QALY). Emicizumab prophylaxis and standard care accrued 25.6 and 25.1 QALYs at costs of $13.12 million and $13.07 million, respectively, resulting in an ICER of $99 900 per QALY (95% credible interval [CI], 84 000-120 000). Scenario analysis examining prophylaxis with low-dose emicizumab resulted in an ICER of $19 600 per QALY (95% CI, 12 000-29 000). Probabilistic sensitivity analyses showed that standard-dose emicizumab is the cost-effective strategy in 100%, 66%, and 0% of 10 000 Monte Carlo iterations at WTP thresholds of $150 000, $104 000, and $50 000 per QALY, respectively, and in 100% across all WTP thresholds for low-dose emicizumab.

SummaryWe performed a double-blind, randomized clinical trial to compare the efficacy and safety of three different subcutaneous (SC) low molecular weight heparin doses (ardeparin sodium 25,35, or 50 anti-XaU/kg twice daily [BID]) to adjusted-dose warfarin (international normalized ratio [INR] = 2.0 to 3.0), as venous thromboembolism prophylaxis after total knee replacement surgery. The primary endpoint was total venous thromboembolism prevalence, defined as deep vein thrombosis discovered at postoperative venography of the operated leg, or symptomatic, objectively-documented pulmonary embolism. Of 860 patients randomized, 680 (79%) had an evaluable venogram or pulmonary embolism. The total venous thromboembolism prevalence was significantly greater among patients prophylaxed with warfarin compared to ardeparin 50 BID (38% vs 27%, p = 0.019); the prevalence among ardeparin 25 BID (37%) and 35 BID (28%) patients was similar to warfarin and ardeparin 50 BID patients, respectively. Overt bleeding occurred in 22 (7.9%) ardeparin 50 BID patients compared to 12 (4.4%) warfarin patients (p = 0.08), and in seven ardeparin 25 and 35 BID patients each (5.2% and 5.0%, respectively). Compared to the warfarin group, blood loss was significantly greater in the ardeparin 50 and 25 BID groups, and not different in the ardeparin 35 BID group. Conclusions: Postoperative, unmonitored, fixed-dose ardeparin 50 anti-Xa U/kg SC BID is significantly more effective than adjusted-dose warfarin for this indication. Although overt bleeding among warfarin and ardeparin 50 BID patients did not differ significantly, ardeparin 50 BID patients had significantly greater blood loss. Ardeparin 35 anti-Xa U/kg SC BID may provide efficacy similar to ardeparin 50 anti-Xa U/kg SC BID but with reduced bleeding.