#ISTH2020 – Unmet Medical Need Found in Mild, Moderate Hemophilia A Care

Adults with mild and moderate hemophilia A have a substantial number of bleeds per year as well as joint problems and surgeries, revealing an unmet medical need in these patients, according to an interim analysis of the CHESS II study.

The findings were shared at the 2020 Virtual Congress of the International Society on Thrombosis and Haemostasis (ISTH), recently held online. The presentation, “An Insight into Clinical Outcomes in Mild, Moderate, and Severe Hemophilia A (HA): A Preliminary Analysis of the CHESS II Study,” was given by Francis Nissen, MD, PhD, a data scientist at Roche. 

Information is limited about the clinical burden for people with hemophilia A across different levels of disease severity. 

The CHESS II (Cost of Haemophilia in Europe: a Socioeconomic Survey-II) study investigated the burden-of-illness in adults with mild, moderate, and severe hemophilia A across eight European countries. 

This study followed the CHESS I study which captured the economic and psychological burden of those with severe hemophilia, and the disease burden in children with moderate to severe disease. 

In CHESS II, researchers analyzed the medical records of hemophilia A patients who had not developed FVIII inhibitors — antibodies that target therapies meant to replace the missing factor VIII clotting factor in patients. Data on bleeding episodes and joint outcomes spanning 12 months were collected. 

Disease severity was determined by the level of FVIII in patients’ blood. Those with mild disease had FVIII levels between 5% and 40%, moderate disease was defined as having 1% to 5%, while people with severe disease had less than 1% FVIII. 

Bleeding data was available for 580 patients, which included 97 with mild disease, 99 with moderate disease, and 284 with severe hemophilia A. Age and body mass index, an indicator of body fat, were similar across all three subgroups. 

The majority of patients with mild disease (71%) did not receive any treatment over the 12-month period. The remaining were given either on-demand FVIII during acute bleeding episodes (27%), or preventive (prophylaxis) treatment (2%). 

In total, about 26% of patients with mild disease had no bleeding episode in the past year, 45% had one bleeding episode, and 39% had two bleeds or more, amounting to an average bleeding rate of 2.12 per year.

Also, 8% of these patients had target joints, meaning they had three or more bleeds in a certain joint in a six-month period, 17% had joint problems (chronically damaged joints), and 7% underwent joint surgery. These results indicated a “potential unmet need in this population,” the researchers wrote.

Among patients with moderate hemophilia A, about 60% did not receive any treatment for their disease, whereas 31% received on-demand treatment, and 9% were on prophylaxis. Despite the large proportion of patients not receiving therapy, these patients had on average 3.06 bleeds per year, with more than half (57%) having experienced two or more bleeding episodes in the past year.

In this group, 23% of patients had a target joint, 39% had joint problems, and 24% underwent joint surgery. 

“The majority of patients with moderate disease experience [two or more] bleeds, which lead to irreversible, long-term joint damage,” said Nissen. 

In the severe hemophilia A group, all patients had received either on-demand treatment (45%) or prophylaxis (55%). The average bleeding rate in this group was 3.91, marginally higher than in moderate cases. About 8% of this group did not experience bleeding in the past year, while more than 70% had two or more bleeds.

Among patients with severe disease, more than 40% had a target joint, over 40% had joint problems, and more than 20% had joint surgery. 

“The proportion of patients with problem joint and the incidence of surgeries to affected joints were similar in patients with moderate and severe HA receiving on-demand treatment indicating the HA may have a similar impact on quality of life in these patients,” according to the presentation for the virtual ISTH congress.

“These data demonstrate that all [people with hemophilia A] experience bleeds regardless of disease severity; they also highlight the unmet need in patients with mild and moderate disease severity,” the investigators concluded. 

The presentation for the congress was an interim analysis of CHESS II. More data reporting on a larger sample will follow, the presenter said.