Groundbreaking gene therapies in store for hemophilia

Hemophilia is an inherited bleeding disorder that prevents a person’s blood from clotting properly and is caused by a mutation in the genes. The most common types of hemophilia are hemophilia A (lack of clotting factor VIII) and hemophilia B (lack of clotting factor IX).

Hemophilia predominantly affects males and according to the CDC, 20,000 Americans have it.

Blankenship

“Although the population of patients with hemophilia is small, cost of treatment for an individual patient can be extremely high, from tens of thousands of dollars for each monthly prescription to over a million dollars per year,” says Crystal Blankenship, PharmD, senior clinical consultant for Accredo specialty pharmacy’s bleeding disorders therapeutic resource center.

The CDC estimates that about 15% to 20% of patients with hemophilia develop inhibitors that prevent treatments from working, further complicating therapy.

Current treatments

Current treatments include both recombinant and plasma-derived direct factor replacements that require intravenous administration, says Blankenship.

Market leaders for hemophilia A include:

• Advate (antihemophilic factor [recombinant])

• Eloctate (zntihemophilic factor [recombinant], Fc fusion protein)

• Humate-P (antihemophilic factor/von Willebrand factor complex [human])

• Adynovate (antihemophilic factor [recombinant], PEGylated)

• Novoeight (antihemophilic factor [recombinant])

• Kovaltry (antihemophilic factor [recombinant])

BeneFix, a recombinant factor IX treatment, is the market leader in the hemophilia B space. Other commonly used factor IX products include:

• Idelvion (coagulation factor IX [recombinant], albumin fusion protein [rFIX-FP])

• Alprolix (coagulation factor IX [recombinant], FC fusion protein)

• Mononine (coagulation factor IX)

• Ixinity (coagulation factor IX [recombinant])

Next: New and emerging therapies

For patients who develop inhibitors expensive clotting factor bypassing agents, such as Feiba (anti-inhibitor coagulant complex) or NovoSeven RT (coagulation factor VIIa [recombinant]), may be needed, says Haita Makanji, vice president, clinical specialty solutions at Magellan Rx Management.

The newest market entry, Hemlibra (emicizumab-kxwh), used to prophylactically manage patients with inhibitors, marks the first weekly subcutaneous option. It is indicated for patients who have hemophilia A with inhibitors.

Seagle

“Due to the highly precise calculations, significant prescriber time is required to evaluate the patient’s current clinical state and the severity of their deficiency,” says Jennifer Seagle, PharmD, area clinical manager for CompleteRx. “When you add in ongoing lab monitoring, pharmacy and infusion clinic time, the current treatments in place result in significant direct medical costs, with approximately 80% of those costs covering the medication alone.”

New and emerging therapies

“Hemophilia has had an extremely active pipeline of treatments in recent years,  “The immediate pipeline includes additional extended half-life products and products that will affect the treatment landscape for patients who develop inhibitors.”

Specific agents in the immediate pipeline include damoctocog alfa pegol and eptacog beta, according to Makanji. Both products are administered via intravenous infusion.

Damoctocog alfa pegol is an extended half-life factor VIII product that uses site-specific PEGylation technology. “Once approved, it will be the first factor VIII product that may be dosed up to once every seven days,” says Makanji.

The main benefits could be fewer infusions and potentially fewer bleeding episodes, says Seagle, adding that it may be more costly.  

Makanji

Eptacog beta is an innovative recombinant form of human Factor VIIa.

“It is anticipated that this new product, in large part due to the technology being used (rPRO Technology), could be a more cost-effective treatment for patients with inhibitors, but the scale of these savings will be difficult to gauge until it is formally released to the public,” says Seagle.

If approved, it will be used for management of congenital hemophilia A or B in adolescents and adults with inhibitors as a bypassing agent.

Seagle says new gene therapy products are expected to be introduced in the next few years, enabling the patient to produce their own clotting factors, and to maintain the factors the patient already has.

Additional agents with new mechanisms of action and administration are also being developed. Fitusiran (ALN-AT3SC) is an RNA interference agent in clinical trials for patients with hemophilia A and B with or without inhibitors. If approved, it will be the second subcutaneous injectable therapy, similar to Hemlibra.