CSL Behring's Hemgenix, the world's most expensive gene therapy with a single-dose cost of $3.5 million (4.67 billion won) for hemophilia B, may enter Korea soon, a local news report said.

Daily Pharm Korea reported on Friday that the Ministry of Food and Drug Safety (MFDS) completed its review of Hemgenix's safety and efficacy, following an application by CSL Behring Korea.

This review typically precedes formal approval, suggesting that this groundbreaking treatment may soon be available to Korean patients.

Hemophilia B is a rare genetic bleeding disorder affecting approximately 1 in 10,000 people. It's caused by a deficiency in blood clotting factor IX due to a mutation on the X chromosome.

Traditional treatments involve regular infusions of clotting factors or plasma products to temporarily control bleeding and require the patient to receive treatment throughout their lifetime.

Hemgenix is designed to be administered directly into the bloodstream, using AAV5 to deliver FIX-Padua, a replica of the mutated blood coagulation factor IX.

This process generates a blood coagulation factor IX with five to eight times higher activity, significantly reducing the risk of abnormal bleeding in patients with Hemophilia B.

The primary study for Hemgenix was the HOPE-B trial, which involved 54 patients with moderate to severe Hemophilia B.

The results were promising. Hemgenix demonstrated 38.6 percent mean Factor IX activity levels sustained at three years, 64 percent reduction in annual bleed rate (ABR) versus routine Factor IX prophylaxis in the lead-in period, and 94 percent of patients discontinued Factor IX prophylaxis and remained prophylaxis-free three years post-treatment.

Notably, between seven and 18 months after Hemgenix administration, the annual bleeding rate decreased by 54 percent compared to patients who received plasma products containing blood coagulation factor IX, meeting the primary endpoint of the study.

Hemgenix received U.S. FDA approval in 2022. In Korea, it was designated as an orphan drug in October 2023, setting the stage for its potential approval and market entry.

While the treatment's efficacy is promising, its price tag of $3.5 million per dose makes it the most expensive drug in the world. This raises important questions about accessibility and reimbursement policies, especially in the context of Korea's national health insurance system.

The global rollout of Hemgenix has been gradual.

While coverage detail in the U.S. is not clear, CSL Behring stated in 2023 that health insurance providers covering nearly two-thirds of the U.S. population have established clear policies regarding if and how the gene therapy will be covered.

"Discussions between CSL Behring and the payer community on the value proposition offered for Hemgenix have been positive, which is reflected in the policies that have been written," said Bob Lojewski, Senior Vice President and General Manager, North America, CSL Behring. "As of May 2023, payers covering roughly 60 percent of the U.S. population have established clear medical policies covering Hemgenix."

For those who have not yet established policies, the company anticipates that coverage decisions for Hemgenix will be reviewed on a case-by-case basis, he added.

In the EU, following approval in February 2023, the first treatments in Europe were administered in July 2024.

In France, two patients received the treatment through the Direct Access program, which provides temporary coverage for innovative drugs before formal reimbursement decisions are made. The slow pace of reimbursement approval is evident, with the first treatments occurring a year and a half after initial approval.

Among Nordic countries, Denmark has successfully included Hemgenix in its reimbursement system, and the U.K. has approved reimbursement under a Managed Access Agreement.

In Canada, the Canadian Drug Expert Committee (CDEC) of the Canadian Agency for Drugs and Technologies in Health (CADTH) has recommended cost support for Hemgenix.