HAE treatment for preventing swelling attacks wins approval in Canada
Developer already seeking public reimbursement for injection therapy
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Dawnzera (donidalorsen), a preventive therapy used to reduce the risk of swelling attacks in people with hereditary angioedema (HAE), has been approved in Canada for adults and adolescents ages 12 and older.
The decision by Health Canada follows Dawnzera’s approval for the same indication in the U.S. last year and in the European Union earlier this year. The injection therapy was shown in a clinical trial to cut the number of HAE attacks requiring on-demand treatment by as much as 90%.
In Canada, Dawnzera will be marketed by Celystra Pharma, which licensed the therapy’s Canadian rights from its developer Ionis Pharmaceuticals. Celystra said in a company press release that it expects Dawnzera to become commercially available in Canada in the coming months.
“Hereditary angioedema can affect many aspects of daily life, and not knowing when an attack may occur can be difficult for patients and their families,” said Michelle Cooper, president and Ontario regional director of the board of directors of HAE Canada, a patient advocacy organization with a website in English and French, as well as other languages.
“We welcome the approval of Dawnzera as another treatment option for Canadians living with HAE,” Cooper said, noting that “access to new therapies remains an important priority for the HAE community.”
Celystra has already begun seeking public reimbursement through Canada’s Drug Agency. In Quebec, a separate assessment is underway with the Institut national d’excellence en santé et en services sociaux (INESSS), which makes recommendations on whether medications should be covered by the province’s public drug plan.
“With Dawnzera, we are continuing to bring new treatment options to Canadians living with rare diseases,” said Paul Lévesque, Celystra’s president and CEO. “Our next priority is to work with healthcare professionals, governments and the HAE community to help expand access for patients across Canada.”
In trials, Dawnzera cut monthly attack rates by over 80%
In HAE, genetic mutations lead to the excessive production of a signaling molecule called bradykinin. Too much bradykinin makes blood vessels more permeable, allowing fluid to build up in surrounding tissues and trigger recurrent episodes of swelling. These attacks can occur almost anywhere in the body; they can become life-threatening if swelling in the throat blocks the airway.
Dawnzera works by reducing prekallikrein production, a protein precursor of kallikrein, an enzyme involved in bradykinin production. Reducing prekallikrein is expected to prevent bradykinin from reaching excessive levels and, in turn, lower the risk of HAE swelling attacks.
According to its prescribing information, Dawnzera should be administered subcutaneously, or by injection under the skin, at a recommended dose of 80 mg every four or eight weeks. The interval may be extended to every eight weeks for individuals whose HAE is well controlled with treatment. The therapy is supplied in a single-dose, prefilled autoinjector that allows patients or caregivers to give the treatment at home after appropriate training.
Preventing attacks is a key part of managing HAE. … The approval of Dawnzera gives physicians and their patients another important option for preventing attacks and managing HAE over the long term.
Health Canada’s approval was mainly supported by data from the Phase 3 OASIS-HAE clinical trial (NCT05139810), and its ongoing open-label extension, OASISplus (NCT05392114),
OASIS-HAE tested 80 mg Dawnzera against a placebo in 90 adults and adolescents, ages 12 and older, with HAE types 1 or 2 who were experiencing recurrent swelling attacks.
Over about six months, Dawnzera reduced monthly HAE attack rates by 81% when given every four weeks and by 55% when given every eight weeks compared with the placebo.
From the second dose through the end of the study, the reduction with every-four-week dosing reached 87%, while moderate to severe attacks and attacks requiring on-demand treatment were reduced by 90%.
Longer-term data from OASISplus, which enrolled patients who completed OASIS-HAE as well as people who had been receiving other preventive HAE therapies, showed that the benefits were sustained.
After one year, mean HAE attack rates had fallen by more than 90% from the study’s start across patients receiving Dawnzera every four or eight weeks.
Swelling attacks dropped for those switching from other therapies
Among patients who switched from other approved preventive HAE therapies, mean monthly attack rates fell by 62% after about four months of monthly Dawnzera treatment. Most surveyed patients preferred Dawnzera to their previous therapy, citing factors such as better disease control, shorter administration time, and reduced injection site pain or reactions.
“Preventing attacks is a key part of managing HAE,” said Stephen Betschel, MD, a staff clinical immunologist and allergist at St. Michael’s Hospital in Toronto and chair of the Canadian Hereditary Angioedema Network, a physician organization focused on HAE. “The approval of Dawnzera gives physicians and their patients another important option for preventing attacks and managing HAE over the long term.”
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