PNH treatment ruxoprubart granted FDA orphan drug status

NovelMed therapy aims to control disease with lower infection risk

Marisa Wexler MS avatar

by Marisa Wexler MS |

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The U.S. Food and Drug Administration (FDA) has granted orphan drug status to ruxoprubart, an experimental treatment for paroxysmal nocturnal hemoglobinuria (PNH) that’s now in Phase 2 clinical testing.

The drug is designed to control the genetic disease while posing a lower infection risk than currently available treatments.

Orphan drug status is awarded by the FDA to treatments that have the potential to meaningfully improve medical care for rare disorders, defined in the U.S. as conditions affecting fewer than 200,000 people.

The idea is to incentivize pharmaceutical companies to invest in developing treatments for rare diseases by giving financial and regulatory advantages to their developers. Orphan drugs that win approval in the U.S. are guaranteed seven years of market exclusivity without competition from generics or other formulations.

“We are delighted by the FDA’s decision to grant orphan drug designation to ruxoprubart, underscoring the pressing need for innovative therapeutic solutions for patients with PNH,” Robert Bard, vice president of regulatory affairs at NovelMed, ruxoprubart’s developer, said in a company press release.

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NovelMed’s PNH antibody therapy NM8074 now called ruxoprubart

Targeting one pathway to lower infection risk

PNH is caused by mutations that occur spontaneously in the stem cells responsible for giving rise to new blood cells. These mutations cause blood cells to be produced without certain surface markers that are needed for the immune system to recognize them as healthy parts of the body. As a result, a part of the immune system called the complement cascade becomes abnormally activated and destroys blood cells.

The complement cascade can be activated by one of two main molecular pathways: the classical pathway or the alternative pathway. In PNH, blood cell destruction is mainly driven by the activation of the alternative complement pathway.

Available treatments for PNH generally block both pathways, which can be effective for controlling the disease. But that also means the complement system isn’t able to do its  job of defending the body against infections, which can lead to a series of safety risks.

Ruxoprubart, previously known as NM8074, is designed to exclusively block the alternative pathway, with the goal of controlling PNH while allowing the classical pathway to function.

NovelMed said the FDA’s decision to name the therapy an orphan drug “marks a significant advancement in the therapeutic landscape, with Ruxoprubart’s unique ability to selectively block the alternative pathway while preserving the classical pathway required for clearing infections in PNH patients.”

The company is conducting a pair of Phase 2 clinical trials — NCT05731050 and NCT05646563 — designed to test ruxoprubart in PNH patients who have previously been on Soliris (eculizumab), the first complement-blocking therapy to win approval for PNH. NovelMed is also sponsoring a Phase 2 trial (NCT05646524) to assess the safety and efficacy of ruxoprubart in adults with PNH who have never received treatment with a complement inhibitor.

Ruxoprubart also is being investigated as a potential treatment for other complement-driven disorders, including atypical hemolytic uremic syndrome (aHUS), and ANCA vasculitis (AAV).