UCB is on an approval roll. Within hours of each other, the Brussels-based company has scored FDA green lights for plaque psoriasis treatment Bimzelx and for generalized myasthenia gravis (gMG) drug Zilbrysq.
Not only that, the Zilbrysq endorsement is UCB’s second in the indication this year, coming on top of the FDA signing off on Rystiggo in June.
The thumbs-up for Zilbrysq is for adults with gMG who are anti-acetylcholine receptor (AChR) antibody-positive. The medicine becomes the first once-daily, subcutaneous gMG-targeted therapy that can be self-administered, according to UCB.
The company acquired the drug in a $2.5 billion buyout of Ra Pharmaceuticals in 2019, paying more than a 100% premium to gain what it believed was a potential blockbuster.
Zilbrysq and Rystiggo have different mechanisms of action. While the peptide Zilbrysq is a targeted C5 inhibitor, Rystiggo is a subcutaneously infused monoclonal antibody that targets the neonatal Fc receptor.
Rystiggo was the first treatment endorsed for the two primary subsets of the disorder—those who are AChR antibody-positive or anti-muscle-specific tyrosine kinase antibody-positive.
“There's a lot of synergies between these two components which is a reason why we made the Ra acquisition," UCB's CEO Jean-Christophe Tellier said in an interview with Fierce Pharma. "We did these acquisitions exactly for this purpose—having an additional tool in our toolbox, providing synergies and complementary actions."
In those with gMG, pathogenic immunoglobulin G autoantibodies destroy the communication between nerves and muscles. The disorder can cause life-threatening weakness of muscles that control breathing, swallowing, chewing and talking.
It can strike anyone at any age but is more frequently seen in young women and men aged 50 and older. Double vision and drooping eyelids are common initial symptoms.
“Until now, people living with gMG have only had access to C5 therapy intravenously, which can be inconvenient and time-consuming,” Iris Loew-Friedrich, Ph.D., chief medical officer at UCB, said in a release.
The approval was based on results from the phase 3, placebo-controlled RAISE study that showed Zilbrysq provided significant benefits as reported by clinicians and patients who received the treatment for 12 weeks.
Zilbrysq’s label contains a boxed warning stating that usage can affect a patient’s ability to fight some infections, including those that are meningococcal, which are life-threatening when not treated early. The most common side effects from the trial were diarrhea, upper respiratory tract infection and injection site reactions.
Zilbrysq inhibits damage to the neuromuscular junction and can be used along with intravenous immunoglobin and plasma exchange, UCB said.
The company did not reveal what it will charge for Zilbrysq. Tellier said that the company hopes to bring it to market by the end of 2023 at "competitive pricing to existing complement inhibitors" in the indication. UCB's list price for Rystiggo comes to $6,050 per vial.
There is formidable competition in the gMG space as AstraZeneca won approval for Ultomiris in the indication last year. In June of this year, Argenx gained an FDA nod for Vyvgart Hytrulo.
Aside from the Zilbrysq nod, UCB also just won an FDA nod for its highly anticipated psoriasis drug Bimzelx. The company expects that medicine to become a blockbuster.