Argenx stock surged Wednesday after Amgen presented "underwhelming" results for a potential competitor to Vyvgart in an autoimmune disease.
The latter is trying to break into the generalized myasthenia gravis, or gMG, market with a drug called Uplizna. This neuromuscular disease causes muscles weakness and fatigue. Argenx's Vyvgart is one of the most successful gMG treatments.
After 26 weeks of treatment with Uplizna, gMG patients showed a 1.9-point improvement over placebo recipients on a 24-point scale measuring the severity of myasthenia gravis symptoms. But that paled in comparison to the 5.2-point improvement shown in Vyvgart studies, Leerink Partners analyst David Risinger said in a client note.
Another Leerink analyst, Thomas Smith, says Amgen's results remove an overhang for companies like Argenx, Immunovant, Kyverna Therapeutics and Cartesian Therapeutics. All four are working in the gMG space.
"Overall, we view the top-line (study called Mint) data from Uplizna as underwhelming, and see incrementally positive read-through for Argenx, Immunovant, Kyverna, and Cartesian in our coverage, based on the removal of a key competitive clinical data overhang and potential commercial implications," Smith said in a report.
On today's stock market, Argenx stock jumped 5.6% to 549.01. Immunovant sank 1.3%, while Cartesian stock edged 2% higher. Kyverna shares, on the other hand, fell 6.3%. Amgen stock toppled 5.5% to 312.86.
Argenx Stock: Taking On The King
Vyvgart is Argenx's bread-and-butter drug. Its sales more than doubled last year, hitting $1.19 billion. That's partially because Argenx continues adding onto the approved uses for Vyvgart, and because it's available for some conditions as an under-the-skin shot vs. an intravenous infusion.
Amgen tested Uplizna — which has approval to treat an eye condition — as an infusion every six months. In comparison, Vyvgart is given weekly or every other week.
But there are key ways Amgen could muscle into the gMG market, analysts said.
Vyvgart has approval for patients with gMG who test positive for anti-acetylcholine receptor antibodies, also known as AChR. Amgen tested Uplizna in that population as well as patients who tested positive for anti-muscle-specific kinase antibodies, or MuSK.
RBC Capital Markets analyst Gregory Renza says Amgen could win approval to treat both types of patients. Though, Leerink's Risinger noted the MuSK positive group is far smaller than the AChR positive population.
"Given that Vyvgart is approved only in AChR positive gMG (where we still see room for Uplizna), the MuSK population lies ahead as a notable commercial opportunity for the franchise," Renza said in a report to clients.
He has an outperform rating on Amgen stock, but didn't list a rating for Argenx stock.
Up To 45% Of The Market Available
Piper Sandler analyst Christopher Raymond says Amgen could take on "the king," Vyvgart, by going after patients who don't respond to it. Based on Argenx's data, some 30% of patients don't respond to Vyvgart. Adding to that, about 15% of patients are not AChR positive.
"We think 40% to 45% of the 80,000 to 100,000 U.S. gMG patients could be candidates for Uplizna therapy," he said. At $400,000 a year, "this could easily become a $1 billion revenue contributor."
He has a buy rating on Amgen stock, but didn't list an Argenx stock rating.
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