Argenx Has Delivered 18 Consecutive Quarters of Sales Growth -- but Is the Biotech Stock Still Underrated?

To say that Argenx (NASDAQ: ARGX) is growing is an understatement. The drugmaker has delivered an impressive 18 consecutive quarters of revenue growth. Its sales soared 60% year over year in the second quarter of 2026 and 17% sequentially.

Investors have recognized Argenx's success. The biotech stock is handily beating the overall market so far this year and has more than doubled over the last three years. But is Argenx still underrated?

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An even stronger business than the stock chart shows

There's no secret about where Argenx's revenue growth is coming from. The company's Vyvgart and Vyvgart Hytrulo therapies continue to gain momentum in treating severe autoimmune diseases.

Vyvgart is approved in the U.S. for generalized myasthenia gravis (gMG) and in Japan for the treatment of immune thrombocytopenia (ITP). Vyvgart Hytrulo combines Vyvgart with recombinant human hyaluronidase PH20, Halozyme's (NASDAQ: HALO) drug delivery technology. It's also approved for gMG and for chronic inflammatory demyelinating polyneuropathy (CIDP).

But Argenx's top line is only part of the story. The company reported earnings of $472 million in Q2, nearly double its profit from the prior year period. Its operating margins are expanding.

Argenx CFO Karl Gubitz recently told Reuters that rivals in the gMG market were "all behind Vyvgart." Gubitz also noted that only about 20% of gMG patients are currently receiving novel biologics, leaving Argenx with significant room for future growth. Meanwhile, the CIDP market penetration for the Vyvgart franchise is only in its early stages.

An exciting period ahead for Argenx

Argenx recently reported a big clinical win. On Aug, 17, 2026, the company announced positive results from a late-stage study evaluating Vyvgart Hytrulo for the treatment of autoimmune myositis, an autoimmune disease that affects around 100,000 people in the U.S. Management believes this indication represents a multibillion-dollar opportunity.

More good news could be right around the corner. Argenx expects to report results from its Phase 3 study of empasiprubart in the treatment of multifocal motor neuropathy (MMN) in the fourth quarter of 2026. If those results look good, the company will be well-positioned to launch its second "pipeline-in-a-product."

Argenx is scheduled to make four other important announcements next year. It plans to report top-line results from a pivotal study of Vyvgart in treating ITP in the first half of 2027 and from another pivotal study in treating Sjogren's disease in the second half. The company also expects to report results from two studies evaluating empasiprubart in treating CIDP in the second half of 2027.

The recent acquisition of Forte Biosciences adds another promising candidate to Argenx's pipeline, the anti-CD122 antibody FB102. Argenx expects to announce results from a Phase 2 study of the experimental therapy for celiac disease and from a Phase 1b study for alopecia areata before the end of 2026.

The verdict

Is Argenx underrated? The verdict is "yes," according to Wall Street. Of the 23 analysts surveyed by S&P Global (NYSE: SPGI) in August, 20 rated the stock as a "buy" or "strong buy." The other three recommended holding Argenx. The 12-month price target for the stock reflects a potential upside of roughly 14%.

Sure, Argenx looks expensive, with shares trading at 37.5 times forward earnings. However, growth stocks with significant opportunities usually command premium valuations.

Given Vyvgart's expansion opportunities and its promising pipeline, I agree with analysts. Despite its tremendous success, Argenx remains an underrated biotech stock.

Keith Speights has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Argenx Se and S&P Global. The Motley Fool has a disclosure policy.