AbbVie's Rinvoq scores pivotal trial win in eczema. But do dermatologists trust JAK inhibitors?

AbbVie's Rinvoq notched an FDA approval in August to treat rheumatoid arthritis. (AbbVie)

AbbVie has hitched its wagon to promising drug launches in a post-Humira future, not the least of which is next-gen JAK inhibitor Rinvoq. Now, the drug is eyeing a blockbuster entry into atopic dermatitis, also known as eczema, and a pivotal trial win could help it get there.

But with the JAK class's black box warning label, is there really any challenging Sanofi and Regeneron's Dupixent?

AbbVie aims to find out, and in data revealed Thursday, Rinvoq did its part: The med topped placebo at helping patients achieve a 75% reduction in their atopic dermatitis symptoms and clear or almost clear skin after 16 weeks of treatment with either a high or low dose of the drug, the company said.

In the phase 3 Measure Up 1 study, 70% of patients treated with a 15-milligram dose of Rinvoq saw significant improvement in their symptoms compared with just 16% of placebo patients. Forty-two percent of Rinvoq patients achieved clear or mostly clear skin at four months compared with just 8% on placebo.

For the higher dose, the effects were even more dramatic. Eighty percent of patients on the 30-mg dose of Rinvoq saw a 75% reduction in symptoms while 62% of patients saw clear or almost clear skin after four months.

A Dupixent challenger?

Those impressive data from the first of three pivotal atopic dermatitis trials posture Rinvoq well against blockbuster eczema drug Dupixent and challengers from the JAK class. However, Rinvoq's future chances in the market could be capped by lingering safety issues that have turned some dermatologists off the JAK class as a whole.

RELATED: Can Sanofi and Regeneron's Dupixent steal half of a $21B eczema market? Not so fast: analyst

In a note to investors Thursday, SVB Leerink analyst Geoffrey Porges said Rinvoq's newest data could help it secure a place as the standard of care for patients who cannot tolerate or don't respond to biologics like Dupixent. But winning previously untreated patients will be a challenge, Porges said, because of Rinvoq's iffy label.

"Despite the compelling efficacy results (potentially superior to Dupixent) and a consistent safety profile, we expect Rinvoq to capture only limited share in the first-line setting given its class labeling of serious infection, malignancy and thrombosis warnings," Porges wrote. "For most younger patients, Dupixent is still likely to be the first choice given its combined robust efficacy and remarkable safety."

Even so, Porges said three pivotal trial wins in atopic dermatitis and a regulatory green light could still add blockbuster armor to Rinvoq's label; he said the indication could chip in up to $2 billion in peak sales to SVB's forecast of $5 billion per year in peak sales without it.

RELATED: How to get to $11B? For Sanofi and Regeneron's Dupixent, 5 new approvals would help

But Dupixent, with $832 million in first-quarter sales, is also on the move. Thursday, the drug scored an approval in China to treat atopic dermatitis, expanding its marketing range to 60 countries.

And earlier this month, Sanofi and Regeneron laid out its plan to get Dupixent up to $11 billion in annual sales, centered on adding five new indications: chronic obstructive pulmonary disease, eosinophilic esophagitis, prurigo nodularis, chronic spontaneous urticaria—otherwise known as chronic hives—and bullous pemphigoid.

Stacking up against JAK rivals

Challenging Dupixent, the top drug in the market, is one thing, but Rinvoq's latest data may have honed its edge in the JAK inhibitor class. The drug's new data bested Pfizer's next-gen JAK1 inhibitor abrocitinib, potentially forecasting a horse race for the top spot in second-line treatment, Piper analysts said.

But a fight between JAKs might be a hard one for dermatologists to jump in on given their skeptical looks at the class label.

"(Dermatologist) feedback indicates that safety remains a huge concern for the JAK class given the black box warnings," Piper analysts wrote in a note to investors Thursday. "That said, we continue to like the upside for Rinvoq in (rheumatoid arthritis)."

RELATED: Abbvie's Rinvoq matches BMS' Orencia in head-to-head rheumatoid arthritis trial

While its chances might be limited in the growing atopic dermatitis market, Rinvoq still has high hopes as a long-term sales replacement for megablockbuster Humira alongside the recent launch of psoriasis drug Skyrizi. Securing its spot in rheumatoid arthritis is the first step.

Big things on the horizon?

Earlier this month, Rinvoq matched Bristol Myers Squibb's Orencia in easing rheumatoid arthritis patients' symptoms at the 12-week mark and bested its older rival in patient remission rates, according to phase 3 head-to-head data.

Exactly 30% of patients treated with Rinvoq achieved clinical remission at 12 weeks compared with 13.3% of Orencia patients, hitting a key secondary endpoint in AbbVie's Select-Choice trial.

Rinvoq, which nabbed an FDA approval to treat RA in August, posted $86 million in sales in the first quarter and is aiming for not only atopic dermatitis to boost its sales but also psoriatic arthritis.

RELATED: JPM: A Humira-beating $20B in sales from Skyrizi and Rinvoq? It's possible, AbbVie CEO says

In February, Rinvoq topped placebo in reducing the signs and symptoms of psoriatic arthritis at 12 weeks in patients who responded inadequately or couldn't tolerate other non-biologic, disease-modifying anti-rheumatic drugs, AbbVie said. Rinvoq's lower dose matched Humira's psoriatic arthritis data at the 12-week mark, and the newer drug beat out its predecessor's results at the higher dosage.

AbbVie is hoping its newest launches will reach combined megablockbuster status to challenge even Humira's best years.

In January, AbbVie CEO Rick Gonzalez forecast that Skyrizi and Rinvoq combined could reach $20 billion in sales per year with a robust pipeline to match––and even outpace––Humira. The older drug is expected U.S. biosimilar competition in 2023.

That expected sales drop was one of the primary drivers of AbbVie's $63 billion merger with Allergan that closed in May.