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Here's Why Galapagos NV Is Skyrocketing 18.3% Today

Todd Campbell, The Motley Fool

What happened

After the company reported that its oral rheumatoid arthritis drug, filgotinib, successfully met the primary endpoint in the first of three phase 3 trials, shares of Galapagos NV (NASDAQ: GLPG) are soaring 18.3% at 11:45 a.m. EDT on Wednesday. 

So what

After the closing bell yesterday, Galapagos and Gilead Sciences (NASDAQ: GILD), which licensed filgotinib in 2015 for $300 million in up-front cash, plus potential milestones and royalties, unveiled impressive phase 3 data that suggest filgotinib could someday reshape rheumatoid arthritis treatment.

Letters shooting out of a megaphone being held in a person's hand.

IMAGE SOURCE: GETTY IMAGES.

Filgotinib, which keeps immune responses in check by inhibiting the JAK1 enzyme, met the study's primary endpoint by eliciting a statistically significant 20% response at week 12 versus placebo, based on American College of Rheumatology scoring system. 

Non-Responder Imputation

Week 12: Placebo
(n=148)#

Week 12: Filgotinib
100 mg
(n=153) #

Week 12: Filgotinib
200 mg
(n=147) #

Week 24: Placebo
(n=148)#

Week 24: Filgotinib
100 mg
(n=153) #

Week 24: Filgotinib
200 mg
(n=147) #

ACR20 (%) 31.1 57.5*** 66.0*** 34.5 54.9*** 69.4***
ACR50 (%) 14.9 32.0*** 42.9*** 18.9 35.3** 45.6***
ACR70 (%) 6.8 14.4* 21.8*** 8.1 20.3** 32.0***
DAS28 (CRP) ≤ 3.2 (Low disease activity) (%) 15.5 37.3*** 40.8*** 20.9 37.9** 48.3***
DAS28 (CRP) < 2.6 (Clinical remission) (%) 8.1 25.5*** 22.4*** 12.2 26.1** 30.6***

Data source: Gilead Sciences. #Number of patients randomized to each treatment group and who received at least one dose of study drug. ACR20/50/70 represents American College of Rheumatology 20%/50%/70% improvements.* p <0.05, compared to placebo. ** p <0.01, compared to placebo. *** p <0.001, compared to placebo.

As you can see in the preceding table, the 200 mg dose was particularly effective, with 69% of patients achieving a 20% improvement, 46% of patients a 50% improvement, and 32% of patients a 70% improvement at 24 weeks. 

In addition to solid efficacy, filgotinib's safety suggests it can differentiate itself from other treatment options, too. For instance, anti-TNF therapies, such as the over-$18-billion-per-year Humira, may expose patients to infection risks at a higher rate than filgotinib. In filgotinib's trial, there were no "deaths, malignancies, gastrointestinal perforations, or opportunistic infections, including active tuberculosis" observed. Most of the adverse events in filgotinib's trial were "mild or moderate in severity" and the rate of serious events was 3.4% in the placebo group, 5.2% in the filgotinib 100 mg arm, and 4.1% in the filgotinib 200 mg arm. 

Now what

The win helps de-risk one of Gilead Sciences and Galapagos' most important R&D programs; however, there's no guarantee the remaining two phase 3 studies will read out similarly to this one. Results from those ongoing rheumatoid arthritis trials are expected in the first half of 2019. 

If filgotinib's remaining studies also succeed, then Galapagos can collect up to $1.35 billion in total milestone payments from Gilead Sciences, as well as royalties on future sales of between 20% to 30% in America. The two companies will split filgotinib profits in Germany, France, Italy, Spain, the U.K., the Netherlands, Belgium, and Luxembourg.

Filgotinib's also in phase 3 studies for ulcerative colitis and Crohn's disease and Galapagos thinks the RA, ulcerative colitis, and Crohn's disease markets could be worth as much as $49 billion by 2027. Given the size of this addressable market and the trial results reported yesterday, it's little wonder investors are bidding shares higher today.

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Todd Campbell owns shares of Gilead Sciences. His clients may have positions in the companies mentioned. The Motley Fool owns shares of and recommends Gilead Sciences. The Motley Fool has a disclosure policy.