Shares of Belgium-based biotech Galapagos NV soared 25% Friday after the company, together with pharmaceutical giant Gilead Sciences Inc., announced that two Phase 3 trials of their investigational rheumatoid arthritis drug had achieved their primary endpoints.
But what really had Wall Street excited was the drug’s safety profile. Filgotinib is an oral, selective JAK inhibitor, a class of drug that has been dogged by safety concerns. JAK inhibitors, including Eli Lilly & Co’s LLY, +0.36% Olumiant and Pfizer Inc.’s PFE, +0.31% Xeljanz, can have serious side effects, including an increased risk for serious infections, malignancies, and in Olumiant’s case, for cardiovascular events like deep vein thromboses and pulmonary embolisms.
But filgotinib, which Galapagos GLPG, +24.57% is developing with Gilead GILD, +2.57% showed promising safety data, while demonstrating similar effectiveness to competitors.
Gilead shares rallied 2.8% in afternoon trade. Galapagos’ U.S.-listed shares were on track to close at the highest level since September 2018.
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“FINCH 1 & 3 confirm filgotinib’s best-in-class safety profile,” analysts at J.P. Morgan wrote in a note Friday, referring to the two trials by name.
In one trial, researchers looked at filgotinib alone and in combination with methotrexate, a mainstay treatment, in patients who had never been treated with methotrexate before. After 24 weeks, a greater proportion of patients on the combination therapy showed a greater than 20% improvement in the number of tender and swollen joints (a measure called ACR20, which was the trial’s primary endpoint) than those on methotrexate alone.
In another trial, researchers looked at how two different doses of filgotinib held up against AbbVie Inc.’s ABBV, +0.81% top-selling Humira or methotrexate. This time, patients enrolled in the trial were already being treated with methotrexate, but had not responded adequately to the drug.
After 12 weeks, the proportion of patients who got to ACR20 was higher in the filgotinib group than in the methotrexate group. However, by most measures, patients on filgotinib did not show statistically significant improvement compared with those on with Humira. The exception: A greater proportion of patients on filgotinib achieved clinical remission than those on Humira.
What really caught Wall Street’s eye was filgotinib’s safety data. Data from three Phase 3 studies showed that among patients who were already receiving methotrexate, 1.5% of those who were given the higher dose of filgotinib had serious infections as a side effect, compared with 2.5% of those given Humira. And none of the patients on the higher dose of filgotinib had malignances, compared with 0.3% of those on Humira.
Filgotinib's safety profile is important to investors. There are other JAK inhibitors on the market, and the Food and Drug administration is reviewing a new drug application that AbbVie submitted in December for its own JAK inhibitor called upadacitinib. It’s what could set it apart from the others.
“Since filgotinib is likely to be the fourth JAKi to market, a clean safety profile could help drive use,” said analysts at Jefferies in a Friday note.
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Some analysts were excited about how filgotinib’s safety data compared with that of AbbVie’s upadacitinib. The Gilead and Galapagos trials did not directly compare filgotinib with upadacitinib, but analysts at J.P. Morgan said they thought filgotinib’s safety data looked stronger, especially when it came to deep vein thromboses and pulmonary embolisms.
However, unlike filgotinib, upadacitinib did show better efficacy than Humira on several measures, “which could be a slight marketing disadvantage for filgotinib,” J.P. Morgan analysts wrote.
Filgotinib’s trial results come at a time when Gilead, amid sliding hepatitis C drug sales, is looking for new ways to expand its business. Shares of the pharmaceutical giant have fallen 13% in the past 12 months, while the S&P 500 SPX, +0.47% has gained 7%. Shares of Galapagos have gained 19%.
