MIRM, INCY Stocks In Focus — Will A September 26 FDA Ruling Reward This Week’s Gains?

• The FDA’s target date is nine days away, but a decision could be announced prior to that as well.
• Zilurgisertib is meant to quiet ALK2, a signal that is overactive in fibrodysplasia ossificans progressiva, or FOP.
• Ipsen’s Sohonos, approved in 2023, is already on the U.S. market.

Shares of Incyte (INCY) have climbed this week, and Mirum Pharmaceuticals (MIRM) has bounced off a midweek low, as investors line up for a September 26 Food and Drug Administration (FDA) decision on zilurgisertib, a once-a-day pill for an ultra-rare bone disease.

Incyte finished at $127.62, up 2.3% on the day and about 5% from last Friday. Mirum closed at $98.82 after climbing 1.5% on Thursday and 3.7% on Wednesday, recovering from a midweek slide rather than posting a clean week-long run.

The FDA’s target date is nine days away, but a decision could be announced prior to that as well.

What The Agency Is Reviewing

Zilurgisertib is meant to quiet ALK2, a signal that is overactive in fibrodysplasia ossificans progressiva, or FOP. In that disease, muscle and other soft tissue gradually harden into bone, stiffening joints and limiting movement. Roughly 300 people in the United States and about 900 worldwide have a diagnosis.

Regulators are reviewing a first-time application for patients 12 and older on a shortened priority clock. Mirum took global rights from Incyte in the spring, paying $16 million upfront. Incyte can still collect extra milestone checks and royalties in the mid- to high-single digits if sales follow.

Ipsen’s Sohonos, approved in 2023, is already on the U.S. market. Regeneron’s garetosmab (Pasatru) was granted approval in August for the same indication. An approval would still give Mirum a fourth commercial product and a royalty stream for Incyte.

What The Study Showed

The filing rests on the first group in the mid-stage PROGRESS trial. Sixty-three teens and adults took a 100 mg daily pill or a dummy tablet for 24 weeks. One person on the drug formed a new extra bone growth (3.1%), versus five on placebo (16.7%). That 81% drop missed the usual statistical cutoff. A second measure was clearer: the total size of new growths fell by more than 99% versus placebo.

Patients who started on placebo then switched to the drug. By week 48, follow-up scans showed no new growths, and existing volume kept shrinking.

Leerink said in June that the volume result may still be enough for a September 26 approval even though the main count missed.

How Did INCY, MIRM Retail Traders React?

On Stocktwits, retail sentiment around MIRM was ‘bullish’ at the time of writing, while sentiment around INCY was ‘neutral.’

While MIRM stock has gained 25% year-to-date, INCY has added 29%. 

Read More: RARE Stock Jumps 13% — Extends Gains After-Hours As FDA Clears First Sanfilippo Gene Therapy

For updates and corrections, email newsroom[at]stocktwits[dot]com.