Key Highlights

  • Zura Bio (NASDAQ:ZURA) shed roughly 76% once its hidradenitis suppurativa study failed to meet the primary and key secondary goals at both tested doses.
  • Faeth Therapeutics dropped 42.5% after early endometrial cancer findings, while Janux gave up about a quarter of its worth following a first healthy volunteer readout.
  • Acadia slid 22.28% to a 52-week trough on its Earnings day, and no single trigger was spelled out for the decline.
  • Arrowhead lost 15.4% without any company announcement, in the wake of a rival trimming its projection for a competing medicine.

1. Zura Bio (NASDAQ:ZURA)

On November 9, 2026 Zura Bio (NASDAQ:ZURA) dropped roughly 76% to around USD 0.97, having dipped to an intraday low of USD 0.93 and being on course for its heaviest single-session loss. The reason is stark: the Phase 2 TibuSHIELD study of tibulizumab, enrolling 247 people with moderate-to-severe hidradenitis suppurativa, did not hit its main endpoint or the key secondary endpoints at either dose. Development in that indication has been stopped, and attention moves to systemic sclerosis and polymyalgia rheumatica. The Balance Sheet still offers USD 187.7 million as of September 30, 2026, which the company says will cover operations through at least 2028. With its lead indication gone, a systemic sclerosis readout slated for the first half of 2027 is now the main path toward any further gains.

2. Faeth Therapeutics (NASDAQ:FTH)

Faeth Therapeutics (NASDAQ:FTH) finished the session 42.5% lower on November 9, among the sharpest slides in the US market that day, even as the S&P 500 climbed about 2.4%. The catalyst was preliminary Phase 2 PIK-201 results for its PIKTOR combined with paclitaxel in advanced endometrial cancer. Confirmed objective response reached 33% among 36 evaluable participants, disease control hit 83%, and median progression-free survival stood at 7.4 months. Those with PIK3CA mutations responded 44% of the time. Grade 3 or worse treatment-related neutropenia appeared in 26% of patients, and just two of 42 discontinued because of side effects. These results do not amount to a failure, yet investors plainly wanted more, and how long the responses last has not been disclosed. It is a sensible early dataset that disappointed because investor hopes ran ahead of the data.

3. Janux Therapeutics (NASDAQ:JANX)

Janux Therapeutics (NASDAQ:JANX) gave up about a quarter of its value on November 9, after debuting first Phase 1 numbers for JANX011 from healthy volunteers. The stock had closed at USD 16.06 before the release. In participants receiving a single 3 mg dose, peripheral B-cell depletion exceeded 90% in three of five people at that level, and the reductions persisted through Day 42. Tolerability looked good, since every cytokine release syndrome event was Grade 1, and no serious adverse events or dose-limiting toxicities emerged among 25 participants spread over five dose cohorts. The selloff hints that shareholders hoped for deeper depletion across a larger share of volunteers, as only three of five reacted strongly at the highest dose. Time remains on Janux's side: it holds USD 945.7 million in cash and short-term investments, an ITP trial is due by the first half of 2027, and a rheumatoid arthritis trial comes during the back half of the year.

4. Acadia Pharmaceuticals (NASDAQ:ACAD)

Acadia Pharmaceuticals (NASDAQ:ACAD) sank 22.28% to a 52-week trough on November 9, the same day it posted third-quarter figures. No specific trigger was spelled out. Certain commentary tied the slide to remlifanserin, yet the Phase 2 setback for that compound in Alzheimer's disease psychosis was disclosed on September 24, 2026, which makes it older background instead of fresh information. In that trial the 60 mg dose fell short of statistical significance on the main measure, though the company intends to run a Phase 3 study at that dose. The quarter appeared sound based on limited figures: Revenue of around USD 342 million beat roughly USD 332.4 million in estimates, and the 2026 revenue forecast was narrowed to USD 1.265 billion through USD 1.295 billion. A steep drop on a results day with no clear reason keeps the shares open to further news in either direction.

5. Arrowhead Pharmaceuticals (NASDAQ:ARWR)

Arrowhead Pharmaceuticals (NASDAQ:ARWR) lost 15.4%, or USD 8.95, closing at USD 49.21 on November 9 versus USD 58.16 on November 6, with trading Volume close to twice the norm. No price-sensitive release came from the company. Two possibilities were discussed. Ionis Pharmaceuticals dropped roughly 27% after lowering its full-year outlook for Tryngolza, a product that rivals Arrowhead's plozasiran, marketed as Redemplo, for very high triglycerides, so a softer market view for one drug can weigh on both. The other is pooled Phase 3 results released on November 7 that showed a 78% cut in acute pancreatitis events, though glycemic control worsened in 14% of treated patients versus 8.7% on placebo. Neither has been confirmed as the trigger. The next checkpoint is Arrowhead's fiscal 2026 report on November 12, where early Redemplo sales will be scrutinized.

Where Things Stand

Causes behind these five November 9 biotech declines, which ran from 15.4% to about 76%, range from a clear trial miss to no company news whatsoever. Zura Bio's study failed at both doses. Faeth and Janux slid after early readouts that looked encouraging on paper yet landed under expectations. Acadia's 22.28% fall coincided with its results release and no clear cause, while Arrowhead's slide was linked to a rival's forecast cut and a glycemic signal, neither confirmed. The takeaway is that these shares dropped hard on a strong market session, so company-specific data counted for much more than the wider rally.