This Fund Has a $200 Million Bet on a Biotech Stock Up 30% in Days After Phase 3 Breakthrough

On February 17, 2026, Driehaus Capital Management disclosed a buy of Xenon Pharmaceuticals (XENE 0.02%), adding 369,577 shares in an estimated $15.52 million trade based on quarterly average pricing.

What happened

According to an SEC filing dated February 17, 2026, Driehaus Capital Management increased its position in Xenon Pharmaceuticals by 369,577 shares during the calendar fourth quarter ended December 31, 2025. The estimated value of the trade was $15.52 million, calculated using the quarter’s average share price. The total value of the position at quarter-end rose by $36.03 million, reflecting both the increased stake and the impact of market price changes.

What else to know

• The fund’s purchase brings its Xenon Pharmaceuticals stake to 1.4% of 13F reportable assets under management.
• Top holdings after the filing:
  • NYSE:TSM: $657.49 million (4.5% of AUM)
  • NASDAQ:CRNX: $297.35 million (2.0% of AUM)
  • NASDAQ: PRAX: $275.01 million (1.9% of AUM)
  • NASDAQ:GH: $218.91 million (1.5% of AUM)
  • NASDAQ:XENE: $203.42 million (1.4% of AUM)
• As of Friday, XENE shares were priced at $58.33, up 66% over the past year and well outperforming the S&P 500’s roughly 19% gain in the same period.

Company overview

Company snapshot

• Xenon Pharmaceuticals develops clinical-stage therapeutics targeting neurological disorders, with a pipeline that includes XEN496, XEN1101, NBI-921352, and XEN007.
• The firm operates a biopharmaceutical business model focused on research and development, advancing drug candidates through clinical trials, and leveraging strategic collaborations for co-development and commercialization.
• It serves patients with neurological and epileptic disorders, developing treatments for these conditions primarily in Canada.

Xenon Pharmaceuticals is a clinical-stage biotechnology company specializing in the development of novel therapeutics for neurological conditions. The company’s strategy centers on advancing a robust pipeline of potassium and sodium channel modulators through late-stage clinical trials, supported by collaborations with leading industry partners. Xenon’s focus on differentiated, first-in-class treatments positions it to address significant unmet medical needs in epilepsy and related disorders.

What this transaction means for investors

Xenon’s lead drug candidate, azetukalner, recently announced strong Phase 3 data in focal onset seizures, one of the most common forms of epilepsy. Patients receiving the higher dose saw seizures fall by a median 53.2% compared with about 10.4% for placebo, while more than half of treated patients achieved at least a 50% reduction in seizure frequency, the firm announced earlier this week.

Those results move the program closer to commercialization, with the company planning to file for U.S. regulatory approval later this year. The data also arrived alongside a large $747.5 million public offering that significantly strengthens Xenon’s balance sheet and will help fund commercialization efforts and pipeline expansion.

The market’s response has been swift. Shares have surged more than 30% in the days following the trial results and financing, pushing the stock up about 66% over the past year.

Meanwhile, within the broader portfolio, the position fits alongside other neuroscience-focused bets such as Crinetics Pharmaceuticals and Praxis Precision Medicines. With this recent momentum, Xenon might be among the standouts.