Xenon and Sionna Fall While Inverse Crypto ETFs Sink

Font: Financial Modeling Prep  • Sep 18, 2026

• Xenon Pharmaceuticals Inc. (NASDAQ: XENE) declined after pausing enrollment in depression studies over safety concerns.
• Sionna Therapeutics, Inc. (NASDAQ: SION) remained volatile following a clinical setback and restructuring.
• Inverse crypto ETFs fell as Strategy, Coinbase, and Ethereum rallied sharply.

Xenon Pharmaceuticals Inc. (NASDAQ: XENE) dropped 30.71% to $39.75 after temporarily pausing new enrollment in studies of azetukalner for major depressive disorder and bipolar depression. The decision followed reports of neurological and psychiatric side effects. Xenon said its epilepsy program remains unaffected. 

Sionna Therapeutics, Inc. (NASDAQ: SION) fell 17.27% to $5.96. The stock remains under pressure after its SION-719 cystic-fibrosis study failed to meet a key endpoint in August. The company later discontinued that program and announced a restructuring affecting approximately 46% of its workforce. A law firm’s investor investigation followed the clinical setback and should not be presented as the primary cause of the decline.

Inverse crypto ETFs also posted substantial losses. The Defiance Daily Target 2X Short MSTR ETF (NASDAQ: SMST) fell 32.56%, the GraniteShares 2x Short COIN Daily ETF (NASDAQ: CONI) declined 23.50%, and the ProShares UltraShort Ether ETF (NYSE Arca: ETHD) lost 15.98%.

These funds target approximately twice the inverse daily performance of Strategy Inc. (NASDAQ: MSTR), Coinbase Global, Inc. (NASDAQ: COIN), and Ethereum, respectively. Their losses reflected strong one-day gains in the underlying assets rather than broad market weakness. U.S. indexes finished mixed, with the S&P 500 and Nasdaq slightly higher.