10 Best Biotech Stocks to Buy Under $10

4. Ardelyx, Inc. (NASDAQ:ARDX)

Number of Hedge Fund Holders: 27 

Share Price: $5.99 

Ardelyx, Inc. (NASDAQ:ARDX) stands fourth on our list among the best biotech stocks. It is a biopharmaceutical company developing therapies for gastrointestinal and cardiorenal diseases, with FDA-approved treatments IBSRELA (tenapanor) for IBS-C and XPHOZAH (tenapanor) for hyperphosphatemia in dialysis patients. The company has established itself as a promising small-cap biotech with strong commercial traction.

Ardelyx, Inc. (NASDAQ:ARDX) reported record prescription volumes and net sales growth in Q2 2025, with revenues reaching $97.7 million, surpassing expectations. IBSRELA sales increased 57% year-over-year in Q1, and XPHOZAH also showed strong growth. The firm raised its 2025 sales guidance for IBSRELA to $250–$260 million, reflecting robust market uptake and physician adoption. This momentum supports investor confidence and positions the company for sustainable revenue growth.

The corporation strengthened its leadership team with executive appointments, including Edward Conner as Chief Medical Officer and John Bishop as Chief Technology and Operating Officer, signaling readiness to accelerate development and commercialization. The company also pursues international expansion through partnerships, such as with Kyowa Kirin, to broaden tenapanor’s global reach.

While growth is currently driven by IBSRELA and XPHOZAH, Ardelyx, Inc. (NASDAQ:ARDX) continues to invest in R&D to address unmet medical needs in gastrointestinal and related conditions.