Ardelyx Charts Aggressive 50%+ Growth Path for IBSRELA as Phosphorus Treatment Faces Headwinds

Ardelyx Inc. (ARDX) has laid out an ambitious expansion blueprint, forecasting IBSRELA sales to surge between $410 million and $430 million in 2026—a leap of at least 50% from the prior year’s results. The announcement reflects the biotech firm’s confidence in its flagship irritable bowel syndrome with constipation (IBS-C) therapy, which posted a breakout 2025 performance.

Blockbuster Year for IBS-C Therapy Overshadows Phosphorus Drug Decline

IBSRELA delivered exceptional momentum throughout 2025, accumulating $274 million in annual sales compared to $158.3 million in 2024, marking a striking 73% year-over-year surge. The fourth quarter alone netted $87 million versus $53.8 million in the same period last year, underscoring sustained market demand for the first-in-class treatment.

The company’s second major asset, XPHOZAH—which functions to reduce serum phosphorus levels in dialysis patients with chronic kidney disease—encountered significant headwinds. The phosphorus-reducing therapy generated $104 million across 2025, declining sharply from $160.9 million the previous year, primarily attributed to the loss of Medicare Part D coverage. Q4 2025 sales plummeted to $28 million from $57.2 million year-over-year, reflecting ongoing access challenges.

Financial Foundation Supports Expansion

Despite XPHOZAH’s setback, Ardelyx’s combined product portfolio drove overall 2025 revenue growth of 18%. The company concluded the year with $265 million in cash and investments—capital reserves the firm plans to deploy toward commercial acceleration and pipeline advancement.

Looking beyond 2026, Ardelyx has committed to achieving $1 billion in IBSRELA revenue by 2029, establishing an ambitious long-term growth anchor. XPHOZAH is projected to generate between $110 million and $120 million in 2026, suggesting relative stabilization following the coverage transition.

Pipeline Momentum and IP Fortification

The biotech has initiated a Phase 3 trial evaluating IBSRELA’s potential in chronic idiopathic constipation, with trial completion anticipated in H2 2027. Simultaneously, Ardelyx is advancing RDX10531, a next-generation sodium/hydrogen exchanger 3 (NHE3) inhibitor, signaling broadened therapeutic ambitions.

The company also secured new patent allowances extending intellectual property coverage for both IBSRELA and XPHOZAH through December 2041, providing extended market exclusivity protection.

Market Positioning and Stock Movement

CEO Mike Raab emphasized that Ardelyx’s 2025 execution has positioned the organization for “durable growth” amid expanding therapeutic opportunities and a strengthened financial position. ARDX stock has traded in a $3.21 to $6.78 range over the trailing twelve months and currently trades at $6.50, reflecting an 11.49% gain from recent lows.