SCHEDULE 13D/A

Ironwood Pharmaceuticals Inc

Class A Common Stock, $0.001 par value · CUSIP: 46333X108

Event date: 2026-03-17

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Sarissa Capital Management LPReported CIK 0001577524

  Shares: 9,188,635 · Class: 5.6%

• Alexander J. Denner

  Shares: 9,444,944 · Class: 5.8%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.