SCHEDULE 13D/A

LARIMAR THERAPEUTICS INC

Common Stock, par value $0.01 per share · CUSIP: 517125100

Event date: 2026-02-27

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

• Deerfield Private Design Fund III, L.P.Reported CIK 0001603333

  Shares: 10,622,928.00 · Class: 10.25%

• Deerfield Healthcare Innovations Fund, L.P.Reported CIK 0001646981

  Shares: 8,153,107.00 · Class: 7.87%

• Deerfield Private Design Fund IV, L.P.Reported CIK 0001680307

  Shares: 10,622,957.00 · Class: 10.25%

• Deerfield Partners, L.P.Reported CIK 0001301041

  Shares: 6,207,982.00 · Class: 5.99%

• Deerfield Mgmt III, L.P.Reported CIK 0001610540

  Shares: 10,622,928.00 · Class: 10.25%

• Deerfield Mgmt HIF, L.P.Reported CIK 0001665736

  Shares: 8,153,107.00 · Class: 7.87%

• Deerfield Mgmt IV, L.P.Reported CIK 0001713467

  Shares: 10,622,957.00 · Class: 10.25%

• Deerfield Mgmt, L.P.Reported CIK 0001010823

  Shares: 6,207,982.00 · Class: 5.99%

• Deerfield Management Company, L.P.Reported CIK 0001009258

  Shares: 35,667,474.00 · Class: 34.41%

• James E. FlynnReported CIK 0001352546

  Shares: 35,667,474.00 · Class: 34.41%

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