SCHEDULE 13G

Merrimack Pharmaceuticals Inc

Common Stock, par value $0.01 per share · CUSIP: 590328209

Event date: 2024-02-13

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

• ADAR1 Partners, LP

  Shares: 902,350.00 · Class: 6.3%

• ADAR1 Capital Management, LLC

  Shares: 902,350.00 · Class: 6.3%

• ADAR1 Capital Management GP, LLC

  Shares: 902,350.00 · Class: 6.3%

• Daniel Schneeberger

  Shares: 902,350.00 · Class: 6.3%

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