13G Filing: EcoR1 Capital and Marinus Pharmaceuticals Inc (MRNS)

Page 2 of 7 – SEC Filing

1. Names of Reporting Persons.

EcoR1 Capital, LLC

2. Check the Appropriate Box if
a Member of a Group (See Instructions)

(a) X

(b)

3. SEC Use Only
4. Citizenship or Place of Organization Delaware
Number of
Shares
Beneficially
Owned by
Each Reporting
Person With:
5. Sole Voting Power -0-
6. Shared Voting Power 3,622,271
7. Sole Dispositive Power -0-
8. Shared Dispositive Power 3,622,271
9. Aggregate Amount Beneficially Owned by Each Reporting Person 3,622,271
10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ______
11. Percent of Class Represented by Amount in Row (9) 12.2%
12. Type of Reporting Person (See Instructions) OO
2

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