X0306 4/A 2015-09-24 2015-09-28 0 0001267813 MARINUS PHARMACEUTICALS INC MRNS 0001400308 Bloch Stephen M C/O CANAAN VII L.P. 285 RIVERSIDE AVENUE SUITE 250 WESTPORT CT 06880 1 0 0 0 Common Stock 2015-09-28 4 M 0 12515 1.04 A 12515 D Common Stock 2015-09-28 4 M 0 27035 1.04 A 39550 D Common Stock 2461398 I See Footnote Stock option (right to buy) 12.98 2015-09-24 4 A 0 6300 0.00 A 2025-09-24 Common Stock 6300 6300 D Stock option (right to buy) 1.04 2015-09-28 4 M 0 12515 0.00 D 2019-06-09 Common Stock 12515 0 D Stock option (right to buy) 1.04 2015-09-28 4 M 0 27035 0.00 D 2022-03-20 Common Stock 27035 0 D Shares held directly by Canaan VII L.P. (the "Canaan Fund"). Canaan Partners VII LLC ("Canaan VII" and together with the Canaan Fund, the "Canaan Entities") is the sole general partner of the Canaan Fund and each may be deemed to have sole voting, investment and dispositive power with respect to the shares held by the Canaan Fund. Canaan VII disclaims Section 16 beneficial ownership of the securities held by the Canaan Fund, except to the extent of any pecuniary interest therein. Stephen Bloch, a manager of the Canaan Fund, serves as the representative of the Canaan Entities on the Issuer's board of directors. Dr. Bloch disclaims beneficial ownership over the securities owned by the Canaan Fund, and this report shall not be deemed an admission that such reporting person is the beneficial owner of such shares, except to the extent of his pecuniary interest, if any, in the securities by virtue of the limited liability company interests he owns in Canaan VII, the general partner of the Canaan Fund. 1,050 options vest on September 30, 2015 and the remaining options vest on the last day of the month in 10 equal monthly installments commencing 10/31/2015. 25% vested on 6/9/09; remaining shares vested in equal installments at the end of each of the 36 months after 6/9/09. These options were granted by the Issuer prior to Dr. Bloch becoming a manager of the Canaan Fund. 100% vested on 3/20/13. These options were granted by the Issuer prior to Dr. Bloch becoming a manager of the Canaan Fund. This amendment is being filed to delete the row on Table I that previously disclosed 1,836,398 shares, as it inadvertently duplicated the number of shares reported as beneficially owned by the Reporting Person. This amendment also makes the same correction to the Reporting Person's Form 4 filings on 06/11/2015 and 10/02/2014. /s/ Jaime Slocum, Attorney-in-Fact 2016-02-04