Marinus Pharmaceuticals, Inc. Announces Exercise of Over-Allotment Option in Public Offering of Common Stock

September 2, 2014

NEW HAVEN, Conn., Sept. 2, 2014 (GLOBE NEWSWIRE) -- Marinus Pharmaceuticals, Inc. (Nasdaq:MRNS), a biopharmaceutical company dedicated to the development of innovative neuropsychiatric therapeutics, today announced that the underwriters of its previously announced public offering of common stock have exercised their option to purchase an additional 133,000 shares at a public offering price of $8.00 per share. Including the sale of the additional shares subject to the over-allotment option, the Company will have issued a total of 5,758,000 shares in the offering and will have received aggregate net proceeds, after underwriting discounts and commissions and other estimated offering expenses, of approximately $41.3 million. The sale of the additional shares under the over-allotment option exercise is expected to close on September 4, 2014, subject to the satisfaction of customary closing conditions.

Stifel, Nicolaus & Company, Incorporated and JMP Securities LLC acted as joint book-running managers for the offering. Oppenheimer & Co. acted as lead manager and Janney Montgomery Scott acted as co-manager for the offering.

The securities described above are being offered by Marinus pursuant to a registration statement previously filed and declared effective by the Securities and Exchange Commission. The offering will be made only by means of a prospectus, copies of which may be obtained from Stifel, Nicolaus & Company, Incorporated, Attention: Syndicate, One Montgomery Street, Suite 3700, San Francisco, California 94104, by calling (415) 364-2720 or by emailing This email address is being protected from spambots. You need JavaScript enabled to view it., and from JMP Securities LLC, Attention: Prospectus Department, 600 Montgomery St., 10th Floor, San Francisco, CA 94111, or by calling (415) 835-8985.

This press release shall not constitute an offer to sell or a solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful, prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Marinus Pharmaceuticals

Marinus Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to the development of innovative neuropsychiatric therapeutics. The Company's clinical stage drug candidate, ganaxolone, is a novel synthetic analog of the endogenous neurosteroid, allopregnanolone. Ganaxolone is known for its anticonvulsive and antianxiety effects, and was designed to avoid hormonal side-effects associated with endogenous neurosteroids. Ganaxolone is presently being studied in a multinational, randomized, placebo-controlled, Phase 2B/3 clinical trial in adult subjects for adjunctive treatment of partial-onset seizures. The Company currently has a Phase 2 proof-of-concept pediatric clinical trial in progress for ganaxolone as a treatment for behaviors in Fragile X Syndrome and is initiating a Phase 2 proof-of-concept clinical study later this year for the treatment of PCDH19 female pediatric epilepsy. Both Fragile X Syndrome and PCDH19 female pediatric epilepsy are potential orphan disorders that have been related to mutations affecting neurosteroid signaling at extrasynaptic GABAA receptors. For additional information, please visit the Company's website at www.marinuspharma.com.

Forward-Looking Statements

To the extent that statements contained in this press release are not descriptions of historical facts regarding Marinus, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as "may," "will," "expect," "anticipate," "estimate," "intend," and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Forward-looking statements in this release involve substantial risks and uncertainties that could cause our clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the conduct of future clinical trials, the timing of the clinical trials, enrollment in clinical trials, availability of data from ongoing clinical trials, expectations for regulatory approvals, and other matters, including the development of formulations of ganaxolone, that could affect the availability or commercial potential of our drug candidates. Marinus undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the Company in general, see filings Marinus has made with the Securities and Exchange Commission.

CONTACT: Edward F. Smith Vice President, CFO, Secretary and Treasurer Marinus Pharmacuticals, Inc. (203) 315-0566 esmith@marinuspharma.com