Exhibit 99.1

Marinus Pharmaceuticals PROVIDES business UPDATE

and reports first quarter 2016 financial results

RADNOR, PA, May 2, 2016 (Globe Newswire) -- Marinus Pharmaceuticals, Inc. (Nasdaq:MRNS), a biopharmaceutical company dedicated to the development of innovative therapeutics to treat epilepsy and neuropsychiatric disorders,  today provided a business update and reported its financial results for the quarter ended March 31, 2016.

“This is a very important year for Marinus,” commented Christopher M. Cashman, Chief Executive Officer of Marinus Pharmaceuticals. “All three of our ongoing ganaxolone clinical studies are fully enrolled with data on track for release over the next few months.  The outcomes from these studies will determine our future development and commercial plans for our ganaxolone franchise.”

Upcoming Milestones for 2016 & Recent Highlights

Financial Update

At March 31, 2016, the Company had cash, cash equivalents and investments of $51.4 million, compared to $57.7 million at December 31, 2015.  The Company believes that its cash, cash equivalents and investments, as of March 31, 2016, are adequate to fund operations into the second half of 2017.

Research and development expenses remained flat at $5.5 million for the three months ended March 31, 2016 and for the same period in the prior year.  

General and administrative expenses increased to $1.6 million for the three months ended March 31, 2016, as compared to $1.4 million for the same period in the prior year. The increase in general and administrative expenses was primarily due to increases in non-cash stock-based compensation expense.

The Company reported net losses of $7.2 million and $7.0 million for the three months ended March 31, 2016 and 2015, respectively.  Cash used in operating activities was $6.1 million for the three months ended March 31, 2016 compared to $4.0 million for the same period a year ago.  

Readers are referred to, and encouraged to read in its entirety, the Company’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2016 to be filed with the Securities and Exchange Commission, which includes further detail on the Company’s business plans and operations, financial condition and results of operations.

About Marinus Pharmaceuticals

Marinus Pharmaceuticals, Inc. is a biopharmaceutical company dedicated to the development of ganaxolone, which offers a new mechanism of action and convenient dosing, to improve the lives of patients suffering from epilepsy and neuropsychiatric disorders.  Ganaxolone is a CNS-selective GABA_A modulator that acts on a well-characterized target in the brain known to have both anti-seizure and anti-anxiety effects. Ganaxolone is being developed in three different dose forms (IV, capsule and liquid) intended to maximize therapeutic reach to adult and pediatric patient populations in both acute and chronic care settings.  Ganaxolone IV is planned to enter clinical trials in 2016 and is being developed to treat status epilepticus. Ganaxolone IV is complemented by its oral dose forms, providing the potential for IV-to-oral continuation therapy for patients transitioning from acute care to outpatient settings.  Ganaxolone capsule is being evaluated in a Phase 3 multi-national clinical trial as adjunctive treatment of focal onset seizures in adults.  Ganaxolone capsule and liquid are being studied in orphan pediatric indications with comorbidities in seizures and behavior disorders – PCDH19 epilepsy and Fragile X Syndrome. For more information visit 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”, “believe”, and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements.  Examples of forward looking statements contained in this press release include, among others, statements regarding our interpretation of preclinical studies, development plans for our product candidate, including the development of dose forms, the clinical trial testing schedule and milestones, the ability to complete enrollment in our clinical trials, interpretation of scientific basis for ganaxolone use, timing for availability and release of data, the safety, potential efficacy and therapeutic potential of our product candidate and our expectation regarding the sufficiency of our working capital. 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:    Company:

Lisa M. Caperelli

Senior Director, Investor Relations & Corporate Communications

Marinus Pharmaceuticals, Inc.

484-801-4674

lcaperelli@marinuspharma.com 

Media Contact:

Tiberend Strategic Advisors, Inc.

Amy S. Wheeler

646-362-5750

awheeler@tiberend.com 

Marinus Pharmaceuticals, Inc.

Selected Financial Data (in thousands, except share and per share amounts)

(unaudited)