HETLIOZ (tasimelteon) Demonstrates Efficacy to Treat Jet Lag Disorder in an 8 Hour Phase Advance Clinical Study H ETLIOZ demonstrates improve ment in Total Sleep Time by 85 minutes versus Placebo (p 0.0001) H ETLIOZ demo

HETLIOZ (tasimelteon) Demonstrates Efficacy to Treat Jet Lag Disorder in an 8 Hour

Phase Advance Clinical Study

conference call today at 8:30 AM ET

WASHINGTON, March 5, 2018 /PRNewswire/ Vanda Pharmaceuticals Inc. (Vanda) (NASDAQ: VNDA) today announced

that HETLIOZ , a circadian regulator, demonstrated significant and clinically meaningful benefits in nighttime and daytime symptoms of jet lag disorder. HETLIOZ is currently approved in the US and Europe for the treatment of Non-24-hour sleep-wake disorder, a rare and chronic

circadian rhythm sleep disorder.

Jet lag disorder is a common circadian disorder frequently observed in millions of travelers who cross multiple time

zones. Jet lag disorder is characterized by nighttime sleep disruption, a decrease in daytime alertness and impairment to social and occupational functioning.

The clinical efficacy results reported today are from the JET8 Phase-III clinical study (3107) (the JET8 study). In

the JET8 study, 318 healthy volunteers were admitted to a sleep unit and were subjected to a circadian challenge of an 8 hours advance to their usual bedtime. The JET8 study design induced the circadian challenge experienced by travelers who cross 8

times zones, which leads to jet lag disorder. This clinical design allowed for the study of HETLIOZ without the confounding effects of sleep deprivation and variable light conditions.

Results from the JET8 study showed significant and clinically meaningful effects of HETLIOZ 20 mg on

the primary endpoint of the study as well as multiple secondary endpoints. The pre-specified primary endpoint was the amount of sleep time in the first two thirds of the night. Secondary endpoints included

measures of sleep parameters (TST, LPS, WASO) and next day alertness (KSS and VAS). (Table 1).

Table 1: Summary of Primary and Key Secondary Endpoint

The results of the JET8 study shown above demonstrate the effectiveness of HETLIOZ in treating jet lag disorder. The magnitude of the total sleep time benefit of 85 minutes improvement over placebo is significant and clinically meaningful. The demonstration of benefits in

measurements of next day alertness on both KSS and VAS is meaningful and it underscores the ability of HETLIOZ to address both nighttime and daytime symptoms of jet lag disorder.

Vanda previously reported on the JET5 study (3101) that examined the effects of HETLIOZ in a

circadian challenge of 5 hours advance of the subjects usual bedtime. The results of that study were published in The Lancet in 2009.1 The observation that HETLIOZ is effective in treating the symptoms caused by an abrupt advance of the circadian cycle of a magnitude of 5 or 8 hours suggests that

HETLIOZ will be an effective therapeutic tool in the treatment of individuals that experience symptoms of jet lag. HETLIOZ will be

potentially useful under circumstances of rapid eastward transmeridian travel experienced by frequent travelers, the rapid deployment of military troops and any circumstances that will necessitate the abrupt phase advance of the sleep wake cycle.

Jet lag disorder affects millions of individuals annually who cross multiple time zones during their travel. Jet lag disorder symptoms are more severe

during eastward travel. It is reported that more than 30 million US residents make trips abroad each year to overseas destinations. Of these, 60% (approximately 20 million) travel to destinations in Europe, Middle East and Asia. It is also

reported that 8% (approximately 1.6 million) travel in Business or First class.2

extremely pleased with the outcome of this study which establishes the utility of HETLIOZ in the treatment of jet lag disorder as

HETLIOZ was shown to overcome a significant circadian challenge of an 8 hour phase advance. This challenge is equivalent to eastward travel across 8 time zones as experienced for example on

travel from Los Angeles to London, Washington DC to Moscow, Paris to Tokyo, or London to Singapore. HETLIOZ improved both nighttime sleep and next day alertness potentially offering

significant benefits to millions of travelers, said Mihael H. Polymeropoulos, MD, Vanda s President and CEO.

Vanda intends to seek marketing

approval for the use of HETLIOZ in the treatment of jet lag disorder. Vanda believes that if HETLIOZ is approved by regulatory

authorities for the treatment of jet lag disorder it will potentially offer a therapeutic solution to many travelers and will likely represent an important commercial opportunity for the company. For review of the current prescribing information of

HETLIOZ please visit www.hetlioz.com.

The Vanda management team will host a conference call and live webcast today, March 5, 2018, at 8:30 AM ET to discuss these updates. Investors can call 1-888-771-4371 (domestic) or

1-847-585-4405 (international) and use passcode 46600533. A replay of the call will be available on Monday, March 5, 2018,

beginning at 11:00 AM ET and will be accessible until Monday, March 12, 2018, at 11:59 PM ET. The replay call-in number is 1-888-843-7419 for domestic callers and 1-630-652-3042 for international callers.

The passcode number is 46600533.

The conference call will be broadcast simultaneously on Vanda s website. Investors should click on the

Investor Relations tab and are advised to go to the website at least 15 minutes early to register, download, and install any necessary software or presentations. The call will also be archived on Vanda s website for a period of 30 days.

HETLIOZ IS NOT CURRENTLY APPROVED BY ANY REGULATORY AUTHORITY FOR THE TREATMENT OF JET LAG

HETLIOZ is a melatonin receptor agonist.

HETLIOZ has been granted market authorization by the U.S. Food and Drug Administration and the European Medicines Agency. For full U.S. prescribing information, please visit www.hetlioz.com.

Important Safety Information

The most common adverse

reactions (incidence >5% and at least twice as high on HETLIOZ (tasimelteon) than on placebo) were headache, increased alanine aminotransferase, nightmares or unusual dreams, and upper

respiratory or urinary tract infection. The risk of adverse reactions may be greater in elderly (>65 years) patients than younger patients because exposure to HETLIOZ is increased by

approximately 2-fold compared with younger patients.

HETLIOZ is indicated for the treatment of Non-24-Hour Sleep-Wake Disorder (Non-24).

Important Safety Information

HETLIOZ may cause somnolence: After taking

HETLIOZ , patients should limit their activity to preparing for going to bed, because HETLIOZ can potentially impair the performance

of activities requiring complete mental alertness.

The most common adverse reactions (incidence >5% and at least twice as high on HETLIOZ than on placebo) were headache, increased alanine aminotransferase, nightmares or unusual dreams, and upper respiratory or urinary tract infection. The risk of adverse reactions may be greater in

elderly (>65 years) patients than younger patients because exposure to HETLIOZ is increased by approximately 2-fold compared with younger patients.

Use of HETLIOZ should be avoided in combination with fluvoxamine or other strong CYP1A2

inhibitors, because of a potentially large increase in exposure of HETLIOZ , and a greater risk of adverse reactions. HETLIOZ should

be avoided in combination with rifampin or other CYP3A4 inducers, because of a potentially large decrease in exposure of HETLIOZ , with reduced efficacy.

There are no adequate and well-controlled studies of HETLIOZ in pregnant women. Based on animal

data, HETLIOZ may cause fetal harm. HETLIOZ should be used during pregnancy only if the potential benefit justifies the potential

risks. Caution should be exercised when HETLIOZ is administered to a nursing woman.

HETLIOZ has not been studied in patients with severe

hepatic impairment and is not recommended in these patients.

Safety and effectiveness of

HETLIOZ in pediatric patients have not been established.

Vanda is a global biopharmaceutical company focused on the development and commercialization of innovative therapies to address high unmet medical needs and

improve the lives of patients. For more on Vanda Pharmaceuticals Inc., please visit www.vandapharma.com.

Polymeropoulos MH, Fisher DM, Roth T, Scott C, Birznieks G, Klerman E. Melatonin agonist tasimelteon (VEC-162) for transient insomnia after sleep-time shift: two randomized controlled multicenter trials. The

Lancet. 2009: 373: 433-516.

2. US Department of Commerce, International Trade Administration, National Travel and

Tourism Office. Profile of U.S. Resident Travelers Visiting Overseas Destinations: 2015 Outbound.

FORWARD LOOKING STATEMENTS

Various statements in this

release and to be made on the conference call are forward-looking statements under the securities laws. Forward-looking statements are based upon current expectations that involve risks, changes in circumstances, assumptions and

uncertainties. Important factors that could cause actual results to differ materially from those reflected in Vanda s forward-looking statements include, among others: the ability of

HETIOZ to provide significant benefit in the treatment of the symptoms of jet lag disorder; Vanda s ability to obtain marketing approval for the use of HETLIOZ in the treatment of jet lag disorder; and other factors that are described in the Risk Factors and Management s Discussion and Analysis of Financial Condition and Results

of Operations sections of Vanda s annual report on Form 10-K for the fiscal year ended December 31, 2017, which is on file with the SEC and available on the SEC s website at www.sec.gov.

In addition to the risks described above and in Vanda s annual report on Form 10-K, other unknown or unpredictable factors also could affect Vanda s results. There can be no assurance that the actual

results or developments

anticipated by Vanda will be realized or, even if substantially realized, that they will have the expected consequences to, or effects on, Vanda. Therefore, no assurance can be given that the

outcomes stated in such forward-looking statements and estimates will be achieved.

All written and verbal forward-looking statements attributable to

Vanda or any person acting on its behalf are expressly qualified in their entirety by the cautionary statements contained or referred to herein. Vanda cautions investors not to rely too heavily on the forward-looking statements Vanda makes or that

are made on its behalf. The information in this release is provided only as of the date of this release, and Vanda undertakes no obligation, and specifically declines any obligation, to update or revise publicly any forward-looking statements,

whether as a result of new information, future events or otherwise.

Executive Vice President and Chief Financial Officer

Vanda Pharmaceuticals Inc.

SOURCE Vanda Pharmaceuticals Inc.