(VICL) Expands Infectious Disease Portfolio With Novel Antifungal From Astellas

• Development and potential commercial synergies with existing CMV program
• Targeting Phase 1 initiation in first half of 2016
• 2015 cash burn guidance remains unchanged

SAN DIEGO, March 25, 2015  — Vical Incorporated (Nasdaq:VICL) today announced that it has expanded its infectious disease portfolio with the addition of a novel antifungal, ASP2397, in-licensed from Astellas Pharma Inc. (TOKYO:4503) (“Astellas”). ASP2397 represents a potential new class of antifungal compounds to address invasive Aspergillus infections, which are major causes of morbidity and mortality in immunocompromised patients, including transplant recipients. ASP2397 is differentiated by a new mechanism of action and has a low propensity for P450 drug-drug interactions. In preclinical studies to date, it has demonstrated faster fungicidal activity than marketed drugs and activity against azole-resistant fungal pathogens. As part of the agreement, Astellas, which is also Vical’s partner for the ASP0113 CMV vaccine program in transplant recipients, will become a shareholder in Vical.

“It is exciting to see a novel antifungal with preclinical data showing potent and rapid fungicidal activity, and low potential for drug-drug interactions. Such a drug could become a treatment of choice for front-line therapy of invasive fungal infections,” said John R. Perfect, M.D., Chief of Division of Infectious Diseases at Duke University Medical Center.

Under the terms and conditions of the license agreement, Astellas granted Vical an exclusive worldwide license to develop and commercialize ASP2397. Astellas will receive Vical common stock equivalent to approximately 1% of outstanding shares and $250 thousand in cash. Astellas will also be eligible for up to $100 million in aggregate milestone payments, the vast majority of which are commercial and sales milestones, and single-digit royalties on net sales. The above agreement does not impact Vical’s cash burn guidance, which remains at between $12 million and $15 million for 2015.

“ASP2397 is an exciting opportunity that has arisen out of the relationship we have built with Astellas,” said Vijay B. Samant, Vical’s President and CEO. “While advancing our CMV and HSV-2 programs remains the top priority at Vical, this novel candidate adds depth to our pipeline and strengthens Vical’s position as an infectious disease company.”

“ASP2397 is a unique antifungal discovered at Astellas, and we are pleased to partner it with Vical, who we believe has the right capabilities to develop this compound and bring it to market,” said Naoki Okamura, Corporate Vice President and Global Head of Business Development at Astellas.

ASP2397 is a novel natural product discovered by Astellas from leaf litter fungus collected in a Malaysian national park. In vitro and in vivo data were featured in two posters presented during the ICAAC 2014 meeting last September. Most of the IND-enabling preclinical studies have been completed by Astellas, and Vical is targeting initiation of a Phase 1 trial in the first half of 2016.

Vical consulted an expert team of advisors during the evaluation of ASP2397 and is forming a Clinical Advisory Board (CAB) to help direct the development program. Initial members of the CAB include:

• John R. Perfect, M.D., Chief of Division of Infectious Diseases, Duke University Medical Center
• Dennis Schmatz, Ph.D., consultant, 30-year veteran of Merck and team leader for Cancidas (caspofungin)
• Michael R. Hodges, M.D., consultant, 17-year veteran of Pfizer and team leader for Vfend (voriconazole)

Vical intends to develop ASP2397 as a front-line therapy for invasive aspergillosis and as part of combination regimen for preemptive treatment of fungal infections, which may represent a meaningful commercial opportunity within the $4 billion global market for systemic antifungals. Current treatment options have limited efficacy, as approximately 50-60% of allogeneic hematopoietic stem cell transplant recipients with invasive aspergillosis infections die within 12 weeks. Over the past 30 years, only one new class of antifungal drugs (echinocandins) has been introduced.

Conference Call

Vical will conduct a conference call and webcast tomorrow, March 26, at 8:30 a.m. Eastern Time. Listeners may access the accompanying slide presentation through the webcast at www.vical.com. The call and webcast will be open on a listen-only basis to any interested parties. To listen to the conference call, dial in approximately ten minutes before the scheduled call to (719) 325-2308 (preferred), or (888) 312-3048 (toll-free), and reference confirmation code 2695093. A replay of the call will be available for 48 hours beginning about two hours after the call. To listen to the replay, dial (719) 457-0820 (preferred) or (888) 203-1112 (toll-free) and enter replay passcode 2695093. The webcast portion of the call will be available live and archived through the events page at www.vical.com. For further information, contact Vical’s Investor Relations department by phone at (858) 646-1127 or by e-mail at ir@vical.com.

About Vical

Vical develops biopharmaceutical products for the prevention and treatment of chronic or life-threatening infectious diseases, based on its patented DNA delivery technologies and other therapeutic approaches. Additional information on Vical is available at www.vical.com.

Forward-Looking Statements

This press release contains forward-looking statements subject to risks and uncertainties that could cause actual results to differ materially from those projected. Forward-looking statements include cash burn guidance, the potential benefits of ASP2397, Vical’s capabilities to develop ASP2397, Vical’s development plans and timelines for ASP2397, the potential market opportunity for ASP2397, and potential payments under the license agreement with Astellas. Risks and uncertainties include whether Vical or others will continue development of ASP2397, whether planned clinical development of ASP2397 will begin when expected, or at all, whether the results of future preclinical or clinical studies will be consistent with prior preclinical studies or will otherwise merit further development; whether Vical will achieve levels of revenues and control expenses to meet its financial projections; whether Vical or its collaborative partners will seek or gain approval to market any product candidates, including ASP2397; whether pending legislation related to the development or drug candidates such as ASP2397 will be enacted in its current form or at all, and the ultimate impact of any such legislation; and additional risks set forth in the company’s filings with the Securities and Exchange Commission. These forward-looking statements represent the company’s judgment as of the date of this release. The company disclaims, however, any intent or obligation to update these forward-looking statements.

CONTACT: Andrew Hopkins
         (858) 646-1127
         Website: www.vical.com