(IMDZ) Announces Phase 2 Cancer Immunotherapy Trial Collaboration

Plan to Evaluate Combination of CMB305 and Genentech’s Atezolizumab in Patients With Soft Tissue Sarcoma

SEATTLE and SOUTH SAN FRANCISCO, Calif., Aug. 12, 2015  — Immune Design (Nasdaq:IMDZ) today announced it has entered into a clinical trial collaboration with Genentech, a member of the Roche Group, to evaluate the safety and efficacy of Immune Design’s CMB305 cancer immunotherapy product candidate combined with the investigational cancer immunotherapy atezolizumab (MPDL3280A; anti-PDL1) in a randomized Phase 2 trial in patients with soft tissue sarcoma.

CMB305 is a “prime-boost” cancer immunotherapy product designed to synergistically induce anti-tumor cytotoxic T lymphocytes (CTLs) to target NY-ESO-1, a tumor antigen found in a broad set of tumors. Atezolizumab is a PD-L1 antagonist and is designed to block inhibitory T-cell checkpoints and allow cytotoxic T cells to reach the tumor. The randomized, open label Phase 2 trial will evaluate CMB305 and atezolizumab in patients with locally advanced, relapsed, or metastatic synovial sarcoma or myxoid/round-cell liposarcoma, two types of sarcoma that tend to express NY-ESO-1 broadly.

“The combination of CMB305, which is designed to generate and expand tumor-specific CD8 T cells, with atezolizumab, which is designed to remove the tumor-induced blockade, makes profound sense from a mechanistic perspective,” said Carlos Paya, M.D., Ph.D., President and Chief Executive Officer of Immune Design. “We are pleased to begin this collaboration with Genentech and explore the potential synergy of these product candidates, which will hopefully bring significant benefit to patients.”

About CMB305

CMB305 is a cancer immunotherapy product candidate combining two potentially synergistic agents, LV305 and G305. LV305 is a hybrid vector from the ZVex^TM discovery platform that specifically targets dendritic cells (DCs) in vivo and delivers the RNA for NY-ESO-1, enabling the DCs to express the entire tumor antigen and potentially induce a diverse set of CTLs targeting NY-ESO-1. G305, in contrast, is designed to boost the CTL response via the induction of antigen-specific CD4 “helper” T cells. G305 consists of recombinant NY-ESO-1 protein formulated with a proprietary synthetic small molecule called glucopyranosyl lipid A (GLA), the novel TLR4 agonist at the core of the GLAAS platform. CMB305 is intended to be an “off-the shelf” therapy that does not require patient-specific manufacturing or ex vivo manipulation of patient samples. Having established the safety and individual immunologic activity of LV305 and G305 in prior studies, Immune Design initiated a new Phase 1B study of the product candidate CMB305 earlier this year.

About Soft Tissue Sarcoma

Soft Tissue Sarcomas (STS) are malignancies that arise from the soft tissues of the body, such as tissues that connect, support and surround other body structures including muscle, fat, blood vessels, nerves, tendons and the lining of joints.¹ In the United States, nearly 12,000 people will be diagnosed and approximately 4,870 are expected to die of STS in 2015.² There are approximately 50 different types of STS including Liposarcomas and Synovial Sarcomas, which are subtypes effecting fat tissue and tissue around the joints, respectively.³ Myxoid/round cell is a type of liposarcoma that accounts for approximately 30% of all liposarcoma cases.⁴ Myxoid and round cell liposarcoma and synovial sarcomas have been shown to have high expression of NY-ESO-1, approximately 90% and approximately 50%, respectively.⁵

About Immune Design

Immune Design is a clinical-stage immunotherapy company employing next-generation in vivo approaches to enable the body’s immune system to fight disease. The company’s technologies are engineered to activate the immune system’s natural ability to generate and/or expand antigen-specific cytotoxic T cells, while also enhancing other immune effectors, to fight cancer and other chronic diseases. CMB305 and G100, the primary focus of Immune Design’s ongoing immuno-oncology clinical programs, are products of its two synergistic discovery platforms, ZVex^TM and GLAAS^TM, the fundamental technologies of which were licensed from the California Institute of Technology and the Infectious Disease Research Institute (IDRI), respectively. Immune Design has offices in Seattle and South San Francisco. For more information, visit www.immunedesign.com.

Cautionary Note on Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “plan,” “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. These forward-looking statements are based on Immune Design’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements about the timing of initiation, progress, scope and outcome of clinical trials for Immune Design’s product candidates and the reporting of clinical data regarding Immune Design’s product candidates. Many factors may cause differences between current expectations and actual results including unexpected safety or efficacy data observed during preclinical or clinical studies, clinical trial site activation or enrollment rates that are lower than expected, changes in expected or existing competition, changes in the regulatory environment, failure of Immune Design’s collaborators to support or advance collaborations or product candidates and unexpected litigation or other disputes. Other factors that may cause Immune Design’s actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Immune Design’s filings with the U.S. Securities and Exchange Commission, including the “Risk Factors” sections contained therein. Except as required by law, Immune Design assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

¹ Mayo Clinic. Disease and Conditions: Soft tissue sarcoma.

Available at: http://www.mayoclinic.org/diseases-conditions/soft-tissue-sarcoma/basics/definition/con-20033386. Accessed: July 2015.

² National Cancer Institute. SEER Stat Fact Sheets: Soft Tissue including Heart Cancer.

Available at: http://seer.cancer.gov/statfacts/html/soft.html. Accessed: July 2015.

³ American Cancer Society. What is a soft tissue sarcoma?

Available at: http://www.cancer.org/cancer/sarcoma-adultsofttissuecancer/detailedguide/sarcoma-adult-soft-tissue-cancer-soft-tissue-sarcoma. Accessed: July 2015

⁴ Orpha.net. Myxoid/round cell liposarcoma.

Available at: http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Expert=99967. Accessed: July 2015.

⁵ Endo, M., et al. (April 2015). NY-ESO-1 (CTAG1B) expression in mesenchymal tumors [Abstract]. Modern Pathology, 28, 587-595.

Available at: http://www.nature.com/modpathol/journal/v28/n4/full/modpathol2014155a.html. Accessed: July 2015.

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