Novel Cancer Vaccine May Improve Survival in Synovial Sarcoma

Investigators are hopeful that CMB305, a vaccine that boosts the immune response to tumor cells expressing the antigen NY-ESO-1, can improve survival outcomes for patients with synovial sarcoma, a rare cancer that develops in the arms and legs and affects about 800 individuals in the United States each year.¹

RATIONALE

After patients with synovial sarcoma stop chemotherapy treatment because of toxicities, their disease often progresses. The clinicians can often re-treat with chemotherapy, but as a result of the toxicities, this is not always an option, and there aren’t agents available for subsequent lines of therapy.

CMB305 combines 2 mechanisms of action in 1 vaccine targeting the antigen NY-ESO-1. The prime component is an engineered lentiviral vector that binds to dendritic cells (DCs), causing them to express NY-ESO-1, thereby boosting the immune response against NY-ESO-1—expressing tumor cells.² The second component of the vaccine, G305, is a toll-like receptor 4 (TLR4) agonist, which also boosts the immune system. G305 binds to TLR4 on immune cells, including DCs, and induces an NY-ESO-1—specific antibody response,² impeding tumor cell proliferation and survival.

“It’s the combination of these 2 things [that] can make [CMB305] very potent, [prompting] the immune system to recognize and want to go after cells that have NY-ESO-1 protein,” said William B. Tap, MD, chief, Sarcoma Medical Oncology Service, Memorial Sloan Kettering Cancer Center.

TRIAL DESIGN

In the phase III Synovate study, CMB305 will be tested as maintenance monotherapy in patients with locally advanced, unresectable, or metastatic synovial sarcoma after initial treatment with chemotherapy.

Progression-free and overall survival as the coprimary endpoints will be assessed. Secondary endpoints will include overall response rate, duration of response, and safety and tolerability.

WHO IS ELIGIBLE?

Investigators seek to enroll approximately 248 patients who have achieved stable disease and will randomize them to CMB305 or a placebo.¹ Eligible participants must have expression of the NY-ESO-1 surface protein, which is commonly found in synovial sarcoma tumors. The Synovate study is accepting participants as young as 12 years to include in this patient population.

REFERENCES

• Immune Design. Harnessing the immune system to fight cancer. ir.immunedesign.com/static-files/cdf2d12b-46d6-4972-b99c-0a30b07e9ddb. Published April 26, 2018. Accessed May 22, 2018.
• NCI drug dictionary: immunotherapeutic combination product CMB305. National Cancer Institute website. cancer.gov/publications/dictionaries/cancer-drug/def/immunotherapeutic-combination-product-cmb305. Accessed May 22, 2018.