This is a single arm, open-label, single center study evaluating the safety, feasibility, clinical efficacy and immunogenicity of GLA-SE administration to patients with Merkel cell carcinoma. Ten patients will be treated. The goal is for GLA-SE to assist the patient's own immune system in attacking the cancer cells.

This is a single arm, open-label, single center study evaluating the safety, feasibility, clinical efficacy and immunogenicity of GLA-SE administration to patients with Merkel cell carcinoma. Ten patients with metastatic or locoregional disease will be treated. The goal is for GLA-SE to assist the patient's own immune system in attacking the cancer cells.

Inclusion Criteria:

• Biopsy-confirmed Merkel cell carcinoma with metastatic or loco-regional disease.
• Patients must have at least one injectable lesion, defined as an easily palpable superficial lesion (cutaneous, subcutaneous or lymph nodal metastasis) that can be accurately localized, stabilized by palpation, and is superficial enough to enable IT injection.
• ECOG performance status score 0, 1 or 2
• ≥ 18 years of age
• Life expectancy of ≥ three months.
• Adequate neutrophil and platelet counts
• Adequate renal and hepatic function
• Willing to undergo pre-treatment lesion biopsy and post-treatment lesion biopsy
• Use of effective contraception
• Signed informed consent document
• Members of all genders, races and ethnic groups are eligible for this trial

Exclusion Criteria:

• Prior chemotherapy or a major surgical procedure within 3 weeks, or radiotherapy within 2 weeks prior to first study treatment
• No concurrent anti-cancer treatment (including topical agents such as imiquimod) or investigational agents
• Active, untreated brain metastases
• Pregnant or nursing
• Use of any systemic immunosuppressive agents
• Immunosuppressed patients
• Uncontrolled depression or other major psychiatric disorder