This is a Phase 1 open-label, multicenter study of the safety and tolerability, immunogenic effects, antitumor activity, and pharmacodynamics of SQZ-PBMC-HPV as monotherapy and in combination with atezolizumab or other immune checkpoint inhibitors in HLA-A*02+ patients with recurrent, locally advanced or metastatic human papillomavirus strain 16 positive (HPV16+) solid tumors. The study includes patients with anal, rectal, cervical, head and neck, penile, vulvar, or vaginal cancer.

Key Inclusion Criteria:

• Male or female patients ≥18 years of age who are HLA-A*02+ (performed during screening locally or centrally, or based on documented historic test results)
• Histologically confirmed incurable or metastatic solid tumors that are HPV16+ (performed during screening locally or centrally, or based on documented historic test results)
• Cancer must have progressed after at least 1 available standard therapy for incurable disease, or the patient is intolerant to or refuses standard therapy(ies) or has a tumor for which no standard therapy(ies) exist
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 to 1
• At least 1 measurable lesion according to RECIST 1.1
• Must have a lesion that can be biopsied with acceptable clinical risk and agree to have a fresh biopsy at Baseline and on Cycle 2 Day 8 (+/- 3 days)
• Patients must agree to venous access for the leukapheresis and be willing to have a central line inserted if venous access is an issue
• Adequate organ function and bone marrow reserve performed within 14 days prior to the leukapheresis

Exclusion Criteria:

• Treatment with anticancer therapy, including investigational therapy, within 2 weeks prior to leukapheresis. For prior therapies with a half-life longer than 3 days, discontinuation of the therapy must have occurred at least 28 days prior to leukapheresis
• Systemic treatment with either corticosteroids (>10 mg of prednisone or the equivalent per day) or other immunosuppressive medications within 14 days prior to leukapheresis
• Patients treated with non-corticosteroid based immunosuppressive agents within the last 6 months may not be eligible and should be discussed with the Sponsor
• Patients with active, known, or suspected autoimmune disease may not be eligible and should be discussed with the Sponsor
• Patients with >Grade 1 AEs related to previous treatment with anticancer or investigational therapy that do not resolve at least 2 weeks prior to leukapheresis, except neuropathy, ototoxicity, mucositis, fatigue, alopecia, or endocrine disorders managed with hormone replacement
• Known active hepatitis B or hepatitis C, or active mycobacterium tuberculosis infection
• History of any Grade 3 immune-related AE (irAE) from prior immunotherapy
• Has known active central nervous system metastases
• History of interstitial lung disease requiring steroids
• Major surgery within 2 weeks of leukapheresis