• Pathologically (histologically or cytologically) proven diagnosis of HPV16+ squamous cell carcinoma of the head and neck post standard of care definitive therapy.

‣ History of histologically confirmed HPV16+ squamous cell cancer (from in-house or local evaluation by HPV16 RNA in situ hybridization (ISH) or PCR) is required for all patients on study.

⁃ Detection of HPV16 specific TTMV-HPV DNA via peripheral blood NavDx assay in combination with historically confirmed p16 expression can be used as a surrogate for enrollment and initiation of treatment as per the discretion of site PI whilst histological confirmation with RNA ISH or PCR is in process.

• No clinical or radiographic evidence of persistent or recurrent disease at time of evaluation (indeterminate findings are allowed based on discretion of P.I.)

• Positive TTMV-HPV DNA score (HPV16 specific) by NavDx® 3 months or more after definitive therapy for HPV16+ squamous cell carcinoma of the head and neck allows for pre-screen consent for a confirmatory NavDx.

• Definitive therapy includes surgery and/or chemotherapy/radiation therapeutic paradigms that are aimed at eradicating and curing disease with the goal of no additional therapies being required afterwards. This will include standard of care treatments and IRB-approved, de-escalation treatment protocols and strategies.For those patients who had surgery only as definitive therapy, a positive TTMV-HPV DNA score after completion of surgery fulfills this inclusion criterion. Enrollment of patients who had de-escalated treatment or nonstandard treatment paradigms, including salvage therapies, performed off an IRB-approved protocol/clinical trial will require the approval of the study P.I.

• Male or female patients 18 years of age or older on the day of consent.

• ECOG Performance Status of 0 to 1.

• Adequate hematologic function within 30 days prior to registration, defined as follows:

‣ Absolute neutrophil count (ANC) ≥ 1,000 cells/mm3

⁃ Platelets ≥ 100,000 cells/mm3

⁃ Hemoglobin ≥ 9.0 g/dl; Note: The use of transfusion or other intervention to achieve Hgb ≥ 9.0 g/dl is acceptable

• Adequate renal function within 30 days prior to registration, defined as follows:

• °Serum creatinine \< 2.0 x upper limit of normal (ULN) or creatinine clearance (CCr) ≥ 30 ml/min determined by 24-hour collection or estimated by Cockcroft-Gault formula: CCr male = \[(140 - age) x (wt in kg)\] \[(Serum Cr mg/dl) x (72)\] CCr female = 0.85 x (CrCl male)

• Adequate hepatic function within 30 days prior to registration, defined as follows:

‣ Total bilirubin ≤ 1.5 × ULN (except for unconjugated hyperbilirubinemia or Gilbert's syndrome). Direct bilirubin ≤ ULN for participants with total bilirubin levels \> 1.5 × ULN.

⁃ AST and ALT ≤ 2.5 x the upper limit of normal

⁃ Albumin ≥ 3 g/dL

• International Normalized Ratio (INR) or Prothrombin Time (PT) ≤ 1.5 × ULN unless participant is receiving anticoagulant therapy as long as PT or partial thromboplastin time (PTT) is within therapeutic range of intended use of anticoagulants.

• Activated Partial Thromboplastin Time (aPTT) or Partial Thromboplastin Time (PTT) ≤ 1.5 × ULN unless participant is receiving anticoagulant therapy as long as PT or PTT is within therapeutic range of intended use of anticoagulants.

• Female patients are eligible to participate if they are not pregnant, not breastfeeding and at least one of the following conditions applies:

‣ Not a woman of childbearing potential

⁃ A woman of childbearing potential who agrees to use highly effective contraception from signing of the ICF through five months after the last study treatment administration.

∙ Notes: i) Female of childbearing potential are those who have not been surgically sterilized or have not been free from menses for \>1 year.

∙ ii) Highly effective contraception methods include:

• Total abstinence.

• Male or female sterilization.

• Combination of any 2 of the following categories (Categories 1+2, 1+3, or 2+3):

‣ Category 1: Use of oral, injected, or implanted hormonal methods of contraception.

⁃ Category 2: Placement of an intrauterine device or intrauterine system.

⁃ Category 3: Barrier methods of contraception: condom or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/vaginal suppository.

• A female participant who is of childbearing potential must have a negative serum βhuman chorionic gonadotrophin (β-hCG) pregnancy test within 72 hours prior to the first administration of study treatment or be surgically/biologically sterile (hysterectomy or bilateral oophorectomy) or postmenopausal. Note: Postmenopausal females are defined as those who are:

‣ Age \> 50 years with amenorrhea for ≥ 12 months.

⁃ Age ≤ 50 years with six months of spontaneous amenorrhea and follicle stimulating hormone level within postmenopausal range (\> 40 mIU/mL).

• Male patients must agree to use contraception and refrain from sperm and egg donation from the time period between signing of the ICF and through five months after the last dose of study drug

• The subject must provide voluntary study-specific informed consent prior to study entry.