A Clinical Trial Investigating the Safety, Tolerability, and Therapeutic Effects of BNT113 in Combination With Pembrolizumab Versus Pembrolizumab Alone for Patients With a Form of Head and Neck Cancer Positive for Human Papilloma Virus 16 and Expressing the Protein PD-L1

Inclusion Criteria:

Pre-screening phase (optional - patients can alternatively perform tumor biomarker testing
as part of the main screening phase):

   - Patients must sign the written pre-screening informed consent form (ICF) before any
   pre-screening procedures.

   - Patients must have histologically confirmed recurrent or metastatic HNSCC with no
   prior systemic anticancer therapy administered in the recurrent or metastatic (R/M)
   setting.

   - Patients have a clinical situation at a relatively high risk of developing R/M
   disease.

   - Patients do not meet any exclusion criteria for the main clinical trial, except for
   time-dependent (e.g., prior systemic treatment in the prior 6 months) or potentially
   reversible conditions that in the opinion of the investigator will be resolved prior
   to potential enrollment into the main phase.

Main trial:

   - Patients must sign the written informed consent form before any screening procedure.
   Informed consent must be documented before any trial-specific screening procedure is
   performed.

   - Patients must be aged ≥18 years on the date of signing the informed consent.

   - Patients must be willing and able to comply with scheduled visits, treatment schedule,
   laboratory tests, and other requirements of the trial.

   - Patients who present histologically confirmed recurrent or metastatic HPV16+ HNSCC
   that is considered incurable by local therapies.

   - Patients who have a tumor that expresses PD-L1 [CPS ≥1] as determined by the approved
   test PD-L1 IHC 22C3 pharmDx kit performed and evaluated according to the
   manufacturer's specifications and relevant regulatory approvals.

   - The eligible primary tumor locations are oropharynx, oral cavity, hypopharynx, and
   larynx.

   - Patients must not have had prior systemic anticancer therapy administered in the
   incurable recurrent or metastatic setting. Systemic therapy which was completed more
   than 6 months prior to randomization, if given as part of multimodal treatment for
   locally advanced disease, is allowed.

   - Patients who have measurable disease based on RECIST 1.1 as determined by the site and
   confirmed by BICR. Tumor lesions situated in a previously irradiated area may be
   considered measurable, if progression has been demonstrated in such lesions disease by
   RECIST 1.1.

   - Patients have Eastern Cooperative Oncology Group (ECOG) performance status ≤1.

   - Patients have adequate bone marrow function as defined by hematological parameters.

   - Patients have adequate hepatic function.

   - Patients should have adequate kidney function, assessed by the estimated glomerular
   filtration rate (eGFR) ≥30 mL/min/1.73m^2 using the Chronic Kidney Disease
   Epidemiology Collaboration (CPK-EPI) equation.

   - Patients should be stable with adequate coagulation, as determined by the
   investigator.

   - All patients must provide a tumor tissue sample (formalin fixed paraffin embedded
   [FFPE] blocks or both slides and curls) from archival tissue, or fresh biopsy if a
   biopsy is performed as part of the patient's standard clinical practice before the
   first dose of trial treatment.

   - Women of childbearing potential (WOCBP) must not be pregnant. WOCBP, male patients who
   are sexually active with WOCBP and female partners of male patients should use a
   highly effective method of contraception up to at least 6 months after receiving the
   last dose of trial treatment, and should agree not to donate eggs (ova, oocytes) or
   sperm.

Exclusion Criteria:

Medical conditions:

   - Patients are pregnant or breastfeeding.

   - Patients present primary tumor site of nasopharynx (any histology).

   - Patients with uncontrolled intercurrent illness, including but not limited to:

      - Ongoing or active infection which requires systemic treatment with antibiotics on
      the first dose of trial treatment.

      - Symptomatic congestive heart failure (Grade III or IV as classified by the New
      York Heart Association), myocardial infarction within 3 months before screening,
      unstable angina pectoris, or cardiac arrhythmia.

      - Arterial thrombosis or pulmonary embolism within ≤6 months before the start of
      trial treatment, if not on a stable dose of anticoagulants or if in the opinion
      of the investigator contra-indicates trial inclusion.

      - Evidence or history of interstitial lung disease that, in the opinion of the
      investigator, is a contraindication for treatment with pembrolizumab, or active
      non-infectious pneumonitis.

      - Uncontrolled hypertension defined as systolic blood pressure ≥160 mmHg and/or
      diastolic blood pressure ≥100 mmHg, despite optimal medical management. Patients
      with arterial hypertension need to be on stable anti-hypertensive medication for
      at least 4 weeks prior to trial entry.

      - Known primary immunodeficiencies.

      - Evidence or history of significant autoimmune disease that (a) required treatment
      with systemic immunosuppressive treatments, (b) was associated with ongoing
      treatment with corticosteroids, or (c) was associated with a record of
      significant end-organ dysfunction (even if transient), which in the opinion of
      the investigator may suggest increased risk for immune-related AEs.

      - Patients with prior allogeneic stem cell or solid organ transplantation.

      - Any other disease, metabolic dysfunction, physical examination finding, and/or
      laboratory finding giving reasonable suspicion of a disease or condition that in
      the opinion of the investigator contraindicates the use of an investigational
      drug or may render the patient at high risk for complications.

   - Patients with a known allergy, hypersensitivity, or intolerance to BNT113 or its
   excipients, or to pembrolizumab or its excipients.

   - Patients who have had a splenectomy.

   - Patients who have had major surgery (e.g., requiring general anesthesia) within 4
   weeks before screening, or have not fully recovered from surgery, or have major
   surgery planned during the time of trial participation.

   - Patients who have a known history or a positive test at screening of any of the
   following:

      1. Human immunodeficiency virus (HIV) 1 or 2. Inclusion is allowed if HIV 1/2
      infection is adequately controlled and stable on a highly effective antiviral
      regimen.

      2. Hepatitis B infection, as defined by the presence of hepatitis B surface antigen
      (HbsAg) or hepatitis B virus (HBV) DNA positivity. Testing of HBV DNA is
      mandatory if hepatitis B core antibody is positive.

      3. Hepatitis C (unless considered cured).

   - Patients with another primary malignancy that has not been in complete remission for
   at least 2 years, with the exception of those with a negligible risk of metastasis or
   death (such as adequately treated carcinoma in situ of the cervix, non-invasive basal
   or non-invasive squamous cell skin cancer, localized prostate cancer, non-invasive
   superficial bladder cancer or breast ductal carcinoma in situ).

   - Patients with any condition for which, in the opinion of the investigator,
   participation would not be in the best interest of the patient (e.g., compromise the
   well-being) or that could prevent, limit, or confound the protocol-specified
   assessments.

Prior/concomitant therapy:

   - Patients who have received or currently receive the following therapy/medication:

      1. Chronic systemic immunosuppressive treatment including corticosteroid treatment
      (prednisone >10 mg daily orally [PO] or intravenously [IV], or equivalent) in the
      7 days prior to the first dose of trial treatment.

      2. Prior treatment with other immune modulating agents that was (a) within fewer
      than 4 weeks (28 days) or 5 half-lives of the agent (whichever is longer) prior
      to the first dose of BNT113, or (b) associated with immune-mediated AEs that have
      not resolved prior to the first dose of BNT113 or that pose an additional risk of
      on-trial complications, per investigator's assessment, or (c) associated with
      toxicity that resulted in discontinuation of the immune-modulating agent and that
      poses an additional risk of on-trial complications, per investigator's
      assessment.

      3. Prior treatment with live attenuated vaccines within 4 weeks before the first
      dose of BNT113.

      4. Prior treatment with an investigational drug (including investigational vaccines)
      within 4 weeks or 5 half-lives of the agent (whichever is longer) before the
      planned first dose of BNT113.

      5. Ongoing treatment with therapeutic PO or IV antibiotics. • Note: Patients
      receiving prophylactic antibiotics (e.g., for prevention of a urinary tract
      infection or chronic obstructive pulmonary disease) may be enrolled.

   - Prior treatment with anti-cancer immunomodulating agents, such as blockers of
   programmed death receptor-1 (PD-1), PD-L1, tumor necrosis factor receptor superfamily
   member 9 (TNRSF9, 4 1BB, CD137), OX 40, therapeutic vaccines, cytokine treatments, or
   any investigational agent within 4 weeks or 5 half-lives of the agent (whichever is
   longer) before the first dose of BNT113.

   - Treatment with non-systemic anti-cancer therapy (e.g., radiotherapy or surgery) within
   2 weeks prior to randomization.

      - Note: Prior treatment with bone resorptive therapy, such as bisphosphonates
      (e.g., pamidronate, zoledronic acid) and denosumab, is allowed.

Other comorbidities:

   - Current evidence of Common Terminology Criteria for Adverse Events (CTCAE) v5.0 Grade
   >1 toxicity before the start of treatment, except for hair loss and those Grade 2
   toxicities listed as permitted in other eligibility criteria. Patients with Grade 2
   neuropathy may be eligible at investigator's discretion.

   - Current evidence of new or growing brain or spinal metastases during screening.
   Patients with known brain or spinal metastases may be eligible if they:

      1. had radiotherapy or another appropriate therapy for the brain or spinal
      metastases,

      2. have no neurological symptoms (excluding Grade ≤2 neuropathy),

      3. have no evidence of clinical or radiological progression within 4 weeks before
      signing the informed consent,

      4. do not require steroid therapy within 7 days before randomization or are
      undergoing slow steroid tapering, currently at doses ≤10 mg and neurologically
      stable.

      5. spinal bone metastases are allowed, unless imminent fracture or cord compression
      is anticipated.

Other exclusions:

   - Patients who have previously been enrolled in this trial (rescreening is allowed
   once).

   - Patients with substance abuse or known medical, psychological, or social conditions
   that in the opinion of the investigator may interfere with the patient's participation
   in the trial or evaluation of the trial results.

   - Patients affiliated with the investigational site (e.g., a close relative of the
   investigator or dependent person, such as an employee or student of the trial site) or
   sponsor. For patients meeting this criterion, a prospective exception and eventual
   contingencies to be put in place may be defined on a case-by-case basis by the local
   Institutional Review Board.

Tumor-related conditions:

   - Patients that have disease suitable for local therapy administered with curative
   intent.

   - Patients that have a life expectancy of less than 3 months and/or have rapidly
   progressive disease, as assessed by the treating investigator.

   - Patients with high-burden of visceral metastatic disease or location in anatomically
   critical areas (e.g., causing significant biliary or respiratory obstruction), that in
   the opinion of the investigator may benefit from treatment with chemotherapy.