Inclusion criteria:

          1. Histologically proven HNSCC of the hypopharynx, oropharynx, oral cavity, supraglottis
             or larynx (except T1 glottic tumours) for whom surgery with curative intent ± post
             operative radiotherapy or chemoradiotherapy is considered the primary treatment of
             choice. Surgery should be scheduled to take place no sooner than 21 days and no later
             than 30 days post first dose of AMG 319 or placebo.

             Patients presenting with recurrence can be considered for inclusion, as long as their
             previous treatment did not include radiotherapy ± chemotherapy or any other anti
             cancer therapy i.e. treated with surgery alone and this did not take place within 6
             months prior to trial entry.

             Patients presenting with a second primary HNSCC can be considered for inclusion, as
             long as any previous radiotherapy, chemotherapy or any other anti cancer therapy was
             completed more than 5 years prior to trial entry.

          2. Patients considered fit to undergo curative resection surgery.

          3. Haematological and biochemical indices within the ranges shown below:

             Laboratory Test Value required

             Haemoglobin (Hb) ≥100 g/L

             Absolute neutrophil count ≥1.5 x 109/L

             Platelet count ≥100 x 109/L

             Bilirubin ≤1.5 x upper limit of normal (ULN) Alanine aminotransferase (ALT) and/or
             aspartate aminotransferase (AST) ≤2.5 x ULN

             Alkaline Phosphatase (alk phos/ALP) ≤2.5 x ULN

             Amylase ≤2.0 x ULN

             Calculated creatinine clearance (using the Wright or Cockcroft-Gault formula) ≥50
             mL/min

          4. 18 years or over at the time informed consent is given.

          5. Written (signed and dated) informed consent and capable of co-operating with treatment
             and follow up.

        Exclusion criteria:

          1. Prior radiotherapy, immunotherapy, chemotherapy or other anti-cancer therapy
             (excluding surgery) for current HNSCC.

          2. Patients should be excluded from the trial if they have active or previous
             malignancies of other types which in the Investigator's opinion would mean they are
             not a good candidate for the clinical trial.

          3. Female patients who are able to become pregnant (or already pregnant or lactating).
             However, those patients who have a negative serum or urine pregnancy test before
             enrolment and agree to use two highly effective forms of contraception (oral; injected
             or implanted hormonal contraception and condom; have an intra uterine device and
             condom; diaphragm with spermicidal gel and condom) effective at the first
             administration of AMG 319, throughout the trial and for 6 months afterwards are
             considered eligible.

          4. Male patients with partners of child bearing potential (unless they agree to take
             measures not to father children by using one form of highly effective contraception
             [condom plus spermicide] effective at the first administration of AMG 319, throughout
             the trial and for 6 months afterwards). Men with pregnant or lactating partners must
             be advised to use barrier method contraception (for example: condom plus spermicidal
             gel) to prevent exposure to the foetus or neonate.

          5. Patients unable to swallow oral medications (trial medication must not be chewed,
             crushed, dissolved or divided).

          6. Major thoracic or abdominal surgery from which the patient has not yet recovered.

          7. At high medical risk because of non malignant systemic disease including active
             uncontrolled infection.

          8. Active or uncontrolled auto immune disease which may require systemic immunomodulator
             therapy during the trial treatment period. Exceptions to this are atopic dermatitis
             and psoriasis not requiring systemic treatment.

          9. Long term use of systemic corticosteroids with the exception of replacement treatment.
             Discontinuation of steroid use within seven days prior to receiving the first dose of
             AMG 319 or placebo would be acceptable. Inhaled and topical steroids are permitted.

         10. Known to be serologically positive for hepatitis B, hepatitis C or human
             immunodeficiency virus (HIV). If there is clinical suspicion of infection this must be
             ruled out by appropriate serological and PCR testing.

         11. QTc >470 msec (Friderica [QTc F] correction) or a history or family history of QT
             prolongation.

         12. Regular and/or prolonged treatment with medications known to cause QTc interval
             prolongation within seven days prior to receiving the first dose of AMG 319 or
             placebo.

         13. Is a participant or plans to participate in another interventional clinical trial,
             whilst taking part in this Phase IIa trial of AMG 319. Participation in an
             observational trial or interventional clinical trial which does not involve
             administration of an IMP would be acceptable.

         14. Any other condition which in the Investigator's opinion would not make the patient a
             good candidate for the clinical trial.