First in Human Study of T3P-Y058-739 (T3P)

Inclusion Criteria:

1. Histologically- or cytologically-proven advanced, unresectable solid tumour forwhich there is no curative therapy and no alternative therapy is felt to beappropriate.

2. At least one measurable lesion

3. Male or female, 18 years of age or older at the time of signing informed consent.

4. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.

5. Estimated life expectancy of ≥12 weeks.

6. Resolution of all acute reversible toxic effects of prior therapy or surgicalprocedure to baseline or Grade ≤1 (except alopecia).

7. Adequate iron stores without significant iron overload

8. Adequate organ function

9. Capable of giving signed informed consent which includes compliance with therequirements and restrictions listed in the informed consent form (ICF).

10. At least one lesion that is measurable according to iRECIST/RECIST 1.1 and amenableto direct IT injection, i.e., a lesion that is visible, palpable, or detectable byultrasound, and accessible for direct IT injection (injection via an endoscope isnot allowed for Part A at least; ultrasound and/or radiological guidance isallowed).

Exclusion Criteria:

1. Current or prior malignancy that could affect compliance with the protocol orinterpretation of results. Patients curatively treated more than 2 years prior toenrolment, and patients with adequately treated basal cell or squamous cell skincancer, or carcinoma in situ, are generally eligible.

2. Known central nervous system (CNS) metastases.

3. Patients who have previously received an allogeneic bone marrow or stem celltransplant or with congenital or acquired immunodeficiency or receivingimmunosuppressive therapy (including any dose of systemic corticosteroids). Patientsshould have recovered immunologically from any prior immunomodulatory therapies suchas CD20-targeted antibodies. Patients receiving inhaled corticosteroids for asthmaor chronic obstructive pulmonary disease, and patients on steroid replacementtherapy (e.g. due to prior adrenalectomy or hypophysectomy) are eligible at theinvestigator's discretion. Patients likely to require immunosuppressive treatmentwith systemic steroids or other agent (e.g., patients with frequent exacerbations ofasthma) should not enter the study.

4. Patients with active uncontrolled infection or known to be serologically positivefor human immunodeficiency virus (HIV), hepatitis B or hepatitis C infection.Patients with recent major infection (such as pneumonia in the previous 4 weeks)should have recovered to preillness levels with resolution of reversibleinfection-related symptoms for at least one week prior to starting T3P.

5. Patients with a documented Yersinia infection in the 12 weeks prior to treatment orwith detectable Y. enterocolitica in a baseline stool sample (based on routineculture at site).

6. Patients who have recently received antibiotics that could affect the viability ofT3P (at least 5 half-lives should have elapsed since the last dose).

7. Patients with known cardiac valvular disease or arterial aneurysms, artificial heartvalves and other implanted prostheses (such as joint replacements) that cannot beeasily removed or replaced. Patients with central venous access devices are allowedin the study but T3P should be administered by peripheral vein, whenever possible.Patients with a history of bacterial endocarditis, regardless of the organism, areexcluded from the study.

8. Patients with a history of clinically significant autoimmune conditions, majorcardiac arrhythmia or ischaemia, requiring any form of regular or "as needed"medication to control symptoms, New York Heart Association class II, III or IVcardiac failure or coronary angioplasty in the previous 6 months.

9. Patients who are allergic to chloramphenicol or to all of the following antibiotics:co-trimoxazole, doxycycline, ceftriaxone and cefotaxime.

10. History of hypersensitivity to desferrioxamine

11. Other severe acute or chronic medical or psychiatric condition or laboratoryabnormality that may increase the risk associated with study participation or T3Padministration or may interfere with the interpretation of study results and, in thejudgment of the Investigator, would make the subject inappropriate for entry intothis study. This includes patients on treatment with anticoagulants within 6 monthsprior to study entry for thromboembolic events.

12. Patients with a bleeding diathesis or receiving therapeutic doses of anticoagulantsunless the lesion(s) to be injected are superficial and at low risk of bleeding.Patients receiving lower doses of anticoagulants, aspirin or clopidogrel may beeligible at the investigator's discretion, depending on the site of lesions to beinjected and perceived risk of bleeding.

13. Previous severe hypersensitivity reaction to treatment with Check Point Inhibitor (CPI) or other monoclonal antibody.

14. History of severe immune-related adverse effects (irAEs) for greater than 12 weeks.CPI-related AEs (including irAEs) must have resolved back to Grade 0-1 and patientsreceived no corticosteroids for irAEs for at least two weeks prior to first dose ofpembrolizumab in the study.

15. History of interstitial lung disease or prior pneumonitis requiring systemiccorticosteroid therapy. In case of uncertainty, a high-resolution computedtomography (HRCT) should be performed at baseline.

16. Patients at high risk of bowel perforation, history of acute diverticulitis,intra-abdominal abscess or abdominal carcinomatosis).