Oncolytic Adenovirus Coding for TNFa and IL2 (TILT-123) With Pembrolizumab or Pembrolizumab (Phase 1a and 2) and Pegylated Liposomal Doxorubicin (Phase 1b) as Treatment for Ovarian Cancer.

Inclusion Criteria:

• Signed and dated informed consent(s) by the participant or legal representativebefore any trial-related activities.

• Female over 18 years of age on day of signing informed consent(s).

• Diagnosis:

1. Phase I part: Histologically confirmed ovarian cancer (including fallopian tubeand primary peritoneal cancer) resistant to platinum (defined as progression ofcancer within 183 days of the most recent dose of cisplatin or carboplatin) orrefractory to platinum (defined as progression of cancer within 30 days of themost recent dose of cisplatin or carboplatin) ovarian cancer, which cannot betreated with curative intent with available therapies.

2. Phase Ib part: Platinum refractory/resistant ovarian cancer treated with up toone line of prior chemotherapy in refractory/resistant setting. Note: A regimenthat contains only one or more biological agents and/or targeted therapies butno cytotoxic drug does not count as a line of chemotherapy Note: For both phaseI and phase Ib, PARP inhibitors should be considered as indicated in clinicalpractice, prior to trial enrollment. Patients who have platinum-sensitivedisease (no recurrence or progression within 183 days of the last dose ofplatinum-containing chemotherapy) but who have an allergy or severe intoleranceto carboplatin and/or cisplatin may be included.

3. Phase II part: 2. Participants who have histologically or cytologicallyconfirmed recurrent, platinum-resistant ovarian, fallopian tube, or primaryperitoneal cancer treated with ≤ 2 lines of prior cytotoxic chemotherapy in theplatinum-resistant setting.

• At least one tumor (>14 mm in diameter) or carcinomatosis must be available forlocal virus injection (intratumoral and/or intraperitoneal).

• The disease burden must be evaluable, but does not need to fulfil RECIST 1.1.

• Have adequate organ function as defined in the following values below. Specimensmust be collected within 10 days prior to the start of study treatment. a. Hematological laboratory values i. Absolute neutrophil count (ANC): ≥1500/µL ii.Platelets: ≥ 100 000/µL iii. Hemoglobin: ≥9.0 g/dL or ≥5.6 mmol/L. Criteria must bemet without packed red blood cell (pRBC) transfusion within the prior 2 weeks.Participants can be on stable dose of erythropoietin (≥ approximately 3 months. iv.Leukocytes (WBC) > 3.0x10^9/L b. Renal laboratory values i. Glomerular FiltrationRate (GFR): >45 ml/min (CKD-EPI formula). c. Hepatic laboratory values i. Totalbilirubin: ≤1.5 × Upper Limit of Normal (ULN) OR direct bilirubin ≤ULN forparticipants with total bilirubin levels >1.5 × ULN (excluding patients withGilber's Disease) ii. Aspartate Aminotransferase (AST) (SGOT) and AlanineAminotransferase (ALT) (SGPT): ≤2.5 × ULN (≤5 × ULN for participants with livermetastases)

• Patients must be willing to use adequate forms of contraception from screening,during the trial, and for a minimum of 120 days after end of treatment, inaccordance with the following: i. Women of childbearing potential: Barrier contraceptive method (i.e. condom) mustbe used in addition to one of the following methods: Intrauterine devices orhormonal contraception (oral contraceptive pills, implants, transdermal patches,vaginal rings or long-acting injections). ii. Women not of childbearing potential:Barrier contraceptive method (i.e. condom) must be used.

• Eastern Cooperative Oncology Group (ECOG)/World Health Organization (WHO)performance score of 0-1 at screening.

• Life expectancy longer than 3 months.

• Capable of understanding and complying with parameters as outlined in the protocol.

Exclusion Criteria:

• Has an active autoimmune disease that has required systemic treatment in past 2years (i.e., with use of disease modifying agents, corticosteroids orimmunosuppressive drugs). Replacement therapy (e.g., thyroxine, insulin, orphysiologic corticosteroid replacement therapy for adrenal or pituitaryinsufficiency) and inhaled and topical treatments are not considered a form ofsystemic treatment and are allowed.

• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form ofimmunosuppressive therapy within 7 days prior the first dose of study drug.

• Prior therapy:

1. Both phase I and phase Ib parts: Treated with any anti-cancer therapy within 30days prior to the first virus injection. Anti-cancer therapy is defined as anticancer agents (e.g. surgery, chemotherapy, immune-checkpoint inhibitors, kinaseinhibitors, PARP inhibitors, biological therapies, hormonal therapies,radiation, etc.). Continuation of hormonal therapy or use of bone modifyingagents (e.g. bisphosphonate or denosumab) is allowed if started at least 3months before.

2. Phase Ib part: Prior oncolytic viruses, immune checkpoint inhibitors oranthracyclines (eg. doxorubicin, liposomal doxorubicin, epirubicin or any otheranthracycline formulations).

• Participants must have recovered from all Adverse Events (AE)s due to previoustherapies to ≤Grade 1or baseline. Participants with ≤Grade 2 neuropathy may beeligible. Participants with endocrine-related AEs Grade ≤2 requiring treatment orhormone replacement may be eligible. If the participant had major surgery, theparticipant must have recovered adequately from the procedure and/or anycomplications from the surgery prior to starting study intervention.

• Treated with a prior radiotherapy, including for palliative purposes, within 2 weeksof start of study treatment (before or after). Participants must have recovered fromall radiation-related toxicities, not require corticosteroids, and not have hadradiation pneumonitis. A 1-week washout is permitted for palliative radiation (≤2weeks of radiotherapy) to non-Central Nervous System (CNS) disease. Palliativeradiation is allowed from day 15 during the trial treatment period, if deemednecessary by the investigator.

• Treated with a prior therapy with an anti-PD-1, anti-PD-L1, or anti PD L2 agent orwith an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., Cytotoxic T lymphocyte-associated Antigen (CTLA)-4, Tumor necrosis factorreceptor superfamily, member 4 (OX40), CD137), and was discontinued from thattreatment due to a Grade 3 or higher immune-related Adverse Events (irAE).

• Is currently participating in or has participated in a study of an investigationalagent or has used an investigational device within 30 days prior to the first virusinjection. An investigational agent is any drug or therapy that is currently notapproved for use in humans. Participants who have entered the follow-up phase of aninvestigational study may participate as long as it has been 4 weeks after the lastdose of the previous investigational agent.

• Uncontrolled cardiac or vascular diseases.

• History of myocardial infarction or cerebral stroke within the previous 12 monthsbefore screening or is not sufficiently recovered from an older infarction orcerebral stroke.

• History of severe hepatic dysfunction.

• History of hepatitis B (defined as HBsAg reactive), Hepatitis C (defined ashepatitis C virus (HCV) RNA [qualitative] is detected) and/or HIV. No testing forHepatitis B, Hepatitis C and HIV is required unless mandated by a local healthauthority.

• History of coagulation disorder.

• Has a history or current evidence of any condition, therapy, or laboratoryabnormality that might confound the results of the study, interfere with theparticipant's participation for the full duration of the study, or is not in thebest interest of the participant to participate, in the opinion of the treatinginvestigator.

• Female patients who are pregnant, breastfeeding or intend to become pregnant. Womenof childbearing potential who has a positive urine pregnancy test (within 72 hours)prior to treatment. If the urine test is positive or cannot be confirmed asnegative, a serum pregnancy test will be required.

• Has a known additional malignancy that is progressing or has required activetreatment within the past 5 years. Participants with basal cell carcinoma of theskin, squamous cell carcinoma of the skin, or carcinoma in situ (e.g., breastcarcinoma, cervical cancer in situ) that have undergone potentially curative therapyare not excluded.

• Has known active CNS metastases and/or carcinomatous meningitis. Participants withpreviously treated brain metastases may participate provided they are radiologicallystable, i.e., without evidence of progression for at least 3 months by repeatimaging (note that the repeat imaging should be performed during study screening),clinically stable and without requirement of steroid treatment for at least 14 daysprior to first dose of study treatment.

• Has an active infection requiring systemic therapy.

• Has a history of (non-infectious) pneumonitis that required steroids or has currentpneumonitis.

• Has a known psychiatric or substance abuse disorder that would interfere with theparticipant's ability to cooperate with the requirements of the study.

• Allergy to ingredients present in the investigational medicinal products (ingredients are listed in the protocol) ie. severe hypersensitivity (≥Grade 3) topembrolizumab and/or any of its excipients.

• Known contraindications to pembrolizumab.

• Has had an allogenic tissue/solid organ transplant.

• Has received a live or live-attenuated vaccine within 30 days prior to the firstdose of study intervention. Administration of killed vaccines are allowed.