A first-in-human, open-label, dose escalation followed by dose expansion phase I/IIa trial to evaluate the safety, preliminary efficacy and pharmacokinetics of intratumoral CyPep-1 monotherapy and in combination with pembrolizumab in patients with advanced solid cancers.

For Phase I and Phase IIa Arms A and C: 1. Histologically or cytologically confirmed locally advanced (unresectable) or metastatic tumors (solid tumor or lymphoma) with an accessible tumor lesion for intratumoral injection of CyPep-1 malignancy (including lymphomas) that is either: a. Refractory to standard-of-care treatment b. Have a disease for which there is no standard therapy considered appropriate. Metastatic deposits (including cutaneous/subcutaneous lesions and metastatic deposits in lymph nodes) of tumors for which IT injections may be performed are eligible. Pure cutaneous infiltrations (e.g., breast cancer cutaneous carcinomatosis) are ineligible. 2. 1 to 3 non-ulcerated transcutaneously accessible lesion(s) for injection and measurable as defined by iRECIST. All other tumor lesion(s) may be selected for efficacy follow-up, but will not be subjected to treatment with CyPep-1. 3. Presence of tumor lesion(s) (that have not been previously irradiated) suitable for biopsy at screening and at Week 6. For Arm C: 4. Confirmation of the presence of at least 1 liver metastasis by imaging. 5. Subjects must have measurable disease which is equal to one or more metastatic liver lesions that can be accurately and serially measured that are greater than 1 cm dimension and for which the longest diameter is greater or equal to 1 cm as measured by CT (computed tomography)scan or magnetic resonance imaging (MRI). The metastatic liver lesion must not be in an area that received prior localized therapies. 6. Metastatic liver lesion for injection with >50% radiological visible necrosis must be avoided and the lesion must be located where any tumor swelling will not lead to gall bladder tract obstruction or lead to bleeding risk. For Arm D: 7. Histologically or cytologically confirmed diagnosis of advanced (unresectable Stage III) or metastatic (Stage IV: M1a and/or M1b) melanoma considered incurable by Standard of Care. For metastatic melanoma, only cutaneous, subcutaneous, lymph node, or lung metastases are allowed. 8. Previously exposed to ICI(s) and be categorized following the SITC Immunotherapy Resistance Taskforce (Kluger 2020) meeting one of the following: a. Have primary resistance: PD-(L)-1 inhibitor exposure >=6 weeks and have the best response as one of the following: i. PD, ii. SD for <6 months. b. Have secondary resistance: PD-(L)-1 inhibitor exposure >=6 weeks and best response CR, PR, or SD >6 months. c. Have adjuvant therapy resistance: recurrence subcategorized into primary resistance/early relapse occurred <12 weeks after the last dose, and late relapse occurred >=12 weeks after the last dose. If BRAF mutated, patients must have progressed to treatment with BRAF inhibitors. d. Have neoadjuvant therapy resistance including subjects with or without major pathologic response and subsequent PD that fulfills criteria for primary or secondary resistance e. Discontinued from ICI(s) therapy due to immune-related adverse events grade 3 or 4 other than endocrine insufficiencies treatable with hormonal replacement therapy, and meet one of the following: i. Remain on SD at discontinuation of PD-(L)1 inhibitor in combination with ipilimumab or show regrowth after <12 weeks of the last dose ii. Have not achieved a CR with single-agent PD-(L)1 inhibitor or combination of PD-(L)1 with LAG-3 inhibitor 9. At least 1 non-ulcerated lesion, not exceeding 5 cm in (the longest) diameter, for intratumoral injection(s) and measurable as defined by iRECIST. 10. Resolution of toxicity due to prior therapy returned to baseline or < Grade 2, except for alopecia or other irreversible immune-mediated AEs, as defined by CTCAE v5.0. and SITC ICI-related AEs (Brahmer et al, 2021). 11. Prior treatment(s) delivered by IT injection to the to-be injected lesion(s), including investigational agents, is allowed. For Phase I and Phase IIa Arms A, C and D in addition: 12. Age >= 18 years. 13. Estimated life expectancy of at least 3 months. 14. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 (Appendix B). 15. Resolution of toxicity due to prior therapy to Grade < 2 (except for alopecia and transaminases in case of liver metastases) as defined by CTCAE v5.0 (Appendix C). 16. Ability to give written informed consent and to comply with the protocol. 17. All subjects of childbearing potential (defined as < 2 years after last menstruation or not surgically sterile) must have a negative highly sensitive pregnancy test at screening (urine/serum) and agree to use highly effective method for contraception according to the EU Clinical Trial Facilitation Group guidance from time of signing the informed consent form (ICF) until at least 120 days after the last administration of CyPep-1. The partners of subjects with childbearing potential must also apply contraceptive methods and are recommended not to donate sperm. 18. A male participant must agree to use contraception and refrain from sperm donation during the treatment period and for at least 120 days after the last dose of trial medication. 19. Adequate bone marrow, liver, and renal function: a. Platelet count >= 100 x 109/L b. Hemoglobin >= 6.0 mmol/L or 9.67 g/dL c. Absolute Neutrophil Count (ANC) >= 1.5 x 109/L d. Total bilirubin <= 1.5 x ULN, except for subjects with familial bilirubinemia (Gilbert*s disease) e. Serum ASAT and ALAT <= 2.5 x ULN (<= 5 x ULN in case of liver metastases) f. Creatinine clearance >= 30 mL/min (Glomerular Filtration Rate [GFR] to be calculated by CKD-EPI formula) For Phase IIa Arm B: Participants are eligible to be included in Arm B of the trial only if all of the following criteria apply: Type of Participant and Disease Characteristics 1. The participant provides written informed consent for the trial. 2. Be >= 18 years of age on day of signing informed consent. 3. Participant with histologically or cytologically confirmed diagnosis of advanced (unresectable Stage III) or metastatic (Stage IV) solid tumor malignancy (including lymphomas) that is refractory to standard-of-care treatment or for which there is no standard therapy considered appropriate. Metastatic deposits (including cutaneous/subcutaneous lesions and metastatic deposits in lymph nodes) of tumors for which IT injections may be performed are eligible. Pure cutaneous infiltrations (e.g., breast cancer cutaneous carcinomatosis) are ineligible. 4. Subjects must have progressed on treatment with an anti-PD1/L1 monoclonal antibody (mAb) administered either as monotherapy, or in combination with other checkpoint inhibitors or other therapies. Treatment progression is defined by meeting all of the following criteria: a. Has received at least 2 doses of an approved anti-PD-1/L1 mAb. b. Has demonstrated clinical or radiological disease progression (PD) after PD-1/L1 5. A male participant must agree to use contraception and refrain from sperm donation during the treatment period and for at least 120 days after the last dose of trial medication. 6. A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: a.) Not a woman of childbearing potential (WOCBP) b.) A WOCBP (defined as < 2 years after last menstruation or not surgically sterile) must have a negative highly sensitive pregnancy test at screening (urine/serum) and must follow contraceptive guidance (highly effective method for contraception according to the EU Clinical Trial Facilitation Group guidance) from time of signing the ICF until at least 120 days after the last administration of trial medication. The partners of subjects with childbearing potential must also apply contraceptive methods, and are recommended not to donate sperm. 7. 1 to 3 non-ulcerated transcutaneously accessible lesion(s) for injection and measurable as defined by iRECIST. All other tumor lesion(s) may be selected for efficacy follow-up, but will not be subjected to treatment with CyPep-1. 8

For Phase I and Phase IIa Arms A, C and D: subjects who meet ANY of the following criteria at screening will be excluded from trial entry: 1. There is no limit to the number of prior treatment regimens, but prior treatment(s) should not include compounds delivered by IT injection to the to-be injected lesion(s), including investigational agents. Subjects with prior IT therapies are allowed in Arm D. 2. Participation in another clinical trial within 4 weeks prior to first dose of CyPep-1. 3. Anti-cancer therapy within 4 weeks prior to the first dose of CyPep-1 (within 2 weeks for palliative radiotherapy, within 1 week for endocrine therapy). 4. Major surgical procedure within 14 days prior to the first dose of CyPep-1. 5. Live vaccine within 30 days prior to first dose of CyPep-1. 6. Expected to require any other form of systemic or localized antineoplastic therapy while in this trial. Localized palliative radiotherapy for pain relief is allowed on tumor lesions that are not selected for evaluation of treatment response. 7. Clinical evidence of an active second malignancy that is progressing or requires active treatment, except for curatively treated early stage (carcinoma in situ or stage 1) carcinomas or non-melanoma skin cancer. 8. Active autoimmune disease requiring immunosuppressive therapy. 9. Any condition requiring continuous systemic treatment with either corticosteroids (> 10 mg daily prednisone equivalents) or other immunosuppressive agents within 2 weeks prior to first dose of CyPep-1. Inhaled, intranasal or topical (only on areas outside the injected lesion(s)) and physiological replacement doses of up to 10 mg daily prednisone equivalent are permitted in the absence of active auto-immune disease. 10. Abnormal or clinically significant coagulation parameters: a. Prothrombin Time - International Normalized Ratio (PT-INR) ) >= 1.5 ULN b. Activated Partial Thromboplastin Time (APTT) ) >= 1.5 ULN Subjects being treated with anticoagulants are excluded if the coagulation parameters are outside the therapeutic intervals as described in the SmPC for the administered treatment. 11. Subjects on anticoagulants with temporarily stop and start, supported by low molecular weight heparin (or other anticoagulation therapy at the discretion of the investigator and/or per local standard of care) during treatment period. 12. Known hypersensitivity to any component of CyPep-1. 13. Prior allogeneic tissue/solid organ transplant, stem cell or bone marrow transplant. 14. Known active human immunodeficiency virus (HIV). Subject is eligible when normal levels of CD4 are present. 15. Central nervous system (CNS) metastasis that is symptomatic or progressing or that requires current therapy (e.g., evidence of new or enlarging CNS metastasis, carcinomatous meningitis or new neurological symptoms attributable to CNS metastasis). 16. QTcF > 480 ms, history of long or short QT syndrome, Brugada syndrome, or known history of QTc prolongation, or Torsade de Pointes. 17. Women who are pregnant or breastfeeding. 18. Any serious and/or unstable pre-existing medical, psychiatric or other condition which in the investigator*s opinion could interfere with subject safety, obtaining written informed consent, or compliance with the trial protocol. 19. Has an active acute or chronic infection requiring systemic therapy at the time of CyPep-1 injection. Note: Subjects treated for mild/moderate infection with oral antibiotics only may be included based on consultation with the study medical monitor and the sponsor. Additional exclusion criteria for Phase IIa Arm C: 20. Subject is a candidate for hepatic surgery or local regional therapy of liver metastases with curative intent. 21. More than one third of the liver is estimated to be involved with metastases. 22. There is invasion by cancer into the main blood vessels such as the portal vein, hepatic vein or the vena cava. 23. Subject is currently receiving or has received liver metastatic-directed therapy (eg: radiation, ablation, embolization) less than 4 weeks prior to enrolmentor hepatic surgery. Exclusion criteria specific for Phase IIa Arm B: Participants are excluded from the trial if ANY of the following criteria apply at screening: Pregnancy Exclusion 1. A WOCBP who has a positive urine pregnancy test (within 72 hours) prior to trial treatment. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required. Prior/Concomitant Therapy 2. Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA 4, OX 40, CD137), and was discontinued from that treatment due to a Grade 3 or higher irAE. 3. Has received prior systemic anti-cancer therapy including investigational agents within 4 weeks (within 1 week for endocrine therapy) prior to first dose of CyPep-1. Note: Participants must have recovered from all AEs due to previous therapies to <=Grade 1 or baseline as defined by CTCAE v5.0 (Appendix C). Participants with <=Grade 2 neuropathy may be eligible. Participants with endocrine-related AEs Grade <=2 requiring treatment or hormone replacement may be eligible. Note: If the participant had major surgery, this should not have been within 14 days prior to the first dose of CyPep-1 and the participant must have recovered adequately from the procedure and/or any complications from the surgery prior to starting study intervention. 4. Has received prior (palliative) radiotherapy within 2 weeks of start of trial treatment. Participants must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (<=2 weeks of radiotherapy) to non-CNS disease. 5. Has received a live or live-attenuated vaccine within 30 days prior to the first dose of CyPep-1. Note: Administration of killed vaccines are allowed. 6. Has received prior compounds delivered by IT injection to the to-be injected lesion(s), including investigational agents. 7. Expected to require any other form of systemic or localized antineoplastic therapy while in this trial. Localized palliative radiotherapy for pain relief is allowed on tumor lesions that are not selected for evaluation of treatment response. 8. Ongoing pembrolizumab-related toxicity event(s) as per TLT definition. Prior/Concurrent Clinical Trial Experience 9. Is currently participating in or has participated in a trial of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of trial treatment. Note: Participants who have entered the follow-up phase of an investigational trial may participate as long as it has been 4 weeks after the last dose of the previous investigational agent. 10. Has had an allogeneic tissue/solid organ transplant. Diagnostic assessments 11. 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 of immunosuppressive therapy within 7 days prior the first dose of CyPep-1. 12. Has a known additional malignancy that is progressing or has required active treatment within the past 3 years, except for curatively treated early stage (carcinoma in situ or stage 1) carcinomas or non-melanoma skin cancer. Note: Participants with basal cell carcinoma of the skin, squamous cell carcinoma of the skin or carcinoma in situ (e.g., breast carcinoma, cervical cancer in situ) that have undergone potentially curative therapy are not excluded. 13. Has known active CNS metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate provided they are radiologically stable, i.e., without evidence of progression for at least 4 weeks by repeat imaging (note that the repeat imaging should be performed during study screening), clinically stable and wi