The aim of this clinical study is to learn more about the effects of urolithin A (MitoPure®) on the immune system of cancer patients receiving immune checkpoint inhibitor-based therapies. Any effects will be compared with patients who take a placebo instead of urolithin A (MitoPure®).

Inclusion Criteria:

1. Newly diagnosed solid cancer without previous systemic anticancer treatment

2. Planned single agent or double agent immune checkpoint inhibitor therapy as first-line standard-of-care treatment either with or without chemotherapy. Of note, patients receiving neoadjuvant therapy are eligible

3. Age ≥ 18 years

4. Life-expectancy ≥ 3 months

5. Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1

6. Patient is willing and able to comply with the protocol for the duration of the study, including hospital visits and scheduled follow-up visits and examinations

7. Female patients of childbearing potential (WOCBP) are only eligible if using highly effective contraceptive measures and must have a negative urine or serum pregnancy test within 7 days prior to start of study treatment and must not be breast-feeding prior to start of trial. Non-child-bearing potential must be evidenced by fulfilling one of the following criteria at screening:

   • Post-menopausal defined as aged more than 50 years and amenorrheic for at least 12 months following cessation of all exogenous hormonal treatments
   • Women under 50 years old would be considered postmenopausal if they have been amenorrheic for 12 months or more following cessation of exogenous hormonal treatments and with LH and FSH levels in the post-menopausal range for the institution.
   • Documentation of irreversible surgical sterilization by hysterectomy, bilateral oophorectomy or bilateral salpingectomy but not tubal ligation

Exclusion Criteria:

1. Patients who currently receive or have received cytostatic chemotherapy, glucocorticoids, or immune modulatory agents (including low-dose methotrexate, TNF alpha inhibitors, calcineurin inhibitors, interleukin inhibitors, etc.) during the last 3 months are not eligible. Of note, topical glucocorticoid treatments and hormone replacement therapy is acceptable
2. Patients who currently take or plan to take mitochondrial supplements like coenzyme q10, NAD+ boosters (e.g. nicotineamide riboside, nicotineamine mononucleotide), or L-carnitine
3. Patients who have received radiotherapy to the mediastinum or to other areas with anticipated strong irradiation of a large blood vessel by the judgement of the investigator are not eligible
4. Patients with known HIV infection are not eligible. Testing is not mandatory
5. Patients with a history of solid organ or hematopoietic cell transplantation6. Any medical condition that in the opinion of the investigators would compromise the study outcome or the safety of the patient