Part 1: 16 to 32 patients with aggressive solid tumors from whom biopsies can be obtained, will receive BO-112 through IT administration.

Injected lesions must be palpable and biopsiable at the time of injection, and biopsied after 7-14 days. Patients will not receive an alternative therapy during the period comprising from first and second biopsy. BO-112 will be administered at a starting dose. Upon confirmation of the safety profile of the starting dose and evaluation of the pharmacokinetic (PK) profile, three additional dose levels are expected to be tested.

During the course of the study, subjects will be examined for any side effects that may occur (safety and tolerability).

Additionally this study will also study BO-112 biological activity, the innate and adaptive immune system response and signaling pathways, as well as signs of clinical relevance, will be studied.

Part 2: An additional 30 patients with progressive disease while on anti-PD1 treatment for an approved indication, will receive BO-112 through IT administration in combination with the anti-PD1 treatment to evaluate the safety and tolerability of the combination.

Injected lesions must be palpable and biopsiable at the time of injection. Patients will continue with their anti-PD1 treatment. During the course of the study, patients will be examined for any side effects that may occur (safety and tolerability).

Additionally this part of the trial will also study BO-112 biological activity, the innate and adaptive immune system response and signaling pathways, as well as signs of clinical response

Inclusion Criteria:

1. Patients age 18 years or more on the day of signing informed consent form.

2. Histologically or cytologically confirmed aggressive solid tumors

3. Patients must have:

   • Biopsy-accessible tumors
   • No prior anticancer treatment during the last 14 days

Additional inclusion criteria for Part 2: disease progression on treatment with anti-PD1 antibody for an approved indication

Exclusion Criteria:

Other relevant and clinically significant concomitant diseases or adverse clinical conditions which may jeopardize patient safety:

• Increased cardiac risk: congestive heart failure; or unstable angina pectoris; or arrhythmia requiring treatment or uncontrolled arterial hypertension; or myocardial infarction within 12 months before inclusion in the study.

• Patients with active central nervous system (CNS) lesions (including carcinomatous meningitis) will be excluded. However, patients will be eligible if:

  • All known CNS lesions have been treated with stereotactic therapy or surgery, AND
  • There has been no evidence of clinical and radiographic disease progression in the CNS for ≥ 4 weeks after radiotherapy or surgery, and has not required to increase in the last 4 weeks their steroids use or has not started a new course of steroids
  • Whole brain radiotherapy is not allowed, with the exception of patients who have had definitive resection or stereotactic therapy of all radiologically detectable parenchymal brain lesions.

• Active infection.

• Significant non-neoplastic liver disease (e.g., cirrhosis, active chronic hepatitis B or C).

• Any clinically significant abnormality on history or examination including diagnosis of immunodeficiency or receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication (physiologic doses of corticosteroids may be approved after consultation with the Sponsor).

Additional exclusion criteria for Part 2: Grade 3-4 toxicity due to anti-PD1 antibody or permanent discontinuation of anti-PD1 antibody due to immune related or other adverse reaction.