Inclusion Criteria:

          1. Signed informed consent must be obtained prior to participation in the study.

          2. Adult patients (age >= 18 years old) with any of the following advanced or metastatic
             solid tumors: breast cancer, lung cancer, prostate cancer, GIST, GBM.

          3. At least one measurable lesion as per RECIST 1.1, RANO (applicable for GBM only)
             criteria detected on the low-dose CT/MRI (for GBM MRI only) acquired together with the
             [68Ga]-NeoB PET.

             The same identified measurable lesion shows [68Ga]-NeoB uptake on PET/CT or PET/MRI.
             If the only matching lesion is located in the bone, the patient will still be
             eligible.

          4. Patients for whom no standard therapy is available, tolerated or appropriate.

          5. Patient Eastern Cooperative Oncology Group (ECOG) performance status =< 2.

          6. Life expectancy more than 6 months.

        Exclusion Criteria:

          1. Patients who have not had resolution, except where otherwise stated in the inclusion/
             exclusion criteria, of all clinically significant toxic effects of prior systemic
             cancer therapy, surgery, or radiotherapy to Grade =<1 (except for alopecia)*.

          2. Creatinine clearance (calculated using Cockcroft-Gault formula, or measured) < 60
             mL/min or serum creatinine > 1.5 x ULN*

          3. Platelet count of < 75 x 109/L*

          4. Absolute neutrophil count (ANC) < 1.0 x 109/L*.

          5. Hemoglobin < 9 g/dL*

          6. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 3 x upper limit
             of normal (ULN) if no demonstrable liver metastases or > 5 x ULN in the presence of
             liver metastases*

          7. Total bilirubin > 1.5 x ULN, except for patients with documented Gilbert's syndrome
             who are eligible if total bilirubin =< 3 x ULN*

          8. Serum amylase and/or lipase > 1.5 x ULN*

          9. Known or expected hypersensitivity to [177Lu]-NeoB, [68Ga]-NeoB or any of their
             excipients.

         10. Impaired cardiac function or clinically significant cardiac disease, including any of
             the following:

               -  Clinically significant and/or uncontrolled heart disease such as congestive heart
                  failure requiring treatment (NYHA grade >= 2), uncontrolled arterial hypertension
                  or clinically significant arrhythmia

               -  LVEF < 50% as determined by echocardiogram (ECHO)*

               -  QTcF >470 msec for females and QTcF >450 msec for males on screening
                  electrocardiogram (ECG) or congenital long QT syndrome

               -  Acute myocardial infarction or unstable angina pectoris < 3 months prior to
                  [177Lu]-NeoB (IMP1) administration.

         11. Patients with diabetes mellitus not stable under current treatment as judged by the
             investigator or with hyperglycemia ≥ CTCAE Grade 2*

         12. Patients with history of or ongoing acute or chronic pancreatitis.

         13. Concurrent bladder outflow obstruction or unmanageable urinary incontinence.

         14. Administration of a radiopharmaceutical with therapeutic intent within a period
             corresponding to 10 half-lives of the radionuclide used prior to injection of
             [68Ga]-NeoB (IMP2).

         15. Prior External Beam Radiation Therapy (EBRT) to more than 25% of the bone marrow.

         16. [223Ra]-therapy within the context of diffuse bone or bone-marrow involvement (i.e.
             "superscan" defined as bone scintigraphy in which there is excessive skeletal
             radioisotope uptake [>20 bone lesions] in relation to soft tissues along with absent
             or faint activity in the genitourinary tract due to diffuse bone/ bone marrow
             metastases).

         17. Patients who have changed the dose of systemic steroid therapy within less than 2
             weeks prior to [177Lu]-NeoB (IMP1) administration or patients for whom steroid dose
             increase is anticipated during the study.

         18. Patients who have received prior systemic anti-cancer treatment within the following
             time frames:

               -  Cyclical chemotherapy within a period that is shorter than the cycle length used
                  for that treatment (e.g. 6 weeks for nitrosourea, mitomycin-C) prior to starting
                  [177Lu]-NeoB treatment

               -  Biologic therapy (e.g. antibodies), continuous or intermittent small molecule
                  therapeutics, or any other investigational agents within a period which is =< 5
                  T1/2 or =< 4 weeks (whichever is shorter) prior to starting [177Lu]-NeoB
                  treatment

         19. History of somatic or psychiatric disease/condition that may interfere with the
             objectives and assessments of the study.

         20. Malignant disease, other than that being treated in this study. Exceptions to this
             exclusion include the following: malignancies that were treated curatively and have
             not recurred within 2 years prior to [177Lu]-NeoB treatment; completely resected basal
             cell and squamous cell skin cancers; any malignancy considered to be indolent and that
             has never required therapy; and completely resected carcinoma in situ of any type.

         21. Pregnant or breast-feeding women

         22. Women of child-bearing potential, defined as all women physiologically capable of
             becoming pregnant, are not allowed to participate in this study UNLESS they are using
             highly effective methods of contraception throughout the study and for 6 months after
             study drug discontinuation. Highly effective contraception methods include:

               -  True abstinence, when this is in line with the preferred and usual lifestyle of
                  the patient. Periodic abstinence (e.g., calendar, ovulation, symptothermal,
                  post-ovulation methods), declaration of abstinence for the duration of exposure
                  to IMPs, and withdrawal are not acceptable methods of contraception.

               -  Male or female sterilization. Vasectomised partner is a highly effective birth
                  control method if the partner is the sole sexual partner of the study participant
                  and the vasectomised partner has received medical assessment of the surgical
                  success.

             Women tubal ligation is an acceptable highly effective contraception method, but
             surgical sterility is defined as bilateral salpingectomy (or bilateral oophorectomy or
             hysterectomy).

             • Combination of any two of the following (a+b or a+c or b+c):

               1. Use of oral, injected, or implanted hormonal methods of contraception. In case of
                  use of oral contraception, women should be stable on the same pill for a minimum
                  of 3 months before taking [177Lu]-NeoB treatment.

               2. Placement of an intrauterine device (IUD) or intrauterine system (IUS)

               3. Barrier methods of contraception: condom or occlusive cap (diaphragm or
                  cervical/vault caps) with spermicidal foam/gel/film/cream/vaginal suppository
                  Post-menopausal women are allowed to participate in this study. Women are
                  considered post-menopausal and not of child bearing potential if they have had 12
                  months of natural (spontaneous) amenorrhea with an appropriate clinical profile
                  (e.g. age appropriate, history of vasomotor symptoms) or six months of
                  spontaneous amenorrhea with serum Follicle-Stimulating Hormone (FSH) levels > 40
                  mIU/mL [for US only: and estradiol < 20 pg/mL] or have had surgical bilateral
                  oophorectomy or bilateral salpingectomy or hysterectomy or tubal ligation at
                  least six weeks prior to screening. In the case of oophorectomy alone, only when
                  the reproductive status of the woman has been confirmed by follow up hormone
                  level assessment is she considered not of child bearing potential.

             Sexually active males must use a condom during intercourse while taking the drug and
             for 6 months after stopping treatment and should not father a child in this period. A
             condom is required to be used also by vasectomized men in order to prevent delivery of
             the drug via seminal fluid.

         23. Participation in any other investigational trial at the time of informed consent
             signature.

               -  To be considered as valid to determine the eligibility of a patient, exam results
                  of exclusion criteria #2, #3, #4, #5, #6, #7, #8, #10 (except QTcF parameter) and
                  #11 must not be older than 1 month prior to [68Ga]-NeoB administration and must
                  be available in the source documents for monitoring.