‣ 1Uptake on DOTATATE PET Patients must have uptake on DOTATATE PET/CT in at least one tumor lesion (corresponding to known disease) equivalent to a Krenning score ≥2 (confirmed by central radiology review).

‣ 2 Prior Therapy Patients must have recovered from the acute treatment related toxicities (defined as ≤ grade 1 if not defined in eligibility criteria) of all prior chemotherapy, immunotherapy, radiotherapy, or any other treatment modality prior to entering this study.

‣ 3 Chemotherapy Patients must have received their last dose of known myelosuppressive anticancer therapy at least 21 days prior to enrollment or at least 42 days if nitrosourea.

‣ 4 Investigational/Biologic Agent

• ●Biologic or investigational agent (anti-neoplastic): Patient must have recovered from any acute toxicity potentially related to the agent and received their last dose of the investigational or biologic agent ≥ 7 days prior to study enrollment.

• For agents that have known adverse events occurring beyond 7 days after administration, this period must be extended beyond the time during which adverse events are known to occur.

• ●Monoclonal Antibodies and agents with known prolonged half-lives: Patient must have recovered from any acute toxicity potentially related to the agent and received their last dose of the agent ≥ 28 days prior to study enrollment.

‣ 5 Radiation

• Patients must have had their last fraction of:

⁃ Craniospinal irradiation or total body irradiation or radiation to \> 50% of pelvis \> 3 months prior to enrollment.

⁃ Focal irradiation \> 4 weeks prior to enrollment

‣ 6 Stem Cell Transplant

• Patient must be:

⁃ ≥ 6 months since allogeneic stem cell transplant prior to enrollment with no evidence of active graft vs. host disease

⁃ ≥ 3 months since autologous stem cell transplant prior to enrollment

‣ 7 Growth Factors Patients must be off all colony-forming growth factor(s) for at least 1 week prior to enrollment (e.g. filgrastim, sargramostim or erythropoietin). Two weeks must have elapsed if patients received long-acting formulations.

‣ 8 Somatostatin analogs Patients must be off long-acting somatostatin analogs for at least 4 weeks and off short-acting somastatin analogs (i.e., octreotide) for at least 24 hours.

‣ 9 Neurologic Status

⁃ Patients with neurological deficits should have deficits that are stable for a minimum of 1 week prior to enrollment, documented by a detailed neurological exam.

⁃ Patients with seizure disorders may be enrolled if seizures are well controlled.

‣ 10 Performance Status Karnofsky Performance Scale (KPS for \> 16 years of age) or Lansky Performance Score (LPS for ≤ 16 years of age) assessed within two weeks of enrollment must be ≥ 50. Patients who are unable to walk because of neurologic deficits, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score

‣ 11 Organ Function

• Patients must have adequate organ and marrow function, both for eligibility for enrollment, and to begin each subsequent cycle of Lutathera, as defined below:

⁃ Adequate Bone Marrow Function as defined as:

• Absolute neutrophil count ≥ 1.0 x 109 cells/ L

∙ Platelets ≥100 x 109 cells/ L (unsupported, defined as no platelet transfusion within 7 days)

∙ Hemoglobin ≥8 g/dl (may receive transfusions)

⁃ Adequate Renal Function as defined as:

• Glomerular filtration rate (GFR) estimated by cystatin C ≥ 60ml/min/1.73 m2

∙ A serum creatinine based on (Schwartz et al. J. Peds, 106:522, 1985) age/gender as follows:

• 1 to \< 2 years: maximum serum creatinine 0.6 mg/dL for males and females. 2 to \< 6 years: maximum serum creatinine 0.8 mg/dL for males and females. 6 to \< 10 years: maximum serum creatinine 1.0 mg/dL for males and females. 10 to \< 13 years: maximum serum creatinine 1.2 mg/dL for males and females. 13 to \< 16 years: maximum serum creatinine 1.5 mg/dL for males and 1.4 mg/dL for females.

• ≥ 16 years: maximum serum creatinine 1.7 mg/dL for males and 1.4 mg/dL for females.

⁃ Adequate Liver Function as defined as:

• Total bilirubin ≤ 3 times institutional upper limit of normal (ULN) for age

∙ AST(SGOT)/ALT(SGPT) ≤ 3 times institutional ULN

∙ Serum albumin ≥ 2g/dL

∙ Coagulation parameters: INR \<1.5 times ULN and aPTT \<1.5 times ULN unless patients are receiving therapeutic anticoagulation which affects these parameters

⁃ Adequate Cardiac Function as defined as:

• Ejection fraction of ≥ 55% by echocardiogram

∙ Serum electrolytes (Sodium, Potassium, Chloride) within institutional limits of normal (patients can be on enteral supplementation)

‣ 12 Corticosteroids Patients who are receiving dexamethasone must be on a stable or decreasing dose for at least 1 week prior to enrollment, with a maximum dexamethasone dose of 2.5mg/m2/day.

‣ 13 Pregnancy Status Female patients of childbearing potential must have a negative serum or urine pregnancy test within 72 hours prior to receiving the first dose of study medication. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required.

‣ 14 Pregnancy Prevention Patients of childbearing or child fathering potential must be willing to use a medically acceptable form of birth control, which includes abstinence, while being treated on this study and for at least 7 months after drug cessation in females of childbearing potential and for at least 4 months after drug cessation in males of child fathering potential.

‣ 15 Informed Consent The patient or parent/guardian is able to understand the consent and is willing to sign a written informed consent document according to institutional guidelines.