How is Lutetium-177 (LU-177) administered?

Administration of Lutetium-177 (LU-177) in Peptide Receptor Radionuclide Therapy

Lutetium-177 (LU-177) is administered intravenously at a dose of 5.55-7.4 GBq (150-200 mCi) per cycle, typically given in three to five cycles with 6-12 week intervals between treatments. 1

Standard Administration Protocol

Dosage and Administration Schedule

• 177Lu-DOTATATE/177Lu-DOTATOC:
  • Administered activity: 5.55-7.4 GBq (150-200 mCi)
  • Number of cycles: Three to five
  • Time interval between cycles: 6-12 weeks 1

Administration Procedure

1. Preparation:

   • A physician must remain nearby during administration
   • A resuscitation cart and trained emergency team must be available
   • The radiopharmaceutical is diluted with saline to a final volume of 10-100 ml

2. Delivery Method:

   • Administered via an indwelling catheter to ensure safe intravenous administration
   • Infusion time: 10-30 minutes, depending on the infusion system
   • The radiopeptide may be co-infused with amino acid solution via a three-way stopcock ("piggy-back")
   • The line should be flushed with saline after completion of the infusion 1

3. Renal Protection:

   • Amino acid solution is co-administered to reduce nephrotoxicity
   • Amino acid infusion typically starts 2 hours before and continues for 6 hours after LU-177 administration 2
   • This reduces tubular renal reabsorption of LU-177 2

Special Considerations

For Compromised Patients

For patients with reduced renal function:

1. Nephrourology consultation
2. Extensive hydration (2-3 L of fluid intake) prior to treatment
3. Diuretics (e.g., furosemide) for dilated renal pelvis and delayed outflow 1

Radiation Safety Precautions

• During the first 2 days after treatment, high levels of radioactivity are excreted in urine

• Patients should:

  • Use double toilet flush after urination
  • Wash hands thoroughly after urination
  • Avoid soiling underclothing or areas around toilet bowls for 1 week
  • Wash contaminated clothing separately 1

• Additional precautions:

  • Limit close contact (<3 feet) with household contacts for 2 days or with children and pregnant women for 7 days
  • Sleep in separate bedroom from household contacts for 3 days, from children for 7 days, or from pregnant women for 15 days 3
  • Women should avoid pregnancy for at least 6 months after treatment
  • Men should consider sperm banking before therapy 1

Monitoring During Administration

• Vital signs (blood pressure and pulse) should be monitored before and after therapy infusion, especially in symptomatic patients
• Be prepared to manage functional syndrome effects or exacerbation (e.g., carcinoid syndrome, hypoglycemia, electrolyte imbalance) 1

Alternative Administration Approaches

Sequential or Combination Therapy

• Sequential administration with 90Y:

  • 90Y administered activity: 2.5-5.0 GBq (68-135 mCi)
  • 177Lu administered activity: 5.55-7.4 GBq (150-200 mCi)
  • Number of cycles: Two to six
  • Time interval between cycles: 6-16 weeks 1

• Concurrent therapies using a cocktail of 177Lu and 90Y peptides are emerging but should be performed only in centers with sufficient expertise 1

Common Pitfalls and Caveats

1. Pharmacokinetic Variability:

   • There is high inter-individual variability in the effect of amino acid co-infusion on LU-177 elimination
   • This variability contributes to differences in plasma exposure and potential toxicity 2

2. Radiation Exposure:

   • Incontinent patients should be catheterized prior to treatment and the catheter kept for 2 days
   • Urine bags should be emptied frequently
   • Staff caring for catheterized patients should wear gloves and protective clothing 1

3. Monitoring for Toxicity:

   • Watch for myelosuppression (neutropenia, thrombocytopenia, lymphopenia)
   • Grade 3 lymphopenia can occur in approximately 33% of patients 4
   • Monitor renal function carefully as kidneys are a critical organ-at-risk 5

4. Quality Control:

   • For formulations labeled with 177Lu, the mass of peptide should be between 100-200 μg and should not exceed 250 μg per patient dose 1
   • Radiochemical purity should not fall below 98% 1

By following these administration guidelines, LU-177 therapy can be delivered safely and effectively to maximize therapeutic benefit while minimizing risks to patients and healthcare providers.