From the FDA Drug Label
The co-administration of amino acids reduced the median radiation dose to the kidneys by 47% (34% to 59%) and increased the mean beta-phase blood clearance of lutetium Lu 177 dotatate by 36%. The FDA drug label for Lutetium Lu 177 dotatate (Lutathera) indicates that amino acids are co-administered to reduce the radiation dose to the kidneys.
- The use of amino acids with Lutathera is intended to decrease kidney radiation exposure.
- In contrast, the FDA drug label for Lutetium Lu 177 psma (Pluvicto) does not mention the co-administration of amino acids for this purpose. Therefore, amino acids are used with Lutathera but not with Pluvicto because they help reduce kidney radiation exposure with Lutathera 1.
From the Research
Introduction to Amino Acid Use in Radiopharmaceuticals
Amino acids are used in conjunction with certain radiopharmaceuticals to enhance their efficacy and reduce side effects. This is particularly relevant in the context of Lutathera (Lutetium Lu 177 dotatate) and Pluvicto (Lutetium Lu 177 psma), two radiopharmaceuticals used in the treatment of neuroendocrine tumors and prostate cancer, respectively.
Rationale for Amino Acid Use with Lutathera
The use of amino acids, such as arginine and lysine, with Lutathera is primarily aimed at reducing the risk of nephrotoxicity associated with the radiopharmaceutical 2. Positively charged amino acids can help mitigate this risk by competing with the radiolabeled compound for uptake in the kidneys, thereby reducing the renal dose and potential for damage.
Comparison of Amino Acid Formulations
Studies have compared the use of different amino acid formulations in conjunction with Lutathera, including commercial parenteral nutrition formulas and compounded arginine/lysine solutions 2. These studies have shown that the use of arginine/lysine can result in lower rates of nausea and vomiting compared to commercial amino acid formulations.
Mechanism of Action
The mechanism by which amino acids reduce nephrotoxicity is thought to involve competition for transport across cell membranes via shared transporter systems 3. Arginine, in particular, has been shown to competitively inhibit the uptake of lysine, which can help reduce the renal dose of the radiopharmaceutical.
Safety of Amino Acid Supplementation
The safety of amino acid supplementation has been evaluated in various studies, including those examining the use of arginine, lysine, and glutamine 4, 5. These studies have generally shown that amino acid supplementation is well-tolerated, although high doses may be associated with gastrointestinal side effects such as nausea and diarrhea.
Use of Amino Acids with Pluvicto
In contrast to Lutathera, amino acids are not typically used in conjunction with Pluvicto. This may be due to differences in the pharmacokinetics and pharmacodynamics of the two radiopharmaceuticals, as well as variations in their mechanisms of action.
Treatment Considerations
When using amino acids in conjunction with Lutathera, treatment considerations include:
- Dosing: Typical dosing regimens involve the administration of 2.5% arginine and 2.5% lysine in 0.9% sodium chloride solution.
- Duration: Amino acid infusion is usually performed concurrently with Lutathera administration.
- Monitoring: Patients should be monitored for signs of nephrotoxicity and gastrointestinal side effects.
- Contraindications: Amino acid supplementation may be contraindicated in patients with certain medical conditions, such as renal impairment or gastrointestinal disorders.
Conclusion
In conclusion, the use of amino acids with Lutathera is a common practice aimed at reducing the risk of nephrotoxicity associated with the radiopharmaceutical. The choice of amino acid formulation and dosing regimen can impact the efficacy and safety of treatment. Further research is needed to fully elucidate the mechanisms of action and optimal treatment strategies for amino acid use in conjunction with radiopharmaceuticals.