Yes — the active ingredient is metabolized by a gene known to vary between individuals.
Relevant genes: NUDT15, TPMT
Lanvis is affected by pharmacogenetics through the NUDT15 and TPMT genes. Your genotype for these genes can change how your body processes Lanvis, which can affect both how well it works and how well you tolerate it. The strongest evidence level on this page is Strong, based on CPIC or FDA guidelines.
Published guidance from CPIC and FDA on how thioguanine should be dosed or substituted based on your NUDT15, TPMT phenotype.
| Phenotype | What it means | Recommendation | Evidence |
|---|---|---|---|
|
Normal Metabolizer
TPMT
|
Your genotype supports standard dosing. |
CPIC
Initiate therapy with standard starting dose of thioguanine (e.g., 40 mg/m2/day for malignancy). During therapy, adjust the doses of myelosuppressive agents, as per standard clinical practice. It usually takes at least 2 weeks of stable dosing to reach steady state after each dose adjustment.
|
Strong |
|
Intermediate Metabolizer
TPMT
|
Your genotype reduces your ability to process thioguanine; a lower starting dose is typically recommended. |
CPIC
Initiate therapy with decreased starting doses (30-80% of standard starting dose) if standard starting dose is ≥40 mg/m2/day. If starting dose is already below standard starting dose, dose reduction might not be necessary. During therapy, adjust the doses of thioguanine based on the degree of myelosuppression and disease-specific guidelines. It usually takes at least 2-4 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, and the patient is on combination therapy, emphasis should be on reducing thioguanine over other agents.
|
Moderate |
|
Possible Intermediate Metabolizer
TPMT
|
Your genotype reduces your ability to process thioguanine; a lower starting dose is typically recommended. |
CPIC
Initiate therapy with decreased starting doses (30-80% of standard starting dose) if standard starting dose is ≥40 mg/m2/day. If starting dose is already below standard starting dose, dose reduction might not be necessary. During therapy, adjust the doses of thioguanine based on the degree of myelosuppression and disease-specific guidelines. It usually takes at least 2-4 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, and the patient is on combination therapy, emphasis should be on reducing thioguanine over other agents.
FDA
Reduce thioguanine dose based on tolerability and monitor for myelosuppression. Refer to FDA labeling for specific dosing recommendations.
|
Strong |
|
Poor Metabolizer
TPMT
|
Your genotype affects how you process thioguanine. A much lower starting dose is typically needed to avoid severe bone marrow toxicity. |
CPIC
Initiate therapy with drastically reduced starting doses. Reduce starting dose by 10-fold and reduce frequency to thrice weekly instead of daily. During therapy, adjust thioguanine doses based on degree of myelosuppression and disease-specific guidelines. It usually takes at least 4-6 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, emphasis should be on reducing thioguanine over other agents.
|
Strong |
|
Indeterminate
TPMT
|
Your TPMT result is unavailable or indeterminate. The other gene may still provide useful guidance, but this missing result is not reassurance about safety. |
CPIC
A combined TPMT/NUDT15 interpretation is unavailable. Retain any available NUDT15 guidance and seek clinical review or additional testing; do not infer a standard dose from the missing TPMT result.
FDA
Initiate therapy with recommended starting dose.
|
— |
|
Not available
TPMT
|
Your TPMT result is unavailable or indeterminate. The other gene may still provide useful guidance, but this missing result is not reassurance about safety. |
CPIC
A combined TPMT/NUDT15 interpretation is unavailable. Retain any available NUDT15 guidance and seek clinical review or additional testing; do not infer a standard dose from the missing TPMT result.
FDA
Initiate therapy with recommended starting dose.
|
— |
|
Normal Metabolizer
NUDT15
|
Your genotype supports standard dosing. |
CPIC
Initiate therapy with standard starting dose of thioguanine (e.g., 40 mg/m2/day for malignancy). During therapy, adjust the doses of myelosuppressive agents, as per standard clinical practice. It usually takes at least 2 weeks of stable dosing to reach steady state after each dose adjustment.
FDA
Initiate therapy with recommended starting dose.
|
Strong |
|
Intermediate Metabolizer
NUDT15
|
Your genotype reduces your ability to process thioguanine; a lower starting dose is typically recommended. |
CPIC
Initiate therapy with decreased starting doses (30-80% of standard starting dose) if standard starting dose is ≥40 mg/m2/day. If starting dose is already below standard starting dose, dose reduction might not be necessary. During therapy, adjust the doses of thioguanine based on the degree of myelosuppression and disease-specific guidelines. It usually takes at least 2-4 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, and the patient is on combination therapy, emphasis should be on reducing thioguanine over other agents.
FDA
Reduce thioguanine dose based on tolerability and monitor for myelosuppression. Refer to FDA labeling for specific dosing recommendations.
|
Strong |
|
Possible Intermediate Metabolizer
NUDT15
|
Your genotype reduces your ability to process thioguanine; a lower starting dose is typically recommended. |
CPIC
Initiate therapy with decreased starting doses (30-80% of standard starting dose) if standard starting dose is ≥40 mg/m2/day. If starting dose is already below standard starting dose, dose reduction might not be necessary. During therapy, adjust the doses of thioguanine based on the degree of myelosuppression and disease-specific guidelines. It usually takes at least 2-4 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, and the patient is on combination therapy, emphasis should be on reducing thioguanine over other agents.
FDA
Reduce thioguanine dose based on tolerability and monitor for myelosuppression. Refer to FDA labeling for specific dosing recommendations.
|
Strong |
|
Poor Metabolizer
NUDT15
|
Your genotype affects how you process thioguanine. A much lower starting dose is typically needed to avoid severe bone marrow toxicity. |
CPIC
Initiate therapy with drastically reduced starting doses. Reduce starting dose by 10-fold and reduce frequency to thrice weekly instead of daily. During therapy, adjust thioguanine doses based on degree of myelosuppression and disease-specific guidelines. It usually takes at least 4-6 weeks of stable dosing to reach steady state after each dose adjustment. If myelosuppression occurs, emphasis should be on reducing thioguanine over other agents.
FDA
Consider an alternative agent or reduce dose to 10% or less of the recommended dosage. Monitor closely for myelosuppression.
|
Strong |
|
Indeterminate
NUDT15
|
Your NUDT15 result is unavailable or indeterminate. The other gene may still provide useful guidance, but this missing result is not reassurance about safety. |
CPIC
A combined TPMT/NUDT15 interpretation is unavailable. Retain any available TPMT guidance and seek clinical review or additional testing; do not infer a standard dose from the missing NUDT15 result.
FDA
Initiate therapy with recommended starting dose.
|
— |
|
Not available
NUDT15
|
Your NUDT15 result is unavailable or indeterminate. The other gene may still provide useful guidance, but this missing result is not reassurance about safety. |
CPIC
A combined TPMT/NUDT15 interpretation is unavailable. Retain any available TPMT guidance and seek clinical review or additional testing; do not infer a standard dose from the missing NUDT15 result.
FDA
Initiate therapy with recommended starting dose.
|
— |
|
Normal Function
TPMT
|
Your body processes thioguanine at a normal rate based on this gene, so the standard dose should be appropriate for you. |
FDA
Initiate therapy with recommended starting dose.
|
Strong |
|
Intermediate Function
TPMT
|
Your body breaks down thioguanine more slowly than normal, which increases the risk of a weakened immune system and low blood cell counts. A lower dose is recommended with close monitoring. |
FDA
Reduce thioguanine dose based on tolerability and monitor for myelosuppression. Refer to FDA labeling for specific dosing recommendations.
|
Strong |
|
Poor Function
TPMT
|
Your body has great difficulty breaking down thioguanine, putting you at serious risk of dangerously low blood cell counts. A drastically reduced dose or a different medication is recommended. |
FDA
Consider an alternative agent or reduce dose to 10% or less of the recommended dosage. Monitor closely for myelosuppression.
|
Strong |
NUDT15 helps limit the cellular effects of active thiopurine metabolites. Reduced function increases susceptibility to thiopurine toxicity. Interpret the result alongside TPMT for azathioprine, mercaptopurine, and thioguanine.
A typical result in one gene does not cancel a reduced-function result in the other. An unresolved combined interpretation retains available per-gene information and its limitations.
TPMT helps inactivate thiopurines, including azathioprine, mercaptopurine, and thioguanine. Reduced function can increase susceptibility to severe bone-marrow toxicity. The CPIC 2025 update interprets TPMT and NUDT15 together.
Intermediate metabolism in both genes differs from an intermediate result in one gene alone. DNA-inferred function is distinct from a measured TPMT enzyme activity. Neither replaces blood-count monitoring.
Browse the full drug-class: Chemotherapy agents.
This page describes the general pharmacogenetics. A Gene2Rx report analyzes your own DNA to tell you which metabolizer group you fall into, across every medication.
Get your report Look up another medicationInformational only — not medical advice. Pharmacogenetic guidance describes population-level patterns; your individual response depends on many factors. Never start, stop, or change a medication without talking to your prescribing clinician.