What Is Carmustine (BICNU)? FDA Approval, Licensing and Reimbursement in Turkey

What Is Carmustine? How Does It Work?

Carmustine is a nitrosourea chemotherapy drug. It directly damages DNA, preventing cancer cell growth and division. It is used particularly for brain tumors, lymphomas and multiple myeloma.

Mechanism of Action

Carmustine adds alkyl groups to intracellular DNA and RNA, disrupting genetic material and creating DNA cross-links. These stop cell division and cause cancer cell death. It also inhibits protein synthesis and repair mechanisms, producing cytotoxic effects.

Its lipid solubility allows carmustine to cross the blood-brain barrier, making it effective against brain tumors.

FDA (US Food and Drug Administration) Approval History

March 07, 1977: Initial FDA approval for palliative treatment of various cancers.

Licensing in Turkey

Licensed by the Ministry of Health.

Therapeutic Indications

• Brain tumors: glioblastoma, medulloblastoma, astrocytoma and metastatic brain tumors.
• Multiple myeloma, combined with a glucocorticoid such as prednisone.
• Hodgkin disease, combined with other approved drugs as second-line treatment after relapse during, or lack of response to, primary treatment.
• Non-Hodgkin lymphomas, combined with other approved drugs as second-line treatment after relapse during, or lack of response to, primary treatment.

SGK Reimbursement Status

• For brain tumors—glioblastoma, brainstem glioma, medulloblastoma, astrocytoma, ependymoma and metastatic brain tumors—SGK reimbursement requires a medical oncology specialist's report. For Hodgkin and non-Hodgkin lymphoma, a hematologist's report is required.
• Combined use with bevacizumab in second-line GBM is reimbursed.

Price: Carmustine 100 mg vial costs 66.558.02 TL.

Resistance Mechanisms

Increased O⁶-Alkylguanine DNA Alkyltransferase (AGT / MGMT):

• Carmustine adds an alkyl group to the O⁶ position of DNA guanine.
• The repair enzyme MGMT (O⁶-methylguanine-DNA methyltransferase) removes this damage.
• Higher cellular levels of this enzyme rapidly repair carmustine-induced DNA damage, making the drug ineffective.

Increased Glutathione and Glutathione S-Transferase Activity:

• Carmustine must remain active within cells to work.
• Glutathione may detoxify and inactivate it.
• Glutathione-S-transferase (GST) binds carmustine, reducing its effect.

Increased DNA Repair Pathway Activation:

• Mechanisms such as base excision repair (BER) may repair carmustine-induced damage.
• Cells develop resistance by overusing these pathways.

Reduced Uptake or Increased Efflux:

Reduced cellular entry or increased efflux (e.g., through ABC transporters) lowers intracellular concentrations and efficacy.

Apoptosis Pathway Dysfunction:

• Carmustine induces death through DNA damage (apoptosis).
• Some cancer cells, however, ignore these signals or suppress apoptosis pathways.

Absorption

• Carmustine is generally given intravenously.
• Oral use is not recommended because gastrointestinal absorption is unstable and inadequate.
• IV administration rapidly delivers it into the blood to begin acting.

Distribution

• It is lipid-soluble (lipophilic).
• This enables blood-brain barrier penetration, improving activity in brain tumors.
• Rapidly distributes into tissues, particularly brain, liver, kidneys and bone marrow.
• Distribution volume is large (approximately 45 L/m²), indicating good tissue penetration.

Metabolism

• Carmustine is rapidly metabolized in the liver.
• The active ingredient quickly disappears from plasma, but active metabolites maintain cytotoxic effects.
• These metabolites continue causing DNA damage.

Elimination

• Most drug and metabolites are excreted in urine (up to 60%).
• Small amounts may be excreted in feces and breath (as carbon dioxide).
• Plasma half-life is short, approximately 15–30 minutes, although active metabolite effects may last hours.

Dosing Interval

Brain Tumors (e.g., Glioblastoma, Astrocytoma):

• 150–200 mg/m² → as a single dose, or
• 75–100 mg/m²/day → on 2 consecutive days, every 6 weeks

Multiple Myeloma:

• 120–200 mg/m² → generally combined with prednisone
• Given as a single dose every 6 weeks

Hodgkin and Non-Hodgkin Lymphoma (Combination Treatment):

• 100–150 mg/m² → single dose

Every 6–8 weeks depending on the combination. Intervals are generally planned at 6 weeks because bone marrow suppression appears late and recovery is prolonged.

Drug Interactions

Bone Marrow-Suppressing Drugs (Myelosuppressive Agents):

• Interaction: Carmustine already suppresses bone marrow.
• Concurrent Risk: Increased severe hematologic toxicities, including neutropenia, anemia and thrombocytopenia.
• Examples: Cyclophosphamide, cisplatin, carboplatin, doxorubicin, fludarabine, paclitaxel

Pulmonary-Toxic Drugs:

• Interaction: Prolonged carmustine use may cause pulmonary fibrosis.
• Drugs intensifying this effect: Bleomycin, busulfan, gemcitabine
• Result: Severe pulmonary toxicity (dyspnea, interstitial fibrosis)

Hepatotoxic Drugs:

• Interaction: Carmustine is metabolized in the liver.
• Hepatotoxicity risk may rise particularly with methotrexate, acetaminophen, isoniazid or allopurinol.

Alcoholic Solutions or Solvents (e.g., Alcohol-Containing Medicines):

• Carmustine solution contains ethanol, so concurrent alcohol requires caution regarding sedation and liver burden.

Live Vaccines:

• Interaction: Carmustine may suppress immunity.
• Risk: Live vaccines (e.g., measles, BCG, yellow fever) may cause infection.
• Recommendation: Do not administer live vaccines during treatment or shortly afterward.

Drugs Affecting Fertility:

• Carmustine alone may impair sperm production.
• Concurrent gonadotoxic drugs increase infertility risk.

Precautions

Bone Marrow Suppression (Myelosuppression): Carmustine's most important dose-dependent toxicity.

May cause neutropenia, thrombocytopenia and anemia. Onset is delayed, generally 3–6 weeks later. Obtain frequent blood counts before and after treatment. Do not redose before complete recovery from the previous cycle.

Pulmonary Toxicity (Pulmonary Fibrosis): Risk increases particularly with high doses and repeated administration.

Cough, dyspnea and interstitial infiltrates may occur. Monitor pulmonary function tests (DLCO, FEV1) regularly. Children and older people face greater risk.

Liver Toxicity: May increase AST/ALT and bilirubin. Use caution with hepatotoxic drugs and monitor liver function tests.

Crossing the Blood-Brain Barrier: Provides therapeutic benefit but may also increase neurotoxicity risk. Altered consciousness or headache may rarely occur.

Pregnancy and Breastfeeding: Pregnancy category: D (demonstrated human fetal risk). There is a risk of fetal toxicity and malformations in pregnancy. Do not use during breastfeeding.

Adhering to Dosing Intervals: Because of toxicity, intervals are generally 6 weeks. Repeating a cycle without a break may cause severe toxicity.

Secondary Cancer Risk: Prolonged use may increase bone marrow-related leukemia risk (AML/MDS).

Preparation and Administration: Use the solution promptly after preparation; do not freeze, and protect it from light. Healthcare staff should use protective measures such as goggles, gloves and masks during administration.

Adverse Effects

• Bone marrow suppression (neutropenia, thrombocytopenia, anemia): 65–100% (dose- and cycle-dependent)
• Nausea and vomiting: 80–90% (early hours)
• Pulmonary fibrosis / Interstitial pulmonary infiltrates: Up to 30% (cumulative dose-related)
• Elevated transaminases (AST/ALT): 20–30%
• Thrombophlebitis (venous inflammation): 10–30%
• Hepatotoxicity (jaundice, elevated bilirubin): 5–10%
• Stomatitis (mouth sores): 5–10%
• Infections (neutropenia-related): 5–10%
• Hypotension: Approximately 5%
• Convulsions / Seizures: <5%
• Nephrotoxicity (increased urea-creatinine): <5%
• Hair loss (alopecia): <5%
• Headache: <5%
• Secondary leukemia / MDS (after prolonged use): <1–2% (late effect)