Boruzu

The dosage of Bortezomib is highly individualized and is calculated based on the patient's Body Surface Area (BSA) in square meters (m²).

• Multiple Myeloma (Previously Untreated): The standard dose is typically 1.3 mg/m² administered as a twice-weekly injection (Days 1, 4, 8, and 11) for two weeks, followed by a 10-day rest period (Days 12–21). This 21-day period constitutes one cycle. In some regimens, after several cycles, the frequency may be reduced to once weekly.
• Multiple Myeloma (Relapsed): The standard dose is 1.3 mg/m² either twice weekly (Days 1, 4, 8, and 11 of a 21-day cycle) or once weekly, depending on the patient's tolerance and the specific combination of other drugs being used.
• Mantle Cell Lymphoma (Previously Untreated): When used in the Vc-CAP regimen, the dose is 1.3 mg/m² administered twice weekly (Days 1, 4, 8, and 11) of a 21-day cycle.

Bortezomib is not currently FDA-approved for use in pediatric patients. Its safety and effectiveness in children and adolescents under the age of 18 have not been established. Clinical trials in pediatric oncology are ongoing, but until definitive data is available, it is not used in standard pediatric practice.

Renal Impairment

Patients with renal impairment (kidney problems), including those on dialysis, do not typically require an initial dose adjustment of Bortezomib. However, because dialysis can remove some of the drug, Bortezomib should be administered after the dialysis procedure is complete. Close monitoring for toxicities is essential in this population.

Hepatic Impairment

Since Bortezomib is primarily metabolized by the liver, patients with moderate to severe hepatic impairment are at an increased risk of toxicity due to reduced clearance. For patients with moderate or severe hepatic impairment, the starting dose should be reduced to 0.7 mg/m² in the first cycle. Subsequent dose increases or further decreases should be based on patient tolerance.

Elderly Patients

In clinical trials, no overall differences in safety or effectiveness were observed between patients over 65 and younger patients. However, older patients may be more sensitive to certain side effects, such as peripheral neuropathy and GI distress. Dosing should be approached with caution, starting at the standard dose but monitoring closely.

Bortezomib is administered exclusively by healthcare professionals in a clinical setting (hospital or infusion center).

• Administration Route: It is given either as an intravenous (IV) injection into a vein or as a subcutaneous (SC) injection under the skin (usually in the thigh or abdomen). SC administration is generally preferred to reduce the risk of nerve damage.
• Site Rotation: If given subcutaneously, the injection site should be rotated for each dose to prevent skin irritation or 'injection site reactions.'
• Hydration: Patients should be well-hydrated before and after treatment to prevent complications like tumor lysis syndrome or low blood pressure.
• Storage: The reconstituted solution should be used within 8 hours of preparation and stored at room temperature in the original vial or a syringe.

If a scheduled dose of Bortezomib is missed, it should be administered as soon as possible, provided there is at least 72 hours between the rescheduled dose and the next planned dose. If the next dose is less than 72 hours away, the missed dose is typically skipped. Your healthcare provider will adjust the schedule to ensure the integrity of the treatment cycle.

An overdose of Bortezomib is a medical emergency. Symptoms of overdose may include severe hypotension (dangerously low blood pressure), thrombocytopenia (dangerously low platelets), or severe neurological impairment. There is no specific antidote for Bortezomib. Treatment involves supportive care, including cardiovascular support (fluids and vasopressors) and monitoring of blood counts.

> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance. Always inform your nurse or doctor if you feel unwell during or after the injection.

Bortezomib is a potent medication, and side effects are common. According to the FDA-approved label (2024), the following occur in more than 10% of patients:

• Peripheral Neuropathy: This is the most significant side effect. It often presents as numbness, tingling, burning sensations, or sharp pain in the hands and feet. It is cumulative, meaning it may worsen with more doses.
• Gastrointestinal Issues: Nausea, vomiting, diarrhea, and constipation are very frequent. Diarrhea can be severe and lead to dehydration if not managed with over-the-counter or prescription anti-diarrheals.
• Thrombocytopenia: A decrease in blood platelets, which increases the risk of bruising and bleeding. Platelet counts typically drop during the treatment days and recover during the rest period of the cycle.
• Fatigue and Asthenia: A general sense of tiredness or profound weakness that does not improve with rest.
• Anemia and Neutropenia: Low red blood cell counts (causing shortness of breath) and low white blood cell counts (increasing infection risk).
• Pyrexia: Fever, often occurring shortly after the injection.

• Orthostatic Hypotension: A sudden drop in blood pressure when standing up, which can cause dizziness or fainting.
• Edema: Swelling of the hands, ankles, or feet due to fluid retention.
• Rash and Pruritus: Skin irritation or itching, particularly at the site of subcutaneous injection.
• Blurred Vision: Temporary changes in eyesight.
• Electrolyte Imbalances: Such as low potassium (hypokalemia) or low magnesium.

• Posterior Reversible Encephalopathy Syndrome (PRES): A rare neurological disorder characterized by headache, seizures, confusion, and vision loss.
• Acute Liver Failure: Rare but severe hepatotoxicity.
• Pulmonary Toxicity: Including pneumonitis and interstitial lung disease, which can cause severe difficulty breathing.

> Warning: Stop taking Bortezomib and call your doctor immediately if you experience any of these.

• Severe Neuropathy: If you lose the ability to walk, experience severe burning pain that prevents sleep, or lose coordination in your hands.
• Hemorrhage: Signs of internal bleeding, such as black/tarry stools, vomiting blood, or an unusually severe headache.
• Congestive Heart Failure: New or worsening shortness of breath, swelling of the legs, or a rapid heartbeat.
• Tumor Lysis Syndrome (TLS): Caused by the rapid breakdown of cancer cells. Symptoms include dark urine, joint pain, or heart palpitations. This is a medical emergency.
• Severe Allergic Reaction: Hives, swelling of the face or throat, and difficulty breathing.

The most concerning long-term effect is chronic peripheral neuropathy. While many patients see improvement after stopping Bortezomib, some may experience permanent nerve damage. Additionally, there is a risk of secondary malignancies (new cancers) associated with many chemotherapy agents, though the specific risk with Bortezomib is still being studied. Long-term use may also lead to persistent changes in immune function, making patients more susceptible to viral reactivations, such as Shingles (Herpes Zoster).

No FDA black box warnings currently exist for Bortezomib. However, the FDA has issued several 'Warnings and Precautions' that are considered critical for patient safety, particularly regarding peripheral neuropathy and the risk of fatal administration if given by the wrong route (intrathecal).

Report any unusual symptoms to your healthcare provider. Early intervention for side effects like neuropathy can often prevent permanent damage.

Bortezomib is a high-risk medication that requires strict clinical oversight. Patients must be monitored closely for hematologic (blood) and neurologic (nerve) toxicities. Because Bortezomib can cause significant drops in blood pressure and platelet counts, regular blood tests and blood pressure monitoring are mandatory throughout the duration of treatment.

As of the 2024 prescribing information, there are no FDA black box warnings for Bortezomib. However, it is critical to note that Intrathecal Administration (injection into the spinal canal) is FATAL. Bortezomib must only be administered intravenously or subcutaneously. Several deaths have been reported globally when this medication was accidentally administered intrathecally.

• Peripheral Neuropathy: This is the most common reason for dose modification or discontinuation. Patients with pre-existing neuropathy (e.g., from diabetes) are at higher risk. Your doctor will assess your nerve function before each dose.
• Hypotension: Bortezomib can cause orthostatic/postural hypotension. Caution is advised for patients with a history of fainting or those taking antihypertensive medications. Dehydration can worsen this risk.
• Cardiac Toxicity: New or worsened heart failure has occurred. Patients with existing heart disease or risk factors should be monitored for signs like edema and dyspnea (shortness of breath).
• Pulmonary Toxicity: Rare cases of acute respiratory distress syndrome (ARDS) and pneumonitis have been reported. Any new cough or shortness of breath must be reported immediately.
• Hepatotoxicity: Liver enzymes should be monitored. Cases of liver failure have occurred in patients taking multiple medications along with Bortezomib.
• Herpes Zoster Reactivation: Bortezomib increases the risk of Shingles. According to the CDC (2023), antiviral prophylaxis (preventative medicine like acyclovir) is strongly recommended for all patients receiving Bortezomib.

To ensure safety, the following tests are typically required:

• Complete Blood Count (CBC): To monitor for low platelets (thrombocytopenia), low white cells (neutropenia), and low red cells (anemia). This is usually done before every dose.
• Liver Function Tests (LFTs): To monitor for potential liver damage.
• Blood Pressure: Monitored before and after administration.
• Neurological Exams: Routine checks for numbness, tingling, or weakness.

Bortezomib may cause fatigue, dizziness, or blurred vision. Do not drive or operate heavy machinery until you know how the medication affects you. If you experience orthostatic hypotension (dizziness upon standing), you are at an increased risk of falls.

While there is no direct chemical interaction between alcohol and Bortezomib, alcohol can worsen certain side effects like dehydration, dizziness, and nausea. It can also strain the liver, which is already processing the medication. It is generally advised to limit or avoid alcohol during treatment.

Bortezomib does not typically cause a 'withdrawal syndrome,' but stopping treatment prematurely can allow the cancer to progress. If side effects become intolerable, your doctor will likely 'hold' the dose (pause treatment) or reduce the dose rather than stopping it entirely.

> Important: Discuss all your medical conditions with your healthcare provider before starting Bortezomib, especially if you have a history of diabetes, heart disease, or liver problems.

While few drugs are strictly contraindicated, the following should be avoided whenever possible:

• Strong CYP3A4 Inducers (e.g., Rifampin, St. John’s Wort): These substances significantly speed up the metabolism of Bortezomib, reducing its concentration in the blood by up to 45%. This can make the treatment ineffective against the cancer.
• Intrathecal Medications: As mentioned, Bortezomib must never be given alongside medications administered into the spine, due to the risk of fatal cross-contamination in a clinical setting.

• Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Ritonavir, Clarithromycin): These drugs slow down the breakdown of Bortezomib, increasing its concentration in the blood. This significantly increases the risk of severe side effects, especially peripheral neuropathy and low platelet counts.
• Antihypertensive Medications: Drugs used to treat high blood pressure (like lisinopril or amlodipine) can worsen the blood-pressure-lowering effects of Bortezomib, leading to fainting or severe dizziness.
• Oral Hypoglycemics: In patients with diabetes, Bortezomib may cause changes in blood sugar levels. Close monitoring of blood glucose is required, and diabetes medication doses may need adjustment.

• Green Tea and Green Tea Extracts: A significant interaction exists where the polyphenols in green tea (specifically EGCG) can bind to the boron atom in Bortezomib, rendering the drug completely inactive. Patients are strongly advised to avoid green tea products on the days of treatment.
• Vitamin C (Ascorbic Acid): High doses of Vitamin C may also interfere with the mechanism of Bortezomib. While normal dietary intake is usually fine, high-dose supplements should be discussed with an oncologist.

• Grapefruit and Grapefruit Juice: Grapefruit is a potent inhibitor of the CYP3A4 enzyme. Consuming grapefruit can lead to dangerously high levels of Bortezomib in the body. It should be avoided entirely during treatment.
• Hydration: While not an interaction in the negative sense, maintaining high fluid intake is required to protect the kidneys from the byproducts of cancer cell death.

• St. John’s Wort: As a strong CYP3A4 inducer, this herbal supplement will likely cause the Bortezomib treatment to fail.
• Antioxidants: Because Bortezomib works partly by creating oxidative stress within cancer cells, high-dose antioxidant supplements (Vitamin E, Selenium, etc.) might theoretically reduce the drug's efficacy.

Bortezomib does not typically interfere with the chemical results of lab tests, but it profoundly changes the values of blood counts (Platelets, WBCs). It may also cause transient increases in liver enzymes or blood glucose levels.

For each major interaction, the management strategy usually involves either selecting an alternative medication, adjusting the Bortezomib dose, or increasing the frequency of safety monitoring.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. Even 'natural' products like green tea can stop this chemotherapy from working.

Bortezomib must NEVER be used in the following circumstances:

1. 1Hypersensitivity to Bortezomib, Boron, or Mannitol: If a patient has had a severe allergic reaction (anaphylaxis) to the drug itself, to boron (a key element in the drug's structure), or to mannitol (an inactive ingredient used as a stabilizer), the drug cannot be used. The mechanism is an IgE-mediated immune response that could lead to fatal respiratory distress or circulatory collapse.
2. 2Intrathecal Administration: This is an absolute contraindication for the route of administration. Injecting Bortezomib into the cerebrospinal fluid is universally fatal due to massive neurotoxicity and brainstem destruction.

These are conditions where the risks of Bortezomib may outweigh the benefits, or where extreme caution is required:

• Severe Pre-existing Peripheral Neuropathy: Patients who already have Grade 3 or 4 neuropathy (e.g., inability to perform basic tasks due to nerve pain or weakness) may experience permanent disability if given Bortezomib. In such cases, alternative proteasome inhibitors like Carfilzomib might be considered.
• Severe Hepatic Impairment: Because the liver is the primary site of metabolism, patients with total bilirubin > 3x the upper limit of normal are at extreme risk of toxicity. Treatment should only proceed with significant dose reductions (starting at 0.7 mg/m²).
• Severe Cardiac Disease: Patients with a recent history of myocardial infarction (heart attack), unstable angina, or severe congestive heart failure (NYHA Class III or IV) may not be able to tolerate the fluid shifts and potential cardiotoxicity of the drug.
• Active Infections: Because Bortezomib lowers white blood cell counts, starting treatment during a severe active infection can be life-threatening.

There is a potential for cross-sensitivity among boron-containing compounds. While rare, patients who have reacted to other boron-based diagnostic or therapeutic agents should be evaluated by an allergist before starting Bortezomib. There is no known cross-reactivity between Bortezomib and traditional 'sulfa' drugs or common antibiotics.

> Important: Your healthcare provider will evaluate your complete medical history before prescribing Bortezomib. Ensure you disclose all past allergic reactions to medications.

Bortezomib is classified as a pregnancy category D (based on old FDA labeling) or has a warning for Embryo-Fetal Toxicity. Based on its mechanism of action and findings in animal studies, Bortezomib can cause fetal harm when administered to a pregnant woman. Animal studies showed that the drug is 'teratogenic' (causes birth defects) and can cause fetal death even at doses lower than the standard human dose.

• Contraception: Females of reproductive potential should use effective contraception during treatment and for at least 7 months after the final dose. Males with female partners of reproductive potential should use effective contraception during treatment and for 4 months after the final dose.
• Pregnancy Testing: A pregnancy test should be performed before starting treatment.

It is not known whether Bortezomib or its metabolites are excreted in human milk. However, because of the potential for serious adverse reactions in a nursing infant (including immune suppression and growth issues), women are advised not to breastfeed during treatment with Bortezomib and for two months after the final dose.

The safety and effectiveness of Bortezomib in pediatric patients have not been established. While some Phase I and II trials have explored its use in pediatric leukemias and solid tumors, it remains an off-label and experimental use in children. Growth and development effects in children are unknown but expected to be significant given the drug's interference with basic cellular protein regulation.

Clinical studies included a significant number of patients aged 65 and over. While no overall differences in the effectiveness of the drug were found compared to younger patients, the elderly are at a higher risk for certain toxicities. Specifically, older patients are more likely to experience Grade 3 or 4 peripheral neuropathy and gastrointestinal distress. Careful monitoring and prompt dose adjustments are essential in the geriatric population to prevent falls and severe dehydration.

Pharmacokinetic studies show that the clearance of Bortezomib is not significantly altered in patients with mild to severe renal impairment. Patients on hemodialysis can receive the drug, but it must be administered after the dialysis session because the procedure may reduce drug concentrations. No starting dose adjustment is required, but monitoring for tumor lysis syndrome is critical in these patients.

Hepatic impairment significantly reduces the clearance of Bortezomib. Patients with mild impairment do not usually require a dose adjustment. However, for those with moderate to severe impairment (as defined by bilirubin levels), the starting dose must be reduced to 0.7 mg/m². These patients must be monitored very closely for signs of 'over-exposure,' such as severe bone marrow suppression.

> Important: Special populations require individualized medical assessment. Always inform your oncology team about your plans for pregnancy or any history of organ dysfunction.

Bortezomib is a reversible inhibitor of the chymotrypsin-like activity of the 26S proteasome in mammalian cells. The 26S proteasome is a large protein complex that degrades ubiquitinated proteins. The ubiquitin-proteasome pathway plays an essential role in regulating the intracellular concentration of specific proteins, thereby maintaining homeostasis within the cell. Inhibition of the 26S proteasome prevents this targeted proteolysis (protein breakdown), which affects multiple signaling cascades within the cell. This disruption of homeostatic mechanisms can lead to cell cycle arrest and apoptosis. In cancer cells, Bortezomib particularly affects the NF-κB pathway, pro-apoptotic proteins, and the unfolded protein response, making the cancer cells more likely to die than healthy cells.

Following administration, Bortezomib causes a rapid inhibition of proteasome activity. Peak inhibition occurs within 1 hour of dosing. In clinical trials, a dose of 1.3 mg/m² resulted in approximately 70% to 90% inhibition of the 20S proteasome activity in whole blood. This inhibition is reversible, with proteasome activity typically returning toward baseline within 48 to 72 hours. This 'pulsatile' inhibition (high inhibition followed by recovery) is thought to be key to its therapeutic window, allowing normal cells to recover while cancer cells are pushed toward apoptosis.

| Parameter | Value |

|---|---|

| Bioavailability | 100% (IV/SC) |

| Protein Binding | ~83% |

| Half-life | 40–193 hours (multiple doses) |

| Tmax | 1–30 minutes (IV/SC) |

| Metabolism | CYP3A4, CYP2C19, CYP1A2 |

| Excretion | Hepatic (Primary), Renal (Minor) |

• Molecular Formula: C19H25BN4O4
• Molecular Weight: 384.24 g/mol
• Solubility: Poorly soluble in water; typically reconstituted in 0.9% Normal Saline.
• Structure: It is a monomeric boronic acid derivative. The boron atom is the pharmacophore (active part) that interacts with the threonine residue in the proteasome's active site.

Bortezomib is the prototypical member of the Proteasome Inhibitor class. Related medications include Carfilzomib (Kyprolis) and Ixazomib (Ninlaro). Unlike Carfilzomib, which is an irreversible inhibitor, Bortezomib's binding is reversible.