Oxaliplatin

Introduction Overview

Generic Name

oxaliplatin

Brand Name

Eloxatin

Dosage Form

intravenous (infusion) injection

Drug Class

Alkylating agents

Pharmacokinetics

Oxaliplatin pharmacokinetics involves several key processes that influence its therapeutic effectiveness and safety profile.

Absorption:
Oxaliplatin is administered exclusively via intravenous infusion; hence, it bypasses the gastrointestinal route and is not absorbed enterally. This administration route allows for complete bioavailability, delivering the agent systemically without the variability associated with oral absorption. The intravenous route ensures a controlled and predictable plasma concentration essential for cytotoxic action.

Distribution:
Upon administration, oxaliplatin undergoes rapid distribution. It is extensively bound to plasma proteins, which modulates its free active drug concentration. The drug shows a triphasic plasma disposition characterized by initial quick distribution phases with half-lives of approximately 0.43 hours and 16.8 hours, followed by a prolonged terminal elimination phase with a half-life ranging up to approximately 392 hours (around 16 days). This prolonged terminal half-life corresponds largely to inactive platinum metabolites and protein-bound platinum species. Oxaliplatin and its active species penetrate various tissues, including tumor tissue, facilitating its cytotoxic effect.

Metabolism:
Biotransformation of oxaliplatin predominantly involves nonenzymatic conversion to reactive platinum complexes. Unlike many chemotherapeutic agents metabolized via hepatic cytochrome P450 systems, oxaliplatin undergoes chemical transformation into DNA-reactive platinum compounds. These metabolites form intra- and inter-strand DNA crosslinks that disrupt DNA replication and transcription. No significant hepatic metabolism has been identified, which reduces the risk of drug interactions via conventional metabolic pathways.

Elimination:
Elimination of oxaliplatin is primarily renal, with approximately 54% of the administered dose excreted in urine within 5 days post-infusion as platinum-containing compounds. The drug and its metabolites are cleared via glomerular filtration and tubular secretion. The prolonged terminal elimination phase reflects elimination of inactive platinum conjugates rather than active drug. Hepatic clearance is considered minimal. Renal impairment can alter clearance and necessitate dose adjustments to prevent toxicity. Understanding the pharmacokinetics facilitates individualized therapy, optimizing dosing intervals, and managing toxicities effectively.

Dosage Forms

Available Dosage Forms:
Oxaliplatin is available exclusively as an intravenous infusion injection. It is supplied as a concentrate for solution for infusion, intended for dilution prior to administration. The commercial preparation under the brand name Eloxatin contains oxaliplatin dissolved in sterile water for injection.

Dosages for Adults and Adolescents:
The standard dosing regimen involves administration of oxaliplatin at 85 mg/m2 via intravenous infusion over approximately 120 minutes. This is typically given concurrently with leucovorin infusion over the same duration but in separate infusion bags. The oxaliplatin dose is part of combination chemotherapy regimens such as FOLFOX (oxaliplatin, leucovorin, fluorouracil) and CAPOX (oxaliplatin with capecitabine). Treatment cycles generally repeat every 14 days. For adjuvant treatment of stage III colon cancer, therapy is continued for up to 12 cycles or until unacceptable toxicity occurs. In advanced colorectal cancer, treatment continues until disease progression or unacceptable toxicity.

Specific Patient Populations:
Dose adjustments may be required for patients with renal impairment due to the renal route of elimination. Patients with pre-existing peripheral neuropathy or those experiencing cumulative neurotoxicity may need dose modifications or treatment delays. There are limited data on pediatric dosing; oxaliplatin is not approved for use in children. For elderly patients, careful monitoring is advised due to potential increased susceptibility to toxic effects, particularly neuropathy and hematologic adverse events. Prior to initiating therapy, evaluation of hepatic and renal function is necessary to ensure safe administration. Pregnant females should avoid oxaliplatin due to potential fetal harm.

Clinical Guidelines:
Oxaliplatin is administered on day 1 of each 14-day cycle. During administration, patients are closely monitored for infusion reactions and other side effects. Pre-medications to mitigate nausea and vomiting are commonly used. Patients receive subsequent doses of leucovorin and fluorouracil according to specific regimen protocols. Since oxaliplatin is associated with cold-induced neuropathy, patients are advised to avoid cold exposure during and shortly after infusion.

Mechanism Of Action

Oxaliplatin is a third-generation platinum-based alkylating chemotherapeutic agent that exerts its anti-cancer effects primarily through interaction with DNA. After intravenous administration, oxaliplatin enters cancer cells and undergoes aquation to form reactive platinum complexes. These activated platinum moieties covalently bind to nucleophilic sites on DNA, predominantly forming intra-strand and inter-strand crosslinks, primarily between guanine bases.

The formation of these platinum-DNA adducts leads to significant distortion of the DNA double helix, thereby inhibiting DNA replication and transcription. This disruption triggers multiple cellular responses including activation of DNA damage recognition and repair pathways, cell cycle arrest, and ultimately leading to apoptosis or programmed cell death. The DNA damage caused by oxaliplatin is distinct structurally from that induced by earlier platinum agents such as cisplatin, which contributes to its unique spectrum of activity and toxicity profile.

At the molecular level, oxaliplatin-induced DNA lesions interfere with the binding and function of DNA-processing enzymes, including DNA polymerases and topoisomerases. Oxaliplatin also modulates various signal transduction pathways that regulate cell survival and apoptosis, such as p53 activation, contributing to its cytotoxic efficacy. The drug's mechanism circumvents some resistance mechanisms seen with other platinum compounds, attributed to differences in DNA adduct formation and repair.

Clinically, oxaliplatin’s effectiveness is enhanced when combined with fluoropyrimidines (5-fluorouracil) and leucovorin, forming regimens like FOLFOX. These combinations exploit complementary mechanisms, with oxaliplatin inducing DNA damage and fluorouracil inhibiting thymidylate synthase, together amplifying cytotoxic effects in colorectal cancer cells. Ongoing research further explores oxaliplatin’s immunomodulatory capacities and potential synergism with targeted therapies, augmenting its therapeutic utility.

Pharmacological Actions

Alkylation of DNA via formation of platinum-DNA adducts leading to crosslinking and DNA strand breaks
Inhibition of DNA replication and transcription in rapidly dividing cancer cells
Induction of apoptosis through activation of DNA damage response pathways including p53 signaling
Cytotoxic activity primarily against colorectal, gastric, and other gastrointestinal malignancies
Synergistic enhancement of anti-tumor effects when combined with fluorouracil and leucovorin (FOLFOX regimen)
Causes neurotoxicity characterized by peripheral sensory neuropathy due to effects on neuronal calcium channels and nerve signal conduction
Exerts anti-proliferative effects by disruption of tumor cell cycle progression at the S-phase
Modulates tumor microenvironment and may have immunomodulatory properties
Associated with dose-dependent hematologic toxicity including myelosuppression
Induces oxidative stress in cancer cells contributing to cell death
Minimal hepatic metabolism leading to reduced cytochrome P450 interactions
High protein binding contributing to prolonged tissue retention
Excreted primarily renally, necessitating renal monitoring
Capable of overcoming some mechanisms of resistance seen with cisplatin and carboplatin
Influences DNA repair mechanisms and cellular repair processes

Therapeutic Or Clinical Uses

Adjuvant treatment of stage III colon cancer post-surgical tumor resection
First-line treatment of advanced or metastatic colorectal and rectal cancer in combination with fluorouracil and leucovorin (FOLFOX regimen)
Part of the CAPOX (XELOX) regimen combining oral capecitabine and intravenous oxaliplatin for colorectal cancer
Treatment of advanced gastrointestinal cancers including some gastric and pancreatic malignancies in combination regimens
Used in combination protocols aiming to improve survival and response rates in resectable gastroesophageal and gastric adenocarcinomas (e.g., FLOT regimen)
Included in multi-agent chemotherapy regimens like FOLFIRINOX for advanced pancreatic cancer
Chemotherapeutic agent indicated for patients who have progressed on prior therapies
Utilized to enhance cytotoxic effect alongside targeted therapies and biological agents in experimental settings
Effective in colorectal cancer patients with specific molecular profiles where platinum-based therapy is indicated
Off-label use in select solid tumors where platinum sensitivity is suspected
Integral component in multi-drug protocols aiming to maximize tumor response and disease control
Utilized in neoadjuvant settings for downstaging tumors prior to surgical intervention
Applied in clinical trials investigating combination with immunotherapies
Used for patients with metastatic disease to prolong progression-free survival
Employs synergistic mechanisms when combined with antifolates and fluoropyrimidines to optimize cancer cell kill

Side Or Adverse Effects

Peripheral sensory neuropathy presenting as numbness, tingling, burning pain especially in hands and feet
Acute cold-induced neuropathy characterized by heightened sensitivity to cold stimuli causing jaw tightness, throat discomfort, and chest pressure
Myelosuppression including neutropenia, thrombocytopenia, and anemia leading to increased infection risk and bleeding
Nausea, vomiting, diarrhea, and mucositis including painful mouth sores
Hypersensitivity reactions ranging from mild rash and flushing to severe anaphylaxis and potential death
Posterior reversible encephalopathy syndrome (PRES) manifesting as headache, seizures, confusion, and vision changes
Hepatotoxicity reflected by abnormal liver function tests and potential liver injury
Pulmonary toxicity including cough, wheezing, and potentially fatal lung complications
Cardiac adverse effects such as arrhythmias, long QT syndrome, chest pain, and syncope
Muscle toxicity including rhabdomyolysis marked by muscle pain, swelling, weakness, and dark urine
Fatigue and generalized weakness frequently reported among treated patients
Risk factors for bleeding, especially when combined with concurrent anticoagulant therapy
Electrolyte imbalances, notably involving potassium, magnesium, and calcium, which may exacerbate cardiac or neuromuscular side effects
Injection site reactions and infusion-related discomfort
Potential for secondary malignancies such as leukemia following prolonged use in combination chemotherapy

Precautions

Patients with known hypersensitivity to platinum compounds should not receive oxaliplatin due to risk of severe allergic reactions
Avoid exposure to cold temperatures and cold objects during and shortly after infusion to reduce neuropathic symptoms
Careful monitoring is required in patients with pre-existing peripheral neuropathy; dose adjustments may be needed
Assessment of renal and hepatic function prior to treatment and periodically during therapy to guide dosing
Use with caution in patients with cardiac abnormalities such as long QT syndrome, arrhythmias, or history of ischemic heart disease
Avoid use in pregnancy due to teratogenic effects; effective contraception recommended during and after treatment
Use contraception for recommended periods post-treatment for both male and female patients to prevent fertility-related and teratogenic risks
Close monitoring of blood counts is essential to detect and manage myelosuppression promptly
Patients should inform clinicians of any bleeding disorders or concurrent anticoagulant use
Patients with history of lung or liver disorders require careful evaluation before and during therapy
Infusion should be administered under medical supervision with resuscitation capabilities available
Educate patients about signs of neurotoxicity and advise reporting promptly
Adjustment or delay of treatment may be necessary if severe adverse effects develop
Avoid concomitant nephrotoxic drugs which may exacerbate renal impairment
Provide antiemetic prophylaxis according to clinical guidelines to manage nausea and vomiting

Warnings

Severe hypersensitivity reactions including anaphylaxis and fatal outcomes have been reported; emergency measures should be accessible during infusion
Risk of cumulative peripheral neuropathy that may be persistent or irreversible; symptoms can be exacerbated by exposure to cold
Potential for life-threatening myelosuppression with risk of infection and bleeding; neutropenic fever requires urgent intervention
Rare but serious posterior reversible encephalopathy syndrome (PRES) necessitates immediate medical evaluation if neurologic symptoms occur
Oxaliplatin use has been associated with secondary malignancies, including leukemia, particularly when combined with other cytotoxic therapy
Pulmonary toxicity, including fatal interstitial lung disease, can develop; respiratory symptoms require immediate assessment
Cardiotoxicity including arrhythmias, QT prolongation, and cardiac arrest has been observed; continuous monitoring in at-risk patients is advised
Muscle toxicity such as rhabdomyolysis can cause life-threatening complications; muscle pain and weakness warrant urgent evaluation
Pregnancy category D: may cause fetal harm; females should avoid pregnancy during treatment and for 9 months after last dose
Breastfeeding is contraindicated during treatment and for at least 3 months afterward due to unknown drug excretion in milk
Patients must avoid cold exposure to minimize risk of acute neuropathy symptoms including throat spasms and breathing difficulty
Use cautiously in patients with electrolyte imbalances which may increase risk of cardiac side effects
Do not freeze; protect from light to maintain drug stability; improper storage can degrade efficacy
Concomitant use with anticoagulants or other agents affecting coagulation may enhance bleeding risk
Inform patients regarding potential cognitive effects (chemobrain) which may affect concentration and memory

Contraindication

Known hypersensitivity to oxaliplatin or any platinum-containing compounds
History of severe allergic reaction to platinum-based chemotherapy drugs
Pregnancy due to teratogenicity and risk of fetal harm
Breastfeeding during therapy due to unknown excretion and potential risk to infant
Severe chemotherapy-induced peripheral neuropathy from prior treatment precluding safe use
Severe renal impairment without dose adjustment or close monitoring
Uncontrolled infections or sepsis at the time of planned chemotherapy initiation
Active bleeding or hemorrhagic disorders without adequate management
Significant baseline cardiac arrhythmia or recent myocardial infarction without stabilization
Severe hepatic dysfunction that may alter metabolism and elimination
Patients unable to tolerate intravenous infusion due to medical or technical reasons
Patients with electrolyte abnormalities not corrected prior to therapy initiation
Concurrent use of contraindicated medications that substantially increase risk of toxicity
Patients with a history of posterior reversible encephalopathy syndrome linked to prior chemotherapy
Patients who cannot provide informed consent or cooperate with necessary clinical follow-up

Drug Interactions

Concomitant administration with other platinum agents may increase cumulative neurotoxicity and allergic reactions
Fluorouracil and leucovorin are commonly co-administered; these combinations have synergistic efficacy and overlapping myelosuppression
Anticoagulants such as warfarin may potentiate bleeding risk when used with oxaliplatin
Drugs causing nephrotoxicity may exacerbate oxaliplatin toxicity due to shared renal elimination pathways
Medications that prolong QT interval may increase cardiac arrhythmia risk if combined with oxaliplatin
Calcium and magnesium infusions have been used to mitigate neurotoxicity but effects on oxaliplatin efficacy are controversial
Potassium, magnesium, and calcium imbalances may alter cardiac and neuromuscular side effects, necessitating electrolyte monitoring
Interactions with immunosuppressants or immunomodulatory drugs may affect treatment response or toxicity profiles
Co-administration with other myelosuppressive agents requires monitoring for enhanced hematologic toxicity
Neurotoxic drugs may have additive adverse effects leading to exacerbated peripheral neuropathy
Certain antiemetics used concurrently may affect oxaliplatin pharmacodynamics and side effect profiles
Herbal supplements and vitamins with anticancer or immune-modulating properties can interfere with treatment outcomes
Drugs affecting hepatic enzyme systems have limited interaction risk due to oxaliplatin's minimal hepatic metabolism
Interactions with renal tubular transport inhibitors can impair elimination and increase toxicity
Use of live vaccines during immunosuppressive therapy with oxaliplatin is generally contraindicated due to infection risk

Preparations Of The Drug

Eloxatin concentrate for solution for infusion containing oxaliplatin dissolved in water for injection
Available in sterile, pyrogen-free intravenous infusion vials; requires dilution prior to administration
Storage recommendations include keeping at 20° to 25°C (68° to 77°F) with permitted excursions between 15°C and 30°C (59°F to 86°F)
Protect from light and do not freeze to maintain chemical stability and potency
Prepared infusions should be used within recommended timeframes to prevent degradation
Infusion solutions are usually prepared in isotonic solutions such as 5% dextrose (D5W) and should not be mixed with saline-containing solutions prior to use
Packaging includes single-use vials to prevent contamination
Instructions specify compatibility with leucovorin and fluorouracil infusions administered sequentially though in separate bags
Handling requires appropriate personal protective equipment due to cytotoxicity
Waste disposal should follow hazardous drug guidelines to minimize environmental contamination
Generic versions are available with similar preparation and storage instructions, but inactive ingredients vary
Reconstitution and dilution procedures must be performed by trained personnel in aseptic conditions
The drug must be labeled with patient identifiers, dosing information, and infusion times for safety
Preparations must adhere to institutional chemotherapy protocols
Stability data guide allowable infusion durations and storage before administration