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Doxorubicin
WARNINGS
Doxil (doxorubicin HCl liposome injection) is doxorubicin hydrochloride (HCl) encapsulated in STEALTH® liposomes for intravenous administration. Note: Liposomal encapsulation can substantially affect a drug’s functional properties relative to those of the unencapsulated drug. In addition, different liposomal drug products may vary from one another in the chemical composition and physical form of the liposomes. Such differences can substantially affect the functional properties of liposomal drug products. DO NOT SUBSTITUTE. Doxorubicin is a cytotoxic anthracycline antibiotic isolated from Streptomyces peucetius var. caesius. Doxorubicin HCl, which is the established name for 8S,10S)-10-[(3-amino-2,3,6-trideoxy-a-L-lyxo-hexopyranosyl)oxy] -8-glycolyl-7,8,9,10-tetrahydro-6,8,11- trihydroxy-1-methoxy-5,12-naphthacenedione hydrochloride. The molecular formula of the drug is C27H29NO11•HCl; its molecular weight is 579.99. Doxil is provided as a sterile,
translucent, red liposomal
dispersion in 10-mL glass, single use vials. Each vial
contains 20 mg doxorubicin
HCl at a concentration
of 2 mg/mL and a pH of 6.5.
The STEALTH liposome carriers are composed of N-(carbonyl-methoxypolyethylene
glycol 2000)-1,2-distearoyl-sn-glycero-
3-phosphoethanolamine sodium
salt (MPEG-DSPE), 3.19
mg/mL; fully hydrogenated soy phosphatidylcholine (HSPC), 9.58 mg/mL;
and cholesterol,
3.19 mg/mL. Each mL also contains ammonium
sulfate, approximately 2 mg; histidine
as a buffer; hydrochloric acid
and/or sodium hydroxide
for pH control; and sucrose
to maintain isotonicity. Greater than 90% of the drug
is encapsulated in the STEALTH liposomes.
Mechanism of Action The active ingredient of Doxil is doxorubicin HCl. The mechanism of action of doxorubicin HCl is thought to be related to its ability to bind DNA and inhibit nucleic acid synthesis. Cell structure studies have demonstrated rapid cell penetration and perinuclear chromatin binding, rapid inhibition of mitotic activity and nucleic acid synthesis, and induction of mutagenesis and chromosomal aberrations. Doxil is doxorubicin HCl encapsulated in long-circulating STEALTH liposomes. Liposomes are microscopic vesicles composed of a phospholipid bilayer that are capable of encapsulating active drugs. The STEALTH liposomes of Doxil are formulated with surface-bound methoxypolyethylene glycol (MPEG), a process often referred to as pegylation, to protect liposomes from detection by the mononuclear phagocyte system (MPS) and to increase blood circulation time. STEALTH liposomes have a half-life of approximately 55 hours in humans. They are stable in blood, and direct measurement of liposomal doxorubicin shows that at least 90% of the drug (the assay used cannot quantify less than 5-10% free doxorubicin) remains liposome-encapsulated during circulation. It is hypothesized that because of their small size (ca. 100 nm) and persistence in the circulation, the pegylated Doxil liposomes are able to penetrate the altered and often compromised vasculature of tumors. This hypothesis is supported by studies using colloidal gold-containing STEALTH liposomes, which can be visualized microscopically. Evidence of penetration of STEALTH liposomes from blood vessels and their entry and accumulation in tumors has been seen in mice with C-26 colon carcinoma tumors and in transgenic mice with Kaposi's sarcoma-like lesions. Once the STEALTH liposomes distribute to the tissue compartment, the encapsulated doxorubicin HCl becomes available. The exact mechanism of release is not understood. Pharmacokinetics The plasma pharmacokinetics of Doxil were evaluated in 42 patients with AIDS-related Kaposi’s sarcoma (KS) who received single doses of 10 or 20 mg/m2 administered by a 30-minute infusion. Twenty-three of these patients received single doses of both 10 and 20 mg/m2 with a 3-week wash-out period between doses. The pharmacokinetic parameter values of Doxil, given for total doxorubicin (mostly liposomally bound), are shown in the following table. Pharmacokinetic Parameters of Doxil® in AIDS Patients with Kaposi’s Sarcoma
Doxil displayed linear pharmacokinetics over the range of 10 to 20 mg/m2. Disposition occurred in two phases after Doxil administration, with a relatively short first phase (»5 hours) and a prolonged second phase (»55 hours) that accounted for the majority of the area under the curve (AUC). The pharmacokinetics of Doxil at a 50 mg/m2 dose is reported to be nonlinear. At this dose, the elimination half-life of Doxil is expected to be longer and the clearance lower compared to a 20 mg/m2 dose. The exposure (AUC) is thus expected to be more than proportional at a 50 mg/m2 dose when compared with the lower doses. Distribution: In contrast to the pharmacokinetics of doxorubicin, which displays a large volume of distribution, ranging from 700 to 1100 L/m2 , the small steady state volume of distribution of Doxil shows that Doxil is confined mostly to the vascular fluid volume. Plasma protein binding of Doxil has not been determined; the plasma protein binding of doxorubicin is approximately 70%. Metabolism: Doxorubicinol, the major metabolite of doxorubicin, was detected at very low levels (range: of 0.8 to 26.2 mg/mL) in the plasma of patients who received 10 or 20 mg/m2 Doxil. Excretion: The plasma clearance of Doxil was slow, with a mean clearance value of 0.041 L/h/m2 at a dose of 20 mg/m2 . This is in contrast to doxorubicin, which displays a plasma clearance value ranging from 24 to 35 L/h/m2 . Because of its slower clearance, the AUC of Doxil , primarily representing the circulation of liposome-encapsulated doxorubicin, is approximately two to three orders of magnitude larger than the AUC for a similar dose of conventional doxorubicin HCl as reported in the literature. Special Populations: The pharmacokinetics of Doxil have not been separately evaluated in women, in members of different ethnic groups, or in individuals with renal or hepatic insufficiency. Drug-Drug Interactions: Although the patient populations for the current indications are on various medications, drug-drug interactions between Doxil and other drugs, including antiviral agents, have not been evaluated. Tissue Distribution Kaposi’s sarcoma lesions and normal skin biopsies were obtained at 48 and 96 hours postinfusion of 20 mg/m2 Doxil in 11 patients. The concentration of Doxil in KS lesions was a median of 19 (range, 3-53) times higher than in normal skin at 48 hours posttreatment; however, this was not corrected for likely differences in blood content between KS lesions and normal skin. The corrected ratio may lie between 1 and 22 times. Thus, higher concentrations of Doxil are delivered to KS lesions than to normal skin. CLINICAL STUDIES Ovarian Carcinoma Doxil (doxorubicin HCl liposome injection) was studied in three open-label, single-arm, clinical trials of 176 patients with metastatic ovarian carcinoma. One hundred forty-six (146) of these patients were refractory to both paclitaxel- and platinum-based chemotherapy regimen. Refractory patients are defined as those having progressive disease while on treatment, or within 6 months of completing treatment. Patients in these studies received Doxil at 50 mg/m2 infused over one hour every 3 or 4 weeks for 3-6 cycles or longer in the absence of dose-limiting toxicity or progression of disease. The baseline demographics and clinical characteristics of the refractory patients are shown in the following table. Patient Demographics for Refractory Patients from Phase 2 Ovarian Cancer Studies
The primary efficacy parameter was response rate for the population of patients refractory to both paclitaxel and a platinum-containing regimen. Assessment of response was based on Southwest Oncology Group (SWOG) criteria, and required confirmation four weeks after the initial observation. Secondary efficacy parameters were time to response, duration of response, and time to progression. The response rates for the individual phase 2 trials are given in the following table: Response Rates in Refractory Patients from single arm Ovarian Cancer Studies
When the data from the single arm trials are combined, the response rate for all patients refractory to paclitaxel and platinum agents was 13.8% (20/145) (95% CI 8.1% to 19.3%). The median time to progression was 15.9 weeks, the median time to response was 17.6 weeks, and the duration of response was 39.4 weeks. Preliminary Results of Ovarian Cancer Randomized Trial Data were also provided from an interim analysis of a randomized comparative study of Doxil . Of the 44 patients in the Doxil arm with tumors refractory to paclitaxel and platinum compounds, 6 had objective responses, a response rate of 13.6% (95% CI 5.2% to 27.4%). AIDS-Related Kaposi’s Sarcoma Doxil was studied in an open-label, single-arm, multicenter study utilizing Doxil at 20 mg/m2 by intravenous infusion every three weeks, generally until progression or intolerance occurred. In an interim analysis, the treatment history of 383 patients was reviewed, and a cohort of 77 patients was retrospectively identified as having disease progression on prior systemic combination chemotherapy (at least 2 cycles of a regimen containing at least two of three treatments: bleomycin, vincristine or vinblastine, or doxorubicin) or as being intolerant to such therapy. Forty-nine of the 77 (64%) patients had received prior doxorubicin HCl. These 77 patients were predominantly white, homosexual males with a median CD4 count of 10 cells/mm3 . Their age ranged from 24 to 54 years, with a mean age of 38 years. Using the ACTG staging criteria,1 78% of the patients were at p.o. risk for tumor burden, 96% at p.o. risk for immune system, and 58% at p.o. risk for systemic illness at baseline. Their mean Karnofsky status score was 74%. All 77 patients had cutaneous or subcutaneous lesions, 40% also had oral lesions, 26% pulmonary lesions, and 14% of patients had lesions of the stomach/intestine. The majority of these patients had disease progression on prior systemic combination chemotherapy. The median time on study for these 77 patients was 155 days and ranged from 1 to 456 days. The median cumulative dose was 154 mg/m2 and ranged from 20 to 620 mg/m2 . Two analyses of tumor response were used to evaluate the effectiveness of Doxil: one analysis based on investigator assessment of changes in lesions over the entire body, and one analysis based on changes in indicator lesions. Investigator Assessment Investigator response was based on modified ACTG criteria.1 Partial response was defined as no new lesions, sites of disease, or worsening edema; flattening of ³50% of previously raised lesions or area of indicator lesions decreasing by ³50%; and response lasting at least 21 days with no prior progression. Indicator Lesion Assessment A retrospectively defined analysis was conducted based on assessment of the response of up to five prospectively identified representative indicator lesions. A partial response was defined as flattening of ³50% of previously raised indicator lesions, or > 50% decrease in the area of indicator lesions and lasting at least 21 days with no prior progression. Only patients with adequate documentation of baseline status and follow-up assessments were considered evaluable for response. Patients who received concomitant KS treatment during study, who completed local radiotherapy to sites encompassing one or more of the indicator lesions within two months of study entry, who had less than four indicator lesions, or who had less than three raised indicator lesions at baseline (the latter applies solely to indicator lesion assessment) were considered nonevaluable for response. Of the 77 patients who had disease progression on prior systemic combination chemotherapy or who were intolerant to such therapy, 34 were evaluable for investigator assessment and 42 were evaluable for indicator lesion assessment. Responses are summarized in the table below. Response in Refractory a AIDS-KS
Doxil (doxorubicin HCl liposome injection) is indicated for:
These indications are based on objective tumor response rates. No results are available from controlled trials that demonstrate a clinical benefit resulting from this treatment, such as improvement in disease-related symptoms or increased survival.
Ovarian Cancer Patients Doxil (doxorubicin HCl liposome injection) should be administered intravenously at a dose of 50 mg/m2 (doxorubicin HCl equivalent) at an initial rate of 1 mg/min to minimize the risk of infusion reactions. If no infusion-related AEs are observed, the rate of infusion can be increased to complete administration of the drug over one hour. The patient should be dosed once every 4 weeks, for as long as the patient does not progress, shows no evidence of cardiotoxicity (see WARNINGS), and continues to tolerate treatment. A minimum of 4 courses is recommended because median time to response in clinical trials was 4 months. To manage adverse events such as PPE, stomatitis or hematologic toxicity the doses may be delayed or reduced (see Dose Modification guidelines below). Pretreatment with or concomitant use of antiemetics should be considered. AIDS-KS Patients Doxil (doxorubicin HCl liposome injection) should be administered intravenously at a dose of 20 mg/m2 (doxorubicin HCl equivalent) over 30 minutes, once every three weeks, for as long as patients respond satisfactorily and tolerate treatment. General Do not administer as a bolus injection or an undiluted solution. Rapid infusion may increase the risk of infusion-related reactions. (See WARNINGS - Infusion REACTIONS.) Each vial contains 20 mg doxorubicin HCl at a concentration of 2 mg/mL. Until specific compatibility data are available, it is not recommended that Doxil be mixed with other drugs. Doxil should be considered an irritant and precautions should be taken to avoid extravasation. With intravenous administration of Doxil, extravasation may occur with or without an accompanying stinging or burning sensation, even if blood returns well on aspiration of the infusion needle. If any signs or symptoms of extravasation have occurred the infusion should be immediately terminated and restarted in another vein. The application of ice over the site of extravasation for approximately 30 minutes may be helpful in alleviating the local reaction. Doxil must not be given by the intramuscular or subcutaneous route. Dose Modification Guidelines Doxil exhibits nonlinear pharmacokinetics at 50 mg/m2 ; therefore, dose adjustments may result in a non-proportional greater change in plasma concentration and exposure to the drug. (see CLINICAL PHARMACOLOGY, Pharmacokinetics.) Patients should be carefully monitored for toxicity. Adverse events, such as PPE, hematologic toxicities, and stomatitis may be managed by dose delays and adjustments. Following the first appearance of a Grade 2 or higher adverse event, the dosing should be adjusted or delayed as described in the following tables. Once the dose has been reduced, it should not be increased at a later time. Recommended Dose Modification Guidelines
Limited clinical experience exists in treating hepatically impaired patients with Doxil . Based on experience with doxorubicin HCl, it is recommended that Doxil dosage be reduced if the bilirubin is elevated as follows: Serum biliribin 1.2 to 3.0 mg/dL give ½ normal dose, >3 mg/dL give ¼ normal dose. Preparation for Intravenous Administration The appropriate dose of Doxil , up to a maximum of 90 mg, must be diluted in 250 mL of 5% Dextrose Injection, USP prior to administration. Aseptic technique must be strictly observed since no preservative or bacteriostatic agent is present in Doxil. Diluted Doxil should be refrigerated at 2°C to 8°C (36°F to 46°F) and administered within 24 hours. Do not use with in-line filters. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Do not use if a precipitate or foreign matter is present. Storage and Stability Refrigerate unopened vials of Doxil at 2°C to 8°C (36°F to 46°F). Avoid freezing. Prolonged freezing may adversely affect liposomal drug products; however, short-term freezing (less than 1 month) does not appear to have a deleterious effect on Doxil. Procedure for Proper Handling and Disposal Caution should be exercised in the handling and preparation of Doxil. The use of gloves is required. If Doxil comes into contact with skin or mucosa, immediately wash thoroughly with soap and water. Doxil should be considered an irritant and precautions should be taken to avoid extravasation. With intravenous administration of Doxil, extravasation may occur with or without an accompanying stinging or burning sensation, even if blood returns well on aspiration of the infusion needle. If any signs or symptoms of extravasation have occurred, the infusion should be immediately terminated and restarted in another vein. Doxil must not be given by the intramuscular or subcutaneous route. Doxil should be handled and disposed of in a manner consistent with other anticancer drugs. Several guidelines on this subject exist.2-8 HOW SUPPLIED Doxil (doxorubicin HCl liposome injection) is supplied as a sterile, translucent, red liposomal dispersion in 10 mL glass, single use vials. Each vial contains 20 mg doxorubicin HCl at a concentration of 2 mg/mL. Refrigerate at 2-8°C. Avoid freezing. Prolonged freezing may adversely affect liposomal drug products; however, short-term freezing (less than 1 month) does not appear to have a deleterious effect on Doxil. Available as individually cartoned vials in packages of six. NDC #61471-295-12. REFERENCES
Ovarian Cancer Patients Safety data are available from 373 ovarian cancer patients treated with Doxil in 4 clinical studies. The patient population was predominantly white (93.6%) with a median age of 60 years. Patients received a median cycle dose of 50 mg/m2 administered with a median cycle length of 29.5 days. They remained on study drug for a median of 56 days and received a median cumulative dose of 137.5 mg/m2. Patients received a median of 3-cycles of Doxil , although some patients remained on study drug for a prolonged period, with 46 patients (12.3%) receiving more than 10 cycles of treatment. Adverse events (AEs) were reported in all but 2 of the 361 patients who had at least one AE form collected. A total of 3,124 AEs were reported, an average of 8.6 AEs per patient. Most (91.7%) patients had AEs that were considered related to study drug. Drug-Related Adverse Events Reported in ³ 5% of Ovarian Cancer Patients
*From concomitant medication or transfusion logs, not reported as AEs. The following additional (not in table) adverse events were observed in ovarian cancer patients with doses administered every four weeks; only events considered at least possibly drug-related by investigators are included. Incidence 1% to 5%
Incidence Less Than 1%
AIDS-KS Patients Information on adverse events is based on the experience reported in 753 patients with AIDS-related KS enrolled in four studies. The majority of patients were treated with 20 mg/m2 of Doxil (doxorubicin HCl liposome injection) every two to three weeks. The median time on study was 127 days and ranged from 1 to 811 days. The median cumulative dose was 120 mg/m2 and ranged from 3.3 to 798.6 mg/m2 . Twenty-six patients (3.0%) received cumulative doses of greater than 450 mg/m2 . Of these 753 patients, 61.2% were considered p.o. risk for KS tumor burden, 91.5% p.o. for immune system, and 46.9% for systemic illness; 36.2% were p.o. risk for all three categories. Patients’ median CD4 count was 21.0 cells/mm3 , with 50.8% of patients having less than 50 cells/mm3 . The mean absolute neutrophil count at study entry was approximately 3000 cells/mm3 . Patients received a variety of potentially myelotoxic drugs in combination with Doxil. Of the 693 patients with concomitant medication information, 58.7% were on one or more antiretroviral medications; 34.9% patients were on zidovudine (AZT), 20.8% on didanosine (ddI), 16.5% on zalcitabine (ddC), and 9.5% on stavudine (D4T). A total of 85.1% patients were on PCP prophylaxis, most (54.4%) on sulfamethoxazole/ trimethoprim. Eighty-five percent of patients were receiving antifungal medications, primarily fluconazole (75.8%). Seventy-two percent of patients were receiving antivirals, 56.3% acyclovir, 29% ganciclovir, and 16% foscarnet. In addition, 47.8% patients received colony stimulating factors (sargramostim/ filgrastim) sometime during their course of treatment. Of the 753 patients enrolled in the Doxil clinical trials, adverse event information was available for 705 patients. In many instances it was difficult to determine whether adverse events resulted from Doxil, from concomitant therapy, or from the patients’ underlying disease(s). Eighty-three percent of the patients reported adverse events that were considered to be possibly or probably related to the treatment with Doxil. Adverse reactions only infrequently (5%) led to discontinuation of treatment. Those that did so included bone marrow suppression, cardiac adverse events, infusion-related reactions, toxoplasmosis, palmar-plantar erythrodysesthesia, pneumonia, cough/dyspnea, fatigue, optic neuritis, progression of a non-KS tumor, allergy to penicillin, and unspecified reasons. Probably and Possibly Drug-Related Adverse Events Reported in ³ 5% of AIDS-KS Patients
The following additional (not in table) adverse events were observed in AIDS-KS patients; only events considered at least possibly drug-related by investigators are included. Incidence 1% to 5%
Incidence Less Than 1%
No formal drug interaction
studies have been conducted with Doxil . Until specific
compatibility
data are available, it is not recommended that Doxil be mixed
with other drugs. Doxil may interact with the conventional formulation
of doxorubicin HCl.
Cardiac Toxicity Experience with large cumulative doses of Doxil (doxorubicin HCl liposome injection) is limited, so that Doxil’s cardiac risk, and its risk compared to conventional doxorubicin formulations, has not been adequately evaluated. At present, therefore, warnings related to the use of conventional formulation doxorubicin HCl should be observed. Special attention must be given to the cardiac toxicity exhibited by doxorubicin HCl. Acute left ventricular failure can occur with doxorubicin, particularly in patients who have received total doxorubicin dosage exceeding the currently recommended limit of 550 mg/m2 . Lower (400 mg/m2) doses appear to cause heart failure in patients who have received radiotherapy to the mediastinal area or concomitant therapy with other potentially cardiotoxic agents such as cyclophosphamide. Caution should be observed in patients who have received other anthracyclines,and the total dose of doxorubicin HCl given should take into account any previous or concomitant therapy with other anthracyclines or related compounds. Congestive heart failure and/or cardiomyopathy may be encountered after discontinuation of therapy. Patients with a history of cardiovascular disease should be administered Doxil only when the potential benefit of treatment outweighs the risk. Cardiac function should be carefully monitored in patients treated with Doxil . The most definitive test for anthracycline myocardial injury is endomyocardial biopsy. Other methods, such as echocardiography or gated radionuclide scans, have been used to monitor cardiac function during anthracycline therapy. Any of these methods should be employed to monitor potential cardiac toxicity during Doxil therapy. If these test results indicate possible cardiac injury associated with Doxil therapy, the benefit of continued therapy must be carefully weighed against the risk of myocardial injury. (See ADVERSE REACTIONS: information concerning Cardiovascular System) In the AIDS-KS studies, 68 (9.6%) patients experienced cardiac-related adverse events. In 30 patients (4.3%), the event was thought to be possibly or probably related to Doxil . Nine cases of possibly or probably related cardiomyopathy and/or congestive heart failure were reported. Seven (1.0%) of the possibly or probably related cardiac events were severe. These severe events included arrhythmia (nonspecific), cardiomyopathy, heart failure, pericardial effusion, and tachycardia. Three patients discontinued study due to cardiac events. Myelosuppression In ovarian cancer patients, myelosuppresion was generally moderate and reversible. Anemia was the most common hematologic adverse event (52.6%), followed by neutropenia (51.7%), leukopenia (42.2%) and thrombocytopenia (24.2%). In ovarian cancer patients, 3.3% received G-CSF (or GM-CSF) to support their blood counts. (See DOSAGE AND ADMINISTRATION: Dose Modification Guidelines.) In AIDS-KS patients, who often present with baseline myelosuppression due to such factors as their HIV disease or concomitant medications, myelosuppression appears to be the dose-limiting adverse event, even at the recommended dose of 20 mg/m2 . Leukopenia is the most common adverse event (about 60%) experienced in this population; anemia (about 20%) and thrombocytopenia (about 10%) can also be expected. Sepsis occurred in 5% of patients; for 0.7% of patients the event was considered possibly or probably related to Doxil . Eleven patients (1.6%) discontinued study because of bone marrow suppression or neutropenia. In all patients, because of the potential for bone marrow suppression, careful hematologic monitoring is required during use of Doxil , including white blood cell, neutrophil, and platelet counts and Hgb/Hct. With the recommended dosage schedule, leukopenia is usually transient. Hematologic toxicity may require dose reduction or delay or suspension of Doxil therapy. Persistent severe myelosuppression may result in superinfection, neutropenic fever, or hemorrhage. Development of sepsis in the setting of neutropenia has resulted in discontinuation of treatment and in rare cases, death. Doxil may potentiate the toxicity of other anticancer therapies. In particular, hematologic toxicity may be more severe when Doxil is administered in combination with other agents that cause bone marrow suppression. Infusion REACTIONS Acute infusion-related reactions, characterized by flushing, shortness of breath, facial swelling, headache, chills, back pain, tightness in the chest and throat, and/or hypotension have occurred in 5% to 10% of patients treated with Doxil . In most patients, these reactions resolve over the course of several hours to a day once the infusion is terminated. In some patients, the reaction resolves when the rate of infusion is slowed. The majority of infusion-related events occurred during the first infusion. Six AIDS-KS patients (0.9%) and 13 (1.7%) solid tumor patients discontinued Doxil therapy because of infusion-related reactions. Similar reactions have not been reported with conventional doxorubicin and they presumably represent a reaction to the Doxil liposomes or one of its surface components. The initial rate of infusion should be 1 mg/min to help minimize the risk of infusion reactions. (See DOSAGE AND ADMINISTRATION.) Palmar-Plantar Erythrodysesthesia In ovarian cancer patients, 37.4% of patients experienced PPE (developed palmar-plantar skin eruptions characterized by swelling, pain, erythema and, for some patients, desquamation of the skin on the hands and the feet), with 16.4% of the patients reporting Grade 3 or 4 events. Thirteen (3.5%) of the ovarian cancer patients discontinued treatment due to PPE or other skin toxicity. (See definitions of PPE grades in DOSAGE AND ADMINISTRATION: Dose Modification Guidelines.) Among 705 patients with AIDS-related Kaposi’s sarcoma treated with Doxil at 20 mg/m2 , 24 (3.4%) developed PPE, with 3 (0.9%) discontinuing. PPE was generally seen after 2 or 3 cycles of treatment but may occur earlier. In most patients the reaction is mild and resolves in one to two weeks so that prolonged delay of therapy need not occur. However, dose modification may be required to manage PPE. (See DOSAGE AND ADMINISTRATION: Dose Modification Guidelines.) The reaction can be severe and debilitating in some patients and may require discontinuation of treatment. Pregnancy Category D Doxil can cause fetal harm when administered to a pregnant woman. Doxil is embryotoxic at doses of 1 mg/kg/day in rats and is embryotoxic and abortifacient at 0.5 mg/kg/day in rabbits (both doses are about one-eighth the 50 mg/m2 human dose on a mg/m2 basis). Embryotoxicity was characterized by increased embryo-fetal deaths and reduced live litter sizes. There are no adequate and well-controlled studies in pregnant women. If Doxil is to be used during pregnancy, or if the patient becomes pregnant during therapy, the patient should be apprised of the potential hazard to the fetus. If pregnancy occurs in the first few months following treatment with Doxil, the prolonged half-life of the drug must be considered. Women of childbearing potential should be advised to avoid pregnancy. Toxicity Potentiation The doxorubicin in Doxil may potentiate the toxicity of other anticancer therapies. Exacerbation of cyclophosphamide-induced hemorrhagic cystitis and enhancement of the hepatotoxicity of 6-mercaptopurine have been reported with the conventional formulation of doxorubicin HCl. Radiation-induced toxicity to the myocardium, mucosae, skin and liver have been reported to be increased by the administration of doxorubicin HCl. Injection Site Effects Doxil is not a vesicant, but should be considered an irritant and precautions should be taken to avoid extravasation. With intravenous administration of Doxil , extravasation may occur with or without an accompanying stinging or burning sensation, even if blood returns well on aspiration of the infusion needle. (See DOSAGE AND ADMINISTRATION.) If any signs or symptoms of extravasation have occurred, the infusion should be immediately terminated and restarted in another vein. The application of ice over the site of extravasation for approximately 30 minutes may be helpful in alleviating the local reaction. Doxil must not be given by the intramuscular or subcutaneous route. In studies with rabbits, lesions that were induced by subcutaneous injection of Doxil were minor and reversible compared to more severe and irreversible lesions and tissue necrosis that were induced after subcutaneous injection of conventional doxorubicin HCl. Hepatic Impairment The pharmacokinetics of Doxil have not been adequately evaluated in patients with hepatic impairment. Doxil dosage should be reduced in patients with impaired hepatic function. (See DOSAGE AND ADMINISTRATION.) Prior to Doxil administration, evaluation of hepatic function is recommended using conventional clinical laboratory tests such as SGOT, SGPT, alkaline phosphatase and bilirubin. (See DOSAGE AND ADMINISTRATION.) Carcinogenesis, Mutagenesis, Impairment of Fertility Secondary acute myelogenous leukemia has been reported in patients treated with topoisomerase II inhibitors, including anthracyclines. Although no studies have been conducted with Doxil , doxorubicin HCl and related compounds have been shown to have mutagenic and carcinogenic properties when tested in experimental models. STEALTH liposomes without drug were negative when tested in Ames, mouse lymphoma and chromosomal aberration assays in vitro, and mammalian micronucleus assay in vivo. The possible adverse effects on fertility in males and females in humans or experimental animals have not been adequately evaluated. However, Doxil resulted in mild to moderate ovarian and testicular atrophy in mice after a single dose of 36 mg/kg (about twice the 50 mg/m2 human dose on a mg/m2 basis). Decreased testicular weights and hypospermia were present in rats after repeat doses ³ 0.25 mg/kg/day (about one thirtieth the 50 mg/m2 human dose on a mg/m2 basis), and diffuse degeneration of the seminiferous tubules and a marked decrease in spermatogenesis were observed in dogs after repeat doses of 1 mg/kg/day (about one half the 50 mg/m2 human dose on a mg/m2 basis).
General Patients receiving therapy with Doxil should be monitored by a physician experienced in the use of cancer chemotherapeutic agents. Most adverse events are manageable with dose reductions or delays. (See DOSAGE AND ADMINISTRATION: Dose Modification Guidelines.) Laboratory Tests Complete blood counts, including platelet counts, should be obtained frequently and at a minimum prior to each dose of Doxil. Drug Interactions No formal drug interaction studies have been conducted with Doxil . Until specific compatibility data are available, it is not recommended that Doxil be mixed with other drugs. Doxil may interact with the conventional formulation of doxorubicin HCl. Pregnancy Pregnancy Category D: (See Nursing Mothers It is not known whether this drug is excreted in human milk. Because many drugs, including anthracyclines, are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Doxil , mothers should discontinue nursing prior to taking this drug. Pediatric Use The safety and effectiveness of Doxil in pediatric patients have not been established. Geriatric Use Of the 373 ovarian cancer patients, 29% were 60 to 69 years old, while 22.8% were 70 years and over. No overall differences were observed between these subjects and younger subjects, but greater sensitivity of some older individuals cannot be ruled out. There are insufficient data for a comparative evaluation of efficacy according to age. Radiation Therapy Recall of skin reaction due to prior radiotherapy has occurred with Doxil administration. Information for the Patient See PATIENT INFORMATION section
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