Caution — Prolongation of the infusion time beyond 60 minutes and more frequent than weekly dosing have been shown to increase toxicity (see CLINICAL STUDIES).
Hematology — Gemzar can suppress bone marrow function as manifested by leukopenia, thrombocytopenia, and anemia (see ADVERSE REACTIONS), and myelosuppression is usually the dose–limiting toxicity. Patients should be monitored for myelosuppression during therapy. See DOSAGE AND ADMINISTRATION for recommended dose adjustments.
Pulmonary — Pulmonary toxicity has been reported with the use of Gemzar. In cases of severe lung toxicity, Gemzar therapy should be discontinued immediately and appropriate supportive care measures instituted (see Pulmonary under Single–Agent Use and under Post–marketing experience in ADVERSE REACTIONS).
Renal — Hemolytic Uremic Syndrome (HUS) and/or renal failure have been reported following one or more doses of Gemzar. Renal failure leading to death or requiring dialysis, despite discontinuation of therapy, has been rarely reported. The majority of the cases of renal failure leading to death were due to HUS (see Renal under Single–Agent Use and under Post–marketing experience in ADVERSE REACTIONS).
Hepatic — Serious hepatotoxicity, including liver failure and death, has been reported very rarely in patients receiving Gemzar alone or in combination with other potentially hepatotoxic drugs (see Hepatic under Single–Agent Use and under Post–marketing experience in ADVERSE REACTIONS).
Pregnancy — Pregnancy Category D. Gemzar can cause fetal harm when administered to a pregnant woman. Gemcitabine is embryotoxic causing fetal malformations (cleft palate, incomplete ossification) at doses of 1.5 mg/kg/day in mice (about 1/200 the recommended human dose on a mg/m2 basis). Gemcitabine is fetotoxic causing fetal malformations (fused pulmonary artery, absence of gall bladder) at doses of 0.1 mg/kg/day in rabbits (about 1/600 the recommended human dose on a mg/m2 basis). Embryotoxicity was characterized by decreased fetal viability, reduced live litter sizes, and developmental delays. There are no studies of Gemzar in pregnant women. If Gemzar is used during pregnancy, or if the patient becomes pregnant while taking Gemzar, the patient should be apprised of the potential hazard to the fetus.
Patients receiving therapy with Gemzar should be monitored closely by a physician experienced in the use of cancer chemotherapeutic agents. Most adverse events are reversible and do not need to result in discontinuation, although doses may need to be withheld or reduced. There was a greater tendency in women, especially older women, not to proceed to the next cycle.
Patients receiving Gemzar should be monitored prior to each dose with a complete blood count (CBC), including differential and platelet count. Suspension or modification of therapy should be considered when marrow suppression is detected (see DOSAGE AND ADMINISTRATION).
Laboratory evaluation of renal and hepatic function should be performed prior to initiation of therapy and periodically thereafter (see WARNINGS).
Carcinogenesis, Mutagenesis, Impairment of Fertility
Long–term animal studies to evaluate the carcinogenic potential of Gemzar have not been conducted. Gemcitabine induced forward mutations in vitro in a mouse lymphoma (L5178Y) assay and was clastogenic in an in vivo mouse micronucleus assay. Gemcitabine was negative when tested using the Ames, in vivo sister chromatid exchange, and in vitro chromosomal aberration assays, and did not cause unscheduled DNA synthesis in vitro. Gemcitabine IP doses of 0.5 mg/kg/day (about 1/700 the human dose on a mg/m2 basis)in male mice had an effect on fertility with moderate to severe hypospermatogenesis, decreased fertility, and decreased implantations. In female mice, fertility was not affected but maternal toxicities were observed at 1.5 mg/kg/day IV (about 1/200 the human dose on a mg/m2 basis) and fetotoxicity or embryolethality was observed at 0.25 mg/kg/day IV (about 1/1300 the human dose on a mg/m2 basis).
Category D. See WARNINGS.
It is not known whether Gemzar or its metabolites are excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions from Gemzar in nursing infants, the mother should be warned and a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother and the potential risk to the infant.
Gemzar clearance is affected by age (see CLINICAL PHARMACOLOGY). There is no evidence, however, that unusual dose adjustments (i.e., other than those already recommended in DOSAGE AND ADMINISTRATION) are necessary in patients over 65, and in general, adverse reaction rates in the single–agent safety database of 979 patients were similar in patients above and below 65. Grade 3/4 thrombocytopenia was more common in the elderly. In the randomized clinical trial of Gemzar in combination with carboplatin for recurrent ovarian cancer (see CLINICAL STUDIES), 125 women treated with Gemzar plus carboplatin were <65 years and 50 were ≥65 years. Similar effectiveness was observed between older and younger women. There was significantly higher Grade 3/4 neutropenia in women 65 years of age or older. Overall, there were no substantial differences in toxicity profile of Gemzar plus carboplatin based on age.
Gemzar clearance is affected by gender (see CLINICAL PHARMACOLOGY). In the single–agent safety database (N=979 patients), however, there is no evidence that unusual dose adjustments (i.e., other than those already recommended in the DOSAGE AND ADMINISTRATION section) are necessary in women. In general, in single–agent studies of Gemzar, adverse reaction rates were similar in men and women, but women, especially older women, were more likely not to proceed to a subsequent cycle and to experience Grade 3/4 neutropenia and thrombocytopenia.
The effectiveness of Gemzar in pediatric patients has not been demonstrated. Gemzar was evaluated in a Phase 1 trial in pediatric patients with refractory leukemia and determined that the maximum tolerated dose was 10 mg/m2/min for 360 minutes three times weekly followed by a one-week rest period. Gemzar was also evaluated in a Phase 2 trial in patients with relapsed acute lymphoblastic leukemia (22 patients) and acute myelogenous leukemia (10 patients) using 10 mg/m2/min for 360 minutes three times weekly followed by a one week rest period. Toxicities observed included bone marrow suppression, febrile neutropenia, elevation of serum transaminases, nausea, and rash/desquamation, which were similar to those reported in adults. No meaningful clinical activity was observed in this Phase 2 trial.
Patients with Renal or Hepatic Impairment
Gemzar should be used with caution in patients with preexisting renal impairment or hepatic insufficiency as there is insufficient information from clinical studies to allow clear dose recommendation for these patient populations. Administration of Gemzar in patients with concurrent liver metastases or a preexisting medical history of hepatitis, alcoholism, or liver cirrhosis may lead to exacerbation of the underlying hepatic insufficiency.
No specific drug interaction studies have been conducted. For information on the pharmacokinetics of Gemzar and cisplatin in combination, see Drug Interactions under CLINICAL PHARMACOLOGY.
A pattern of tissue injury typically associated with radiation toxicity has been reported in association with concurrent and non–concurrent use of Gemzar.
Non–concurrent (given >7 days apart) — Analysis of the data does not indicate enhanced toxicity when Gemzar is administered more than 7 days before or after radiation, other than radiation recall. Data suggest that Gemzar can be started after the acute effects of radiation have resolved or at least one week after radiation.
Concurrent (given together or ≤7 days apart) — Preclinical and clinical studies have shown that Gemzar has radiosensitizing activity. Toxicity associated with this multimodality therapy is dependent on many different factors, including dose of Gemzar, frequency of Gemzar administration, dose of radiation, radiotherapy planning technique, the target tissue, and target volume. In a single trial, where Gemzar at a dose of 1000 mg/m2 was administered concurrently for up to 6 consecutive weeks with therapeutic thoracic radiation to patients with non–small cell lung cancer, significant toxicity in the form of severe, and potentially life–threatening mucositis, especially esophagitis and pneumonitis was observed, particularly in patients receiving large volumes of radiotherapy [median treatment volumes 4795 cm3]. Subsequent studies have been reported and suggest that Gemzar administered at lower doses with concurrent radiotherapy has predictable and less severe toxicity. However, the optimum regimen for safe administration of Gemzar with therapeutic doses of radiation has not yet been determined in all tumor types.