TOPOTECAN Drug Interactions: What You Need to Know

INTERACTIONS G-CSF: Concomitant administration of G-CSF can prolong the duration of neutropenia, so if G-CSF is to be used, do not initiate it until day 6 of the course of therapy, 24 hours after completion of treatment with Topotecan Injection. Platinum and Other Cytotoxic Agents: Myelosuppression was more severe when topotecan, at a dose of 1.25 mg/m 2 /day for 5 days, was given in combination with cisplatin at a dose of 50 mg/m 2 in Phase 1 studies. In one study, 1 of 3 patients had severe neutropenia for 12 days and a second patient died with neutropenic sepsis. Greater myelosuppression is also likely to be seen when Topotecan Injection is used in combination with other cytotoxic agents, thereby necessitating a dose reduction. However, when combining topotecan with platinum agents (e.g., cisplatin or carboplatin), a distinct sequence-dependent interaction on myelosuppression has been reported. Coadministration of a platinum agent on day 1 of dosing with topotecan required lower doses of each agent compared to co-administration on day 5 of the dosing schedule for topotecan. For information on the pharmacokinetics, efficacy, safety, and dosing of Topotecan Injection at a dose of 0.75 mg/m 2 /day on days 1, 2, and 3 in combination with cisplatin 50 mg/m 2 on day 1 for cervical cancer [see Dosage and Administration ( 2 ) , Adverse Reactions ( 6 ), Clinical Pharmacology ( 12.3 ) and Clinical Studies ( 14 ) ] . Do not initiate G-CSF until 24 hours after completion of treatment with Topotecan Injection. Concomitant administration can prolong duration of neutropenia. ( 7 ) Greater myelosuppression is likely to be seen when used in combination with other cytotoxic agents. ( 7 )

Topotecan Injection is contraindicated in patients who have a history of severe hypersensitivity reactions (e.g., anaphylactoid reactions) to topotecan or to any of its ingredients.

Topotecan

Injection should not be used in patients with severe bone marrow depression. History of severe hypersensitivity reactions (e.g., anaphylactoid reactions) to topotecan or any of its ingredients ( 4 ) Severe bone marrow depression ( 4 )

AND PRECAUTIONS Bone marrow suppression: Administer Topotecan Injection only to patients with adequate bone marrow reserves. Monitor peripheral blood counts and adjust the dose if needed. ( 5.1 ) Topotecan-induced neutropenia can lead to neutropenic colitis. ( 5.2 ) Interstitial lung disease: topotecan has been associated with reports of interstitial lung disease. Monitor patients for symptoms and discontinue Topotecan Injection if the diagnosis is confirmed. ( 5.3 ) Pregnancy: Can cause fetal harm. Advise women of potential risk to the fetus. ( 5.4 , 8.1 )

5.1 Bone Marrow Suppression Bone marrow suppression (primarily neutropenia) is the dose-limiting toxicity of Topotecan Injection. Neutropenia is not cumulative over time. In the comparative study, in small cell lung cancer, the treatment-related death rates were 5% for topotecan and 4% for CAV (cyclophosphamide-doxorubicin-vincristine).

Neutropenia

From a combined experience of patients receiving topotecan which included patients treated for small cell lung cancer: Grade 4 neutropenia (<500 cells/mm 3 ) was most common during course 1 of treatment (60% of patients) and occurred in 39% of all courses, with a median duration of 7 days. The nadir neutrophil count occurred at a median of 12 days. Therapy-related sepsis or febrile neutropenia occurred in 23% of patients, and sepsis was fatal in 1%. Pancytopenia has been reported. Cervical cancer experience: Grade 3 and grade 4 neutropenia affected 26 % and 48 % of patients, respectively.

Thrombocytopenia

From a combined experience of patients receiving topotecan which included patients treated for small cell lung cancer: Grade 4 thrombocytopenia (<25,000/mm 3 ) occurred in 27% of patients and in 9% of courses, with a median duration of 5 days and platelet nadir at a median of 15 days. Platelet transfusions were given to 15% of patients in 4% of courses. Cervical cancer experience: Grade 3 and grade 4 thrombocytopenia affected 26 % and 7 % of patients, respectively.

Anemia

From a combined experience of patients receiving topotecan which included patients treated for small cell lung cancer: Grade 3/4 anemia (<8 g/dL) occurred in 37% of patients and in 14% of courses. Median nadir was at day 15. Transfusions were needed in 52% of patients in 22% of courses. Cervical cancer experience: Grade 3 and grade 4 anemia affected 34 % and 6 % of patients, respectively. Monitoring of Bone Marrow Function Administer Topotecan Injection only in patients with adequate bone marrow reserves, including baseline neutrophil count of at least 1,500 cells/mm 3 and platelet count at least 100,000/mm 3 . Monitor peripheral blood counts frequently during treatment with Topotecan Injection. Do not treat patients with subsequent courses of Topotecan Injection until neutrophils recover to >1,000 cells/mm 3 , platelets recover to >100,000 cells/mm 3 , and hemoglobin levels recover to 9 g/dL (with transfusion if necessary).Severe myelotoxicity has been reported when Topotecan Injection is used in combination with cisplatin [see Drug Interactions ( 7 ) ]

5.2 Neutropenic Colitis Topotecan-induced neutropenia can lead to neutropenic colitis. Fatalities due to neutropenic colitis have been reported in clinical trials with Topotecan Injection. In patients presenting with fever, neutropenia, and a compatible pattern of abdominal pain, consider the possibility of neutropenic colitis.

5.3 Interstitial Lung Disease Topotecan Injection has been associated with reports of interstitial lung disease (ILD), some of which have been fatal <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.2 ) ]</span>. Underlying risk factors include history of ILD, pulmonary fibrosis, lung cancer, thoracic exposure to radiation, and use of pneumotoxic drugs and/or colony stimulating factors. Monitor patients for pulmonary symptoms indicative of interstitial lung disease (e.g., cough, fever, dyspnea, and/or hypoxia), and discontinue Topotecan Injection if a new diagnosis of ILD is confirmed.

5.4 Pregnancy Pregnancy Category D Topotecan Injection can cause fetal harm when administered to a pregnant woman. Topotecan caused embryolethality, fetotoxicity, and teratogenicity in rats and rabbits when administered during organogenesis. There are no adequate and well controlled studies of Topotecan Injection in pregnant women. If this drug is used during pregnancy, or if a patient becomes pregnant while receiving Topotecan Injection, the patient should be apprised of the potential hazard to the fetus. <span class="opacity-50 text-xs">[see Use in Specific Populations, Pregnancy ( 8.1 ) ]</span>

5.5 Inadvertent Extravasation Inadvertent extravasation with topotecan has been observed, most reactions have been mild but severe cases have been reported.