Irinotecan

1 INDICATIONS AND USAGE Irinotecan hydrochloride injection is indicated as a component of first-line therapy in combination with 5-fluorouracil (5-FU) and leucovorin (LV) for patients with metastatic carcinoma of the colon or rectum. Irinotecan hydrochloride injection is indicated for patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed following initial fluorouracil-based therapy. Irinotecan hydrochloride injection is a topoisomerase inhibitor indicated for: • First-line therapy in combination with 5-fluorouracil and leucovorin for patients with metastatic carcinoma of the colon or rectum, ( 1 ) • Patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed following initial fluorouracil-based therapy. ( 1 )

12.1 Mechanism of Action Irinotecan is a derivative of camptothecin. Camptothecins interact specifically with the enzyme topoisomerase I, which relieves torsional strain in DNA by inducing reversible single-strand breaks. Irinotecan and its active metabolite SN-38 bind to the topoisomerase I-DNA complex and prevent religation of these single-strand breaks. Current research suggests that the cytotoxicity of irinotecan is due to double-strand DNA damage produced during DNA synthesis when replication enzymes interact with the ternary complex formed by topoisomerase I, DNA, and either irinotecan or SN-38. Mammalian cells cannot efficiently repair these double-strand breaks.

2 DOSAGE AND ADMINISTRATION • Colorectal cancer combination regimen 1: Irinotecan hydrochloride injection 125 mg/m2 intravenous infusion over 90 minutes on days 1, 8, 15, 22 with LV 20 mg/m2 intravenous bolus infusion on days 1, 8, 15, 22 followed by 5-FU intravenous bolus infusion on days 1, 8, 15, 22 every 6 weeks. (2.1) • Colorectal cancer combination regimen 2: Irinotecan hydrochloride injection 180 mg/m2 intravenous infusion over 90 minutes on days 1, 15, 29 with LV 200 mg/m2 intravenous infusion over 2 hours on days 1, 2, 15, 16, 29, 30 followed by 5-FU 400 mg/m2 intravenous bolus infusion on days 1, 2, 15, 16, 29, 30 and 5-FU 600 mg/m2 intravenous infusion over 22 hours on days 1, 2, 15, 16, 29, 30. (2.1) • Colorectal cancer single agent regimen 1: Irinotecan hydrochloride injection 125 mg/ m 2 intravenous infusion over 90 minutes on days 1, 8, 15, 22 then 2-week rest. ( 2.2 ) • Colorectal cancer single agent regimen 2: Irinotecan hydrochloride injection 350 mg/ m 2 intravenous infusion over 90 minutes on day 1 every 3 weeks. ( 2.2 ) 2.1 Colorectal Cancer Combination Regimens 1 and 2 Administer irinotecan hydrochloride injection as a 90-minute intravenous infusion followed by LV and 5-FU. The currently recommended regimens are shown in Table 1. A reduction in the starting dose by one dose level of irinotecan hydrochloride injection may be considered for patients with any of the following conditions: prior pelvic/abdominal radiotherapy, performance status of 2, or increased bilirubin levels. Dosing for patients with bilirubin >2 mg/dL cannot be recommended because there is insufficient information to recommend a dose in these patients. Table 1: Combination-Agent Dosage Regimens and Dose Modifications a Regimen 1 6-wk cycle with bolus 5-FU/LV (next cycle begins on day 43) Irinotecan Hydrochloride Injection LV 5-FU 125 mg/m 2 intravenous infusion over 90 minutes, days 1,8,15,22 20 mg/m 2 intravenous injection bolus, days 1,8,15,22 500 mg/m 2 intravenous injection bolus, days 1,8,15,22 Starting Dose & Modified Dose Levels (mg/m 2 ) Starting Dose Dose Level -1 Dose Level -2 Irinotecan Hydrochloride Injection LV 5-FU 125 20 500 100 20 400 75 20 300 Regimen 2 6-wk cycle with infusional 5-FU/LV (next cycle begins on day 43) Irinotecan Hydrochloride Injection LV 5-FU Bolus 5-FU Infusion b 180 mg/m 2 intravenous infusion over 90 minutes, days 1,15,29 200 mg/m 2 intravenous infusion over 2 hours, days 1,2,15,16,29,30 400 mg/m 2 intravenous injection bolus, days 1,2,15,16,29,30 600 mg/m 2 intravenous infusion over 22 hours, days 1,2,15,16,29,30 Starting Dose & Modified Dose Levels (mg/m 2 ) Starting Dose Dose Level -1 Dose Level -2 Irinotecan Hydrochloride Injection LV 5-FU Bolus 5-FU Infusion b 180 200 400 600 150 200 320 480 120 200 240 360 a Dose reductions beyond Dose Level –2 by decrements of ≈ 20% may be warranted for patients continuing to experience toxicity. Provided intolerable toxicity does not develop, treatment with additional cycles may be continued indefinitely as long as patients continue to experience clinical benefit. b Infusion follows bolus administration. Dosing for patients with bilirubin >2 mg/dL cannot be recommended because there is insufficient information to recommend a dose in these patients [see Warnings and Precautions (5.10) , Use in Specific Populations (8.7 ) and Clinical Pharmacology (12.3) ] . Dose Modifications Based on recommended dose levels described in Table 1, Combination Regimens of irinotecan hydrochloride injection and Dose Modifications, subsequent doses should be adjusted as suggested in Table 2, Recommended Dose Modifications for Combination Regimens. All dose modifications should be based on the worst preceding toxicity. Table 2: Recommended Dose Modifications for Irinotecan Hydrochloride Injection/5-Fluorouracil (5-FU)/Leucovorin (LV) Combination Schedules Patients should return to pre-treatment bowel function without requiring antidiarrhea medications for at least 24 hours before th

6 ADVERSE REACTIONS Common adverse reactions (≥30%) observed in combination therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, mucositis, neutropenia, leukopenia (including lymphocytopenia), anemia, thrombocytopenia, asthenia, pain, fever, infection, abnormal bilirubin, alopecia. ( 6.1 ) Common adverse reactions (≥30%) observed in single agent therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, neutropenia, leukopenia (including lymphocytopenia), anemia, asthenia, fever, body weight decreasing, alopecia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Northstar Rx LLC at 1-800-206-7821 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. Common adverse reactions (≥30%) observed in combination therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, mucositis, neutropenia, leukopenia (including lymphocytopenia), anemia, thrombocytopenia, asthenia, pain, fever, infection, abnormal bilirubin, and alopecia. Common adverse reactions (≥30%) observed in single agent therapy clinical studies are: nausea, vomiting, abdominal pain, diarrhea, constipation, anorexia, neutropenia, leukopenia (including lymphocytopenia), anemia, asthenia, fever, body weight decreasing, and alopecia. First-Line Combination Therapy A total of 955 patients with metastatic colorectal cancer received the recommended regimens of irinotecan in combination with 5-FU/LV, 5-FU/LV alone, or irinotecan alone. In the two phase 3 studies, 370 patients received irinotecan in combination with 5-FU/LV, 362 patients received 5-FU/LV alone, and 223 patients received irinotecan alone [see Dosage and Administration (2) ] . In Study 1, 49 (7.3%) patients died within 30 days of last study treatment: 21 (9.3%) received irinotecan in combination with 5-FU/LV, 15 (6.8%) received 5-FU/LV alone, and 13 (5.8%) received irinotecan alone. Deaths potentially related to treatment occurred in 2 (0.9%) patients who received irinotecan in combination with 5-FU/LV (2 neutropenic fever/sepsis), 3 (1.4%) patients who received 5-FU/LV alone (1 neutropenic fever/sepsis, 1 CNS bleeding during thrombocytopenia, 1 unknown) and 2 (0.9%) patients who received irinotecan alone (2 neutropenic fever). Deaths from any cause within 60 days of first study treatment were reported for 15 (6.7%) patients who received irinotecan in combination with 5-FU/LV, 16 (7.3%) patients who received 5-FU/LV alone, and 15 (6.7%) patients who received irinotecan alone. Discontinuations due to adverse events were reported for 17 (7.6%) patients who received irinotecan in combination with 5FU/LV, 14 (6.4%) patients who received 5-FU/LV alone, and 26 (11.7%) patients who received irinotecan alone. In Study 2, 10 (3.5%) patients died within 30 days of last study treatment: 6 (4.1%) received irinotecan in combination with 5-FU/LV and 4 (2.8%) received 5-FU/LV alone. There was one potentially treatment-related death, which occurred in a patient who received irinotecan in combination with 5-FU/LV (0.7%, neutropenic sepsis). Deaths from any cause within 60 days of first study treatment were reported for 3 (2.1%) patients who received irinotecan in combination with 5-FU/LV and 2 (1.4%) patients who received 5-FU/LV alone. Discontinuations due to adverse events were reported for 9 (6.2%) patients who received irinotecan in combination with 5FU/LV and 1 (0.7%) patient who received 5-FU/LV alone. The most clinically significant adverse events for patients receiving irinotecan-based therapy were diarrhea, nausea, vomiting, neutropenia, and alopecia. The most clinically significant adverse events for pat

5 WARNINGS AND PRECAUTIONS • Diarrhea and Cholinergic Reactions: Early diarrhea (occurring during or shortly after infusion of irinotecan hydrochloride injection) is usually transient and may be accompanied by cholinergic symptoms. Consider prophylactic or therapeutic administration of 0.25 mg to 1 mg of intravenous or subcutaneous atropine (unless clinically contraindicated). Late diarrhea (generally occurring more than 24 hours after administration of irinotecan hydrochloride injection) can occur. Monitor and replace fluid and electrolytes. Treat with loperamide. Use antibiotic support for ileus and fever. Interrupt irinotecan hydrochloride injection and reduce subsequent doses if severe diarrhea occurs. ( 5.1 ) • Myelosuppression: Manage promptly with antibiotic support. Interrupt irinotecan hydrochloride injection and reduce subsequent doses if necessary. ( 5.2 ) • Patients with Reduced UGT1A1 Activity: Individuals who are homozygous for the UGT1A1*28 allele are at increased risk for neutropenia following initiation of irinotecan hydrochloride injection treatment. ( 5.3 ) • Hypersensitivity: Hypersensitivity reactions including severe anaphylactic or anaphylactoid reactions have been observed. Discontinue irinotecan hydrochloride injection if this occurs. ( 5.4 ) • Renal Impairment/Renal Failure: Rare cases of renal impairment and acute renal failure have been identified, usually in patients who became volume depleted from severe vomiting and/or diarrhea. ( 5.5 ) • Pulmonary Toxicity : Interstitial Pulmonary Disease (IPD)-like events, including fatalities, have occurred. Interrupt for new or progressive dyspnea, cough, and fever pending evaluation. If IPD diagnosed, discontinue and institute appropriate treatment as needed. ( 5.6 ) • Toxicity of the 5 Day Regimen: Irinotecan hydrochloride injection should not be used in combination with a regimen of 5-FU/LV administered for 4-5 consecutive days every 4 weeks outside of a clinical study. ( 5.7 ) • Embryo-Fetal Toxicity: Irinotecan hydrochloride injection can cause fetal harm. Advise females of reproductive potential of the potential risk to a fetus and to use effective contraception. Advise male patients with female partners of reproductive potential to use condoms. ( 5.9 , 8.1 , 8.3 ) • Patients with Hepatic Impairment: In clinical trials, irinotecan hydrochloride injection has not been administered to patients with serum bilirubin > 2.0 mg/dL, or transaminases > 3 times ULN if no liver metastases, or transaminases > 5 times ULN if liver metastases. With the weekly dosage schedule, patients with total bilirubin levels 1.0-2.0 mg/dL had greater likelihood of grade 3-4 neutropenia. ( 5.10 ) 5.1 Diarrhea and Cholinergic Reactions Early diarrhea (occurring during or shortly after infusion of irinotecan hydrochloride injection) is usually transient and infrequently severe. It may be accompanied by cholinergic symptoms of rhinitis, increased salivation, miosis, lacrimation, diaphoresis, flushing, and intestinal hyperperistalsis that can cause abdominal cramping. Bradycardia may also occur. Early diarrhea and other cholinergic symptoms may be prevented or treated. Consider prophylactic or therapeutic administration of 0.25 mg to 1 mg of intravenous or subcutaneous atropine (unless clinically contraindicated). These symptoms are expected to occur more frequently with higher irinotecan doses. Late diarrhea (generally occurring more than 24 hours after administration of irinotecan hydrochloride injection) can be life threatening since it may be prolonged and may lead to dehydration, electrolyte imbalance, or sepsis. Grade 3 to 4 late diarrhea occurred in 23 to 31% of patients receiving weekly dosing. In the clinical studies, the median time to the onset of late diarrhea was 5 days with 3-week dosing and 11 days with weekly dosing. Late diarrhea can be complicated by colitis, ulceration, bleeding, ileus, obstruction, and infection. Cases of megacolon and intestinal perforation have b

4 CONTRAINDICATIONS • Irinotecan hydrochloride injection is contraindicated in patients with a known hypersensitivity to the drug or its excipients. • Hypersensitivity to irinotecan hydrochloride injection or its excipients ( 4 )

10 OVERDOSAGE In U.S. phase 1 trials, single doses of up to 345 mg/m 2 of irinotecan were administered to patients with various cancers. Single doses of up to 750 mg/m 2 of irinotecan have been given in non-U.S. trials. The adverse events in these patients were similar to those reported with the recommended dosage and regimen. There have been reports of overdosage at doses up to approximately twice the recommended therapeutic dose, which may be fatal. The most significant adverse reactions reported were severe neutropenia and severe diarrhea. There is no known antidote for overdosage of irinotecan hydrochloride injection. Maximum supportive care should be instituted to prevent dehydration due to diarrhea and to treat any infectious complications.