Irinotecan

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 hydrochloride injection is a topoisomerase inhibitor indicated for: • Patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed following initial fluorouracil-based therapy. ( 1 ) • 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.

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

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 ) 2.2 Colorectal Single Agent Regimens 1 and 2 Administer irinotecan hydrochloride injection as a 90-minute intravenous infusion. The currently recommended regimens are shown in Table 3. 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 3. Single-Agent Regimens of irinotecan hydrochloride injection and Dose Modifications a Subsequent doses may be adjusted as high as 150 mg/m 2 or to as low as 50 mg/m 2 in 25 to 50 mg/m 2 decrements depending upon individual patient tolerance. b Subsequent doses may be adjusted as low as 200 mg/m 2 in 50 mg/m 2 decrements depending upon individual patient tolerance. c Provided intolerable toxicity does not develop, treatment with additional cycles may be continued indefinitely as long as patients continue to experience clinical benefit.

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.

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 1-888-557-1212 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 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. Serious opportunistic infections have not been observed, and no complications have specifically been attributed to lymphocytopenia. Second-Line Single-Agent Therapy Weekly Dosage Schedule In three clinical studies evaluating the weekly dosage schedule, 304 patients with metastatic carcinoma of the colon or rectum that had recurred or progressed following 5-FU-based therapy were treated with Irinotecan hydrochloride. Seventeen of the patients died within 30 days of the administration of Irinotecan hydrochloride; in five cases (1.6%, 5/304), the deaths were potentially drug-related.

Nursing Mothers: Discontinue nursing when receiving therapy with irinotecan hydrochloride injection. ( 8.3 ) Geriatric Use: Closely monitor patients greater than 65 years of age because of a greater risk of early and late diarrhea in this population. ( 8.5 ) Patients with Renal Impairment : Use caution and do not use in patients on dialysis. ( 8.6 ) Patients with Hepatic Impairment : Use caution. ( 2 , 5.10 , 8.7 , 12.3 ) 8.1 Pregnancy Pregnancy Category D [see Warnings and Precautions (5.9) ] Irinotecan hydrochloride can cause fetal harm when administered to a pregnant woman. Radioactivity related to 14 C-irinotecan crosses the placenta of rats following intravenous administration of 10 mg/kg (which in separate studies produced an irinotecan C max and AUC about 3 and 0.5 times, respectively, the corresponding values in patients administered 125 mg/m 2 ). Intravenous administration of irinotecan 6 mg/kg/day to rats and rabbits during the period of organogenesis resulted in increased post-implantation loss and decreased numbers of live fetuses. In separate studies in rats, this dose produced an Irinotecan C max and AUC of about 2 and 0.2 times, respectively, the corresponding values in patients administered 125 mg/m 2 . In rabbits, the embryotoxic dose was about one-half the recommended human weekly starting dose on a mg/m 2 basis.

Metabolism

After intravenous infusion of irinotecan in humans, irinotecan plasma concentrations decline in a multiexponential manner, with a mean terminal elimination half-life of about 6 to 12 hours. The mean terminal elimination half-life of the active metabolite SN-38 is about 10 to 20 hours.

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. Maximum supportive care should be instituted to prevent dehydration due to diarrhea and to treat any infectious complications.

• Jun 14, 1996NDANDA020571Pfizer Inc
• Feb 27, 2008ANDAANDA077915Hospira
• Feb 27, 2008ANDAANDA078589Actavis Totowa
• Feb 27, 2008ANDAANDA077776Fresenius Kabi Usa
• Dec 20, 2010ANDAANDA091032Hikma Farmaceutica
• Dec 16, 2011ANDAANDA090675Hengrui Pharma
• Oct 22, 2015NDANDA207793Ipsen
• May 3, 2016ANDAANDA203380Qilu Pharm Hainan

1. 1Diarrhoea1,65313%
2. 2Off Label Use1,0658.6%
3. 3Nausea9147.4%
4. 4Death8727.1%
5. 5Vomiting8286.7%
6. 6Disease Progression6755.5%
7. 7Myelosuppression6505.3%
8. 8Neutropenia6115.0%
9. 9Febrile Neutropenia5914.8%
10. 10Fatigue5494.4%
11. 11Malignant Neoplasm Progression5284.3%
12. 12Pyrexia5224.2%
13. 13Asthenia4873.9%
14. 14Abdominal Pain4523.7%
15. 15Neuropathy Peripheral4353.5%

Recent PubMed references pinned to Irinotecan as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Pancreatic metastases are suppressed by photodynamic therapy and irinotecan through macrophage reprogramming in immunodeficient mice.
  Neoplasia (New York, N.Y.) · 2026 · Cabral FV, Quilez-Alburquerque J, Mooradian O, et al.
  PMID 42061234DOI 10.1016/j.neo.2026.101311
• Ratiometric Fluorescent Chemosensing for Predicting Response to Irinotecan-Based Therapies in Pancreatic Ductal Adenocarcinoma.
  ACS sensors · 2026 · Kailass K, Tassielli AF, Dai R, et al.
  PMID 42043185DOI 10.1021/acssensors.5c04552
• An open-label, two-cohort, phase 1a/b study of weekly irinotecan hydrochloride liposome injection combined with vincristine and temozolomide (NALIRI-VT) in patients with advanced Ewing sarcoma.
  European journal of cancer (Oxford, England : 1990) · 2026 · Zhao Y, Xu J, Yu Y, et al.
  PMID 42019227DOI 10.1016/j.ejca.2026.116743
• A Self-Assembled Irinotecan Nanomedicine Abrogates Steatohepatitis-Induced Liver Metastasis and Potentiates Antitumor Efficacy against Colorectal Cancer.
  ACS nano · 2026 · Xiang M, Zhou C, Yao C, et al.
  PMID 42007878DOI 10.1021/acsnano.6c00855
• Strain-Dependent and Site-Specific Differences in Irinotecan-Induced Skin Pigmentation in Mice.
  Biological & pharmaceutical bulletin · 2026 · Imai M, Hiramoto K, Ooi K, et al.
  PMID 41987385DOI 10.1248/bpb.b26-00047
• Irinotecan with trifluridine/tipiracil and bevacizumab for second-line metastatic colorectal cancer: a phase II multicenter study.
  Signal transduction and targeted therapy · 2026 · Yang W, Zhang J, Liang P, et al.
  PMID 41956997DOI 10.1038/s41392-026-02634-3
• Dual benefits of Xiao Chai Hu Tang and its active compounds in CPT-11 therapy: intestinal protection via barrier restoration and anti-inflammation combined with enhanced tumor apoptosis.
  Journal of ethnopharmacology · 2026 · Zhang Y, Cao X, Hou Z, et al.
  PMID 41932664DOI 10.1016/j.jep.2026.121621
• Second-line liposomal irinotecan plus S-1 vs. liposomal irinotecan plus 5-fluorouracil in metastatic pancreatic cancer: The phase I/II randomized NAPAN trial.
  European journal of cancer (Oxford, England : 1990) · 2026 · Gehrels AM, Pijnappel EN, van Daalen EH, et al.
  PMID 41921365DOI 10.1016/j.ejca.2026.116683

The 10 most recently updated of 2,151 ClinicalTrials.gov registrations naming Irinotecan as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• A Study to Evaluate Investigational Agents With or Without Pembrolizumab (MK-3475) in Participants With Advanced Esophageal Cancer Previously Exposed to Programmed Cell Death 1 Protein (PD-1)/ Programmed Cell Death Ligand 1 (PD-L1) Treatment (MK-3475-06B)
  Recruiting · Phase 1 · Phase 2 · Interventional · 230 enrolled · Merck Sharp & Dohme LLC
  NCT05319730updated 2026-06-12
• A Study to Assess Intravenous (IV) Telisotuzumab Adizutecan in Combination With Fluorouracil, Folinic Acid, and Oxaliplatin (FOLFOX) Compared to Standard of Care in Adult Participants With First-Line Metastatic Pancreatic Ductal Adenocarcinoma
  Recruiting · Phase 2 · Phase 3 · Interventional · 900 enrolled · AbbVie
  NCT07490301updated 2026-06-12
• Dinutuximab With Chemotherapy, Surgery and Stem Cell Transplantation for the Treatment of Children With Newly Diagnosed High Risk Neuroblastoma
  Recruiting · Phase 3 · Interventional · 478 enrolled · National Cancer Institute (NCI)
  NCT06172296updated 2026-06-12
• Testing the Addition of an Individualized Vaccine to Durvalumab and Tremelimumab and Chemotherapy in Patients With Metastatic Triple Negative Breast Cancer
  Recruiting · Phase 2 · Interventional · 70 enrolled · National Cancer Institute (NCI)
  NCT03606967updated 2026-06-12
• A Study of Fruquintinib Plus FOLFIRI as Second-Line Treatment for Participants With Metastatic Colorectal Cancer (FRUITFUL)
  Recruiting · Phase 2 · Interventional · 60 enrolled · SCRI Development Innovations, LLC
  NCT07011576updated 2026-06-12
• Personalize (Signature Driven) Neoadjuvant Chemotherapy Trial for Patients With Resectable Borderline Pancreatic Ductal Adenocarcinoma.
  Not yet recruiting · Phase 2 · Interventional · 110 enrolled · Federation Francophone de Cancerologie Digestive
  NCT07616362updated 2026-06-11
• A Study of Encorafenib Plus Cetuximab With or Without Chemotherapy in People With Previously Untreated Metastatic Colorectal Cancer
  Active not recruiting · Phase 3 · Interventional · 841 enrolled · Pfizer
  NCT04607421updated 2026-06-11
• Chemotherapy Followed by Pelvic Reirradiation Versus Chemotherapy Alone as Pre-operative Treatment for Locally Recurrent Rectal Cancer
  Active not recruiting · Phase 3 · Interventional · 58 enrolled · University Hospital, Bordeaux
  NCT03879109updated 2026-06-11
• Clinical Study in Adult and Young Adult Patients With Advanced Desmoplastic Small Round Cell Tumor (DSRCT) ISG-TULIPS
  Recruiting · Phase 2 · Interventional · 20 enrolled · Italian Sarcoma Group
  NCT07328425updated 2026-06-11
• A Phase Ib/II Study of AK104 and AK117 in Combination With or Without Chemotherapy in Advanced Malignant Tumors
  Completed · Phase 1 · Phase 2 · Interventional · 128 enrolled · Akeso
  NCT05235542updated 2026-06-11

CPIC-curated drug–gene pairs for Irinotecan. Levels describe the strength of curated evidence and guideline status — never a recommendation to test or to adjust therapy.

• C8orf34CPIC D (provisional)ClinPGx 3
• SEMA3CCPIC D (provisional)ClinPGx 3
• UGT1A1CPIC A (provisional)ClinPGx 1AFDA label: Testing Recommended

Frequently asked questions

How does Irinotecan work?

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.

What is Irinotecan used for?

According to FDA labeling, Irinotecan carries indications including: Irinotecan hydrochloride injection is a topoisomerase inhibitor indicated for: • Patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed following initial fluorouracil-based therapy. ( 1 ) • 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.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Irinotecan?

Irinotecan is classified as Topoisomerase 1 (TOP1) inhibitors, Topoisomerase Inhibitor, Topoisomerase Inhibitors, Cellular Proliferation Alteration, Decreased DNA Integrity, Increased Cellular Death.

What are the brand names for Irinotecan?

Irinotecan is marketed under brand names including Camptosar, Onivyde.

What are the contraindications for Irinotecan?

Irinotecan labeling lists contraindications including: Hypersensitivity to Irinotecan hydrochloride injection or its excipients ( 4 ) Irinotecan hydrochloride injection is contraindicated in patients with a known hypersensitivity to the drug or its excipients.. Always consult the full prescribing information and a clinician.