Canfosfamide

Summary

Canfosfamide (Telcyta, TLK286) is an investigational glutathione‑analog prodrug that is administered intravenously. It is being evaluated primarily for platinum‑refractory or -resistant ovarian cancer, where it is combined with pegylated liposomal doxorubicin or used as a third‑line single agent. The drug is activated inside tumour cells by glutathione‑S‑transferase P1‑1, leading to DNA damage and cell death.

Mechanism of Action

Canfosfamide is a prodrug that mimics glutathione. Inside cells that over‑express glutathione‑S‑transferase P1‑1, the enzyme converts the compound into a reactive alkylating species. This species forms covalent bonds with DNA, causing strand breaks and inhibiting DNA‑repair pathways. The resulting oxidative stress and S‑glutathionylation also trigger apoptotic signalling, contributing to tumour cell death.

What the Research Shows

Phase III trials in platinum‑refractory or -resistant ovarian cancer have shown mixed results. In a three‑arm study, canfosfamide monotherapy produced lower progression‑free and overall survival than control regimens (pegylated liposomal doxorubicin or topotecan). A separate phase III trial of canfosfamide plus pegylated liposomal doxorubicin did not improve overall progression‑free survival, but a pre‑planned subgroup of platinum‑refractory patients experienced a significant PFS benefit (5.6 vs 2.9 months). A phase II study of the same combination reported a 27.8 % objective response rate, 80.6 % disease‑stabilisation, median PFS of 6 months and median survival of 17.8 months, with manageable toxicity. Reviews cite canfosfamide as a redox‑targeting agent under clinical evaluation.

Reported Benefits

Evidence suggests canfosfamide can achieve tumour responses in heavily pre‑treated ovarian cancer, especially when combined with pegylated liposomal doxorubicin. In a phase II cohort, more than one‑quarter of patients had measurable tumour shrinkage and most experienced disease stabilisation. Subgroup analysis of a phase III trial indicated a statistically significant progression‑free survival advantage in platinum‑refractory disease, and the drug may reduce the incidence of pegylated liposomal doxorubicin‑related hand‑foot syndrome and stomatitis.

Limitations of the Evidence

Overall, large phase III studies have not demonstrated a survival advantage for canfosfamide compared with existing agents, and the drug failed to improve progression‑free or overall survival in the broader trial populations. Benefits appear limited to specific subgroups, and the data are confined to ovarian cancer; no efficacy has been shown in other tumour types. The compound remains investigational and has not received regulatory approval.

Safety Considerations

The most common grade 3–4 toxicities are hematologic, including anemia (≈5 %), neutropenia (≈4 %) and thrombocytopenia (≈4 %). Myelosuppression is generally manageable with dose reductions or growth‑factor support; febrile neutropenia was rare (≈5 %). Non‑hematologic adverse events are similar to those of pegylated liposomal doxorubicin, though the combination showed lower rates of hand‑foot syndrome and stomatitis. Gastrointestinal toxicity (vomiting) occurred in about 7 % of patients. Overall, the safety profile is considered tolerable for a third‑line regimen.

How It Is Administered

Canfosfamide is supplied as a hydrochloride salt for intravenous infusion. Clinical studies have used a dose of 1000 mg/m² administered every three weeks, either alone or together with pegylated liposomal doxorubicin (50 mg/m²). The drug is given as an infusion over a period consistent with standard chemotherapy protocols.

Routes of Administration

Goals & Uses

• Colorectal cancer treatmentOncologyLow
• Ovarian cancer treatmentOncologyModerate
• Tumor-selective cytotoxicity via GST Pi overexpressionMechanismModerate
• Non-small cell lung cancer treatmentOncologyLow

Contraindications

• Hypersensitivity to canfosfamide or its componentsAllergyHigh
• Severe bone marrow suppressionHematologicHigh

Adverse Effects

• ThrombocytopeniaHematologicCommonLow platelet count
• AnemiaHematologicCommonLow red blood cell count or hemoglobin
• HypotensionCardiovascularUncommonLow blood pressure
• Nausea and vomitingGastrointestinalCommon
• NeutropeniaHematologicCommonLow neutrophil count
• FatigueGeneralCommonLow energy or tiredness

Drug Interactions

• Platinum-based chemotherapy (e.g., carboplatin)Moderate
• Other myelosuppressive agentsHigh

Population Constraints

• PregnancyReproductive SafetyAbsolute
• Severe renal impairmentOrgan ImpairmentRelative
• Pediatric patientsAgeRelative
• Severe hepatic impairmentOrgan ImpairmentRelative

Regulatory Status

• European UnionInvestigationalEvaluated in European clinical trials; no marketing authorization granted
• United StatesInvestigationalReceived Fast Track designation from FDA for ovarian cancer; Phase III trials failed; never approved
• United KingdomInvestigationalNo approval; development discontinued following negative Phase III results

Never received FDA, EMA, or other major regulatory approval. Phase III clinical trials (e.g., ASSIST-1, ASSIST-2 in ovarian cancer) did not meet primary endpoints. Development by Telik, Inc. was halted following negative trial results.

Evidence & Sources

• New emerging drugs targeting the genomic integrity and replication machinery in ovarian cancer
  Journal ArticleModerateBrüning A, Mylonas I2011-01-01T00:00:00.000000Z
• Randomized phase III study of canfosfamide in combination with pegylated liposomal doxorubicin compared with pegylated liposomal doxorubicin alone in platinum-resistant ovarian cancer
  Journal ArticleModerateVergote I, et al.2010-01-01T00:00:00.000000Z
• Cellular redox pathways as a therapeutic target in the treatment of cancer
  Journal ArticleModerateMontero AJ, Jassem J2011-01-01T00:00:00.000000Z
• Phase 3 randomised study of canfosfamide (Telcyta, TLK286) versus pegylated liposomal doxorubicin or topotecan as third-line therapy in patients with platinum-refractory or -resistant ovarian cancer
  Journal ArticleModerateVergote I, et al.2009-01-01T00:00:00.000000Z
• Phase 2 study of canfosfamide in combination with pegylated liposomal doxorubicin in platinum and paclitaxel refractory or resistant epithelial ovarian cancer
  Journal ArticleModerateKavanagh JJ, et al.2010-01-01T00:00:00.000000Z
• Gateways to clinical trials
  Journal ArticleModerateBayés M, Rabasseda X, Prous JR2004-01-01T00:00:00.000000Z

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