Klertis (Sunitinib Cyclamate)

Klertis (sunitinib cyclamate) is used in oncology to inhibit tumor growth driven by tyrosine‑kinase pathways.

• Metastatic renal cell carcinoma: slows disease progression and extends survival.
• Advanced gastrointestinal stromal tumor: reduces tumor burden and delays progression.
• Other solid tumours (off‑label): may be considered under specialist supervision when standard options are exhausted.

• Sunitinib cyclamate blocks the intracellular ATP‑binding sites of multiple receptor tyrosine kinases, including VEGFR‑1/2/3, PDGFR‑α/β, KIT, and FLT3. By inhibiting these pathways, it suppresses angiogenesis, tumor cell proliferation, and survival signals, leading to reduced tumor vascularization and growth.

Klertis may cause a range of adverse reactions, which are classified by frequency and severity.

Common Side Effects

• Fatigue: persistent tiredness affecting daily activities.
• Hypertension: elevated blood pressure requiring monitoring.
• Diarrhoea: loose stools that may lead to dehydration.
• Nausea: feeling of sickness often managed with anti‑emetics.
• Hand‑foot syndrome: redness or swelling of palms and soles.
• Anorexia: loss of appetite and possible weight loss.

Serious or Rare Side Effects

• Neutropenia: dangerously low white‑blood‑cell count.
• Thrombocytopenia: reduced platelet levels increasing bleeding risk.
• Cardiac dysfunction: reduced left‑ventricular ejection fraction.
• Hepatic failure: severe liver enzyme elevation.
• Severe hypertension: hypertensive crisis requiring urgent care.
• Pulmonary haemorrhage: bleeding in the lungs, potentially life‑threatening.

Before initiating Klertis, clinicians should evaluate baseline health status and monitor patients regularly.

• Blood pressure monitoring: check at baseline and periodically during therapy.
• Liver function tests: assess hepatic enzymes before and during treatment.
• Cardiac assessment: perform echocardiogram if pre‑existing heart disease is present.
• Complete blood count: monitor for neutropenia and thrombocytopenia.
• Contraindication in severe hepatic impairment: avoid or adjust dose.
• Store at ambient temperature below 25°C: keep in the original container, protect from moisture and direct sunlight.

Klertis interacts with several drug classes; awareness helps prevent adverse events.

Major Interactions (Avoid)

• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): may increase sunitinib exposure.
• Strong CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce efficacy.
• Anticoagulants (e.g., warfarin, direct oral anticoagulants): heightened bleeding risk.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents: may require dose adjustment due to additive blood‑pressure effects.
• CYP2C9 substrates (e.g., phenytoin): monitor plasma levels.
• Digoxin: potential increase in serum concentration.
• St. John’s wort: may modestly lower sunitinib levels.
• Proton‑pump inhibitors: assess for any impact on absorption, though clinically modest.