Epistemis

Multikinase Inhibitors: Sorafenib and Regorafenib

  • Targeted Multikinase and Antiangiogenic Therapies

Common trade names: Nexavar (Sorafenib); Stivarga (Regorafenib).

Mechanism

Pharmacological Class and Group

Oral synthetic small molecules, systemic multikinase inhibitors aimed at blocking neoangiogenesis and tumor cell signal transduction.

Mechanism of Action

These molecules simultaneously block multiple membrane and intracellular receptor tyrosine kinases:

  • Sorafenib: Inhibits the intracellular kinase enzymatic activity of the VEGF membrane receptor (VEGFR-1, VEGFR-2, VEGFR-3), platelet-derived growth factor beta receptor (PDGFR-β), KIT, FLT-3, in addition to specifically blocking the serine tyrosine kinase of the intracellular RAF pathway (C-RAF and B-RAF mutated and native type). This induces a double effect of direct tumor cell inhibition combined with persistent antiangiogenic blockade.
  • Regorafenib: Fluorinated molecule structurally analogous to sorafenib, but with greater inhibitory potency and a broader spectrum of target receptors, including angiopoietin-1 (TIE-2), FGFR, RET, KIT and PDGFR receptors, forcing high-density tumor blockade.

RAF-MEK-ERK Cellular Survival and Angiogenesis Axis Blockade

By Sorafenib or Regorafenib binding to the intracellular catalytic pocket of VEGF receptors on endothelial cells, the mitogenic signaling cascade that promotes vascular cell growth is abolished:

Regorafenib VEGFR and TIE-2 Autophosphorylation Blockade Suppression of Tumor Neovascularization

At the tumor cellular level, concomitant inhibition of RAF kinase isoforms robustly silences the gene transcription of cyclins necessary for tumor replication, inducing metabolic arrest and apoptotic death of tumor cells.

Pharmacokinetics

High Resolution Pharmacokinetics

  • Oral absorption and Bioavailability: Rapid oral absorption of approximately 30-50% for sorafenib, decreased when consumed with high-fat foods. Regorafenib has a bioavailability of 70% ingested with a light, low-fat breakfast.
  • Metabolism: Phase I oxidative hepatic metabolism mediated exclusively by the isoenzyme CYP3A4, undergoing phase II conjugation by the glucuronosyltransferase UGT1A9. Sorafenib produces the active circulating metabolite pyridine-N-oxide; Regorafenib is biotransformed into two active metabolites with long half-lives (M-2 and M-5).
  • Elimination: Predominant biliary and intestinal clearance, with more than 70-80% of the dose excreted in the feces. Less than 20% is recovered through the kidneys.
  • Half-life (t1/2): The half-life of sorafenib is 25 to 48 hours; that of regorafenib is approximately 28 hours, but that of its active metabolites (M-2 and M-5) is prolonged to 70-100 hours.

Indicators and dose

Clinical Indications and Frequent Regimens

  • Sorafenib: First-line advanced hepatocellular carcinoma (HCC) (in Child-Pugh A stages), advanced renal cell carcinoma refractory to cytokines, differentiated thyroid carcinoma refractory to radioactive iodine with a progressive course.
  • Regorafenib: Pretreated metastatic colorectal cancer (refractory to conventional chemotherapy, anti-VEGF and anti-EGFR), advanced GIST refractory or intolerant to third-line Imatinib and Sunitinib.

Dosage and Clinical Adjustment

  • Oral Sorafenib: 400 mg orally twice a day (total 800 mg daily) continuously on an empty stomach or with a low-fat meal.
  • Oral Regorafenib: 160 mg orally once daily for 21 consecutive days, followed by 7 days of complete rest (28-day cycle).
  • Hand-Foot Reaction Adjustments: In case of severe grade 2 toxicity, interrupt treatment for 7 days until resolution to grade 1 and resume with permanent dose reduction (400 mg per day for sorafenib, 120 mg per day for regorafenib). Discontinue if grade 3 refractory after two consecutive dose reductions.

Security

Absolute and Relative Contraindications

Contraindications of Sorafenib / Regorafenib
  • Pre-existing severe liver dysfunction (decompensated Child-Pugh B or Child-Pugh C).
  • Hypersensitivity to the active ingredient.
  • Severe uncontrolled arterial hypertension.
  • Pregnancy confirmed.
Relative Contraindications
  • Risk of digestive bleeding due to unlinked or active esophageal varices in underlying cirrhotics.
  • Major surgical intervention scheduled in the next 2 weeks.

Adverse Effects (ADR) and Specific Toxicity

  • Dermatological: Hand-Foot Skin Reaction (Palmo-Plantar Erythrodysesthesia Syndrome due to ITK) in more than 40% of the patients treated. It presents with painful reactive hyperkeratosis in areas under pressure on the palms and soles, bullous erythema and limiting paresthesias. Requires the prophylactic use of creams with 10-20% urea and comfortable footwear.
  • Gastrointestinal: Frequent watery diarrhea (due to intestinal microvillus atrophy due to local VEGF blockage), extreme fatigue that is difficult to manage, anorexia and rapid weight loss.
  • Cardiovascular: Early-onset systemic arterial hypertension, increased risk of minor bleeding and coronary ischemia.

Epistemis is educational review material. It is not a medical device, does not diagnose or prescribe treatment, and does not replace formal medical training, current clinical guidelines, or professional clinical judgment.

PreviousSelective Tyrosine Kinase Inhibitors: Imatinib and Osimertinib
System
Oncology
Cluster
Targeted Multikinase and Antiangiogenic Therapies
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