Targeted anticancer drugs are therapies designed to specifically attack cancer cells by interfering with molecules involved in tumor growth and survival, while minimizing damage to normal cells. Unlike chemotherapy (which kills rapidly dividing cells broadly), these drugs act on specific genetic, molecular, or immune pathways driving cancer.
Key Types of Targeted Cancer Therapies
1. Small-Molecule Inhibitors
- Target: Intracellular proteins (e.g., kinases).
- Examples:
- Tyrosine Kinase Inhibitors (TKIs) – Imatinib (BCR-ABL in CML), osimertinib (EGFR in NSCLC).
- PARP Inhibitors – Olaparib (for BRCA-mutated ovarian/breast cancer).
- How They Work: Block signaling pathways needed for cancer cell growth.
2. Monoclonal Antibodies (mAbs)
- Target: Cell surface proteins or blood supply factors.
- Examples:
- Anti-HER2 – Trastuzumab (breast/gastric cancer).
- Anti-CD20 – Rituximab (B-cell lymphomas).
- Anti-VEGF – Bevacizumab (blocks tumor blood vessels).
- How They Work: Bind to targets, triggering immune attack or blocking growth signals.
3. Immune Checkpoint Inhibitors
- Target: PD-1, PD-L1, CTLA-4 (immune checkpoints).
- Examples: Pembrolizumab, nivolumab (melanoma, lung cancer).
- How They Work: “Release the brakes” on T-cells to attack cancer.
4. Hormone Therapies
- Target: Hormone receptors (e.g., estrogen, androgen).
- Examples: Tamoxifen (breast cancer), enzalutamide (prostate cancer).
5. CAR-T Cell Therapy
- Target: Cancer-specific antigens (e.g., CD19 in leukemia).
- How It Works: Patient’s T-cells are engineered to attack tumors.
Advantages Over Chemotherapy
- More precise (targets cancer-specific mutations).
- Fewer side effects (less damage to healthy cells).
- Used for metastatic/resistant cancers.
Limitations
- Tumor heterogeneity (some cells may escape targeting).
- Resistance (mutations can render drugs ineffective).
- High cost and need for biomarker testing.
Conclusion
Targeted therapies represent a precision medicine approach, improving outcomes in cancers with defined molecular drivers. They are often combined with chemotherapy, immunotherapy, or radiation for enhanced effects.