Targeted Therapy

Targeted therapy represents a revolutionary shift in cancer treatment by:
✔️ Focusing on specific molecular/genetic cancer drivers
✔️ Minimizing damage to healthy cells (unlike chemotherapy)
✔️ Offering personalized treatment based on tumor biomarkers
✔️ Often causing fewer and less severe side effects

How Targeted Therapy Works

Key Mechanisms of Action:

1. Blocking Growth Signals

   • Inhibits receptors like EGFR, HER2 that promote cancer growth

2. Preventing Angiogenesis

   • Drugs like bevacizumab stop tumor blood vessel formation

3. Promoting Cell Death

   • Triggers apoptosis in cancer cells

4. Disabling DNA Repair

   • PARP inhibitors exploit BRCA mutations (synthetic lethality)

Common Targets:

• HER2 (breast/gastric cancers)

• BRAF V600E (melanoma)

• ALK/ROS1 (lung cancer)

• CDK4/6 (hormone receptor+ breast cancer)

Major Classes of Targeted Drugs

1. Small Molecule Inhibitors

• Oral medications (e.g., imatinib for CML)

• Target proteins inside cancer cells

2. Monoclonal Antibodies

• IV/injected biologics (e.g., trastuzumab for HER2+ cancer)

• Bind to surface antigens

3. Other Targeted Agents

• PARP inhibitors (olaparib)

• Angiogenesis inhibitors (lenvatinib)

• Immunoconjugates (antibody-drug combinations)

Diagnostic Testing for Targeted Therapy

Essential biomarker tests include:

• Next-generation sequencing (NGS)

• Immunohistochemistry (IHC)

• Fluorescence in situ hybridization (FISH)

• PD-L1 testing for immunotherapy combinations

Clinical Benefits & Limitations

Advantages:

✅ Higher response rates in biomarker-selected patients
✅ Often better tolerated than chemotherapy
✅ Can overcome treatment resistance when combined
✅ Enables maintenance therapy approaches

Challenges:

⚠️ Only works for cancers with actionable targets
⚠️ Can develop resistance over time
⚠️ Some targeted drugs have unique side effects
⚠️ High costs and accessibility issues

Combination Strategies

Modern oncology increasingly uses:

• Targeted therapy + immunotherapy

• Targeted therapy + chemotherapy

• Dual targeted agent combinations

• Sequential targeted therapies

Future Directions

Emerging developments include:
🔹 Fourth-generation TKIs for resistant mutations
🔹 Bispecific antibodies targeting multiple pathways
🔹 PROTAC degraders to eliminate target proteins
🔹 Liquid biopsy for real-time monitoring

Is Targeted Therapy Right for You?

Key considerations:

• Tumor molecular profiling results

• Previous treatment history

• Overall health status

• Mutation-specific clinical trials

Targeted therapy has transformed outcomes for many cancer types, with over 100 FDA-approved targeted drugs now available. Consult your oncologist to determine if your cancer has actionable targets for these precision treatments.

💡 Early molecular testing maximizes treatment options – ask about comprehensive genomic profiling at diagnosis.