Standard First-Line Regimen: Cisplatin + Pemetrexed
Pemetrexed (Alimta), approved by the FDA in 2004, was the first chemotherapy drug specifically approved for mesothelioma. It works by blocking multiple enzymes needed for DNA and RNA synthesis. When combined with cisplatin (a platinum-based drug), the combination produces:
- Response rates of 40–45% (tumor shrinkage)
- Median survival of approximately 12–16 months
- Improved quality of life compared to cisplatin alone
Treatment is typically administered in 21-day cycles, with 4–6 cycles recommended depending on response and tolerance. Vitamin supplementation (folic acid and vitamin B12) is required before and during pemetrexed treatment to reduce toxicity.
Carboplatin: The Alternative Platinum
For patients who cannot tolerate cisplatin (due to kidney disease, hearing loss, or significant neuropathy), carboplatin is often substituted. Carboplatin + pemetrexed produces comparable outcomes to cisplatin + pemetrexed in many patients, with a more manageable side effect profile. It is the preferred regimen for older patients or those with pre-existing kidney impairment.
Chemotherapy + Immunotherapy Combinations
Emerging evidence supports combining chemotherapy with immunotherapy for improved outcomes:
- Pemetrexed + platinum + pembrolizumab (Keytruda) — studied in the KEYNOTE-189 trial for lung cancer and being explored for mesothelioma
- Pemetrexed + platinum as induction before immunotherapy — used in some protocols to debulk disease before immunotherapy maintenance
The optimal sequencing and combination of chemotherapy and immunotherapy for mesothelioma continues to evolve; clinical trial enrollment is strongly encouraged.
Neoadjuvant and Adjuvant Chemotherapy
In surgical candidates, chemotherapy may be given:
- Neoadjuvant (before surgery) — to shrink the tumor and test chemosensitivity before committing to major surgery
- Adjuvant (after surgery) — to kill remaining microscopic disease
The optimal timing of chemotherapy relative to surgery varies by center and patient factors, and is an active area of clinical trial research.
Common Side Effects
| Side Effect | Drug | Management |
|---|---|---|
| Nausea and vomiting | Both | Anti-emetics (ondansetron, aprepitant) |
| Fatigue | Both | Activity pacing, erythropoiesis-stimulating agents if anemic |
| Kidney damage (nephrotoxicity) | Cisplatin | IV hydration, dose reduction; carboplatin if severe |
| Hearing loss (ototoxicity) | Cisplatin | Baseline audiometry; switch to carboplatin if progressive |
| Peripheral neuropathy | Cisplatin | Dose reduction; gabapentin for symptoms |
| Low blood counts | Both | Growth factors (Neupogen), transfusions if needed |
| Mouth sores | Pemetrexed | Folic acid + B12 supplementation reduces severity |