Integration of the PD-L1 Inhibitor Atezolizumab and WT1/DC Vaccination Into Platinum/Pemetrexed-based First-line Treatment for Epithelioid Malignant Pleural Mesothelioma

WT1/DC vaccines (8-10 x 10\^6 cells in 500 μL saline solution with 5% human albumin) will be administered through intradermal injection at 5 sites (100 μL/site) in the ventromedial region of the upper arm (5-10 cm from the axillary lymph nodes). Injection sites will alternate between left and right arms. WT1/DC vaccines are administered on day 14 of each 3-weekly platinum/pemetrexed-based chemotherapy cycle. Additional WT1/DC vaccinations after the study treatment schedule can be administered (optional) at 4-weekly intervals (± 1 week).

Atezolizumab (1200 mg) will be administered on day 0 of each 3-weekly platinum/pemetrexed-based chemotherapy cycle. Atezolizumab should be administered before chemotherapy administration as an IV infusion over 60 (±15) minutes. If the first infusion is tolerated, all subsequent infusions may bedelivered over 30 (±10) minutes. Additional atezolizumab treatment (1680 mg) after the study treatment schedule can be administered (optional) at 4-weekly intervals (± 1 week) as an IV infusion over 30-60 minutes.

On the first day of each cycle (day 0), pemetrexed 500 mg/m2 should be administered as intravenous (IV) infusion over 10 minutes, followed by cisplatin 75 mg/m2 as IV over approximately 2 hours. The actual doses of the drugs to be administered to patients will be determined by calculating the patient's body surface area at the beginning of each cycle. For ease of dose administration, the protocol allows ± 5% variance in the calculated total dose per infusion. If deemed necessary, the treating physician can decide to replace cisplatin by carboplatin. In that case, carboplatin will be delivered to an area under the concentration-time curve (AUC) of 5 as an IV infusion over 1 hour.