Malignant Pleural Mesothelioma: Is Tailoring the Second-Line Therapy Really "Raising the Bar?".

Unresectable or relapsed malignant pleural mesothelioma (MPM) has dismal prognosis. First-line combination therapy with pemetrexed and a platinum analog allows a modest survival benefit, while no clear therapeutic options exist for the second-line therapy. In this setting, pemetrexed seems to be the most active drug; however, the inclusion in front-line treatment limits its use in further lines. Nevertheless, rechallenge with one or both drugs used in first-line remains a feasible strategy for responder patients. Alternatively, only few cytotoxic drugs have demonstrated a mild activity in refractory MPM. Among other options, targeted therapy has unfortunately produced disappointing results as salvage treatment probably due to the lack of a clear understanding of the tumor biology. In contrast, recent data suggest moderate efficacy and mild toxicity of immunotherapy also for the treatment of MPM. The combination of checkpoint inhibitors with chemotherapy or other immunological agents seems promising and could really "raise the bar" in this setting.