Treatment options for non-naive malignant pleural mesothelioma (MPM) are limited. Few phase II trials have provided evidence for the treatment. Till date, antineoplastic activity has been observed in phase II trials in patients with MPM treated with anthracyclines, doxorubicin, or pegylated-liposomal doxorubicin. However, few studies have reported on these treatments because of severe toxicities. Conversely, amrubicin (AMR) is an anthracycline drug that is commonly used for treating thoracic tumors; therefore, we know that the treatment is generally well tolerated. We performed this phase II trial to determine whether AMR monotherapy is a promising treatment approach for non-chemotherapy naive patients with MPM. Non-randomized phase II trial Patients diagnosed with MPM based on the histological and cytological examination of specimens, with disease progression after pemetrexed/platinum, 1–2 prior regimens, age 18–74 years, AMR naïve status, and performance status (PS) 0–2 were enrolled. Patients received 35 mg/m2 AMR (days 1–3) every 3 weeks until tumor progression and had unacceptable toxicities. The primary endpoint was tumor response rate, and secondary endpoints were progression-free survival, overall survival, and toxicity rate. From September 2013 to July 2018, five patients with MPM were enrolled, and the treatment responses were evaluated. All subjects in this case series were men with a median age of 65 (range, 49–76) years; the mean number of treatment cycles was 3 (range, 2–11). Stable disease was observed in three patients (60%) and progressive disease in two (40%). The median progression-free survival was 2.4 (range, 1.2–11.2) months, and the median overall survival was 9.1 (range, 6.2–22.0) months. Grade 1/2 toxicities, such as nausea and malaise, were reported in all subjects, and most of the toxicities were controllable. Grade 3/4 neutropenia occurred in four patients (80%), and there was no case of febrile neutropenia. Three of our patients achieved stable disease with AMR treatment. These data suggest that AMR is a promising treatment for previously treated MPM in the absence of another treatment. Moreover, AMR is associated with modest toxicities, similar to that in previous reports.