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Aim To evaluate the activity and safety of the PD-1 antibody pembrolizumab in adult patients with advanced osteosarcoma. Material and methods The study was a single-arm, open-label, phase 2 trial in patients with unresectable, relapsed osteosarcoma. The primary endpoint was clinical benefit rate (CBR) at 18 weeks of treatment, defined as complete response, partial response, or stable disease using RECIST v1.1. The trial had a Simon´s two-stage design, and ≥ 3 of 12 patients with clinical benefit in stage 1 were required to proceed to stage 2. The trial is registered with ClinicalTrials.gov, number NCT03013127. NanoString analysis was performed to explore tumor gene expression signatures and pathways. Results Twelve patients were enrolled and received study treatment. No patients had clinical benefit at 18 weeks of treatment, and patient enrollment was stopped after completion of stage 1. Estimated median progression-free survival was 1.7 months (95% CI 1.2–2.2). At time of data cut-off, 11 patients were deceased due to osteosarcoma. Median overall survival was 6.6 months (95% CI 3.8–9.3). No treatment-related deaths or drug-related grade 3 or 4 adverse events were observed. PD-L1 expression was positive in one of 11 evaluable tumor samples, and the positive sample was from a patient with a mixed treatment response. Conclusion In this phase 2 study in advanced osteosarcoma, pembrolizumab was well-tolerated but did not show clinically significant antitumor activity. Future trials with immunomodulatory agents in osteosarcoma should explore combination strategies in patients selected based on molecular profiles associated with response.

This mono-institutional observational study was conducted to determine incidence, severity, risk factors, and outcome of sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) in high-risk Ewing sarcoma (ES) patients treated with intravenous busulfan and melphalan (BU-MEL) followed by autologous stem cell transplantation (ASCT). During the past 10 years, 75 consecutive ES patients resulted evaluable for the analysis. After diagnosis of SOS/VOD, defibrotide therapy was started as soon as the medication was available. The variables analyzed as potential risk factors were: gender, patient's age at diagnosis, primary tumor site, disease stage, and prior radiation therapy (RT) given, focusing on RT liver exposure. The median age at diagnosis was 18.8 years. Five patients developed moderate to severe SOS/VOD (cumulative incidence, 6.67%). None of 32 pediatric patients (≤17 years) developed SOS/VOD (p = 0.0674). In univariate analysis, prior RT liver exposure resulted statistically significant (p = 0.0496). There was one death due to severe SOS/VOD. This study reports the largest series of high-risk ES patients treated with intravenous BU-MEL before ASCT. The incidence of SOS/VOD was lower when compared with other studies that used oral busulfan. Any prior RT liver exposure should be avoided. Earlier defibrotide treatment confirms to be effective.

Background Dermatofibrosarcoma protuberans (DFSP) is a relatively common soft-tissue tumor. A more aggressive appearing fibrosarcoma may arise in DFSP, changing its biological behavior. CD34 and apolipoprotein-D are highly expressed in DFSP, but their prognostic significance is uncertain. Methods DFSP and fibrosarcomatous-DFSP (FS-DFSP) patients referred to our institute between 1982 and 2009 were identified. Fibrosarcomatous changes, expression of CD34 and apolipoprotein-D were evaluated. Results 40 patients, (median age 43 years, 55% males) were identified. Tumor was located in the limbs in 60%, in the trunk in 40%. Thirty-seven patients had localized and 3 had metastatic disease. Thirteen (32%) patients were FS-DFSP. All but one underwent surgery with adequate surgical margins in 72%. 7 FS-DFSP received also radiotherapy (RT). Chemotherapy was administered to 3 patients with FS-DFSP. With a median follow-up of 49 months, the 5-OS was 90%. Local recurrence rate was 23%: 42% FS-DFSP, 15% DFSP. Metastases developed in three FS-DFSP patients. The 5-year EFS was 70% in localized patients. Histology (DFSP 75% vs. FS-DFSP 52%, p = 0.002), surgical margins (adequate 74% vs. inadequate 55%, p = 0.02), site (limb 47% vs. trunk 100%), CD34 expression (CD34 positive: 70% vs. CD34 negative: 33%, p = 0.05), and apolipoprotein-D expression (Apo-D positive: 73% vs. Apo-D negative: 33%, p = 0.02) influenced the 5-year EFS, whereas sex, use of RT or number of previous surgical treatments did not. Conclusions Patients with DFSP have a high survival probability. Site, adequate surgical margins, presence of the fibrosarcomatous component, lack of CD34 expression and apolipoprotein-D influence outcome.