Assessment of Doxorubicin and Pembrolizumab in Patients With Advanced Anthracycline-Naive Sarcoma: A Phase 1/2 Nonrandomized Clinical Trial.

IMPORTANCE: Anthracycline-based therapy is standard first-line treatment for most patients with advanced and metastatic sarcomas. Although multiple trials have attempted to show improved outcomes in patients with soft-tissue sarcoma over doxorubicin monotherapy, each has fallen short of demonstrating improved outcomes. OBJECTIVE: To evaluate the safety and efficacy of doxorubicin in combination with pembrolizumab in patients with advanced, anthracycline-naive sarcomas. DESIGN, SETTING, AND PARTICIPANTS: This nonrandomized clinical trial used a 2-stage phase 2 design and was performed at a single, academic sarcoma specialty center. Patients were adults with good performance status and end-organ function. Patients with all sarcoma subtypes were allowed to enroll with the exception of osteosarcoma, Ewing sarcoma, and alveolar and embryonal rhabdomyosarcoma. INTERVENTIONS: Two dose levels of doxorubicin (45 and 75 mg/m2) were tested for safety in combination with pembrolizumab. MAIN OUTCOMES AND MEASURES: Objective response rate (ORR) was the primary end point. Overall survival (OS) and progression-free survival (PFS) were secondary end points. Correlative studies included immunohistochemistry, gene expression, and serum cytokines. RESULTS: A total of 37 patients (22 men; 15 women) were treated in the combined phase 1/2 trial. The median (range) patient age was 58.4 (25-80) years. The most common histologic subtype was leiomyosarcoma (11 patients). Doxorubicin plus pembrolizumab was well tolerated without significant unexpected toxic effects. The ORR was 13% for phase 2 patients and 19% overall. Median PFS was 8.1 (95% CI, 7.6-10.8) months. Median OS was 27.6 (95% CI, 18.7-not reached) months at the time of this analysis. Two of 3 patients with undifferentiated pleomorphic sarcoma and 2 of 4 patients with dedifferentiated liposarcoma had durable partial responses. Tumor-infiltrating lymphocytes were present in 21% of evaluable tumors and associated with inferior PFS (log-rank P = .03). No dose-limiting toxic effects were observed. CONCLUSIONS AND RELEVANCE: In this nonrandomized clinical trial, doxorubicin plus pembrolizumab was well tolerated. Although the primary end point for ORR was not reached, the PFS and OS observed compared favorably with prior published studies. Further studies are warranted, especially those focusing on undifferentiated pleomorphic sarcoma and dedifferentiated liposarcoma. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02888665.

Doxorubicin and Olaratumab Versus Doxorubicin, Ifosfamide, and Mesna for Treatment of Advanced Soft Tissue Sarcomas.

OBJECTIVE: We compared the outcomes in soft tissue sarcoma (STS) treated with olaratumab and doxorubicin (OD) versus doxorubicin, ifosfamide, and mesna (AIM) to assess whether OD could supersede AIM in STS therapy. METHODS: A single-institution, retrospective study of STS treated for advanced disease with OD or AIM in 2013 to 2017 was conducted. Demographic and clinical parameters were compared by Fisher's exact test. Kaplan-Meier and Cox analyses examined progression-free survival (PFS) and overall survival (OS). Adverse events were compared. RESULTS: Thirty patients (13 OD, 17 AIM) were included. OD was administered more commonly after first-line therapy (54% OD vs. 6% AIM, P=0.0005). The 2 groups did not differ in other parameters. Median OS [OD: 14.2 mo, 95% confidence interval (CI): 7.1-not reached; AIM 19.9 mo, 95% CI 9.5-35.5; hazard ratio: 0.99, 95% CI: 0.38-2.59, P=0.99] and PFS (OD: 2.6 mo, 95% CI: 1.3-7; AIM 6.4 mo, 95% CI: 1.5-14.5; hazard ratio: 0.57, 95% CI: 0.26-1.24, P=0.16) were not statistically different, although median values favored AIM. Grade 3 to 4 neutropenia, but not febrile neutropenia, was more frequent with OD. CONCLUSIONS: OD and AIM did not differ with respect to either OS or PFS. Although this study's size initially appeared the most likely explanation, lack of significant activity of olaratumab was subsequently reported in the phase III trial of OD. Our results suggest that future conditional oncology drug approvals should be accompanied by mandated registries to monitor outcomes of patients treated after conditional approval, but before full approval.