Inclusion Criteria:  Adult patients with a histologically confirmed diagnosis of metastatic or recurrent soft tissue sarcoma Patients for whom treatment with doxorubicin is considered to be appropriate Left ventricular ejection fraction ≥ 50% Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 Disease that is considered measurable according to RECIST v1.1.  Exclusion Criteria:  Histologically or cytologically confirmed Kaposi's sarcoma, gastrointestinal stromal tumor (GIST), extra-skeletal myxoid chondrosarcoma, epithelioid hemangioendothelioma, and desmoid tumor Untreated metastases to the central nervous system Received previous treatment with anthracyclines and anthracenediones Previous radiation therapy to the mediastinal or pericardial area A known allergy to any of the treatment components Patient not willing to use suppositories Patients with a colostomy Patients who have had a colectomy (total or left hemicolectomy) with re-anastomosis Patients for whom administration of the suppositories are likely to cause pain (e.g., inflamed hemorrhoids, fissures, or lesions of the anus or rectum) Patients with fecal impaction, chronic idiopathic constipation, or chronic diarrhea or alternating irritable bowel disease Patients with inflammatory bowel disease Previous treatment with an investigational agent or the non-approved use of a drug or device within 4 weeks before study entry Uncontrolled diabetes mellitus Patients who require concomitant use of strong inhibitors or inducers of CYP3A4, CYP2D6 or P- glycoprotein (P- gp)