BACKGROUND Fusions involving one of three tropomyosin receptor kinases (TRK) occur in diverse cancers in children and adults. We evaluated the efficacy and safety of larotrectinib, a highly selective TRK inhibitor, in adults and children who had tumors with these fusions. METHODS We enrolled patients with consecutively and prospectively identified TRK fusion–positive cancers, detected by molecular profiling as routinely performed at each site, into one of three protocols: a phase 1 study involving adults, a phase 1–2 study involving children, or a phase 2 study involving adolescents and adults. The primary end point for the combined analysis was the overall response rate according to independent review. Secondary end points included duration of response, progression-free survival, and safety. RESULTS A total of 55 patients, ranging in age from 4 months to 76 years, were enrolled and treated. Patients had 17 unique TRK fusion–positive tumor types. The overall response rate was 75% (95% confidence interval [CI], 61 to 85) according to independent review and 80% (95% CI, 67 to 90) according to investigator assessment. At 1 year, 71% of the responses were ongoing and 55% of the patients remained progression-free. The median duration of response and progression-free survival had not been reached. At a median follow-up of 9.4 months, 86% of the patients with a response (38 of 44 patients) were continuing treatment or had undergone surgery that was intended to be curative. Adverse events were predominantly of grade 1, and no adverse event of grade 3 or 4 that was considered by the investigators to be related to larotrectinib occurred in more than 5% of patients. No patient discontinued larotrectinib owing to drug-related adverse events. CONCLUSIONS Larotrectinib had marked and durable antitumor activity in patients with TRK fusion–positive cancer, regardless of the age of the patient or of the tumor type. (Funded by Loxo Oncology and others; ClinicalTrials.gov numbers, NCT02122913, NCT02637687, and NCT02576431.)

Adenosarcomas are rare malignancies of the female genital tract, accounting for approximately 5 % of uterine sarcomas. Occasionally, adenosarcoma occurs in the ovaries or in extra-uterine tissue, which may be related to endometriosis. These tumors are characterized by benign epithelial elements and a malignant mesenchymal component. Pathologic diagnosis is dependent on the identification of the characteristic morphologic features. The most common immunohistochemical markers for adenosarcoma are CD10 and WT1, but these are not specific. The most frequent presenting symptom is abnormal uterine bleeding. The majority of patients present with stage I disease, with a 5-year overall survival of 60 to 80 %. Survival is influenced by the presence of myometrial invasion, sarcomatous overgrowth, lymphovascular invasion, necrosis, and the presence of heterologous elements including rhabdomyoblastic differentiation. Patients with sarcomatous overgrowth have significantly increased risk of recurrence 23 versus 77 % and decreased 5-year overall survival 50 to 60 %. Standard of care treatment is total hysterectomy with bilateral salpingo-oophorectomy without lymphadenectomy, as the incidence of lymph node metastasis is rare. Retrospective data does not support the use of adjuvant pelvic radiotherapy in uterine adenosarcomas as no survival benefit is seen. Insufficient data exists to recommend routinely neoadjuvant or adjuvant chemotherapy for uterine adenosarcomas. Limited evidence exists for the role of hormonal therapy in uterine adenosarcomas. The PIK3/AKT/PTEN pathway is mutated in ∼70 % of adenosarcomas, and this may represent a possible therapeutic target. This article reviews the current state of knowledge concerning uterine adenosarcoma and discusses the management of this rare tumor.

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