Purpose: Uterine-serous-carcinoma (USC) is an aggressive variant of endometrial cancer. On the basis of preliminary results of a multicenter, randomized phase II trial, trastuzumab (T), a humanized-mAb targeting Her2/Neu, in combination with carboplatin/paclitaxel (C/P), is recognized as an alternative in treating advanced/recurrent HER2/Neu-positive USC. We report the updated survival analysis of NCT01367002. Patients and Methods: Eligible patients had stage III to IV or recurrent disease. Participants were randomized 1:1 to receive C/P for six cycles ± T followed by maintenance T until progression or toxicity. Progression-free survival (PFS) was the primary endpoint; overall survival (OS) and toxicity were secondary endpoints. Results: Sixty-one patients were randomized. After a median-follow-up of 25.9 months, 43 progressions and 38 deaths occurred among 58 evaluable patients. Updated median-PFS continued to favor the T-arm, with medians of 8.0 months versus 12.9 months in the control and T-arms (HR = 0.46; 90% CI, 0.28–0.76; P = 0.005). Median-PFS was 9.3 months versus 17.7 months among 41 patients with stage III to IV disease undergoing primary treatment (HR = 0.44; 90% CI, 0.23–0.83; P = 0.015), and 7.0 months versus 9.2 months among 17 patients with recurrent disease (HR = 0.12; 90% CI, 0.03–0.48; P = 0.004). OS was higher in the T compared with the control arm, with medians of 29.6 months versus 24.4 months (HR = 0.58; 90% CI, 0.34–0.99; P = 0.046). The benefit was most notable in those with stage III to IV disease, with survival median not reached in the T-arm versus 24.4 months in the control arm (HR = 0.49; 90% CI, 0.25–0.97; P = 0.041). Toxicity was not different between arms. Conclusions: Addition of T to C/P increased PFS and OS in women with advanced/recurrent HER2/Neu-positive USC, with the greatest benefit seen for the treatment of stage III to IV disease.

Purpose: The management of endometrial carcinoma no longer amenable to treatment with surgery or radiotherapy has not improved significantly with modern chemotherapy. Alternative therapeutic options are desperately needed. Experimental Design: We describe 2 heavily pretreated patients with recurrent disease refractory to surgery, radiotherapy, and chemotherapy who were treated with the anti–PD-1 immune checkpoint inhibitor nivolumab. Results: Patient #1 harbored an ultra-mutated tumor (mutation load/MB = 117.3, total mutations = 4,660) driven by mutation in the exonuclease domain of the DNA polymerase ε gene. Patient #2 harbored a hyper-mutated tumor (mutation load/MB = 33.5, total mutations = 1,037) due to a germinal MSH6 gene mutation. Both patients demonstrated a remarkable clinical response to the anti–PD-1 immune checkpoint inhibitor nivolumab. Patients' clinical responses remain unchanged at the time of the writing of this report, with no grade 3 or higher side effects reported to date. Conclusions: Anti–PD-1 inhibitors represent a novel treatment option for recurrent/metastatic, ultra/hyper-mutated human tumors refractory to salvage treatment. Clin Cancer Res; 22(23); 5682–7. ©2016 AACR. See related commentary by Piulats and Matias-Guiu, p. 5623