Citations

6010 Background: The efficacy of treatment for recurrent endometrial cancer (EC) remains limited. Vascular endothelial growth factor and inflammatory chemokines are proangiogenic factors and immune modulators involved in immune suppression. Reprogramming the tumor microenvironment by combining antiangiogenic and immunotherapy (IO) could enhance antitumor responses. Methods: A 2:1 randomized phase 2 trial compared the combination of cabozantinib and nivolumab (Arm A) versus nivolumab (Arm B) in recurrent EC. Primary endpoint was progression free survival (PFS) assessed by RECIST 1.1 (NCT03367741). Women with recurrent measurable EC were eligible. There were no limits on prior therapy, but at least one prior platinum-based chemotherapy was required. Patients (pts) were stratified according to MSI status and assessed by CT every 8 weeks. Cabozantinib was given at 40 mg daily (Arm A) and nivolumab at 240 mg, on D1 and D15 of a 28-day cycle for 4 cycles, followed by 480 mg every 4 weeks (Arms A & B). Pts with carcinosarcoma or prior IO were enrolled in an exploratory cohort and received combination treatment (Arm C). A baseline biopsy was required for all pts. CyTOF analysis was performed on fresh biopsies. Results: 76 evaluable pts were enrolled (Arm A: 36, Arm B: 18, Arm C: 9 carcinosarcoma, and 20 post IO including 7 pts crossed over from Arm B). 55% of pts had received ≥3 prior lines of therapy. Two pts were MSI high in Arm A and none in Arm B. The Kaplan-Meier estimated median PFS was 5.3 (95% CI: 3.5-9.5) months in Arm A and 1.9 (95% CI: 1.6-3.8) months in Arm B, with a log-rank p = 0.07, which met the significance level of 0.1 used for sample size calculation. Objective response rate (ORR) was 25% for Arm A and 16.7% for Arm B; stable disease (SD) was seen in 44.4% vs 11.1%, respectively. Clinical benefit (ORR+SD) was significantly higher in arm A vs B (p < 0.001). In Arm C-carcinosarcoma, one patient had a partial response (11.9 months duration) and four SD. In Arm C-prior IO, six pts responded and eight had SD. The most common related AEs in Arm A were diarrhea (47.2%), elevated liver enzymes (44.4%), fatigue (38.9%), anorexia, hypertension, and nausea (30.6%), mainly grade 1/2. Preliminary CyTOF analysis across treatment arms identified multiple immune subsets for further interrogation including activated CD8+ and CD4+ T cells. Conclusions: Cabozantinib plus nivolumab demonstrates improved PFS compared to nivolumab in heavily pre-treated women with recurrent EC. In-depth CyTOF analysis of the tumor microenvironment to identify predictive immune biomarkers of response is ongoing. Clinical trial information: NCT03367741.

551 Background: Sorafenib inhibits various pro-angiogenesis pathways including PDGFR-B, a factor associated with resistance to anti-VEGF therapy. A previous phase II trial in patients with chemorefractory metastatic CRC demonstrated a 63% disease control rate with a combination of bevacizumab (BEV) and sorafenib. This phase I trial sought to determine the MTD of BEV and sorafenib combined with standard cytotoxic therapy for advanced gastrointestinal (GI) cancers. Methods: Patients with advanced GI malignancies appropriate for irinotecan-based therapy were enrolled (14 with CRC, 3 gastroesophageal). A standard 3 + 3 design was used with 3 escalating sorafenib dose levels (DL): (1) 200 mg po daily, days 3-7, 10-14; (2) 200 mg po twice daily, days 3-6, 10-13; and (3) 200 mg po twice daily, days 3-7, 10-14. FOLFIRI: irinotecan 180 mg/m2 d1, leucovorin 400 mg/m2 d1, 5-fluorouracil (FU) bolus 400 mg/m2 d1, 5-FU infusion 2400 mg/m2d1-2 and BEV 5 mg/kg d1. 1 cycle = 14 days. Results: Seventeen pts were enrolled, median age of 56 (range 32 and 81). Two pts were replaced, as they did not complete DLT evaluation, leaving 15 evaluable pts. Four evaluable pts at DL1 and 6 pts at DL2 had no DLTs. At DL 3, the first cohort of 3 pts did not experience any DLTs. In the second cohort of 3 pts, 2 pts experienced DLTs (asymptomatic G3 hypophosphatemia, G3 dehydration and diarrhea). MTD was determined to be DL2: sorafenib 200 mg PO twice daily, days 3-6, 10-13 combined with FOLFIRI and BEV at standard doses. Of the 15 evaluable pts, 4 pts had PR, 8 pts had SD as best response, 1 pt had PD, and 2 pts discontinued treatment prior to first tumor assessment. The median number of cycles was 10 (range 1-37). Three pts with CRC had disease control > 12 months. Conclusions: The MTD of this regimen is sorafenib 200 mg PO twice daily, days 3-6,10-13 combined with standard doses of FOLFIRI and BEV. Dual VEGF inhibition combined with cytotoxic therapy may provide prolonged disease stabilization for select patients with advanced GI malignancies. Supported by CA69912 and CA15083. Clinical trial information: NCT01383343.

Purpose Romidepsin (depsipeptide or FK228) is a member of a new class of antineoplastic agents active in T-cell lymphoma, the histone deacetylase inhibitors. On the basis of observed responses in a phase I trial, a phase II trial of romidepsin in patients with T-cell lymphoma was initiated. Patients and Methods The initial cohort was limited to patients with cutaneous T-cell lymphoma (CTCL), or subtypes mycosis fungoides or Sézary syndrome, who had received no more than two prior cytotoxic regimens. There were no limits on other types of therapy. Subsequently, the protocol was expanded to enroll patients who had received more than two prior cytotoxic regimens. Results Twenty-seven patients were enrolled onto the first cohort, and a total of 71 patients are included in this analysis. These patients had undergone a median of four prior treatments, and 62 patients (87%) had advanced-stage disease (stage IIB, n = 15; stage III, n= 6; or stage IV, n = 41). Toxicities included nausea, vomiting, fatigue, and transient thrombocytopenia and granulocytopenia. Pharmacokinetics were evaluated with the first administration of romidepsin. Complete responses were observed in four patients, and partial responses were observed in 20 patients for an overall response rate of 34% (95% CI, 23% to 46%). The median duration of response was 13.7 months. Conclusion The histone deacetylase inhibitor romidepsin has single-agent clinical activity with significant and durable responses in patients with CTCL.