Faculty Bibliography

BACKGROUND AND PURPOSE: Resistance to endocrine therapies in hormone receptor (HR)-positive breast cancer is a significant challenge. Prior studies have shown that low-dose oral cyclophosphamide can transiently deplete regulatory T cells (Tregs) and improve anti-tumor immunity. We investigated the combination of exemestane with cyclophosphamide in patients with advanced HR-positive breast cancer and assessed changes in circulating immune cell subsets. METHODS: This was a single-arm phase II trial of exemestane with cyclophosphamide in patients with metastatic HR-positive/HER2-negative breast cancer who had progressed on prior endocrine therapy (ClinicalTrials.gov: NCT01963481). Primary endpoint was progression-free survival (PFS) at 3 months (RECIST 1.1). Secondary objectives included median PFS, objective response rate, duration of response, and safety. Circulating Tregs (FOXP3+Helios+) and other immune cell subsets were monitored during treatment and compared with healthy controls. RESULTS: Twenty-three patients were enrolled. Treatment was well tolerated, without grade 4/5 toxicities. Objective responses were seen in 6/23 patients (26.1%; 95% CI 10.2-48.4%) and were durable (median 11.6 months). Three-month PFS rate was 50.1% (95% CI 33.0-76.0%); median PFS was 4.23 months (95% CI 2.8-11.7). No treatment-related decrease in Tregs was observed. However, elevated baseline levels of Naive Tregs [greater than 2.5 (the median of the naive Tregs)] were associated with relative risk of disease progression or death [hazard ratio 11.46 (95% CI 2.32-56.5)]. In addition, the baseline levels of Naive Tregs (adj-p = 0.04), Memory Tregs (adj-p = 0.003), CD4 + Central Memory T cells (adj-p = 0.0004), PD-1 + CD4 + Central Memory T cells (adj-p = 0.008), and PD-1 + CD4 + Effector Memory T cells (adj-p = 0.009) were significantly greater in the patients than in the healthy controls; the baseline levels of %CD4 + Naive T cells (adj-p = 0.0004) were significantly lower in patients compared with healthy controls (n = 40). CONCLUSION: Treg depletion was not observed with low-dose cyclophosphamide when assessed by the specific marker FOXP3 + Helios +; however, baseline naive Tregs were associated with 3-month PFS. Exemestane/cyclophosphamide combination had favorable safety profile with evidence of clinical activity in heavily pretreated patients.

Could hydroxychloroquine and quinacrine antimalarial therapy for dermatomyositis later attributed to a paraneoplasic manifestation of an ovarian cancer enhance its subsequent response to chemotherapy? Five months after being diagnosed with dermatomyositis, while somewhat improved with hydroxychloroquine, quinacrine and methotrexate, this 63-year-old woman presented with an advanced intra-abdominal epithelial ovarian cancer documented (but not resected) at laparotomy. Neoadjuvant carboplatin/paclitaxel resulted in remarkable improvement of symptoms, tumour markers and imaging findings leading to thorough cytoreductive surgery at completion of five cycles. No tumour was found in the resected omentum, gynaecologic organs, as well as hepatic and nodal sampling thus documenting a complete pathologic response; a subcutaneous port and an intraperitoneal (IP) catheter were placed for two cycles of IP cisplatin consolidation. She remains free of disease 3 years after such treatment and her dermatomyositis is in remission in the absence of any treatment. We discuss a possible role of autophagy in promoting tumour cell survival and chemoresistance that is potentially reversed by antimalarial drugs. Thus, chemotherapy following their use may subsequently lead to dramatic potentiation of anticancer treatment.

PURPOSE:We examined disparities in prognosis between patients with ovarian clear cell carcinoma (OCCC) and serous epithelial ovarian cancer (SOC). METHODS:We reviewed data from FIGO stage I-IV epithelial ovarian cancer patients who participated in 12 prospective randomized GOG protocols. Proportional hazards models were used to compare progression-free survival (PFS) and overall survival (OS) by cell type (clear cell versus serous). RESULTS:There were 10,803 patients enrolled, 9531 were eligible, evaluable and treated with platinum, of whom 544 (6%) had OCCC, 7054 (74%) had SOC, and 1933 (20%) had other histologies and are not included further. In early stage (I-II) patients, PFS was significantly better in OCCC than in SOC patients. For late stage (III, IV) patients, OCCC had worse PFS and OS compared to SOC, OS HR=1.66 (1.43, 1.91; p<0.001). After adjusting for age and stratifying by protocol and treatment arm, stage, performance status, and race, OCCC had a significantly decreased OS, HR=1.53 (1.33, 1.76; p<0.001). In early stage cases, there was a significantly decreased treatment effect on PFS for consolidative therapy with weekly Paclitaxel versus observation in OCCC compared to SOC (p=0.048). CONCLUSIONS:This is one of the largest analyses to date of OCCC treated on multiple cooperative group trials. OCCC histology is more common than SOC in early stage disease. When adjusted for prognostic factors, in early stage patients, PFS was better for OCCC than for SOC; however, in late-stage patients, OCCC was significantly associated with decreased OS. Finally, treatment effect was influenced by histology.

OBJECTIVES: To evaluate the efficacy and safety of irinotecan and bevacizumab in recurrent ovarian cancer. The primary objective was to estimate the progression free survival (PFS) rate at 6months. Secondary objectives included estimation of overall survival (OS), objective response rate (ORR), duration of response, and an evaluation of toxicity. METHODS: Recurrent ovarian cancer patients with no limit on prior treatments were eligible. Irinotecan 250mg/m2 (amended to 175mg/m2 after toxicity assessment in first 6 patients) and bevacizumab 15mg/kg were administered every 3weeks until progression or toxicity. Response was assessed by RECIST or CA-125 criteria every 2cycles. RESULTS: Twenty nine patients enrolled (10 were platinum-sensitive and 19 were platinum-resistant). The median number of prior regimens was 5 (range 1-12); 13 patients had prior bevacizumab and 11 prior topotecan. The PFS rate at 6months was 55.2% (95% CI: 40%-77%). The median number of study cycles given was 7 (range 1-34). Median PFS was 6.8months (95% CI: 5.1-12.1months); median OS was 15.4months (95% CI: 11.9-20.4months). In this study, no complete response (CR) was observed. The objective response rate (ORR; PR or CR) for all patients entered was 27.6% (95% CI: 12.7%-47.2%) and the clinical benefit rate (CR+PR+SD) was 72.4% (95% CI: 52.8%-87.3%); twelve patients experienced duration of response longer than 6months. In the 24 patients with measurable disease, a partial response (PR) was documented in 8 (30%) patients; 13 patients maintained stable disease (SD) at first assessment. The most common grade 3/4 toxicity was diarrhea. No treatment-related deaths were observed. CONCLUSIONS: Irinotecan and bevacizumab has activity in heavily pre-treated patients with recurrent ovarian cancer, including those with prior bevacizumab and topoisomerase inhibitor use.

Evidence suggests that stromal cells play critical roles in tumor growth. Uncovering new mechanisms that control stromal cell behavior and their accumulation within tumors may lead to development of more effective treatments. We provide evidence that the HU177 cryptic collagen epitope is selectively generated within human ovarian carcinomas and this collagen epitope plays a role in SKOV-3 ovarian tumor growth in vivo. The ability of the HU177 epitope to regulate SKOV-3 tumor growth depends in part on its ability to modulate stromal cell behavior because targeting this epitope inhibited angiogenesis and, surprisingly, the accumulation of alpha-smooth muscle actin-expressing stromal cells. Integrin alpha10beta1 can serve as a receptor for the HU177 epitope in alpha-smooth muscle actin-expressing stromal cells and subsequently regulates Erk-dependent migration. These findings are consistent with a mechanism by which the generation of the HU177 collagen epitope provides a previously unrecognized alpha10beta1 ligand that selectively governs angiogenesis and the accumulation of stromal cells, which in turn secrete protumorigenic factors that contribute to ovarian tumor growth. Our findings provide a new mechanistic understanding into the roles by which the HU177 epitope regulates ovarian tumor growth and provide new insight into the clinical results from a phase 1 human clinical study of the monoclonal antibody D93/TRC093 in patients with advanced malignant tumors.