Targeting Galectin 3 illuminates its contributions to the pathology of uterine serous carcinoma.

BACKGROUND: Uterine serous cancer (USC) comprises around 10% of all uterine cancers. However, USC accounts for approximately 40% of uterine cancer deaths, which is attributed to tumor aggressiveness and limited effective treatment. Galectin 3 (Gal3) has been implicated in promoting aggressive features in some malignancies. However, Gal3's role in promoting USC pathology is lacking. METHODS: We explored the relationship between LGALS3 levels and prognosis in USC patients using TCGA database, and examined the association between Gal3 levels in primary USC tumors and clinical-pathological features. CRISPR/Cas9-mediated Gal3-knockout (KO) and GB1107, inhibitor of Gal3, were employed to evaluate Gal3's impact on cell function. RESULTS: TCGA analysis revealed a worse prognosis for USC patients with high LGALS3. Patients with no-to-low Gal3 expression in primary tumors exhibited reduced clinical-pathological tumor progression. Gal3-KO and GB1107 reduced cell proliferation, stemness, adhesion, migration, and or invasion properties of USC lines. Furthermore, Gal3-positive conditioned media (CM) stimulated vascular tubal formation and branching and transition of fibroblast to cancer-associated fibroblast compared to Gal3-negative CM. Xenograft models emphasized the significance of Gal3 loss with fewer and smaller tumors compared to controls. Moreover, GB1107 impeded the growth of USC patient-derived organoids. CONCLUSION: These findings suggest inhibiting Gal3 may benefit USC patients.

Losartan treatment enhances chemotherapy efficacy and reduces ascites in ovarian cancer models by normalizing the tumor stroma.

In ovarian cancer patients, tumor fibrosis and angiotensin-driven fibrogenic signaling have been shown to inversely correlate with survival. We sought to enhance drug delivery and therapeutic efficacy by remodeling the dense extracellular matrix in two orthotopic human ovarian carcinoma xenograft models. We hypothesized that targeting the angiotensin signaling axis with losartan, an approved angiotensin system inhibitor, could reduce extracellular matrix content and the associated "solid stress," leading to better anticancer therapeutic effect. We report here four translatable findings: (i) losartan treatment enhances the efficacy of paclitaxel-a drug used for ovarian cancer treatment-via normalizing the tumor microenvironment, resulting in improved vessel perfusion and drug delivery; (ii) losartan depletes matrix via inducing antifibrotic miRNAs that should be tested as candidate biomarkers of response or resistance to chemotherapy; (iii) although losartan therapy alone does not reduce tumor burden, it reduces both the incidence and the amount of ascites formed; and (iv) our retrospective analysis revealed that patients receiving angiotensin system inhibitors concurrently with standard treatment for ovarian cancer exhibited 30 mo longer overall survival compared with patients on other antihypertensives. Our findings provide the rationale and supporting data for a clinical trial on combined losartan and chemotherapy in ovarian cancer patients.

Critical questions in ovarian cancer research and treatment: Report of an American Association for Cancer Research Special Conference.

Substantial progress has been made in understanding ovarian cancer at the molecular and cellular level. Significant improvement in 5-year survival has been achieved through cytoreductive surgery, combination platinum-based chemotherapy, and more effective treatment of recurrent cancer, and there are now more than 280,000 ovarian cancer survivors in the United States. Despite these advances, long-term survival in late-stage disease has improved little over the last 4 decades. Poor outcomes relate, in part, to late stage at initial diagnosis, intrinsic drug resistance, and the persistence of dormant drug-resistant cancer cells after primary surgery and chemotherapy. Our ability to accelerate progress in the clinic will depend on the ability to answer several critical questions regarding this disease. To assess current answers, an American Association for Cancer Research Special Conference on "Critical Questions in Ovarian Cancer Research and Treatment" was held in Pittsburgh, Pennsylvania, on October 1-3, 2017. Although clinical, translational, and basic investigators conducted much of the discussion, advocates participated in the meeting, and many presentations were directly relevant to patient care, including treatment with poly adenosine diphosphate ribose polymerase (PARP) inhibitors, attempts to improve immunotherapy by overcoming the immune suppressive effects of the microenvironment, and a better understanding of the heterogeneity of the disease.

Impact of race on dose selection of molecular-targeted agents in early-phase oncology trials.

BACKGROUND: We examined the impact of race on the maximum tolerated doses (MTD) and final approved doses (FAD) of single-agent molecular-targeted agents (MTA) in North America/Europe (NA/EU) and Asia. METHODS: We searched PubMed and regulatory databases to identify targeted drugs approved globally and compared their FAD and MTD in corresponding phase I/II studies conducted separately in NA/EU and Asia. To evaluate this further, we conducted parallel, prospective, first-in-human studies of DS-7423, a dual PI3K/mTOR inhibitor, in patients with advanced solid tumours in the US and Japan. We pooled and compared the pharmacokinetics (PK), pharmacodynamics (PD), toxicity, and efficacy between these populations. RESULTS: 17 MTA were approved in NA/EU and Asia from 2001 to 2015. Recommended phase 2 doses (RP2D) were identical across races in 14 of 17 (80%) studies and differences were not clinically meaningful. FAD were identical across all regions. 42 and 27 patients from US and Japan, respectively, were enrolled in the phase I studies of DS-7423. Despite differences in race, body weight, and body mass index, the RP2D were 240 mg/day with no differences in toxicities, PK, PD, or efficacy. CONCLUSIONS: Conducting separate clinical trials of single-agent MTA in Caucasian and Asian populations may be redundant.

A Randomized Trial of Prophylactic Extended Carboplatin Infusion to Reduce Hypersensitivity Reactions in Recurrent Ovarian Cancer.

OBJECTIVE: Hypersensitivity with repeated exposure to platinum agents is common and can preclude continued treatment, even in patients with disease that remains platinum sensitive. We sought to compare the effects of prophylactic, extended carboplatin infusion versus standard infusion on the rate of carboplatin hypersensitivity reactions (HSRs) in women with recurrent ovarian cancer. METHODS: This was a single-institution, randomized, nonblinded trial comparing a graded, 3-hour extended infusion of carboplatin with a standard 30-minute infusion in patients with recurrent ovarian cancer who were enrolled from January 2011 to April 2015. The study was designed to detect a decrease in the HSR rate from 20% (standard infusion) to 5% (extended infusion) assuming a type 1 error of 10% and power of 80% using a 1-sided test. RESULTS: Of 146 enrolled patients, 114 were evaluable. Fifteen (13%) had an HSR-11% (6/56) in the extended-infusion and 16% (9/58) in the standard-infusion groups (P = 0.582). Planned treatment completion was achieved in 50 (89%) of 56 patients and 49 (84%) of 58 patients, respectively. Of 25 patients who received single-agent carboplatin, 8 (32%) had an HSR (53% of all patients who had an HSR [8/15]). Of 23 patients who received carboplatin with gemcitabine, 4 (17%) had an HSR (27% of all patients who had an HSR [4/15]). Of 8 patients who received carboplatin with paclitaxel, 3 (38%) had an HSR (20% of all patients who had an HSR [3/15]). There were no HSRs with pegylated liposomal doxorubicin, the most commonly given concurrent chemotherapy (46% of all patients). CONCLUSIONS: A prophylactic, extended carboplatin infusion was not associated with a decreased HSR rate. The overall low HSR rate suggests that premedication may help reduce HSRs.

Beyond the dose-limiting toxicity period: Dermatologic adverse events of patients on phase 1 trials of the Cancer Therapeutics Evaluation Program.

BACKGROUND: Dermatologic adverse events (AEs) can be key determinants of overall drug tolerability and of the maximum tolerated and recommended phase 2 doses in phase 1 trials. The authors present the largest dedicated analysis of dermatologic AEs on phase 1 trials to date. METHODS: Data from a prospectively maintained database of patients with solid tumors who were enrolled onto Cancer Therapeutics Evaluation Program (CTEP)-sponsored phase 1 trials of cytotoxic or molecularly targeted agents (MTAs) from 2000 to 2010 were analyzed. Cumulative incidence, site, and type of drug-related dermatologic AEs were described and compared. The timing of worst drug-related dermatologic AEs was summarized. RESULTS: In total, 3517 patients with solid tumors and 6165 unique, drug-related dermatologic AEs were analyzed, including 1545 patients on MTA-only trials, 671 on cytotoxic-only trials, and 1392 on combination MTA and cytotoxic trials. Of 1270 patients who had drug-related dermatologic events, the timing of the worst AE was as follows: 743 (cycle 1), 303 (cycle 2), and 224 (cycle 3 or later). Although the cumulative incidence of grade ≥3 drug-related AEs increased to 2.4% by cycle 6, it was only 1.6% at the end of cycle 1. The cumulative incidence of drug-related AEs was highest in patients who received MTA-only therapy (P < .001) and differed by dose level (P < .001). In patients who received MTA-only therapy, drug-related AEs were most common for combination kinase inhibitor-containing therapy (P < .001). CONCLUSIONS: A substantial proportion of drug-related dermatologic AEs occur after the traditional dose-limiting toxicity monitoring period of phase 1 clinical trials. Future designs should account for late toxicities.

Tumor Inhibition by Enzalutamide in a Xenograft Model of Ovarian Cancer.

OBJECTIVES: To investigate the tumor-suppressive properties of enzalutamide in androgen-driven ovarian cancer. METHODS: Mice were implanted subcutaneously with OVCAR-3 cells and treated with dihydrotestosterone in combination with enzalutamide or vehicle control. Tumor volumes were measured twice weekly until day 56. RESULTS: Dihydrotestosterone exposure led to a significant increase in tumor growth, while concomitant treatment with enzalutamide led to significant reductions in tumor volume compared to the androgen-exposed groups. CONCLUSIONS: We present the first evidence that the second-generation anti-androgen enzalutamide may possess efficacy in the treatment of ovarian cancer, paving the way for the future clinical trials.

A phase I clinical trial of adoptive T cell therapy using IL-12 secreting MUC-16(ecto) directed chimeric antigen receptors for recurrent ovarian cancer.

PURPOSE: Recurrent platinum-resistant ovarian cancer has no curative options, necessitating the development of novel treatments, including immunotherapy. RATIONALE: Patient-derived T cells can be genetically modified to express chimeric antigen receptors (CARs) specific to tumor-associated antigens in an HLA-independent manner, with promising preclinical results. MUC16(ecto) is highly expressed on most epithelial ovarian carcinomas but at low levels on normal tissues, offering an excellent immunotherapeutic target for this cancer. CAR T cells further modified to secrete IL-12 show enhanced cytotoxicity, persistence, and modulation of the tumor microenvironment. DESIGN: We propose a dose escalation phase I clinical trial for patients with recurrent MUC-16(ecto+) ovarian cancer to test the safety of intravenous and intraperitoneal administration and the preliminary efficacy of autologous IL-12 secreting, MUC-16(ecto) CAR T cells containing a safety elimination gene. INNOVATION: This trial targets MUC-16(ecto), a novel and promising tumor-associated antigen. This will be the first time CAR T cells are injected intraperitoneally directly into the site of the tumor within the abdomen in humans. Furthermore, the ability of genetically modified cells to secrete IL-12 will potentially enhance CAR T cell persistence and modulate the tumor microenvironment. For safety purposes, an elimination gene has been incorporated into the CAR T cells to mitigate any on-target, off-tumor or other unforeseen toxicity.

Intravenous aflibercept in patients with platinum-resistant, advanced ovarian cancer: results of a randomized, double-blind, phase 2, parallel-arm study.

BACKGROUND: In this randomized phase 2 study, the authors assessed the efficacy and safety of intravenous aflibercept at 2 different doses (2 mg/kg or 4 mg/kg) in patients with recurrent, platinum-resistant ovarian, peritoneal, or fallopian tube cancer who developed disease progression after receiving topotecan and/or pegylated liposomal doxorubicin. METHODS: Patients were randomized to receive intravenous aflibercept at a dose of either 2 mg/kg or 4 mg/kg every 2 weeks until they developed disease progression or significant toxicity. The primary endpoint was to evaluate Response Evaluation Criteria in Solid Tumor response rates (overall response rate [ORR] = complete responses plus partial responses) and to test the null hypothesis (ORR, >5%). Secondary endpoints included time to tumor progression, safety, progression-free survival/overall survival, drug pharmacokinetics, and immunogenicity. In total, 67 evaluable patients per cohort were planned based on a Simon 2-stage design, and, if those patients responded, then enrollment could extend to 200 patients. Tumor radiographic response was assessed by investigators and by an independent review committee. RESULTS: After the first 84 evaluable patients, 8 unconfirmed partial responders were noted (ORR, 10%) across both arms; the Independent Data Monitoring Committee recommended continuing blinded accrual. At study completion, 215 evaluable patients were accrued, including 1 responder of 106 patients (0.9%) in the 2-mg/kg cohort and 5 responders of 109 patients (4.6%) in the 4-mg/kg cohort according to the independent review committee. The clinical benefit rate (ORR plus stable disease >6 months) was 12.3% and 11% in the 2-mg/kg and 4-mg/kg cohorts, respectively. Treatment-related grade 3 and 4 adverse events included hypertension (25.5% and 27.5% in the 2-mg/kg and 4-mg/kg cohorts, respectively), proteinuria (9.4% and 7.3%, respectively), and fatigue (5.7% and 3.7%, respectively). The gastrointestinal perforation rate was low (3 patients; 1.4%). CONCLUSIONS: Aflibercept at a dose of either 2 mg/kg or 4 mg/kg was generally well tolerated but did not meet the primary endpoint for response.

Structural basis for antibody recognition of the proximal MUC16 ectodomain.

BACKGROUND: Mucin 16 (MUC16) overexpression is linked with cancer progression, metastasis, and therapy resistance in high grade serous ovarian cancer and other malignancies. The cleavage of MUC16 forms independent bimodular fragments, the shed tandem repeat sequence which circulates as a protein bearing the ovarian cancer biomarker (CA125) and a proximal membrane-bound component which is critical in MUC16 oncogenic behavior. A humanized, high affinity antibody targeting the proximal ectodomain represents a potential therapeutic agent against MUC16 with lower antigenic potential and restricted human tissue expression. RESULTS: Here, we demonstrate the potential therapeutic versatility of the humanized antibody as a monoclonal antibody, antibody drug conjugate, and chimeric antigen receptor. We report the crystal structures of 4H11-scFv, derived from an antibody specifically targeting the MUC16 C-terminal region, alone and in complex with a 26-amino acid MUC16 segment resolved at 2.36 Å and 2.47 Å resolution, respectively. The scFv forms a robust interaction with an epitope consisting of two consecutive ß-turns and a ß-hairpin stabilized by 2 hydrogen bonds. The VH-VL interface within the 4H11-scFv is stabilized through an intricate network of 11 hydrogen bonds and a cation-π interaction. CONCLUSIONS: Together, our studies offer insight into antibody-MUC16 ectodomain interaction and advance our ability to design agents with potentially improved therapeutic properties over anti-CA125 moiety antibodies.

Sialyl-Tn serves as a potential therapeutic target for ovarian cancer.

BACKGROUND: Ovarian cancer remains the deadliest of the gynecologic cancers in the United States. There have been limited advances in treatment strategies that have seen marked increases in overall survival. Thus, it is essential to continue developing and validating new treatment strategies and markers to identify patients who would benefit from the new strategy. In this report, we sought to further validate applications for a novel humanized anti-Sialyl Tn antibody-drug conjugate (anti-STn-ADC) in ovarian cancer. METHODS: We aimed to further test a humanized anti-STn-ADC in sialyl-Tn (STn) positive and negative ovarian cancer cell line, patient-derived organoid (PDO), and patient-derived xenograft (PDX) models. Furthermore, we sought to determine whether serum STn levels would reflect STn positivity in the tumor samples enabling us to identify patients that an anti-STn-ADC strategy would best serve. We developed a custom ELISA with high specificity and sensitivity, that was used to assess whether circulating STn levels would correlate with stage, progression-free survival, overall survival, and its value in augmenting CA-125 as a diagnostic. Lastly, we assessed whether the serum levels reflected what was observed via immunohistochemical analysis in a subset of tumor samples. RESULTS: Our in vitro experiments further define the specificity of the anti-STn-ADC. The ovarian cancer PDO, and PDX models provide additional support for an anti-STn-ADC-based strategy for targeting ovarian cancer. The custom serum ELISA was informative in potential triaging of patients with elevated levels of STn. However, it was not sensitive enough to add value to existing CA-125 levels for a diagnostic. While the ELISA identified non-serous ovarian tumors with low CA-125 levels, the sample numbers were too small to provide any confidence the STn ELISA would meaningfully add to CA-125 for diagnosis. CONCLUSIONS: Our preclinical data support the concept that an anti-STn-ADC may be a viable option for treating patients with elevated STn levels. Moreover, our STn-based ELISA could complement IHC in identifying patients with whom an anti-STn-based strategy might be more effective.

BRAF mutation is associated with early stage disease and improved outcome in patients with low-grade serous ovarian cancer.

BACKGROUND: Low-grade serous (LGS) ovarian cancer is a chemoresistant disease that accounts for 10% of serous ovarian cancers. Prior studies have reported that 28% to 35% of serous borderline (SB)/LGS ovarian tumors harbor a BRAF mutation, suggesting that BRAF inhibitors may be a rational therapeutic approach for this disease. In the current study, the authors sought to determine whether BRAF or KRAS mutation status was associated with disease stage and/or histology in patients with SB and LGS ovarian cancer. METHODS: Genetic profiles were constructed for 75 SB and LGS ovarian tumors to determine BRAF and KRAS mutation status. The incidence and identity of BRAF and KRAS mutations were defined, and the results were correlated with disease stage, response to treatment, and overall survival. RESULTS: Of 75 samples examined, 56 tumors (75%) had SB histology, and 19 tumors (25%) had LGS histology. Fifty-seven percent of tumors harbored either a KRAS mutation (n = 17) or a BRAF mutation (a valine-to-glutamate substitution at residue 600 [V600E]; n = 26). The BRAF V600E mutation was associated significantly with early disease stage (stage I/II; P < .001) and SB histology (P = .002). KRAS mutations were not associated significantly with disease stage or histology. Of the 22 patients (29%) who required chemotherapy, 20 had tumors with wild-type KRAS/BRAF, 2 had KRAS mutant tumors, and none had tumors that harbored a BRAF mutation. All patients with BRAF tumors remained alive at a median follow-up of 3.6 years (range, 1.9-129.3 months). CONCLUSIONS: V600E BRAF mutations were present in 35% of patients who had SB/LGS ovarian cancers. The presence of the BRAF V600E mutation in SB/LGS ovarian cancer was associated with early stage disease and improved prognosis. The authors concluded that patients with SB/LGS ovarian cancer who require systemic therapy are unlikely to have BRAF mutant tumors.

Improved survival for BRCA2-associated serous ovarian cancer compared with both BRCA-negative and BRCA1-associated serous ovarian cancer.

BACKGROUND: Multiple observational studies have suggested that breast cancer gene (BRCA)-associated ovarian cancers have improved survival compared with BRCA-negative ovarian cancers. However, most of those studies combined BRCA1 and BRCA2 patients or evaluated only BRCA1 patients. The objective of the current study was to examine whether BRCA1-associated and BRCA2-associated ovarian cancers were associated with different outcomes. METHODS: This was a single-institution, retrospective analysis of patients who had a new diagnosis of histologically confirmed stage III or IV serous ovarian, fallopian tube, or primary peritoneal cancer between January 1, 1996 and February 1, 2011 and who underwent BRCA mutation testing on 1 of 2 institutional review board-approved follow-up studies. Patients who had been tested for BRCA mutations beyond 24 months of diagnosis were excluded from analysis to minimize selection bias from including patients who were referred for genetic testing because of long survival. RESULTS: Data from 190 patients (143 BRCA-negative patients, 30 BRCA1-positive patients, and 17 BRCA2-positive patients) were analyzed. During the study period, 73 deaths were observed (60 BRCA-negative patients, 10 BRCA1-positive patients, 3 BRCA2-positive patients). The median follow-up for the remaining 117 survivors was 2.5 years. At 3 years, 69.4%, 90.7%, and 100% of BRCA-negative patients, BRCA1-positive patients, and BRCA2-positive patients were alive, respectively. On univariate analysis, age, BRCA2 mutations, debulking status, and type of first-line therapy (intravenous or intraperitoneal) were significant predictors of overall survival. On multivariate analysis, BRCA2 mutations (hazard ratio, 0.20; 95% confidence interval, 0.06-0.65; P = .007), but not BRCA1 mutations (hazard ratio, 0.70; 95% confidence interval, 0.36-1.38; P = .31), predicted for improved overall survival compared with BRCA-negative patients. When carriers of BRCA2 mutations were directly compared with carriers of BRCA1 mutations, BRCA2 mutations appeared to confer improved overall survival (hazard ratio, 0.29; 95% confidence interval, 0.08-1.05; P = .060), although this finding did not reach significance. CONCLUSIONS: The current data suggests that BRCA2 mutations confer an overall survival advantage compared with either being BRCA-negative or having a BRCA1 mutation in high-grade serous ovarian cancer. This finding may have important implications for clinical trial design.

Morphologic patterns associated with BRCA1 and BRCA2 genotype in ovarian carcinoma.

This study was undertaken with the hypothesis that certain common morphologic features of ovarian carcinomas are predictably associated with BRCA1 and BRCA2 deficiencies. We selected 43 high-grade serous carcinomas diagnosed at Memorial Sloan-Kettering Cancer Center that were studied as part of The Cancer Genome Atlas pilot project. In addition to 12 randomly selected nonfamilial BRCA-unassociated cases, all 31 Memorial Sloan-Kettering Cancer Center cases with BRCA1 or BRCA2 abnormality were included (n=43). Slides were examined to assess tumor architecture, mitotic index, tumor-infiltrating lymphocytes (TILs), nuclear pleomorphism, necrosis, and involvement of fallopian tube epithelium. Comparing BRCA1-associated cases (BRCA1 germline mutation, n=4, BRCA1 somatic mutation, n=6, BRCA1 promoter methylation, n=13) with unassociated cases (n=12) identified statistically significant differences in morphology. BRCA1-associated high-grade serous carcinomas had more frequent Solid, pseudoEndometrioid, and Transitional cell carcinoma-like morphology (SET features) (P=0.0045), higher mitotic indexes (P=0.012), more TILs (P=0.034), and either geographic or comedo necrosis (P=0.034). BRCA2-associated cases (germline mutation, n=4 and somatic mutation, n=4) tended to show SET features, but they were relatively deficient in TILs and necrosis. Two algorithms incorporating tumor architecture, necrosis, and either mitotic indexes or TILs separated cases that showed 2 of 3 features (BRCA1 associated) from those with 0 of 3 features (BRCA unassociated; P=0.0016 and P=0.0033). A test set comprising 9 BRCA1 germline mutants and 14 high-grade serous carcinoma controls lacking BRCA1 and BRCA2 germline mutation was used to validate the algorithms, with specific emphasis on the ability to detect cases with BRCA1 germline mutation. Best results were obtained with the algorithm that incorporated SET features, necrosis, and mitotic index (P=0.0072; sensitivity of 1.0 (95% CI, 0.66-1.0); specificity of 0.57 (95% CI, 0.29-0.82); positive predictive value of 0.60 (95% CI, 0.32-0.84) and a negative predictive value of 1.0 (95% CI, 0.63-1.0)). These preliminary data indicate potential strong associations between morphology and genotype in high-grade serous carcinomas.

A phase I study of subcutaneously administered aflibercept (VEGF trap) in a new formulation in patients with advanced solid tumors.

Targeting angiogenesis is a valid anti-cancer strategy. Aflibercept is designed to sequester circulating vascular endothelial growth factor (VEGF) by preventing VEGF from binding to its receptors. This phase I study was to evaluate a new formulation of subcutaneously administered aflibercept in patients with advanced solid tumors. Here we report our experience with the toxicity, pharmacokinetic profile and efficacy of the new 100 mg/mL subcutaneous (SC) formulation of aflibercept administered at a dose of at 4 mg/kg every 2 weeks.