Hilli, M. Al

Abstract Purpose: The therapeutic potential of PARP inhibitors is predicted to extend beyond BRCA mutant phenotypes to homologous recombination (HR)-deficient cancers. Response of individual ovarian cancers to niraparib was characterized using treatment naïve, patient-derived tumorgraft models and correlated with predicted HR status and gene expression profile. Methods: Utilizing a living tumor bank of patient-derived ovarian xenografts (PDXs), niraparib (MK-4827) was evaluated in five high-grade ovarian cancer tumorgrafts (PDX077, PDX087, PDX039, PDX080 and PDX95) as monotherapy, combination with carboplatin ± paclitaxel and maintenance therapy. Intraperitoneal tumorgrafts were monitored for tumor growth with twice-weekly transabdominal ultrasound imaging. In vivo response to niraparib was correlated to massively parallel sequencing data (BROCA) for HR genes and with each source patient's platinum response. Tumorgrafts were accordingly classified into predicted HR-proficient and HR-deficient phenotypes. PARP1 and poly(ADP-ribose) polymer (pADPr) expression as well as gene expression by DNA microarray were compared between treatment and control tumor replicates, and HR-deficient vs. HR-proficient tumors. Results: PDX077 (verified to harbor a somatic BRCA2 mutation (predicted HR deficient)) and PDX039 without any HR mutations detected by BROCA (predicted HR proficient) both responded to niraparib monotherapy and combination therapy in vivo (p=0.002 and 0.009 for treated vs. control groups, respectively). Significant growth attenuation, but not regression, in response to single agent treatment was demonstrated in PDX080 (CDK12 mutation; predicted HR-deficient; p=0.02 vs. control). In comparison, a BRCA2-mutant model (PDX095) failed to respond to niraparib monotherapy (p=0.97). As predicted, niraparib was not active as a single agent or in combination with chemotherapy in a BRCA wild-type, predicted HR-proficient tumorgraft (PDX087; p=not significant). Niraparib enhanced tumor regression with carboplatin but not with paclitaxel/carboplatin in an HR-deficient tumorgraft (PDX077), and maintenance niraparib therapy was effective in prolonging recurrence-free survival. pADPr inhibition was demonstrated in all niraparib-treated tumorgrafts, while PARP1 degrada-tion was evident in tumorgrafts responsive to single agent niraparib. Differential gene expression was seen in niraparib treated vs. control tumors in HR-deficient tumorgrafts in comparison to HR-proficient tumors at the end of 4 weeks of treatment. Clustering of 6 most/least differentially expressed genes was predictive of response to niraparib. Furthermore, RAD51C and PTEN gene expression were diminished in PDX039 (HR proficient by BROCA; niraparib responsive), suggesting a possible mechanism for its sensitivity to niraparib. Conclusion: Response to niraparib was seen in both BRCA-mutant and BRCA-wildtype xenografts. Thus, BRCA or HR gene mutational status alone was not sufficient to predict response to niraparib. Low RAD51C, PTEN and loss of PARP1 expression following treatment were most characteristic of tumors responding to niraparib. Paclitaxel may be detrimental to the sensitizing effects of PARP inhibition on carboplatin, which may have clinical implications for the incorporation of PARP inhibitors in front-line treatment. Our data are supportive of the phase III study of niraparib as maintenance therapy in patients with platinum-sensitive ovarian cancer. This abstract is also presented as Poster A30. Citation Format: Mariam Al Hilli, S. John Weroha, Marc Becker, Xiaonan Hou, Sean Harrington, Sarah McKinstrey, Kimberly Kalli, Karin Goodman, Keith Wilcoxen, Elizabeth Swisher, Scott Kaufmann, Paul Haluska. In vivo antitumor activity of the PARP inhibitor niraparib (MK-4827) in homologous recombination deficient and proficient ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr PR05.

Background Patient-reported signs and symptoms are often the first indication of clinically relevant lymphedema. Objective The purpose of this study was to develop and assess the diagnostic accuracy of a screening questionnaire to detect lower-extremity lymphedema (LEL) among normal-weight women and women with obesity. Design This was a cross-sectional survey study. Methods The authors reviewed existing questionnaires assessing upper-extremity lymphedema (UEL) for potential questions and worked with content experts to generate new items. A draft questionnaire with 59 items was reviewed by 5 physicians and 5 physical therapists who specialized in lymphedema management and 5 female patients with clinically confirmed secondary LEL. A revised questionnaire with 45 items was administered by mail to 186 women with clinically confirmed LEL (n=116) or UEL (n=70). A total of 99 women (53.2% of 186) completed the mailed survey, and 28 women with lymphedema who were recruited directly in a lymphedema clinic waiting area also completed the survey. A parsimonious subset of items that best discriminated patients with and without LEL was identified using chi-square tests and logistic regression. Sensitivity and specificity for detecting LEL and positive and negative likelihood ratios (LR+, LR−) were estimated for the entire sample and for subsamples defined by obesity (body mass index ≥30 versus <30 kg/m2), which may confound the accurate diagnosis of LEL. Results Questionnaires were completed by 127 women (LEL group, n=88; UEL group, n=39). A sum of 13 items (score range=0–52) was the most discriminating. Using a cutoff score of ≥5 points, the sensitivity and specificity for detecting LEL among all participants were 95.5% and 86.5%, respectively (LR+=7.1, LR−=0.05), and 94.8% and 76.5%, respectively (LR+=4.0, LR−=0.07), for participants who were obese. Limitations By enumerating a sample with a high prevalence of LEL, a spectrum bias may have been introduced, which may have affected the accuracy of the screening questionnaire. Conclusions The brief, 13-item self-report questionnaire is a sensitive and specific tool for detecting clinically relevant LEL among women, including those with a body mass index of ≥30 kg/m2.