Haluska, Paul

Abstract Purpose: Tigatuzumab (TIG), an agonistic anti-DR5 antibody, triggers apoptosis in DR5+ human tumor cells without crosslinking. TIG has strong in vitro/in vivo activity against basal-like breast cancer cells enhanced by chemotherapy agents. This study evaluates activity of TIG and chemotherapy in patients with metastatic triple-negative breast cancer (TNBC). Experimental Design: Randomized 2:1 phase II trial of albumin-bound paclitaxel (nab-PAC) ± TIG in patients with TNBC stratified by prior chemotherapy. Patients received nab-PAC weekly × 3 ± TIG every other week, every 28 days. Primary objective was within-arm objective response rate (ORR). Secondary objectives were safety, progression-free survival (PFS), clinical benefit, and TIG immunogenicity. Metastatic research biopsies were required. Results: Among 64 patients (60 treated; TIG/nab-PAC n = 39 and nab-PAC n = 21), there were 3 complete remissions (CR), 8 partial remissions (PR; 1 almost CR), 11 stable diseases (SD), and 17 progressive diseases (PD) in the TIG/nab-PAC arm (ORR, 28%), and no CRs, 8 PRs, 4 SDs, and 9 PDs in the nab-PAC arm (ORR, 38%). There was a numerical increase in CRs and several patients had prolonged PFS (1,025+, 781, 672, 460, 334) in the TIG/nab-PAC arm. Grade 3 toxicities were 28% and 29%, respectively, with no grade 4–5. Exploratory analysis suggests an association of ROCK1 gene pathway activation with efficacy in the TIG/nab-PAC arm. Conclusions: ORR and PFS were similar in both. Preclinical activity of TIG in basal-like breast cancer and prolonged PFS in few patients in the combination arm support further investigation of anti-DR5 agents. ROCK pathway activation merits further evaluation. Clin Cancer Res; 21(12); 2722–9. ©2015 AACR. See related article by Paoletti et al., p. 2771

AbstractThe many improvements in breast cancer therapy in recent years have so lowered rates of recurrence that it is now difficult or impossible to conduct adequately powered adjuvant clinical trials. Given the many new drugs and potential synergistic combinations, the neoadjuvant approach has been used to test benefit of drug combinations in clinical trials of primary breast cancer. A recent FDA-led meta-analysis showed that pathologic complete response (pCR) predicts disease-free survival (DFS) within patients who have specific breast cancer subtypes. This meta-analysis motivated the FDA's draft guidance for using pCR as a surrogate endpoint in accelerated drug approval. Using pCR as a registration endpoint was challenged at ASCO 2014 Annual Meeting with the presentation of ALTTO, an adjuvant trial in HER2-positive breast cancer that showed a nonsignificant reduction in DFS hazard rate for adding lapatinib, a HER-family tyrosine kinase inhibitor, to trastuzumab and chemotherapy. This conclusion seemed to be inconsistent with the results of NeoALTTO, a neoadjuvant trial that found a statistical improvement in pCR rate for the identical lapatinib-containing regimen. We address differences in the two trials that may account for discordant conclusions. However, we use the FDA meta-analysis to show that there is no discordance at all between the observed pCR difference in NeoALTTO and the observed HR in ALTTO. This underscores the importance of appropriately modeling the two endpoints when designing clinical trials. The I-SPY 2/3 neoadjuvant trials exemplify this approach. Clin Cancer Res; 21(13); 2911–5. ©2015 AACR.

Abstract The majority of ovarian cancer patients acquire resistance to standard platinum chemotherapy and novel therapies to reduce tumor burden and ascites accumulation are needed. Pregnancy-associated plasma protein-A (PAPP-A) plays a key role in promoting insulin-like growth factor (IGF) pathway activity, which directly correlates to ovarian cancer cell transformation, growth, and invasiveness. Herein, we evaluate PAPP-A expression in tumors and ascites of women with ovarian cancer, and determine the antitumor efficacy of a neutralizing monoclonal PAPP-A antibody (mAb-PA) in ovarian cancer using primary patient ovarian tumorgrafts (“Ovatars”). PAPP-A mRNA expression in patient ovarian tumors correlated with poor outcome and was validated as a prognostic surrogate in Ovatar tumors. Following confirmation of mAb-PA bioavailability and target efficacy in vivo, the antitumor efficacy of mAb-PA in multiple Ovatar tumor models was examined and the response was found to depend on PAPP-A expression. Strikingly, the addition of mAb-PA to standard platinum chemotherapy effectively sensitized platinum-resistant Ovatar tumors. PAPP-A protein in ascites was also assessed in a large cohort of patients and very high levels were evident across the entire sample set. Therefore, we evaluated targeted PAPP-A inhibition as a novel approach to managing ovarian ascites, and found that mAb-PA inhibited the development, attenuated the progression, and induced the regression of Ovatar ascites. Together, these data indicate PAPP-A as a potential palliative and adjunct therapeutic target for women with ovarian cancer. Mol Cancer Ther; 14(4); 973–81. ©2015 AACR.

Abstract Edmonston vaccine strains of measles virus (MV) have significant antitumor activity in mouse xenograft models of ovarian cancer. MV engineered to express the sodium iodide symporter gene (MV-NIS) facilitates localization of viral gene expression and offers a tool for tumor radiovirotherapy. Here, we report results from a clinical evaluation of MV-NIS in patients with taxol- and platinum-resistant ovarian cancer. MV-NIS was given intraperitoneally every 4 weeks for up to 6 cycles. Treatment was well tolerated and associated with promising median overall survival in these patients with heavily pretreated ovarian cancer; no dose-limiting toxicity was observed in 16 patients treated at high-dose levels (108–109 TCID50), and their median overall survival of 26.5 months compared favorably with other contemporary series. MV receptor CD46 and nectin-4 expression was confirmed by immunohistochemistry in patient tumors. Sodium iodide symporter expression in patient tumors after treatment was confirmed in three patients by 123I uptake on SPECT/CTs and was associated with long progression-free survival. Immune monitoring posttreatment showed an increase in effector T cells recognizing the tumor antigens IGFBP2 and FRα, indicating that MV-NIS treatment triggered cellular immunity against the patients' tumor and suggesting that an immune mechanism mediating the observed antitumor effect. Our findings support further clinical evaluation of MV-NIS as an effective immunovirotherapy. Cancer Res; 75(1); 22–30. ©2014 AACR.

Abstract Ovarian cancer is the fifth leading cause of cancer death among women in the United States. Despite advances in treatment for other cancers, ovarian cancer patient prognosis has not improved significantly since the advent of platinum-based chemotherapy. It is a highly heterogeneous disease with at least four distinct histological subtypes: serous, mucinous, endometrioid, and clear cell. However, no subtype- or biomarker-specific therapies are approved for ovarian cancer. Identifying targeted therapies is crucial to improving clinical outcomes. Specific therapies will likely vary based on tumor histology and biomarkers. Expression of estrogen receptor alpha (ER) is a well established biomarker of response to endocrine therapies in breast cancer. Despite the success of anti-estrogen therapies in treating breast cancer, little attention has been given to their potential in ovarian cancer. However, epidemiologic studies show that approximately 70% of epithelial ovarian tumors express ER, particularly serous and endometrioid subtypes, and that estrogen plays a role in ovarian cancer etiology. Further, clinical data suggest that a subset of ovarian cancer patients can be successfully treated with endocrine therapy. We hypothesize that some ovarian tumors require estrogen for growth and that predictive biomarkers will identify patients who will benefit from endocrine therapy. Using cell line models, we examined the response of ovarian cancer cells to estrogen (E2) and anti-estrogens with regard to gene expression and cell proliferation. E2 induces expression of canonical ER target genes (e.g. GREB1) in these cells, suggesting that they are estrogen-responsive. We observe that 4-hydroxytamoxifen and fulvestrant inhibit growth of ovarian cancer cells including the chemo-resistant line PEO4. Gene expression microarray studies identified additional E2-regulated genes in ovarian cancer cells that may be utilized as biomarkers of ER activity. We are expanding our studies to in vivo models (human primary tumor xenografts) to evaluate the role of E2 in driving tumor progression and determine the efficacy of anti-estrogens in treating serous ovarian cancer. There is a critical need for targeted therapies in ovarian cancer. Our studies will determine if endocrine responsiveness correlates with gene expression of specific biomarkers, which may lead to the identification of predictive clinical markers of response to endocrine therapy. Citation Format: Courtney L. Andersen, Matthew J. Sikora, Paul Haluska, Steffi Oesterreich. Identifying biomarkers of estrogen response in models of serous ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 94. doi:10.1158/1538-7445.AM2013-94

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.

Abstract Purpose: This phase I, multicenter, open-label, single-arm, dose-escalation, and dose-expansion study evaluated the safety, tolerability, and antitumor activity of MEDI-573 in adults with advanced solid tumors refractory to standard therapy or for which no standard therapy exists. Experimental Design: Patients received MEDI-573 in 1 of 5 cohorts (0.5, 1.5, 5, 10, or 15 mg/kg) dosed weekly or 1 of 2 cohorts (30 or 45 mg/kg) dosed every 3 weeks. Primary end points included the MEDI-573 safety profile, maximum tolerated dose (MTD), and optimal biologic dose (OBD). Secondary end points included MEDI-573 pharmacokinetics (PK), pharmacodynamics, immunogenicity, and antitumor activity. Results: In total, 43 patients (20 with urothelial cancer) received MEDI-573. No dose-limiting toxicities were identified, and only 1 patient experienced hyperglycemia related to treatment. Elevations in levels of insulin and/or growth hormone were not observed. Adverse events observed in >10% of patients included fatigue, anorexia, nausea, diarrhea, and anemia. PK evaluation demonstrated that levels of MEDI-573 increased with dose at all dose levels tested. At doses >5 mg/kg, circulating levels of insulin-like growth factor (IGF)-I and IGFII were fully suppressed. Of 39 patients evaluable for response, none experienced partial or complete response and 13 had stable disease as best response. Conclusions: The MTD of MEDI-573 was not reached. The OBD was 5 mg/kg weekly or 30 or 45 mg/kg every 3 weeks. MEDI-573 showed preliminary antitumor activity in a heavily pretreated population and had a favorable tolerability profile, with no notable perturbations in metabolic homeostasis. Clin Cancer Res; 20(18); 4747–57. ©2014 AACR.

In the era of targeted therapies, patients with gynecologic malignancies have not yet been major beneficiaries of this new class of agents. This may reflect the fact that the main tumor types—ovarian, uterine, and cervical—are a highly heterogeneous group of cancers with variable response to standard chemotherapies and the lack of models in which to study the diversity of these cancers. Cancer-derived cell lines fail to adequately recapitulate molecular hallmarks of specific cancer subsets and complex microenvironments, which may be critical for sensitivity to targeted therapies. Patient-derived xenografts (PDX) generated from fresh human tumor without prior in vitro culture, combined with whole genome expression, gene copy number, and sequencing analyses, could dramatically aid the development of novel therapies for gynecologic malignancies. Gynecologic tumors can be engrafted in immunodeficient mice with a high rate of success and within a reasonable time frame. The resulting PDX accurately recapitulates the patient's tumor with respect to histologic, molecular, and in vivo treatment response characteristics. Orthotopic PDX develop complications relevant to the clinic, such as ascites and bowel obstruction, providing opportunities to understand the biology of these clinical problems. Thus, PDX have great promise for improved understanding of gynecologic malignancies, serve as better models for designing novel therapies and clinical trials, and could underpin individualized, directed therapy for patients from whom such models have been established.

BACKGROUNDChemotherapy‐induced peripheral neuropathy (CIPN) is a significant side effect of taxane and platinum‐based chemotherapy. Several studies have supported the potential benefit of glutathione for the prevention of platinum‐induced CIPN. The current trial was designed to determine whether glutathione would prevent CIPN as a result of carboplatin/paclitaxel therapy.METHODSIn total, 185 patients who received treatment with paclitaxel and carboplatin were accrued between December 4, 2009 and December 19, 2011. Patients were randomized to receive either placebo (n = 91) or 1.5 g/m2 glutathione (n = 94) over 15 minutes immediately before chemotherapy. CIPN was assessed using the European Organization for Research and Treatment of Cancer Quality‐of‐Life (EORTC‐QLQ) 20‐item, CIPN‐specific (CIPN20) sensory subscale and the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE), version 4.0.RESULTSThere were no statistically significant differences between the 2 study arms with regard to: 1) peripheral neurotoxicity, as assessed using both the EORTC‐QLQ‐CIPN20 (P = .21) and the CTCAE scales (P = .449 for grade ≥2 neurotoxicity; P = .039 for time to development of grade ≥2 neuropathy, in favor of the placebo); 2) the degree of paclitaxel acute pain syndrome (P = .30 for patients who received paclitaxel every 3‐4 weeks and P = .002, in favor of the placebo, for patients who received weekly paclitaxel); 3) the time to disease progression (P = .63); or 4) apparent toxicities. Subgroup analyses did not reveal any evidence of benefit in any particular subgroup.CONCLUSIONSThe results from this study do not support the use of glutathione for the prevention of paclitaxel/carboplatin‐induced CIPN. Cancer 2014;120:1890–1897. © 2014 American Cancer Society.

Abstract Purpose: Ovarian cancer has a high recurrence and mortality rate. A barrier to improved outcomes includes a lack of accurate models for preclinical testing of novel therapeutics. Experimental Design: Clinically relevant, patient-derived tumorgraft models were generated from sequential patients and the first 168 engrafted models are described. Fresh ovarian, primary peritoneal, and fallopian tube carcinomas were collected at the time of debulking surgery and injected intraperitoneally into severe combined immunodeficient mice. Results: Tumorgrafts demonstrated a 74% engraftment rate with microscopic fidelity of primary tumor characteristics. Low-passage tumorgrafts also showed comparable genomic aberrations with the corresponding primary tumor and exhibit gene set enrichment of multiple ovarian cancer molecular subtypes, similar to patient tumors. Importantly, each of these tumorgraft models is annotated with clinical data and for those that have been tested, response to platinum chemotherapy correlates with the source patient. Conclusions: Presented herein is the largest known living tumor bank of patient-derived, ovarian tumorgraft models that can be applied to the development of personalized cancer treatment. Clin Cancer Res; 20(5); 1288–97. ©2014 AACR.