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Purpose: Metastatic triple-negative breast cancer (TNBC) is a phenotypic breast cancer subgroup with a very poor prognosis, despite standard treatments. Combined twice-weekly iniparib and gemcitabine/carboplatin (GC+tw-iniparib) showed benefit over gemcitabine/carboplatin in a randomized phase II trial, and a phase III was initiated comparing these regimens. The present phase II study was initiated to compare GC+tw-iniparib with a more practical once-weekly schedule (GC+w-iniparib) in TNBC. Methods: Metastatic TNBC patients were randomized to receive iniparib weekly (11.2 mg/kg on days 1 and 8) or twice-weekly (5.6 mg/kg on days 1, 4, 8, and 11) with gemcitabine (1000 mg/m2) and carboplatin (area under the curve 2 on days 1 and 8), every 3 weeks. The primary endpoint was the overall response rate (ORR). Pharmacokinetics of iniparib and its two metabolites were analyzed. Results: A total of 163 patients were randomized, 82 GC+w-iniparib and 81 GC+tw-iniparib. Demographic and baseline characteristics were well balanced. ORR was 34.1% (95% CI 23.9–44.4%) vs. 29.6% (95% CI 19.7–39.6%) and median progression-free survival was 5.5 months (95% CI 4.2–5.7) vs. 4.3 months (95% CI 3.0–5.8) for GC+w-iniparib and GC+tw-iniparib, respectively. Safety was similar across treatment arms in terms of event severity and type. Iniparib plasma concentrations and exposure were two-fold higher with w-iniparib compared to tw-iniparib. Iniparib and its metabolites were cleared rapidly with a terminal half-life of < 1 h, without accumulation. Conclusions: Despite a doubled maximum concentration with weekly iniparib, no detectable differences in safety or efficacy were observed between the weekly and twice-weekly administration schedules in this population. Trial registration: ClinicalTrial.gov Identifier NCT01045304. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to evaluate the activity and tolerability of iniparib monotherapy in women with BRCA1 or BRCA2-associated advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer. Methods and Materials: Eligible patients had advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer, germline BRCA1 or BRCA2 mutation, measurable disease, and at least 1 previous treatment regimen of platinum/taxane chemotherapy. Patients received iniparib 8 mg/kg intravenously on days 1 and 4 weekly, with imaging every 8 weeks. Treatment continued until disease progression or adverse events (AEs) prohibited further therapy. Common Terminology Criteria for AEs v3.0 was used to grade AEs. The primary endpoint was tumor response. The study was conducted with a Simon 2-stage designwith 12 and 23 patients planned in the first and second stage, respectively. The study was designed to distinguish between 10% and 30% responding with types 1 and 2 error of 0.10. Results: Twelve patients were treated on study, with median exposure to iniparib of 7.5 weeks. The median number of previous chemotherapeutic regimens was 7. Treatmentrelated AEs (Q10%) included asthenia (83.3%), constipation (25%), diarrhea (25%), nausea (25%), abdominal pain (16.7%), and decreased hemoglobin (16.7%). All treatmentrelated AEs were grades 1 or 2 with the following 2 exceptions: 1 grade 3 diarrhea and 1 grade 3 hypertension. One patient had stable disease lasting 2 cycles; the remaining 11 patients had progressive disease. The study did not proceed to second stage enrollment. Conclusions: Iniparib did not show significant activity in this heavily pretreated ovarian cancer population, all of whom had BRCA1 or BRCA2 mutations. [ABSTRACT FROM AUTHOR]

Iniparib is an investigational agent with antitumor activity of controversial mechanism of action. Two previous trials in advanced triple-negative breast cancer (TNBC) in combination with gemcitabine and carboplatin showed some evidence of efficacy that was not confirmed. This phase II randomized neoadjuvant study was designed to explore its activity and tolerability with weekly paclitaxel (PTX) as neoadjuvant treatment in TNBC patients. 141 patients with Stage II-IIIA TNBC were randomly assigned to receive PTX (80 mg/m, d1; n = 47) alone or in combination with iniparib, either once-weekly (PWI) (11.2 mg/kg, d1; n = 46) or twice-weekly (PTI) (5.6 mg/kg, d1, 4; n = 48) for 12 weeks. Primary endpoint was pathologic complete response (pCR) in the breast. pCR rate was similar among the three arms (21, 22, and 19 % for PTX, PWI, and PTI, respectively). Secondary efficacy endpoints were comparable: pCR in breast and axilla (21, 17, and 19 %); best overall response in the breast (60, 61, and 63 %); and breast conservation rate (53, 54, and 50 %). Slightly more patients in the PTI arm presented grade 3/4 neutropenia (4, 0, and 10 %). Grade 1/2 (28, 22, and 29 %), but no grade 3/4 neuropathy, was observed. There were no differences in serious adverse events and treatment-emergent adverse events leading to treatment discontinuation among the three arms. Addition of iniparib to weekly PTX did not add relevant antitumor activity or toxicity. These results do not support further evaluation of the combination of iniparib at these doses plus paclitaxel in early TNBC. [ABSTRACT FROM AUTHOR]

Addition of iniparib to gemcitabine/cisplatin in a randomized phase II trial in metastatic NSCLC patients gave a comparable safety profile to gemcitabine/cisplatin alone, but did not improve the overall response rate. Marginal trends towards a survival benefit were seen with gemcitabine/cisplatin/iniparib. Imbalances in performance status and gender distribution may have impacted PFS and OS.Background Iniparib is a novel anticancer agent initially considered a poly (ADP-ribose) polymerase (PARP) inhibitor, but subsequently shown to act via non-selective protein modification through cysteine adducts. This randomized phase II study investigated the addition of iniparib to gemcitabine–cisplatin in metastatic non-small-cell lung cancer (NSCLC) patients. Patients and methods Patients with histologically confirmed stage IV NSCLC were randomized 2 : 1 to receive gemcitabine (1250 mg/m2, days 1/8) and cisplatin (75 mg/m2, day 1) with [gemcitabine/cisplatin/iniparib (GCI)] or without [gemcitabine/cisplatin (GC)] iniparib (5.6 mg/kg, days 1/4/8/11) every 3 weeks for six cycles. The primary end point was the overall response rate (ORR). Secondary objectives included progression-free survival (PFS), overall survival (OS), and safety. The study was not designed for formal efficacy comparison, the control arm being to benchmark results against the literature. Results One hundred and nineteen patients were randomized (39 GC and 80 GCI). More GCI patients were male (80% GCI and 67% GC) and had PS 0 (61% GCI and 49% GC). The ORR was 25.6% [95% confidence interval (CI) 13.0%–42.1%] with GC versus 20.0% (95% CI 11.9%–30.4%) with GCI, which did not allow rejection of the null hypothesis (ORR with GCI ≤20%; P = 0.545). Median PFS was 4.3 (95% CI 2.8–5.6) months with GC and 5.7 (95% CI 4.6–6.6) months with GCI (hazard ratio 0.89, 95% CI 0.56–1.40). Median OS was 8.5 (95% CI 5.5 to not reached) months with GC, and 12.0 (95% CI 8.9–17.1) months with GCI (hazard ratio 0.78, 95% CI 0.48–1.27). More GCI patients received second-line treatment (51% GC and 68% GCI). Toxicity was similar in the two arms. Grade 3–4 toxicities included asthenia (28% GC and 8% GCI), nausea (3% GC and 14% GCI), and decreased appetite (10% in each). Conclusions Addition of iniparib to GC did not improve ORR over GC alone. The GCI safety profile was comparable to GC alone. Imbalances in PS and gender distribution may have impacted study results regarding PFS and OS. Trial Registration ClinicalTrial.gov Identifier NCT01086254. [ABSTRACT FROM PUBLISHER]

Nearly half of patients with advanced triple negative breast cancer (TNBC) develop brain metastases (BM) and most will also have uncontrolled extracranial disease. This study evaluated the safety and efficacy of iniparib, a small molecule anti-cancer agent that alters reactive oxygen species tumor metabolism and penetrates the blood brain barrier, with the topoisomerase I inhibitor irinotecan in patients with TNBC-BM. Eligible patients had TNBC with new or progressive BM and received irinotecan and iniparib every 3 weeks. Time to progression (TTP) was the primary end point; secondary endpoints were response rate (RR), clinical benefit rate (CBR), overall survival (OS), toxicity, and health-related quality of life. Correlative endpoints included molecular subtyping and gene expression studies on pre-treatment archival tissues, and determination of germline BRCA1/2 status. Thirty-seven patients began treatment; 34 were evaluable for efficacy. Five of 24 patients were known to carry a BRCA germline mutation (4 BRCA1, 1 BRCA2). Median TTP was 2.14 months and median OS was 7.8 months. Intracranial RR was 12 %, while intracranial CBR was 27 %. Treatment was well-tolerated; the most common grade 3/4 adverse events were neutropenia and fatigue. Grade 3/4 diarrhea was rare (3 %). Intrinsic subtyping revealed 19 of 21 tumors (79 %) were basal-like, and intracranial response was associated with high expression of proliferation-related genes. This study suggests a modest benefit of irinotecan plus iniparib in progressive TNBC-BM. More importantly, this trial design is feasible and lays the foundation for additional studies for this treatment-refractory disease. [ABSTRACT FROM AUTHOR]

Background Mutations in the DNA damage response (DDR) factors, breast cancer 1 (BRCA1) and BRCA2, sensitize tumor cells to poly(ADP-ribose) polymerase (PARP) inhibitors. The ataxia telangiectasia mutated (ATM) kinase is a key DDR protein whose heterozygous germline mutation is a moderate-risk factor for developing breast cancer. In this study, we examined whether ATM inactivation in breast cancer cell lines confers sensitivity to PARP inhibitors. Methods Wild-type BRCA1/2 breast cancer cells (i.e., MCF-7 and ZR-75-1 lines) were genetically manipulated to downregulate ATM expression then assayed for cytostaticity/cytotoxicity upon treatment with PARP inhibitors, olaparib and iniparib. Results When ATM-depleted cells and their relative controls were treated with olaparib (a competitive PARP-1/2 inhibitor) and iniparib (a molecule originally described as a covalent PARP-1 inhibitor) a different response to the two compounds was observed. ATM-depletion sensitized both MCF-7 and ZR-75-1 cells to olaparib-treatment, as assessed by short and long survival assays and cell cycle profiles. In contrast, iniparib induced only a mild, ATMdependent cytostatic effect in MCF-7 cells whereas ZR-75-1 cells were sensitive to this drug, independently of ATM inactivation. These latest results might be explained by recent observations indicating that iniparib acts with mechanisms other than PARP inhibition. Conclusions These data indicate that ATM-depletion can sensitize breast cancer cells to PARP inhibition, suggesting a potential in the treatment of breast cancers low in ATM protein expression/activity, such as those arising in mutant ATM heterozygous carriers. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To estimate the activity and tolerability of iniparib plus paclitaxel and carboplatin as initial therapy of uterine carcinosarcoma. Methods: Eligible patients had advanced, persistent or recurrent carcinosarcoma of the uterus, measurable disease and no prior chemotherapy. Patients received paclitaxel 175mg/m2 IV over 3h followed by carboplatin area under the curve (AUC)=six over 30min on day one of 21day cycles plus iniparib 4mg/kg IV over 1h twice weekly beginning on day one. Treatment continued until disease progression or adverse effects prohibited further therapy. Common Terminology Criteria for Adverse Events (CTCAE) v3.0 was used to grade adverse events. The primary endpoint was tumor response. The study was conducted with a 2-stage group sequential design, targeting 20 and 25 patients in each stage. The study was designed to distinguish between 45% versus 65% responding with alpha=10% and 90% power. Results: Twenty-two patients were entered onto the study with five excluded from analysis, leaving 17 evaluable for analysis. Treatment resulted in the expected hematologic and non-hematologic toxicities of the paclitaxel–carboplatin backbone. The observed proportion responding was 23.5% (4/17 patients). The two-sided, 90% confidence interval for the true probability of response was 8.5–46.1%. The required minimal number of responses to proceed to second stage was eight. Conclusions: Iniparib plus paclitaxel and carboplatin did not show significant activity to warrant further study. The rate of exclusion upon central pathology review (23%) suggests that review of pathology slides for confirmation of eligibility is important in this tumor type. [Copyright &y& Elsevier]

Introduction: Poly (ADP-ribose) polymerase inhibitors (PARPi) are already part of the armamentarium of drugs available against ovarian and breast cancer. There is less data available on the efficacy of these drugs in the treatment of non-small cell lung cancer (NSCLC)., Areas Covered: The authors have analyzed the preclinical studies that justified the use of PARPi in NSCLC. They then evaluate the in vivo efficacy of the combination of these drugs with chemotherapy, radiotherapy, and immunotherapy., Expert Opinion: Data from clinical trials available to date have discouraged the use of PARPi in association with chemotherapy or radiotherapy in NSCLC. The knowledge available to date opens the door to the use of PARPi in association with immunotherapy. In fact, the activity of these drugs would not be based only on direct cytotoxic action, but also on the modification of the intra-tumor microenvironment, in particular by increasing the expression of PD-L1 on tumor cells. This action might potentially enhance available treatments with a modest increase in toxicity.

Introduction: Attrition in clinical development is widely recognised as a key factor negatively impacting overall R&D efficiency. Gaining an understanding of the reasons for candidate failure may lead to improvements in success rates and return on R&D investment. Areas covered: This report provides an analysis of reasons for discontinuation of development of 40 drugs dropped from the global oncology pipeline in 2013 - the largest number of terminations reported since this annual analysis began in 2005. The article also provides discussion on the observations in the context of contemporary views of anticancer drug development. Expert opinion: Twelve drugs (30% of the 2013 discontinuations) failed in Phase III development. None of the pivotal trials investigating these agents incorporated molecular biomarkers for patient stratification. The largest number of drug terminations (20 out of 40) occurred in Phase I development with reasons for termination commonly reported as strategic or undisclosed. Raising the bar in terms of requirements for progression from preclinical development, including the identification of robust pharmacodynamic biomarkers and biomarkers potentially predictive of clinical benefit may lead to an increase in success rates in clinical development and of overall R&D efficiency.