Addition Of Olaparib Research Articles

Budget Impact Analysis of Olaparib in Combination with Bevacizumab for Maintenance Therapy for Ovarian Cancer in Argentina.

To perform a budget impact analysis (BIA) of introducing olaparib as maintenance therapy in women who have BRCA mutations (BRCAm) with platinum-sensitive recurrent ovarian cancer (PSROC) in combination with bevacizumab in Argentina. A BIA model was used to analyse over a 5-year time horizon the change in the health system's budget following the adoption of olaparib as maintenance therapy in BRCAm patients with PSROC. The BIA for each year was estimated by comparing the cost difference between the current scenario (treatment with bevacizumab) and the new scenario (the addition of olaparib) for a third-party payer. The BIA is estimated at the national health system level, and by healthcare sectors in Argentina (public sector, social security and private sector). International and national epidemiological data were used to determine the target patient population. Clinical efficacy, safety outcomes and duration of treatments were obtained from the pivotal clinical study report. Relevant direct medical costs were obtained from public data in Argentina and expert consultation. All the costs are reported in US dollars as of October 2022 ($1 = 152.59 Argentine pesos). A scenario analysis assessed the full coverage of the homologous recombination deficiency (HRD) test in Argentina. In addition, one-way sensitivity analysis was conducted to evaluate the model robustness. For a third-party payer with a cohort of 1,000,000 women covered, the estimated target population was 2 individuals in year 1 and 6 individuals in year 5. The incorporation of olaparib, with a wholesale price per pack of $3176.32, was associated with a weighted average of the budget impact per member per month (PMPM) of $0.062 for the national health system, being above the estimated health system budget impact threshold ($0.0153). By healthcare sector, the results of budget impact PMPM for year 5 ranged between $0.08 (public sector) and $0.114 (private sector). For all perspectives, the variables that most influenced the budget impact was the incidence of ovarian cancer, the drug acquisition cost and the treatment duration. The introduction of olaparib for the treatment of BRCAm women with PSROC has a high budget impact for all three health systems in Argentina.

Abstract 541: Establishment of Inotuzumab ozogamicin resistant leukemia cell lines; Focusing on p-gp and DNA damage repair for overcoming drug resistance

Abstract Introduction: Inotuzumab Ozogamicin (IO) is a humanized anti-CD22 monoclonal antibody conjugated with chalicheamicin, which causes single- and double-strand DNA breaks. Although IO shows a high CR/CRi rate in relapsed/refractory CD22-positive B-cell acute lymphoblastic leukemia (ALL), the duration of remission is short due to early acquisition of resistance. Therefore, the present study attempted to enhance the cytotoxicity of IO by focusing on polyadenosine diphosphate-ribose polymerase (PARP) inhibition. Furthermore, IO-resistant cell lines were newly established to investigate the mechanism of IO resistance. Methods: Reh cell line derived from Ph-negative B-ALL cells was used. To establish IO-resistant cell lines, Reh cells were long-term exposed to IO, followed by limiting dilution. FACS analysis evaluated the CD22 positivity and the induction of apoptosis. WTS assay determined the cell growth inhibition effects. The Comet assay quantitatively assessed DNA damage. Gene expression profiles were determined by using DNA microarray. Results: The 50%-inhibitory concentration (IC50) of IO was 2.1 ng/mL in Reh cells. Reh cells were synergistically sensitized to IO by the addition of non-toxic concentrations of PARP inhibitors, olaparib or talazoparib, with the Combination Index of 0.19 and 0.42, respectively. Moreover, these combinations augmented the induction of apoptosis (23.5% in IO alone, 51.7% in IO + olaparib, 66.1% in IO + talazoparib). The Comet assay demonstrated that DNA strand breaks observed 1h after IO administration were repaired 6h later. In the combination of IO with olaparib or talazoparib, DNA damage remained even at 6h, suggesting the inhibition of DNA repair by PARP inhibitors. Next, six IO-resistant cell lines were established with IC50 more than 60-fold that of parental cells. All these cell lines kept CD22 expression. These cell lines were also resistant to apoptosis induced by IO. In addition of olaparib or talazoparib to IO, the IC50 of IO decreased by 40% to 70% in 6 IO-resistant cells. These combinations also augmented the induction of apoptosis (24.2% in IO alone, 45.3% in IO+olaparib, and 56.8% in IO+talazoparib). DNA microarray was performed to compare gene expression profiles between parental and IO-resistant cell lines. ABCB1 (p-gp), a drug efflux pump that causes multi-drug resistance, was overexpressed in resistant cell lines. Moreover, the addition of p-gp inhibitor, PSC-833, to IO enhanced the cell growth inhibition and induction of apoptosis due to more DNA strand break. Conclusion: The present study demonstrated that the combination of IO with PARP inhibitors exerted synergistic cytotoxicity via the inhibition of DNA repair. In addition, it was suggested that overexpression of p-gp caused IO resistance, which was partially reversed with the combination of PARP inhibitors or a p-gp inhibitor. Citation Format: Naoko Ida, Miyuki Okura, Naoko Hosono, Takahiro Yamauchi. Establishment of Inotuzumab ozogamicin resistant leukemia cell lines; Focusing on p-gp and DNA damage repair for overcoming drug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 541.

Abstract A041: Development of novel in-vitro mixed-cell models to capture genomic heterogeneity in prostate tumors

Abstract Prostate cancer (PC), especially castration resistant PC (CRPC), is known to exhibit a high degree of intra- and inter-tumoral (inter-individual) heterogeneity, which have been linked to treatment resistance and disease recurrence. Yet, models employed for PC drug development so far have been derived from cell lines or individual (single) patients and screened independently without consideration of heterogeneity. We hypothesized that the inability to address this critical aspect of tumor biology, has in part led to translational failure in broader patient cohorts. Therefore, we created a number of mixture cell models where multiple PC cell lines, were labeled and co-cultured to capture genomic heterogeneity observed clinically in CRPC patients. Specifically, expression profiles of PC cell lines were clustered with patient-derived single-cell (intra-) or bulk RNA-seq datasets (inter-) to identify cell lines representative of heterogeneous PC tumors, based on their transcriptomic signatures. Cell lines assigned to distinct patient clusters were systematically selected and combined for the mixture model, to reflect the complex in-vivo genomic landscape. To apply these models to drug combination testing, we employed a computational approach to nominate efficacious combinations with Docetaxel (Doc), current Standard of Care. Our mixed-cell model created to recapitulate inter-patient diversity, successfully validated the efficacy of a novel combination of Doc with COL3 (Incyclinide), which is currently in Phase I trial for Refractory Metastatic Cancer. The combination was confirmed to be more potent than individual monotherapies over a range of concentrations. We further tested Doc +Olaparib (clinically approved for patients harboring BRCA mutations), a combination predicted to be inefficacious in the heterogeneous patient cohort as negative control. Indeed, addition of Olaparib did not improve on the inhibitory effect of Doc. To address intra-tumoral heterogeneity, we created a mixture of cell lines which were representative of distinct clonal fractions in single-cell patient datasets. In both models, it was evident that cell lines with similar molecular and phenotypic attributes (such as AR dependency) co-clustered, lending further credibility to our pipeline. We further explored intra-tumoral heterogeneity in the context of acquired phenotypes and advanced disease states, by mixing parent and Doce-resistant clones of DU145 and 22RV1. The binary mixtures were challenged with combinations of Doc and Rigosertib/Selumitinib, drugs that were predicted to selectively target the resistant clone. The combinations produced a higher tumor kill than either single agent drug. Additionally, we observed the effects of altering the relative proportion of constituent clones on drug response. Development of these preclinical models holds enormous promise not only for advancing combinatorial therapies for cancer, but also for providing valuable insights into the mechanisms of resistance and recurrence, by accurately modeling genomic heterogeneity in cancer. Citation Format: Sampreeti Jena, Daniel Kim, Adam M. Lee, Weijie Zhang, R. Stephanie Huang. Development of novel in-vitro mixed-cell models to capture genomic heterogeneity in prostate tumors [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr A041.

Olaparib enhances the Resveratrol-mediated apoptosis in breast cancer cells by inhibiting the homologous recombination repair pathway

Although sensitization of BRCA-mutated, homologous recombination (HR)-deficient breast cancer cells through PARP inhibitor is widely studied, not much is known about the treatment of BRCA-wild-type, HR-proficient breast cancer. Here, we aim to investigate whether a bioactive compound, Resveratrol (RES), can induce DNA double-strand breaks in HR-proficient breast cancer cells and Olaparib (OLA), a PARP inhibitor, can enhance the RES-mediated apoptosis by deregulating the HR repair pathway. The detailed mechanism of anti-cancer action of RES + OLA combination in breast cancer has been evaluated using in vitro, ex vivo, and in vivo preclinical model systems. OLA increased RES-mediated DNA damage, downregulated the HR pathway proteins, caused a late S/G2 cell cycle arrest, enhanced apoptosis and cell death in RES pre-treated breast cancer cells at much lower concentrations than their individual treatments. Direct measurement of HR pathway activity using a GFP plasmid-based assay demonstrated reduced HR efficiency in I-SceI endonuclease-transfected cells treated with OLA. Moreover, RES + OLA treatment also caused significant reduction in PARP1-mediated PARylation and efficiently trapped PARP1 at the DNA damage site. Upon RES treatment, PARylated PARP1 was found to interact with BRCA1, which then activated other HR pathway proteins. But after addition of OLA in RES pre-treated cells, PARP1 could not interact with BRCA1 due to inhibition of PARylation. This resulted in deregulation of HR pathway. To further confirm the role of BRCA1 in PARP1-mediated HR pathway activation, BRCA1 was knocked down that caused complete inhibition of HR pathway activity, and further enhanced apoptosis after RES + OLA treatment in BRCA1-silenced cells. In agreement with in vitro data, similar experimental results were obtained in ex vivo patient-derived breast cancer cells and in vivo xenograft mice. Thus, RES + OLA combination treatment enhanced breast cancer cell death by causing excessive DNA damage and also simultaneously inhibiting the HR pathway.

Abstract CT562: PARTNER: Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of Olaparib to Platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients

Abstract Background: Triple Negative Breast Cancers (TNBC) are a biologically diverse and aggressive subgroup lacking targeted therapy. TNBC and Germline BRCA (gBRCA) breast cancer share certain phenotypic and molecular similarities, with gBRCA mutations seen in 10% to 20% of TNBC patients. Homologous recombination deficient tumours, especially those caused by germline or somatic BRCA mutations, are thought to be particularly sensitive to PARP inhibitors. Aim: To establish if the addition of Olaparib to neoadjuvant Platinum-based chemotherapy in the treatment of basal TNBC and/or gBRCA breast cancer is safe and increases efficacy. Trial design: 3-stage open label randomised phase II/III trial of neoadjuvant Paclitaxel and Carboplatin +/- Olaparib, followed by clinicians' choice of Anthracycline regimen. Stages 1 and 2: Randomisation (1:1:1) to control (3-weekly carboplatin AUC5/weekly with paclitaxel 80mg/m2 for 4 cycles), or to one of two research arms. These use an identical chemotherapy regimen and also include different treatment schedules of Olaparib 150mg BD for 12 days. Stage 3: Randomisation (1:1) to either the control or research arm chosen following stage 2. End-points: Stage 1: Safety; Stage 2: Schedule selection based on pCR rate and Olaparib completion rate using a “pick-the-winner” design. Stage 3: pCR rate. This trial includes an optional pathway (PARTNERING) for patients with evidence of residual disease after six chemotherapy cycles. This aims to establish if the addition of new agents (ATR inhibitor and PD-L1 inhibitor) improves treatment response. Eligibility criteria: Aged 16-70; histologically confirmed invasive breast cancer; ER-negative, HER2-negative with TNBC basal phenotype or gBRCA positive, HER2-negative irrespective of hormone status; stage T1-4 N0-2; performance status 0-1; treatment within 6 weeks of diagnostic biopsy; biomarker scores: TILs, CK 5/6, EGFR +/- AR. Statistical methods: The recruitment of TNBC non-gBRCA and gBRCA patients is independent. Enrichment design is applied with an overall significance level 0.05(α) and 80% power. A minimum of 780 patients will be included to detect an absolute improvement of 15% (all patients and TNBC non-gBRCA cohort) and 20% (gBRCA patients) by combining Olaparib with Platinum based chemotherapy. A minimum of 478 TNBC non-gBRCA and 188 gBRCA patients will be recruited. Each PARTNERING cohort will consist of 15 patients. Current Enrollment: Since May 2016, 756 patients from 30 sites have been enrolled. Stages 1 and 2 are completed. An IDSMC review identified no safety concerns and Research Arm 2 was selected. This arm involves Olaparib administration on days 3-14. Stage 3 Phase I (recruitment of non-gBRCA and gBRCA patients) completed in December 2021. Stage 3 Phase II (recruitment of gBRCA patients only) remains open to patients to UK and internationally. 5 patients have been enrolled in PARTNERING. ClinicalTrials.gov Identifier: NCT03150576 Citation Format: Lynsey Drewett, Karen A. Pinilla, Louise Grybowicz, Jerome Wulff, Alimu Dayimu, Nikolaos Demiris, Rebecca Lucey, Anne-Laure Vallier, Wendi Qian, Andrea Machin, PARTNER Research Team, Karen McAdam, Rebecca Roylance, Ellen R. Copson, Anne Armstrong, Nicola Levitt, Elena Provenzano, Marc Tischkowitz, Emma McMurtry, Helena Earl, Jean E. Abraham. PARTNER: Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of Olaparib to Platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT562.

Abstract OT2-24-01: PARTNER: Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients

Abstract Background: Triple Negative Breast Cancers (TNBC) are a biologically diverse and aggressive subgroup lacking targeted therapy. Germline BRCA (gBRCA) breast cancer and TNBC share some phenotypic and molecular similarities, with 10%-20% of TNBC patients having gBRCA mutations. Homologous recombination deficient tumours are particularly sensitive to PARP inhibitors such as olaparib (Lynparza). It has been shown that adjuvant olaparib for patients with high-risk, HER2-negative early breast cancer and gBRCA pathogenic or likely pathogenic variants after adjuvant or neoadjuvant chemotherapy significantly improves 3-year invasive and distant disease-free survival compared to placebo (OlympiA). Aim: To establish if the addition of olaparib to neoadjuvant platinum based chemotherapy for basal TNBC and/or gBRCA breast cancer is safe and improves efficacy (pathological complete response (pCR) rate). Trial design: 3-stage open label randomised phase II/III trial of neoadjuvant paclitaxel and carboplatin +/- olaparib, followed by clinicians' choice of anthracycline regimen. Stage 1 and 2: Randomisation (1:1:1) to either control (3 weekly carboplatin AUC5/weekly paclitaxel 80mg/m2 for 4 cycles) or one of two research arms with the same chemotherapy regimen but with two different schedules of olaparib 150mg BD for 12 days. Stage 3: Randomisation (1:1) to either control arm or to the research arm selected in stage 2. End-points: Stage 1: Safety; Stage 2: Schedule selection using pCR rate and completion rate of olaparib using a “pick-the-winner” design. Stage 3: pCR rate. This trial includes an optional pathway (PARTNERING) aiming to establish if the addition of new agents (ATR inhibitor and PDL1 inhibitor) can improve response in those patients with evidence of residual disease before surgery. Eligibility criteria: Aged 16-70; histologically confirmed invasive breast cancer; ER-negative, HER2-negative with TNBC basal phenotype or gBRCA positive, HER2-negative irrespective of hormone status; clinical stage T1-4 N0-2; performance status 0-1; treatment commenced within 6 weeks of diagnostic biopsy; biomarker scores: TILs, CK 5/6, EGFR +/- AR. Statistical methods: The recruitment of TNBC non-gBRCA and gBRCA patients is independent. Enrichment design is applied with an overall significance level 0.05(α) and 80% power. A minimum of 780 patients will be included to detect an absolute improvement of 15% (all patients and the TNBC non-gBRCA cohort) and 20% (gBRCA patients) by adding olaparib to platinum based chemotherapy. It is planned to recruit a minimum of 188 gBRCA patients. A maximum of 15 patients will be allocated into each PARTNERING cohort. Present accrual: Recruitment commenced 27 May 2016 and 678 patients from 30 sites have been accrued to date. The IDSMC reviewed the trial after Stages 1 and 2 and recommended to continue the trial without change. Data analysis for Stage 2 revealed no safety concerns and research arm 2 (olaparib on day 3 to day 14) was selected. Stage 3 Phase I recruitment is in progress (recruiting TNBC non-gBRCA and gBRCA patients) and we anticipate moving to Phase II (recruiting gBRCA patients only) by early 2022. Four patients have been accrued to the PARTNERING optional pathway to date. The trial is open and enrolling patients to UK and international sites. Contact information: partner@addenbrookes.nhs.uk Citation Format: Lynsey M Drewett, Karen A Pinilla, Louise Grybowicz, Jerome Wulff, Alimu Dayimu, Nikolaos Demiris, Jessica Martin, Camila Maida de Pontes, Nicola Johnson, Caron Harvey, Erdem Demir, Kimberley St John Green, James Jones, Gemma Young, Anne-Laure Vallier, Wendi Qian, Andrea Machin, Karen McAdam, Rebecca Roylance, Ellen R Copson, Anne Armstrong, Nicola Levitt, Elena Provenzano, Marc Tischkowitz, Emma McMurtry, Helena Earl, Jean E Abraham. PARTNER: Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-24-01.

DDRE-23. THE COMBINATION PARP INHIBITOR OLAPARIB WITH TEMOZOLOMIDE IN AN EXPERIMENTAL GLIOBLASTOMA MODEL

Abstract Poly (ADP-ribose) polymerase (PARP) inhibition could enhance the efficacy of temozolomide and prolong survival in patients with glioblastoma. The aim of this study was to evaluate the combination of the PARP inhibitor olaparib with temozolomide in the treatment of glioblastoma by evaluating in vitro and in vivo antitumor effects in an experimental glioblastoma model. The authors investigated antitumor effects of olaparib on temozolomide-induced cytotoxicity on O6-methylguanine methyltransferase (MGMT) promotor methylated (U87MG, U251MG) and MGMT promotor unmethylated (T98G) glioblastoma cell lines using in vitro cell viability and apoptosis assay. We found that the combination of olaparib with temozolomide enhanced temozolomide-induced cytotoxicity in all glioblastoma cell lines regardless of the status of MGMT promotor methylation. For in vivo studies, nude mice bearing orthotopically xenografted glioblastoma cell lines (U87MG) were randomized to four experimental groups: (i) untreated, (ii) temozolomide alone, (iii) olaprib alone and, (iv) olaparib+temozolomide. Mice were treated daily for 4 weeks and monitored for tumor growth, and survival. However, the addition of olaparib had no impact on the efficacy of temozolomide. The combination of PARP inhibitor olaparib with temozolomide could be an effective therapeutic approach for treatment of glioblastoma regardless of MGMT promotor methylation status, although the efficacy still should be evaluated by in vivo and clinical studies.

Health-related quality of life (HRQoL) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with olaparib in combination with abiraterone.

234 Background: A Phase II trial showed that addition of olaparib (O) to abiraterone (A) led to significant radiographic progression-free survival benefit for patients (pts) with mCRPC vs placebo (P) + A (hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.44–0.97). We report predefined exploratory HRQoL analyses. Methods: This randomized, double-blind trial enrolled pts with mCRPC, post-docetaxel. Pts were randomized (71 per arm) to receive either O (300 mg bd, tablets) + A (1000 mg od) or P + A; all received prednisone (5 mg bd). Pts completed Functional Assessment of Cancer Therapy-Prostate (FACT-P total score [TS]; range 0–156, higher score = better HRQoL), Brief Pain Inventory–Short Form (BPI-SF) and worst bone pain (wbp) questionnaires (both range 0–10, higher score = more severe pain). Adjusted mean change from baseline was analysed using a mixed model for repeated measures, improvement by logistic regression and deterioration by log-rank test. Results: Overall compliance rates (O + A vs P + A) were 97% vs 96%, 92% vs 85%, and 96% vs 92% for FACT-P, BPI-SF and wbp, respectively. Best FACT-P TS response of ‘improved’ (increase ≥6 points from baseline at two consecutive visits) was reported by 22/67 (33%) evaluable pts in the O + A vs 18/64 (28%) pts in the P + A arm; the odds ratio (1.32; 95% CI 0.64–2.78) favored the O + A arm. Best FACT-P TS response of ‘worsened’ (decrease ≥6 points from baseline) was reported by 15 (22%) vs 22 (34%) pts. Adjusted mean change from baseline in FACT-P TS across all visits was -0.60 vs -2.09 in the O + A and P + A arms, respectively (difference 1.48; 95% CI -3.96–6.92). Time to deterioration (TTD) results are shown in the table. Clinical trial information: NCT01972217. Conclusions: Whilst not statistically significant, in this study a higher percentage of pts treated with O + A vs P + A had improved HRQoL, with fewer pts negatively affected. Ongoing phase III studies will help elucidate the impact of O on HRQoL in pts with mCRPC. (NCT01972217)[Table: see text]

Abstract OT3-03-03: PARTNER: Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients

Abstract Background: No specific targeted therapies are available for Triple Negative Breast Cancers (TNBC), an aggressive and diverse subgroup. The basal TNBC sub-group share some phenotypic and molecular similarities with germline BRCA (gBRCA) tumours. In gBRCA patients, and potentially other homologous recombination deficiencies, these already compromised pathways may allow drugs called PARP inhibitors (Olaparib) to work more effectively. Aims: To establish if the addition of olaparib to neoadjuvant platinum based chemotherapy for basal TNBC and/or gBRCA breast cancer is safe and improves efficacy (pathological complete response (pCR)). Methods: Trial design: 3-stage open label randomised phase II/III trial of neoadjuvant paclitaxel and carboplatin +/- olaparib, followed by clinicians' choice of anthracycline regimen. Stage 1 and 2: Randomisation (1:1:1) to either control (3 weekly carboplatin AUC5/weekly paclitaxel 80mg/m2 for 4 cycles) or one of two research arms with the same chemotherapy regimen but with two different schedules of olaparib 150mg BD for 12 days. Stage 3: Patients are randomised (1:1) to either control arm or to the research arm selected in stage 2. End-points: Stage 1: Safety; Stage 2: Schedule selection using pCR rate and completion rate of olaparib using a “pick-the-winner” design. Stage 3: pCR rate. Enrichment design is applied with an overall significance level 0.05(α) and 80% power. A total of 527 patients will be included to detect an absolute improvement of 15% (all patients) and 20% (gBRCA patients) by adding olaparib to platinum based chemotherapy. Trial Progress: PARTNER has been recruiting in UK since 27th May 2016. IDSMC recommended to continue the trial without change after reviewing the Stage 1 safety data. The recruitment of stage 2 was completed in April 2018 and results to be reviewed by the IDSMC in early 2019. The trial is open and enrolling patients to national and international sites. Citation Format: Abraham J, Vallier A-L, Qian W, Machin A, Grybowicz L, Thomas S, Weiss M, Harvey C, McAdam K, Hughes-Davies L, Roberts A, Roylance R, Copson E, Pinilla K, Armstrong A, Provenzano E, Tischkowitz M, McMurty E, Earl H. PARTNER: Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT3-03-03.

Abstract OT3-04-03: PARTNER randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients

Abstract Background: No specific targeted therapies are available for Triple Negative Breast Cancers (TNBC), an aggressive and diverse subgroup. The basal TNBC subgroup show some phenotypic and molecular similarities with germline BRCA (gBRCA). In gBRCA patients, and potentially other homologous recombination deficiencies, these already compromised pathways may allow drugs called PARP inhibitors (olaparib) to work more effectively. Aims: To establish if the addition of olaparib to neoadjuvant platinum based chemotherapy for basal TNBC and/or gBRCA breast cancer is safe and improves efficacy (pathological complete response (pCR)). Trial design: 3 stage open label randomised phase II/III trial of neoadjuvant paclitaxel and carboplatin +/olaparib, followed by clinicians' choice of anthracycline regimen. Stage 1 and 2: Patients are randomised (1:1:1) to either control (3 weekly carboplatin AUC5/weekly paclitaxel 80mg/m2 for 4 cycles) or one of two research arms with the same chemotherapy regimen but with two different schedules of olaparib 150mg BD for 12 days. Stage 3: Patients are randomised (1:1) to either control arm or to the research arm selected in stage 2. Methods: Stage 1 Safety: both research arms combined. Stage 2 Schedule selection criteria: pCR rate and completion rate of olaparib protocol treatment. It is a “pickthewinner” design with 53 patients in each research arm. This allows a 90% power, 5% onesided significance level to test null hypothesis of pCR ≤35% versus an alternative hypothesis of pCR ≥55% in each of the research arms. Stage 3 Efficacy:anticipated pCR ˜55-60% for all trial patients and ˜60-65% for gBRCA patients. The trial is powered to detect an absolute improvement of 15% (all patients) and 20% (gBRCA patients) by adding olaparib to chemotherapy (enriched design). TNBC patient recruitment will be capped, to ensure required gBRCA patients are enrolled. Enrichment design is applied with overall significance level 0.05(α) = 0.025(αall)+ 0.025(αgBRCA) and 80% power. Target accrual: 527 [gBRCA 220] Current accrual: 56 Sites activated: 15 [expected number of sites 30-50]. Citation Format: Abraham J, Vallier A-L, Qian W, Grybowicz L, Thomas S, Machin A, Harvey C, Chiu E, McAdam K, Hughes-Davies L, Roylance R, Copson E, Armstrong A, Provenzano E, Tischkowitz M, McMurtry E, Earl H. PARTNER randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-04-03.

Abstract OT2-01-15: PARTNER - Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients

Abstract Background: Triple Negative Breast Cancers (TNBC) are a biologically diverse and aggressive sub-group. Early effective treatment can lead to cure. Current standard treatment is systemic chemotherapy either pre-/post-definitive surgery. No specific targeted therapies are available for TNBC. There are phenotypic and molecular similarities between germline BRCA (gBRCA) breast cancer and TNBC. In TNBC 10%-20% harbour gBRCA mutations. In gBRCA patients, and potentially other homologous recombination deficiencies, these already compromised pathways allow drugs called PARP inhibitors (olaparib) to work particularly effectively. Aims: To establish if the addition of olaparib to neoadjuvant platinum-based chemotherapy for TNBC and/or gBRCA breast cancer is safe and improves efficacy. Trial design: 3-stage open label randomised phase II/III trial of neoadjuvant olaparib +/- platinum containing chemotherapy followed by clinicians' choice of anthracycline regimen. Stage 1 and 2, patients are randomised (1:1:1) to either control (3 weekly carboplatin AUC5/weekly paclitaxel 80mg/m2 chemotherapy - 4 cycles) or one of two research arms which uses the same chemotherapy regimen but with two different schedules of olaparib 150mg BD). Stage 3: patients are randomised (1:1) to either control arm or to the research arm selected in stage 2. Primary outcome measures: Stage 1: safety of the addition of olaparib to chemotherapy. Prophylactic G-CSF is mandatory. Stage 2: pathological complete response (pCR) in each of the two research arms. At the end of stage 2, one of the research arms will be dropped. Stage 3: pCR at surgery after neoadjuvant treatment. pCR - defined as no residual invasive carcinoma within the breast (ductal carcinoma in situ permitted) AND no evidence of metastatic disease within the lymph nodes. Eligibility: •Aged 16 to 70. •Written informed consent. •Histologically confirmed invasive breast cancer. •Clinical stage T1-4 N0-2 (tumour or metastatic node diameter>10mm) •Confirmed ER-negative and HER2-negative or gBRCA mutation positive, irrespective of hormone status. •Performance Status 0-1 Statistical Methods: Stage 1, Safety: both research arms combined. Stage 2, Schedule selection criteria: pCR rate and completion rate of olaparib protocol treatment. It is a “pick-the winner” design with 53 patients in each research arm. This allows a 90% power, 5% one-sided significance level to test null hypothesis of pCR ≤35% versus an alternative hypothesis of pCR ≥55% in each of the research arms. Stage 3, Efficacy: anticipated pCR ∼45-55% for all trial patients and ∼50-60% for gBRCA patients. The trial is powered to detect an absolute improvement of 15% (all patients) and 20% (gBRCA patients) by adding olaparib to chemotherapy (enriched design). TNBC patient recruitment will be capped, to ensure the required number of gBRCA patients are enrolled. Enrichment design is applied with the overall significance level 0.05(α)=0.025(αall)+ 0.025(αgBRCA) and 80% power. Present accrual: 1 [Trial opened: 23rd May 2016] Target accrual: 527 (TNBC 307; gBRCA 220) Contact information: Dr. Jean Abraham; Email: ja344@medschl.cam.ac.uk. Citation Format: Abraham JE, Vallier A-L, Qian W, Grybowicz L, Thomas S, Mahmud S, Harvey C, McAdam K, Hughes-Davies L, Roylance R, Copson E, Brown J, Provenzano E, Tischkowitz M, Earl HM. PARTNER - Randomised, phase II/III trial to evaluate the safety and efficacy of the addition of olaparib to platinum-based neoadjuvant chemotherapy in triple negative and/or germline BRCA mutated breast cancer patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-01-15.

Abstract A35: Olaparib causes premature loss of cohesion in cancer cells

Abstract Although it has been decades since PARP inhibitors were initially discovered and various clinical trials have been performed, their mode of action in killing tumor cells subsequent to PARP inhibition is still not fully understood. We have recently identified poly(ADP-ribosyl)ation (PARylation) as a new post-translational modification of the cohesin complex, a key player in chromosome segregation during mitosis. We investigated the effect of PARP inhibition on mitosis in a panel of cells of cancer (cervical, breast, ovarian) and normal tissue origin. We treated cancerous and non-cancerous cell lines labelled with chromatin markers with a selected set of PARP inhibitors and imaged them with fluorescence live microscopy. Out of 5 tested inhibitors, a well-known and clinically relevant PARP inhibitor olaparib, induced strongest perturbations in mitotic progression. Olaparib induced a delay in entering anaphase, problems aligning chromosomes at the metaphase plate and premature loss of cohesion (cohesion fatigue) after a prolonged metaphase arrest. Cohesion fatigue, leading to cell death, was observed in cancer cell lines exhibiting S-phase stalling or G2/M arrest with increased protein levels of PARP1. Olaparib is known to entrap PARP1 at replication forks and thereby perturb replication fork movement. While its addition before the onset of mitosis did not result in mitotic defects, addition of olaparib only in S-phase was sufficient to cause mitotic phenotypes. Our results indicate that PARP inhibition by olaparib in S phase has downstream effects on mitotic progression. PARP1 RNAi in addition to olaparib treatment rescues the cohesion fatigue phenotype, suggesting that entrapment of PARP1 at the replication fork upon its inhibition is the main cause of cohesion fatigue. Cohesion fatigue was observed only in highly aneuploid cancer cells that are described to have an increased rate of chromosome mis-segregation. In conclusion, higher susceptibility of aneuploid cancer to cohesion fatigue and cell death upon olaparib treatment relative to normal cells would support its use as anti-mitotic chemotherapy. Citation Format: Eva Kukolj, Tanja Kaufmann, Amalie E. Dick, Robert Zeillinger, Daniel W. Gerlich, Dea Slade. Olaparib causes premature loss of cohesion in cancer cells. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Targeting the Vulnerabilities of Cancer; May 16-19, 2016; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(1_Suppl):Abstract nr A35.

Abstract CT338: Combination of a PI3K- and a PARP-inhibitor to treat high-grade serous ovarian or triple-negative breast cancer

Abstract Clinical trials have shown promising responses of BRCA-linked breast and ovarian cancers to PARP inhibitor therapy, but remissions are often short-lived and incomplete. The PI3K pathway is frequently activated in these malignancies. Recently, we reported in vivo synergy of a PI3K- and a PARP-inhibitor in a mouse model of BRCA1-related breast cancer. While the PARP-inhibitor olaparib alone attenuated tumor growth modestly, a dramatic reduction in tumor growth was observed when olaparib was combined with the PI3K-inhibitor BKM120. In BRCA1-mutant HCC1937 BC cells, PI3K- (but not akt-) inhibition increased indicators of DNA damage, such as poly-ADP-ribosylation and γH2AX, suggesting a critical role of PI3K activity for the maintenance of genomic stability. Here, we report on the molecular mechanism underlying this synergy, on treatment outcomes in an improved mouse model system and the development of an early-phase clinical study. Pre-clinical modeling was done in BRCA1-mutant HCC1937 cells and in a mouse model based on the syngenic transplantation of tumors derived on the K14-Cre BRCA1f/fp53f/f background. Metabolic profiling in vitro and in vivo showed that PI3K-inhibition decreased flux through glycolysis and specifically through the non-oxidative pentose-phosphate pathway, the main source of ribose-5-phosphate required for the de novo synthesis of nucleotides in HCC1937 cells. Within 3 hours and preceding cell cycle changes, BKM120 caused a decrease in nucleotide pools that was further exacerbated by the addition of olaparib. Nucleotide shortage led to to replication stress with the appearance of γH2AX and increased poly-ADP-ribosylation. Tumors with complete loss of BRCA1 and p53 proved particularly vulnerable to this treatment strategy. We were able to induce complete and durable remissions of murine tumors arising on the K14-Cre BRCA1f/fp53f/f background with a 28-day course of BKM120 and Olaparib. These preclinical data have served as the rationale for a phase I, multi-center study (NCT01623349) combining the oral PARP inhibitor olaparib with the oral PI3-kinase inhibitor BKM120 in patients with recurrent HGSC or recurrent TNBC. The study is being conducted through the Stand Up to Cancer (SU2C)'s Targeting PI3-kinase in Women's Cancers Dream Team. It has a 3 + 3 design, escalating if 0/3 or 1/6 participants have a DLT during the first cycle of therapy. The study objectives are to determine the recommended phase II dose (RP2D) of daily continuous oral olaparib (using the tablet formulation) and BKM120, assess toxicities, safety, and preliminary activity of this combination, and determine pharmacokinetic profiles of both agents as well as translational endpoints. The study serves as an example for the development of a clinical trials concept for TNBC and HGSC based on a close collaboration of basic and clinical scientists through the SU2C mechanism. Citation Format: Gerburg M. Wulf, Ashish Juvekar, Costas A. Lyssiotis, Hai Hu, Sina Yadegarynia, Hui Liu, Baek Kim, Eric Winter, Ralph Scully, John Asara, Lewis C. Cantley, Ursula Matulonis. Combination of a PI3K- and a PARP-inhibitor to treat high-grade serous ovarian or triple-negative breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT338. doi:10.1158/1538-7445.AM2014-CT338

Abstract 5357: Pediatric preclinical evaluation of the PARP inhibitor olaparib

Abstract Purpose: Olaparib (AZD2281) is an oral poly(ADP)-ribose polymerase (PARP) inhibitor in clinical development as a single agent and in combination with cytotoxic therapy in adults with solid malignancies. In BRCA-1 deficient tumors, olaparib concentrations of 30 nM result in significant PARP inhibition (Rottenberg, PNAS, 2008). Adult patients appear to tolerate olaparib doses associated with a Cmax of 10 µM (Fong, NEJM, 2009). We evaluated the interaction of olaparib with commonly used cytotoxic drugs in a panel of pediatric solid tumor cell lines. Methods: In vitro growth inhibition was assessed using the sulforhodamine B assay in pediatric solid tumor cell lines including: osteosarcoma (MG-63), neuroblastoma (NGP), Ewings sarcoma (RD-ES), medulloblastoma (Daoy), and rhabdomyosarcoma (RD). IC50's were determined following a 120 h exposure to vehicle, olaparib, cytotoxic agent (carboplatin, melphalan, irinotecan, doxorubicin, vincristine) or olaparib in combination with each cytotoxic agent. The combination index (CI) of Chou-Talalay was used to test for synergy of combinations. Results: As a single agent, olaparib was cytotoxic in all cell lines studied, with a median (range) IC50 of 1.7 (0.3-5.3) μM. The Ewings sarcoma cell line was the most sensitive line with a mean (SD) IC50 of 0.7 (0.3) μM. The combination of olaparib with melphalan or irinotecan was synergistic (CI < 1), while the addition of olaparib to doxorubicin or carboplatin appeared additive to synergistic (CI < 1). The combination of olaparib and vincristine trended toward antagonism (CI > 1). Conclusions: The addition of olaparib to DNA damaging agents resulted in additive or synergistic growth inhibition in a panel of pediatric solid tumor cell lines. Further preclinical and clinical evaluation to determine if olaparib can enhance the efficacy of current pediatric chemotherapy regimens is warranted. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5357. doi:10.1158/1538-7445.AM2011-5357