Darren Hodgson

Olaparib maintenance therapy in patients with platinum-sensitive relapsed serous ovarian cancer: a preplanned retrospective analysis of outcomes by BRCA status in a randomised phase 2 trial

BACKGROUND Maintenance monotherapy with the PARP inhibitor olaparib significantly prolonged progression-free survival (PFS) versus placebo in patients with platinum-sensitive recurrent serous ovarian cancer. We aimed to explore the hypothesis that olaparib is most likely to benefit patients with a BRCA mutation. METHODS We present data from the second interim analysis of overall survival and a retrospective, preplanned analysis of data by BRCA mutation status from our randomised, double-blind, phase 2 study that assessed maintenance treatment with olaparib 400 mg twice daily (capsules) versus placebo in patients with platinum-sensitive recurrent serous ovarian cancer who had received two or more platinum-based regimens and who had a partial or complete response to their most recent platinum-based regimen. Randomisation was by an interactive voice response system, stratified by time to progression on penultimate platinum-based regimen, response to the most recent platinum-based regimen before randomisation, and ethnic descent. The primary endpoint was PFS, analysed for the overall population and by BRCA status. This study is registered with ClinicalTrials.gov, number NCT00753545. FINDINGS Between Aug 28, 2008, and Feb 9, 2010, 136 patients were assigned to olaparib and 129 to placebo. BRCA status was known for 131 (96%) patients in the olaparib group versus 123 (95%) in the placebo group, of whom 74 (56%) versus 62 (50%) had a deleterious or suspected deleterious germline or tumour BRCA mutation. Of patients with a BRCA mutation, median PFS was significantly longer in the olaparib group than in the placebo group (11·2 months [95% CI 8·3-not calculable] vs 4·3 months [3·0-5·4]; HR 0·18 [0·10-0·31]; p<0·0001); similar findings were noted for patients with wild-type BRCA, although the difference between groups was lower (7·4 months [5·5-10·3] vs 5·5 months [3·7-5·6]; HR 0·54 [0·34-0·85]; p=0·0075). At the second interim analysis of overall survival (58% maturity), overall survival did not significantly differ between the groups (HR 0·88 [95% CI 0·64-1·21]; p=0·44); similar findings were noted for patients with mutated BRCA (HR 0·73 [0·45-1·17]; p=0·19) and wild-type BRCA (HR 0·99 [0·63-1·55]; p=0·96). The most common grade 3 or worse adverse events in the olaparib group were fatigue (in ten [7%] patients in the olaparib group vs four [3%] in the placebo group) and anaemia (seven [5%] vs one [<1%]). Serious adverse events were reported in 25 (18%) patients who received olaparib and 11 (9%) who received placebo. Tolerability was similar in patients with mutated BRCA and the overall population. INTERPRETATION These results support the hypothesis that patients with platinum-sensitive recurrent serous ovarian cancer with a BRCA mutation have the greatest likelihood of benefiting from olaparib treatment. FUNDING AstraZeneca.

Transcriptional Pathway Signatures Predict MEK Addiction and Response to Selumetinib (AZD6244)

Selumetinib (AZD6244, ARRY-142886) is a selective, non-ATP-competitive inhibitor of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK)-1/2. The range of antitumor activity seen preclinically and in patients highlights the importance of identifying determinants of response to this drug. In large tumor cell panels of diverse lineage, we show that MEK inhibitor response does not have an absolute correlation with mutational or phospho-protein markers of BRAF/MEK, RAS, or phosphoinositide 3-kinase (PI3K) activity. We aimed to enhance predictivity by measuring pathway output through coregulated gene networks displaying differential mRNA expression exclusive to resistant cell subsets and correlated to mutational or dynamic pathway activity. We discovered an 18-gene signature enabling measurement of MEK functional output independent of tumor genotype. Where the MEK pathway is activated but the cells remain resistant to selumetinib, we identified a 13-gene signature that implicates the existence of compensatory signaling from RAS effectors other than PI3K. The ability of these signatures to stratify samples according to functional activation of MEK and/or selumetinib sensitivity was shown in multiple independent melanoma, colon, breast, and lung tumor cell lines and in xenograft models. Furthermore, we were able to measure these signatures in fixed archival melanoma tumor samples using a single RT-qPCR-based test and found intergene correlations and associations with genetic markers of pathway activity to be preserved. These signatures offer useful tools for the study of MEK biology and clinical application of MEK inhibitors, and the novel approaches taken may benefit other targeted therapies.

Randomized, Double-Blind Phase II Trial With Prospective Classification by ATM Protein Level to Evaluate the Efficacy and Tolerability of Olaparib Plus Paclitaxel in Patients With Recurrent or Metastatic Gastric Cancer

PURPOSE Gastric cancer cell lines, particularly those with low levels of ataxia telangiectasia mutated (ATM), a key activator of DNA damage response, are sensitive to the poly (ADP-ribose) polymerase inhibitor olaparib. We compared the efficacy of olaparib plus paclitaxel (olaparib/paclitaxel) with paclitaxel alone in patients with recurrent or metastatic gastric cancer and assessed whether low ATM expression is predictive of improved clinical outcome for olaparib/paclitaxel. PATIENTS AND METHODS In this phase II, double-blind study (Study 39; NCT01063517), patients were randomly assigned to oral olaparib 100 mg twice per day (tablets) plus paclitaxel (80 mg/m(2) per day intravenously on days 1, 8, and 15 of every 28-day cycle) or placebo plus paclitaxel (placebo/paclitaxel), followed by maintenance monotherapy with olaparib (200 mg twice per day) or placebo. The study population was enriched to 50% for patients with low or undetectable ATM levels (ATMlow). Primary end point was progression-free survival (PFS). RESULTS One hundred twenty-three of 124 randomly assigned patients received treatment (olaparib/paclitaxel, n = 61; placebo/paclitaxel, n = 62). The screening prevalence of ATMlow patients was 14%. Olaparib/paclitaxel did not lead to a significant improvement in PFS versus placebo/paclitaxel (overall population: hazard ratio [HR], 0.80; median PFS, 3.91 v 3.55 months, respectively; ATMlow population: HR, 0.74; median PFS, 5.29 v 3.68 months, respectively). However, olaparib/paclitaxel significantly improved overall survival (OS) versus placebo/paclitaxel in both the overall population (HR, 0.56; 80% CI, 0.41 to 0.75; P = .005; median OS, 13.1 v 8.3 months, respectively) and the ATMlow population (HR, 0.35; 80% CI, 0.22 to 0.56; P = .002; median OS, not reached v 8.2 months, respectively). Olaparib/paclitaxel was generally well tolerated, with no unexpected safety findings. CONCLUSION Olaparib/paclitaxel is active in the treatment of patients with metastatic gastric cancer, with a greater OS benefit in ATMlow patients. A phase III trial in this setting is under way.

Biomarkers in oncology drug development

Biomarker measurements have become an essential component of oncology drug development, particularly so in this era of targeted therapies. Such measurements ensure that clinical studies are testing our biological hypotheses and can help make the difficult decisions required to choose which drugs to stop developing or de‐prioritise. For those drugs taken forward, biomarker measurements may also help choose the appropriate dose, schedule and patient population. In this review we discuss the intrinsic properties of biological sample based efficacy measurements and how these relate to their implementation in oncology drug development by way of points to consider and examples.

Concordance of ATM (Ataxia Telangiectasia Mutated) Immunohistochemistry between Biopsy or Metastatic Tumor Samples and Primary Tumors in Gastric Cancer Patients

ATM (ataxia telangiectasia mutated) is one of several DNA repair proteins that are suggested to sensitize tumor cells to the poly(ADP-ribose) polymerase inhibitor olaparib when deficient. The aim of this study was to assess the spatiotemporal concordance of ATM immunohistochemistry (IHC) in gastric cancer in order to determine if measurements made at the level of various sample types and times could be inferred as having the potential to be relevant to treatment decisions made at the patient level. Two independent cohorts composed of 591 gastric cancer patients divided into a gastrectomy cohort (n = 450) and a metastasis cohort (n = 141) were used in this study. A total of 2,705 ATM IHC samples were examined, including 450 whole tissue, 3 sets of 450 tissue microarray (TMA), 301 biopsy, 222 metastatic tumor and 2 additional whole tissue samples of 50 cases from the gastrectomy cohort, and 141 pairs of primary and metastatic tumors from the metastasis cohort. The prevalence of ATM negativity was 13.1% in biopsies, 13.9, 15.1, and 16.0% in TMAs and 15.9% in whole tissue samples of the gastrectomy cohort, and 21.4% in primary tumor and 21.5% in metastatic tumor samples of the metastasis cohort. coefficients were 0.341 for biopsy, 0.572 as the average of 3 TMAs and 0.415 for the largely synchronous metastatic tumors of the gastrectomy cohort, and 0.153 for the largely asynchronous metastatic tumors of the metastasis cohort. Using whole tissue sections from tumor resections or primary tumor, respectively, as the reference standards, specificity and sensitivity were 91.6 and 41.0% for biopsy, 93.9 and 61.9% as the average of 3 TMAs, and 86.6 and 58.8% for metastatic tumors of the gastrectomy cohort and 81.7 and 33.3% for metastatic tumors of the metastasis cohort, respectively. Although we have demonstrated that the IHC assay for ATM was robust and reproducible in gastric tumor samples, we have also found that measurements were subject to significant discordance across multiple sample types from the same patient. Further work will be necessary to determine if classification may be made more consistent by multiple sampling. However, the lack of agreement between primary and asynchronous metastatic samples suggests that such sampling would need to be performed at the time of any treatment decision.

Circulating tumour-derived predictive biomarkers in oncology

Molecular characterization of tumour material will become increasingly important in selecting patients for clinical trials and offering appropriate treatment for patients in clinical practice. Recent advances in the field have indicated that the molecular characteristics of a tumour can be determined from circulating tumour cells and circulating tumour DNA; thus, a simple blood sample could provide these data in a simple, convenient and efficient manner. This article discusses progress towards guiding treatment decisions through measuring tumour-derived factors in the circulation.

Validation of the BRCA1 antibody MS110 and the utility of BRCA1 as a patient selection biomarker in immunohistochemical analysis of breast and ovarian tumours

BRCA1 protein measurement has previously been evaluated as a potential diagnostic marker without reaching a conclusive recommendation. In this study, we applied current best practice in antibody validation to further characterize MS110, a widely used antibody targeting BRCA1. Antibody specificity was investigated using different biochemical validation techniques. We found that BRCA1 could not be reliably detected using immunoprecipitation and Western blot in endogenously expressing cells. We used immunohistochemistry on formalin-fixed paraffin-embedded cell pellets to establish compatibility with formalin-fixed paraffin-embedded samples. We demonstrated that in transfected cells and cell lines with known genetic BRCA1 status, MS110 successfully detected BRCA1 giving the expected level of staining in immunohistochemistry. Following this, we investigated the use of BRCA1 protein measurement by immunohistochemistry in a cohort of triple negative breast and serous ovarian tumour samples to explore the use of BRCA1 protein measurement by immunohistochemistry for patient stratification. Using MS110 in repeated standardized experiments, on serial sections from a panel of patient samples, results demonstrated considerable run-to-run variability. We concluded that in formalin-fixed tissue samples, MS110 does detect BRCA1; however, using standard methodologies, BRCA1 expression levels in tissue samples is incompatible with the use of this protein as a statistically robust patient selection marker in immunohistochemistry. These results demonstrate the need for further development to deliver BRCA1 protein quantification by immunohistochemistry as a patient stratification marker.

Olaparib combined with abiraterone in patients with metastatic castration-resistant prostate cancer: a randomised, double-blind, placebo-controlled, phase 2 trial

BACKGROUND Patients with metastatic castration-resistant prostate cancer and homologous recombination repair (HRR) mutations have a better response to treatment with the poly(ADP-ribose) polymerase inhibitor olaparib than patients without HRR mutations. Preclinical data suggest synergy between olaparib and androgen pathway inhibitors. We aimed to assess the efficacy of olaparib plus the androgen pathway inhibitor abiraterone in patients with metastatic castration-resistant prostate cancer regardless of HRR mutation status. METHODS We carried out this double-blind, randomised, placebo-controlled phase 2 trial at 41 urological oncology sites in 11 countries across Europe and North America. Eligible male patients were aged 18 years or older with metastatic castration-resistant prostate cancer who had previously received docetaxel and were candidates for abiraterone treatment. Patients were excluded if they had received more than two previous lines of chemotherapy, or had previous exposure to second-generation antihormonal drugs. Patients were randomly assigned (1:1) using an interactive voice or web response system, without stratification, to receive oral olaparib 300 mg twice daily or placebo. All patients received oral abiraterone 1000 mg once daily and prednisone or prednisolone 5 mg twice daily. Patients and investigators were masked to treatment allocation. The primary endpoint was investigator-assessed radiographic progression-free survival (rPFS; based on Response Evaluation Criteria in Solid Tumors version 1.1 and Prostate Cancer Clinical Trials Working Group 2 criteria). Efficacy analyses were done in the intention-to-treat population, which included all randomly assigned patients, and safety analyses included all patients who received at least one dose of olaparib or placebo. This trial is registered with ClinicalTrials.gov, number NCT01972217, and is no longer recruiting patients. FINDINGS Between Nov 25, 2014, and July 14, 2015, 171 patients were assessed for eligibility. Of those, 142 patients were randomly assigned to receive olaparib and abiraterone (n=71) or placebo and abiraterone (n=71). The clinical cutoff date for the final analysis was Sept 22, 2017. Median rPFS was 13·8 months (95% CI 10·8-20·4) with olaparib and abiraterone and 8·2 months (5·5-9·7) with placebo and abiraterone (hazard ratio [HR] 0·65, 95% CI 0·44-0·97, p=0·034). The most common grade 1-2 adverse events were nausea (26 [37%] patients in the olaparib group vs 13 [18%] patients in the placebo group), constipation (18 [25%] vs eight [11%]), and back pain (17 [24%] vs 13 [18%]). 38 (54%) of 71 patients in the olaparib and abiraterone group and 20 (28%) of 71 patients in the placebo and abiraterone group had grade 3 or worse adverse events, including anaemia (in 15 [21%] of 71 patients vs none of 71), pneumonia (four [6%] vs three [4%]), and myocardial infarction (four [6%] vs none). Serious adverse events were reported by 24 (34%) of 71 patients receiving olaparib and abiraterone (seven of which were related to treatment) and 13 (18%) of 71 patients receiving placebo and abiraterone (one of which was related to treatment). One treatment-related death (pneumonitis) occurred in the olaparib and abiraterone group. INTERPRETATION Olaparib in combination with abiraterone provided clinical efficacy benefit for patients with metastatic castration-resistant prostate cancer compared with abiraterone alone. More serious adverse events were observed in patients who received olaparib and abiraterone than abiraterone alone. Our data suggest that the combination of olaparib and abiraterone might provide an additional clinical benefit to a broad population of patients with metastatic castration-resistant prostate cancer. FUNDING AstraZeneca.

Olaparib in combination with paclitaxel in patients with advanced gastric cancer who have progressed following first-line therapy (GOLD): a double-blind, randomised, placebo-controlled, phase 3 trial

BACKGROUND Olaparib combined with paclitaxel has previously shown a significant improvement in overall survival versus placebo plus paclitaxel as second-line therapy in a phase 2 study in Asian patients with advanced gastric cancer, especially in those with ataxia-telangiectasia mutated protein (ATM)-negative tumours. Here, we report the primary efficacy and safety analyses from a subsequent phase 3 trial. METHODS This double-blind, randomised, placebo-controlled, phase 3 study (GOLD) recruited Asian patients aged 18 years or older (≥20 years if Japanese) with advanced gastric cancer that had progressed following, or during, first-line chemotherapy. Patients were randomly assigned (1:1) to receive oral olaparib (100 mg twice daily) plus paclitaxel (80 mg/m2 intravenously) or matching placebo plus paclitaxel. Randomisation was done through an interactive voice response system and no stratification factors were used. Patients and investigators were masked to treatment allocation. Two co-primary populations were assessed: the overall population of all patients and patients whose tumours were ATM-negative (identified after randomisation, before the data cutoff date, March 28, 2016). The primary endpoint in both populations was overall survival (defined as the time from the date of randomisation until death from any cause before data cutoff); a significant difference was defined as p<0·025. Efficacy was assessed in the intention-to-treat populations and safety in patients who received at least one dose of treatment. This trial is registered with ClinicalTrials.gov, number NCT01924533 (study ID, D081BC00004), and is ongoing but no longer recruiting participants. FINDINGS Between Sept 3, 2013, and March 28, 2016, 643 patients were enrolled from 58 study sites in hospitals and medical centres in China, Japan, South Korea, and Taiwan. 525 eligible patients were randomly assigned: 263 to receive olaparib plus paclitaxel and 262 to receive placebo plus paclitaxel. 94 patients were determined to have ATM-negative tumours before unmasking for the primary analysis (48 in the olaparib plus paclitaxel group and 46 in the placebo plus paclitaxel group). Overall survival did not differ between treatment groups in the overall patient population (median overall survival 8·8 months [95% CI 7·4-9·6] in the olaparib group vs 6·9 months [6·3-7·9] in the placebo group; HR 0·79 [97·5% CI 0·63-1·00]; p=0·026) or in the ATM-negative population (12·0 months [7·8-18·1] vs 10·0 months [6·4-13·3]; 0·73 [0·40-1·34]; p=0·25). In the overall patient population, the most common grade 3 or worse adverse events in the olaparib plus paclitaxel group were neutropenia (78 [30%] of 262 patients), leucopenia (42 [16%]), and decreased neutrophil count (40 [15%]); in the placebo plus paclitaxel group, they were neutropenia (59 [23%] of 259 patients), leucopenia (27 [10%]), and decreased white blood cell count (21 [8%]). Adverse events with an outcome of death causally related to study treatment (according to investigator assessment) were reported in two patients: liver injury in one patient (<1%) in the olaparib plus paclitaxel group and cardiac failure in one patient (<1%) in the placebo plus paclitaxel group. INTERPRETATION The GOLD study did not meet its primary objective of showing a significant improvement in overall survival with olaparib in the overall or ATM-negative population of Asian patients with advanced gastric cancer. The study generated informative efficacy and safety data regarding the use of olaparib in combination with a chemotherapeutic agent and provides a foundation for future studies in this difficult-to-treat patient population. FUNDING AstraZeneca.

Long-term responders on olaparib maintenance in high-grade serous ovarian cancer: Clinical and molecular characterization

Purpose: Maintenance therapy with olaparib has improved progression-free survival in women with high-grade serous ovarian cancer (HGSOC), particularly those harboring BRCA1/2 mutations. The objective of this study was to characterize long-term (LT) versus short-term (ST) responders to olaparib. Experimental Design: A comparative molecular analysis of Study 19 (NCT00753545), a randomized phase II trial assessing olaparib maintenance after response to platinum-based chemotherapy in HGSOC, was conducted. LT response was defined as response to olaparib/placebo >2 years, ST as <3 months. Molecular analyses included germline BRCA1/2 status, three-biomarker homologous recombination deficiency (HRD) score, BRCA1 methylation, and mutational profiling. Another olaparib maintenance study (Study 41; NCT01081951) was used as an additional cohort. Results: Thirty-seven LT (32 olaparib) and 61 ST (21 olaparib) patients were identified. Treatment was significantly associated with outcome (P < 0.0001), with more LT patients on olaparib (60.4%) than placebo (11.1%). LT sensitivity to olaparib correlated with complete response to chemotherapy (P < 0.05). In the olaparib LT group, 244 genetic alterations were detected, with TP53, BRCA1, and BRCA2 mutations being most common (90%, 25%, and 35%, respectively). BRCA2 mutations were enriched among the LT responders. BRCA methylation was not associated with response duration. High myriad HRD score (>42) and/or BRCA1/2 mutation was associated with LT response to olaparib. Study 41 confirmed the correlation of LT response with olaparib and BRCA1/2 mutation. Conclusions: Findings show that LT response to olaparib may be multifactorial and related to homologous recombination repair deficiency, particularly BRCA1/2 defects. The type of BRCA1/2 mutation warrants further investigation. Clin Cancer Res; 23(15); 4086–94. ©2017 AACR.