Population exposure-efficacy and exposure-safety analyses for rucaparib in patients with recurrent ovarian carcinoma from Study 10 and ARIEL2

OBJECTIVE

To evaluate correlations between rucaparib exposure and selected efficacy and safety endpoints in patients with recurrent ovarian carcinoma using pooled data from Study 10 and ARIEL2.

METHODS

Efficacy analyses were limited to patients with carcinomas harboring a deleterious BRCA1 or BRCA2 mutation who had received ≥2 prior lines of chemotherapy. Safety was evaluated in all patients who received ≥1 rucaparib dose. Steady-state daily area under the concentration-time curve (AUCss) and maximum concentration (Cmax,ss) for rucaparib were calculated for each patient and averaged by actual dose received over time (AUCavg,ss and Cmax,avg,ss) using a previously developed population pharmacokinetic model.

RESULTS

Rucaparib exposure was dose-proportional and not associated with baseline patient weight. In the exposure-efficacy analyses (n = 121), AUCavg,ss was positively associated with independent radiology review-assessed RECIST response in the subgroup of patients with platinum-sensitive recurrent disease (n = 75, p = 0.017). In the exposure-safety analyses (n = 393, 40 mg once daily to 840 mg twice daily [BID] starting doses), most patients received a 600 mg BID rucaparib starting dose, with 27% and 21% receiving 1 or ≥2 dose reductions, respectively. Cmax,ss was significantly correlated with grade ≥2 serum creatinine increase, grade ≥3 alanine transaminase/aspartate transaminase increase, platelet decrease, fatigue/asthenia, and maximal hemoglobin decrease (p < 0.05).

CONCLUSION

The exposure-response analyses provide support for the approved starting dose of rucaparib 600 mg BID for maximum clinical benefit with subsequent dose modification only following the occurrence of a treatment-emergent adverse event in patients with BRCA-mutated recurrent ovarian carcinoma.

Molecular and clinical determinants of response and resistance to rucaparib for recurrent ovarian cancer treatment in ARIEL2 (Parts 1 and 2)

ARIEL2 (NCT01891344) is a single-arm, open-label phase 2 study of the PARP inhibitor (PARPi) rucaparib in relapsed high-grade ovarian carcinoma. In this post hoc exploratory biomarker analysis of pre- and post-platinum ARIEL2 samples, RAD51C and RAD51D mutations and high-level BRCA1 promoter methylation predict response to rucaparib, similar to BRCA1/BRCA2 mutations. BRCA1 methylation loss may be a major cross-resistance mechanism to platinum and PARPi. Genomic scars associated with homologous recombination deficiency are irreversible, persisting even as platinum resistance develops, and therefore are predictive of rucaparib response only in platinum-sensitive disease. The RAS, AKT, and cell cycle pathways may be additional modulators of PARPi sensitivity.

High-dimensional analysis of the adenosine pathway in high-grade serous ovarian cancer

BACKGROUND

Hydrolysis of extracellular ATP to adenosine (eADO) is an important immune checkpoint in cancer immunology. We here investigated the impact of the eADO pathway in high-grade serous ovarian cancer (HGSC) using multiparametric platforms.

METHODS

We performed a transcriptomic meta-analysis of eADO-producing CD39 and CD73, an eADO signaling gene signature, immune gene signatures and clinical outcomes in approximately 1200 patients with HGSC. Protein expression, localization and prognostic impact of CD39, CD73 and CD8 were then performed on approximately 1000 cases on tissue microarray, and tumor-infiltrating lymphocytes (TILs) were analyzed by flow cytometry and single-cell RNA sequencing on a subset of patients.

RESULTS

Concomitant CD39 and CD73 gene expression, as well as high levels of an eADO gene signature, were associated with worse prognosis in patients with HGSC, notably in the immunoregulatory molecular subtype, characterized by an immune-active microenvironment. CD39 was further associated with primary chemorefractory and chemoresistant human HGSC and platinum-based chemotherapy of murine HGSC was significantly more effective in CD39-deficient mice. At protein level, CD39 and CD73 were predominantly expressed by cancer-associated fibroblasts, and CD39 was expressed on severely exhausted, clonally expanded and putative tissue-resident memory TILs.

CONCLUSIONS

Our study revealed the clinical, immunological, subtype-specific impacts of eADO signaling in HGSC, unveiled the chemoprotective effect of CD39 and supports the evaluation of eADO-targeting agents in patients with ovarian cancer.

Tubulosquamous Polyp of the Vagina: Misplaced Skene's Glands Analogous to the Male Prostate

Tubulosquamous polyp (TSP) of the vagina is a rare and benign lesion, best considered along the spectrum of lesions derived from Skene's glands, the female counterpart of male prostatic glands. It is likely underdiagnosed and represents a challenging diagnosis if one is unfamiliar with this entity. We present an illustrative case of TSP occurring as an upper vaginal wall nodule of a 75-year-old woman, with characteristic morphology and broad immunophenotype. It should be suspected in postmenopausal women with a polyp that demonstrates biphasic squamous and glandular components, which show a prostatic immunophenotype.

Investigating the causal role of MRE11A p.E506* in breast and ovarian cancer

The nuclease MRE11A is often included in genetic test panels for hereditary breast and ovarian cancer (HBOC) due to its BRCA1-related molecular function in the DNA repair pathway. However, whether MRE11A is a true predisposition gene for HBOC is still questionable. We determined to investigate this notion by dissecting the molecular genetics of the c.1516G > T;p.E506* truncating MRE11A variant, that we pinpointed in two unrelated French-Canadian (FC) HBOC patients. We performed a case–control study for the variant in ~ 2500 breast, ovarian, and endometrial cancer patients from the founder FC population of Quebec. Furthermore, we looked for the presence of second somatic alterations in the MRE11A gene in the tumors of the carriers. In summary, these investigations suggested that the identified variant is not associated with an increased risk of developing breast or ovarian cancer. We finally performed a systematic review for all the previously reported MRE11A variants in breast and ovarian cancer. We found that MRE11A germline variants annotated as pathogenic on ClinVar often lacked evidence for such classification, hence misleading the clinical management for affected patients. In summary, our report suggests the lack of clinical utility of MRE11A testing in HBOC, at least in the White/Caucasian populations.

Carboplatin sensitivity in epithelial ovarian cancer cell lines: The impact of model systems

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy in North America, underscoring the need for the development of new therapeutic strategies for the management of this disease. Although many drugs are pre-clinically tested every year, only a few are selected to be evaluated in clinical trials, and only a small number of these are successfully incorporated into standard care. Inaccuracies with the initial in vitro drug testing may be responsible for some of these failures. Drug testing is often performed using 2D monolayer cultures or 3D spheroid models. Here, we investigate the impact that these different in vitro models have on the carboplatin response of four EOC cell lines, and in particular how different 3D models (polydimethylsiloxane-based microfluidic chips and ultra low attachment plates) influence drug sensitivity within the same cell line. Our results show that carboplatin responses were observed in both the 3D spheroid models tested using apoptosis/cell death markers by flow cytometry. Contrary to previously reported observations, these were not associated with a significant decrease in spheroid size. For the majority of the EOC cell lines (3 out of 4) a similar carboplatin response was observed when comparing both spheroid methods. Interestingly, two cell lines classified as resistant to carboplatin in 2D cultures became sensitive in the 3D models, and one sensitive cell line in 2D culture showed resistance in 3D spheroids. Our results highlight the challenges of choosing the appropriate pre-clinical models for drug testing.

Genomic analysis of low-grade serous ovarian carcinoma to identify key drivers and therapeutic vulnerabilities

Low-grade serous ovarian carcinoma (LGSOC) is associated with a poor response to existing chemotherapy, highlighting the need to perform comprehensive genomic analysis and identify new therapeutic vulnerabilities. The data presented here represent the largest genetic study of LGSOCs to date (n = 71), analysing 127 candidate genes derived from whole exome sequencing cohorts to generate mutation and copy-number variation data. Additionally, immunohistochemistry was performed on our LGSOC cohort assessing oestrogen receptor, progesterone receptor, TP53, and CDKN2A status. Targeted sequencing identified 47% of cases with mutations in key RAS/RAF pathway genes (KRAS, BRAF, and NRAS), as well as mutations in putative novel driver genes including USP9X (27%), MACF1 (11%), ARID1A (9%), NF2 (4%), DOT1L (6%), and ASH1L (4%). Immunohistochemistry evaluation revealed frequent oestrogen/progesterone receptor positivity (85%), along with CDKN2A protein loss (10%) and CDKN2A protein overexpression (6%), which were linked to shorter disease outcomes. Indeed, 90% of LGSOC samples harboured at least one potentially actionable alteration, which in 19/71 (27%) cases were predictive of clinical benefit from a standard treatment, either in another cancer's indication or in LGSOC specifically. In addition, we validated ubiquitin-specific protease 9X (USP9X), which is a chromosome X-linked substrate-specific deubiquitinase and tumour suppressor, as a relevant therapeutic target for LGSOC. Our comprehensive genomic study highlighted that there is an addiction to a limited number of unique 'driver' aberrations that could be translated into improved therapeutic paths. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract 5833: Senescence is a central response to chemotherapy in ovarian cancer

High-grade serous ovarian carcinoma (HGSOC) commonly responds to initial therapy, but this response is rarely durable. Understanding the cell fate decisions taken by HGSOC cells in response to treatment could guide new therapeutic opportunities. Here, we find that more than 90% of tissue-derived primary HGSOC cultures, reflecting the original disease, retain the capacity to undergo stress-induced cellular senescence and primarily undergo therapy-induced senescence (TIS) in response to first-line carboplatin/taxol chemotherapy. HGSOC-TIS displays senescence-associated hallmarks, including a stable proliferation arrest, increased p16INK4A expression, persistent DNA damage, an inflammatory secretome, and senolytic sensitivity, suggesting new avenues for selective pharmacological manipulation of these cells. Comparison of pre- and post-chemotherapy patient HGSOC tissue samples revealed changes in physio-pathological senescence biomarkers supporting the occurrence of post-treatment TIS. Whether cell senescence induced by cancer therapy is beneficial or detrimental to treatment outcomes remains unknown. We find that patients with stronger TIS biomarkers in post-chemotherapy tissues have a more favorale 5-year survival, suggesting that the induction of senescence in HGSOC cells accounts, at least in part, for beneficial responses to treatment. Given that HGSOC cells almost universally retain the capacity to undergo senescence and that senescence appears beneficial in this context, senescence-centric therapeutic avenues should be further explored.

Citation Format: Michael Skulimowski, Llilians Calvo-Gonzales, Shuofei Cheng, Isabelle Clément, Lise Portelance, Yu Zhan, Euridice Carmona, Manon de Ladurantaye, Julie Lafontaine, Kurosh Rahimi, Diane Provencher, Anne-Marie Mes-Masson, Francis Rodier. Senescence is a central response to chemotherapy in ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5833.

Ran GTPase: A Key Player in Tumor Progression and Metastasis

Ran (Ras-related nuclear protein) GTPase is a member of the Ras superfamily. Like all the GTPases, Ran cycles between an active (GTP-bound) and inactive (GDP-bound) state. However, Ran lacks the CAAX motif at its C-terminus, a feature of other small GTPases that ensures a plasma membrane localization, and largely traffics between the nucleus and the cytoplasm. Ran regulates nucleo-cytoplasmic transport of molecules through the nuclear pore complex and controls cell cycle progression through the regulation of microtubule polymerization and mitotic spindle formation. The disruption of Ran expression has been linked to cancer at different levels - from cancer initiation to metastasis. In the present review, we discuss the contribution of Ran in the acquisition of three hallmarks of cancer, namely, proliferative signaling, resistance to apoptosis, and invasion/metastasis, and highlight its prognostic value in cancer patients. In addition, we discuss the use of this GTPase as a therapeutic target in cancer.

Low-grade serous carcinoma (LGSC): A Canadian multicenter review of practice patterns and patient outcomes

OBJECTIVE

Patients with advanced low-grade serous carcinoma (LGSC) have poor long-term survival rates. As a rare histotype, there are uncertainties regarding the use of current therapies. Thus, we studied practice patterns and treatment outcomes as part of a national initiative to better understand and improve the care of women with advanced LGSC.

METHODS

This retrospective cohort study was conducted in 5 Canadian referral institutions from 2000 to 2016. Data collection and pathology reporting were standardized. Outcome measures included overall survival (OS), progression-free survival (PFS), progression-free intervals (PFI), and time to next treatment (TTNT). Cox regression analysis was used to evaluate the effects of clinical and pathologic factors on outcomes and prognosis.

RESULTS

There were 134 patients (stage II-IV) with a median follow-up of 32.4 months (range 1.6-228). Four primary treatments were compared across institutions: 1) surgery followed by chemotherapy (56%), 2) neoadjuvant chemotherapy (NACT) followed by surgery (27%), 3) surgery alone (9%), and 4) surgery followed by anti-hormone therapy (4%). Primary platinum/paclitaxel chemotherapy was used in 81%. Patients treated with NACT had worse PFS. Multivariable Cox regression analysis identified lesser residual disease, younger age, and primary peritoneal origin as variables significantly associated with better OS/PFS (p < 0.03). One institution had significantly better PFS than the others (p = 0.025), but this finding could be related to a higher frequency of primary peritoneal LGSC. PFI and TTNT intervals in patients with relapsed disease were not significantly different after the first relapse irrespective of treatment type.

CONCLUSIONS

There are notable differences in practice patterns across Canada. This underscores the need for ongoing strategies to measure, evaluate and achieve optimal patient outcomes for women with advanced LGSC.

Hormone receptor expression and outcomes in low-grade serous ovarian carcinoma

OBJECTIVE

Low-grade serous ovarian carcinomas (LGSC) are frequently ER/PR positive, though the mechanisms by which ER/PR regulate prognosis or anti-estrogen treatment efficacy are poorly understood. We studied ER/PR expression in LGSC tumors and cell lines to evaluate patient outcomes and cellular treatment responses.

METHODS

LGSC tumors and patient-derived cell lines were studied from patients with advanced-stage (III/IV) disease. Tumor samples and clinical data were obtained from the Canadian Ovarian Experimental Unified Resource (COEUR-tissue microarray) and the Ovarian Cancer Research (OvCaRe) tissue bank. ER/PR expression was assessed by both Western blot and immunohistochemistry (IHC). Two different IHC scoring systems (simple and Allred) were used. Cox regression was used to identify factors (age, disease residuum, ER/PR status, etc.) associated with progression-free (PFS) and overall survival (OS). Estradiol and tamoxifen proliferation and viability experiments were performed in LGSC cell lines.

RESULTS

In 55 LGSC cases studied, median follow-up was 56 months (range 1-227). Fifty-three (96%) cases strongly expressed ER whereas 37 (67%) expressed PR. Cox-regression analysis showed that residuum (p < 0.001) was significantly associated with PFS, whereas both ER Allred score (p = 0.005) and residuum (p = 0.004) were significant for OS. None of the LGSC cell lines expressed PR. Loss of PR and ER expression over time was detected in LGSC tumors and cell lines respectively. Estrogen and tamoxifen treatment did not alter LGSC cell proliferation or viability in-vitro.

CONCLUSIONS

In patients with advanced LGSC, higher ER Allred scores were significantly associated with better overall survival. ER/PR expression changed over time in both LGSC tumors and cell lines. Better translational research models are needed to elucidate the molecular mechanisms of ER/PR signalling in LGSC.

Clinicopathological features of women with epithelial ovarian cancer and double heterozygosity for BRCA1 and BRCA2: A systematic review and case report analysis

BACKGROUND

Carriers of pathogenic variants in both BRCA1 and BRCA2 genes as a double mutation (BRCA1/2 DM) have been rarely reported in women with epithelial ovarian cancer (EOC).

METHODS

We reviewed the English literature and interrogated three repositories reporting EOC patients carrying BRCA1/2 DM. The clinicopathological parameters of 36 EOC patients carrying germline BRCA1/2 DM were compared to high-grade serous EOC women of the COEUR cohort with known germline BRCA1/BRCA2 mutation carrier status (n = 376 non-carriers, n = 65 BRCA1 and n = 38 BRCA2). Clinicopathological parameters evaluated were age at diagnosis, stage of disease, loss of heterozygosity, type of mutation, immunohistochemistry profile, progression occurrence and survival.

RESULTS

Median age at diagnosis of BRCA1/2 DM patients was 51.9 years, similar to BRCA1 mutation carriers (49.7 years, p = .58) and younger than BRCA2 mutation carriers (58.1 years, p = .02). Most patients were diagnosed at advanced stage (III-IV; 82%) and were carriers of founder/frequent mutations (69%). Tissue immunostainings revealed no progesterone receptor expression and low intraepithelial inflammation. The 5-year survival rate (60%) was significantly lower than that of BRCA2 mutation carriers (76%, p = .03) but not of BRCA1 mutation carriers (51%, p = .37).

CONCLUSIONS

Our data suggests some co-dominant effect of both mutations but the outcome of these patients more closely resembled that of BRCA1 mutation carriers with poor prognosis factors.

Exploring the Clinical Impact of Predictive Biomarkers in Serous Ovarian Carcinomas

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. Although initial response rates to standard platinum-based treatment are at 70-80%, long-term response in advanced EOC disease is rarely achieved with the development of chemoresistance and recurrence, contributing to overall survival rates below 45%. Additional challenges stem from EOC heterogeneity, reflecting at least five histological subtypes, each with different underlying molecular characteristics and clinicopathology that have significant implications in treatment effectiveness and management. Since the last decade, technologies in genomics, proteomics and pathology have been deployed to find reliable clinical markers that can identify patients sensitive to standard chemotherapy treatments and stratify patients for more suitable targeted therapies. These efforts have identified several molecular markers of prognostic value that have been validated as biomarkers, such as BRCA and KRAS mutations, or are currently under investigation in clinical trials, such as CD8 T cells, immune checkpoint inhibitors and progesterone receptor. Recent advancements in biomarker research have also revealed new targets that have expanded treatment options, introducing poly (ADP-ribose) polymerase (PARP) inhibitors, anti-angiogenic agents, inhibitors targeting signaling pathways, and immunotherapy to improve maintenance therapies or enhance first-line therapy. This review presents a summary of current biomarkers, in clinical use or under evaluation, demonstrating a potential to inform on patient selection for treatment efficacy and predict response to EOC therapies, with particular focus on the serous subtypes, including high-grade and low-grade serous carcinomas.

Adjuvant chemoradiotherapy versus radiotherapy alone in women with high-risk endometrial cancer (PORTEC-3): patterns of recurrence and post-hoc survival analysis of a randomised phase 3 trial

BACKGROUND

The PORTEC-3 trial investigated the benefit of combined adjuvant chemotherapy and radiotherapy versus pelvic radiotherapy alone for women with high-risk endometrial cancer. We updated the analysis to investigate patterns of recurrence and did a post-hoc survival analysis.

METHODS

In the multicentre randomised phase 3 PORTEC-3 trial, women with high-risk endometrial cancer were eligible if they had International Federation of Gynaecology and Obstetrics (FIGO) 2009 stage I, endometrioid grade 3 cancer with deep myometrial invasion or lymphovascular space invasion, or both; stage II or III disease; or stage I-III disease with serous or clear cell histology; were aged 18 years and older; and had a WHO performance status of 0-2. Participants were randomly assigned (1:1) to receive radiotherapy alone (48·6 Gy in 1·8 Gy fractions given on 5 days per week) or chemoradiotherapy (two cycles of cisplatin 50 mg/m² given intravenously during radiotherapy, followed by four cycles of carboplatin AUC5 and paclitaxel 175 mg/m² given intravenously), by use of a biased coin minimisation procedure with stratification for participating centre, lymphadenectomy, stage, and histological type. The co-primary endpoints were overall survival and failure-free survival. Secondary endpoints of vaginal, pelvic, and distant recurrence were analysed according to the first site of recurrence. Survival endpoints were analysed by intention-to-treat, and adjusted for stratification factors. Competing risk methods were used for failure-free survival and recurrence. We did a post-hoc analysis to analyse patterns of recurrence with 1 additional year of follow-up. The study was closed on Dec 20, 2013; follow-up is ongoing. This study is registered with ISRCTN, number ISRCTN14387080, and ClinicalTrials.gov, number NCT00411138.

FINDINGS

Between Nov 23, 2006, and Dec 20, 2013, 686 women were enrolled, of whom 660 were eligible and evaluable (330 in the chemoradiotherapy group, and 330 in the radiotherapy-alone group). At a median follow-up of 72·6 months (IQR 59·9-85·6), 5-year overall survival was 81·4% (95% CI 77·2-85·8) with chemoradiotherapy versus 76·1% (71·6-80·9) with radiotherapy alone (adjusted hazard ratio [HR] 0·70 [95% CI 0·51-0·97], p=0·034), and 5-year failure-free survival was 76·5% (95% CI 71·5-80·7) versus 69·1% (63·8-73·8; HR 0·70 [0·52-0·94], p=0·016). Distant metastases were the first site of recurrence in most patients with a relapse, occurring in 78 of 330 women (5-year probability 21·4%; 95% CI 17·3-26·3) in the chemoradiotherapy group versus 98 of 330 (5-year probability 29·1%; 24·4-34·3) in the radiotherapy-alone group (HR 0·74 [95% CI 0·55-0·99]; p=0·047). Isolated vaginal recurrence was the first site of recurrence in one patient (0·3%; 95% CI 0·0-2·1) in both groups (HR 0·99 [95% CI 0·06-15·90]; p=0·99), and isolated pelvic recurrence was the first site of recurrence in three women (0·9% [95% CI 0·3-2·8]) in the chemoradiotherapy group versus four (0·9% [95% CI 0·3-2·8]) in the radiotherapy-alone group (HR 0·75 [95% CI 0·17-3·33]; p=0·71). At 5 years, only one grade 4 adverse event (ileus or obstruction) was reported (in the chemoradiotherapy group). At 5 years, reported grade 3 adverse events did not differ significantly between the two groups, occurring in 16 (8%) of 201 women in the chemoradiotherapy group versus ten (5%) of 187 in the radiotherapy-alone group (p=0·24). The most common grade 3 adverse event was hypertension (in four [2%] women in both groups). At 5 years, grade 2 or worse adverse events were reported in 76 (38%) of 201 women in the chemoradiotherapy group versus 43 (23%) of 187 in the radiotherapy-alone group (p=0·002). Sensory neuropathy persisted more often after chemoradiotherapy than after radiotherapy alone, with 5-year rates of grade 2 or worse neuropathy of 6% (13 of 201 women) versus 0% (0 of 187). No treatment-related deaths were reported.

INTERPRETATION

This updated analysis shows significantly improved overall survival and failure-free survival with chemoradiotherapy versus radiotherapy alone. This treatment schedule should be discussed and recommended, especially for women with stage III or serous cancers, or both, as part of shared decision making between doctors and patients. Follow-up is ongoing to evaluate long-term survival.

FUNDING

Dutch Cancer Society, Cancer Research UK, National Health and Medical Research Council, Project Grant, Cancer Australia Grant, Italian Medicines Agency, and the Canadian Cancer Society Research Institute.

Dose-Ranging and Cohort-Expansion Study of Monalizumab (IPH2201) in Patients with Advanced Gynecologic Malignancies: A Trial of the Canadian Cancer Trials Group (CCTG): IND221

PURPOSE

Monalizumab binds CD94/NKG2A, preventing HLA-E inhibition of tumor lymphocytes. A dose-ranging/cohort expansion trial of monalizumab for recurrent gynecologic malignancies was conducted to determine the recommended phase II dose (RP2D) and to explore clinical activity, pharmacokinetics, pharmacodynamics, safety, and immunogenicity.

PATIENTS AND METHODS

Participants (and part 2 expansion cohorts) included (i) platinum-sensitive ovarian, (ii) platinum-resistant ovarian, (iii) squamous cervical (CX), and (iv) epithelial endometrial (END) carcinomas. Part 1 assessed monalizumab at 1, 4, or 10 mg/kg every 2 weeks. In part 2, ≥4 patients/cohort underwent pre- and on-treatment tumor biopsies. Preset criteria determined cohort expansion.

RESULTS

A total of 58 participants were evaluable. The RP2D was 10 mg/kg i.v. every 2 weeks. Dose proportionality and 100% NKG2A saturation were observed. Related adverse events were mild: headache, abdominal pain, fatigue, nausea, and vomiting. Grade 3 related adverse events were nausea (1), vomiting (1), dehydration (1), fatigue (2), anorexia (1), dyspnea (1), and proctitis (1). Dose-limiting toxicities were not observed. Hematologic and biochemical changes were mild and not dose related. Best response was SD: part 1, 7 of 18 (39%) [3.4 months (1.4-5.5)], and part 2, 7 of 39 (18%) [1.7 months (CX) to 14.8 months (END)]. Neither a predictive biomarker for SD nor evidence of pharmacodynamic effects was identified. There was a trend to significance between a reduction in lymphocyte HLA-E total score and pharmacodynamics.

CONCLUSIONS

Monalizumab 10 mg/kg i.v. every 2 week is well tolerated in patients with pretreated gynecologic cancers. Short-term disease stabilization was observed. Future studies should assess combinations with other agents, including immunotherapeutics.

Exploiting interconnected synthetic lethal interactions between PARP inhibition and cancer cell reversible senescence

Senescence is a tumor suppression mechanism defined by stable proliferation arrest. Here we demonstrate that the known synthetic lethal interaction between poly(ADP-ribose) polymerase 1 inhibitors (PARPi) and DNA repair triggers p53-independent ovarian cancer cell senescence defined by senescence-associated phenotypic hallmarks including DNA-SCARS, inflammatory secretome, Bcl-XL-mediated apoptosis resistance, and proliferation restriction via Chk2 and p21 (CDKN1A). The concept of senescence as irreversible remains controversial and here we show that PARPi-senescent cells re-initiate proliferation upon drug withdrawal, potentially explaining the requirement for sustained PARPi therapy in the clinic. Importantly, PARPi-induced senescence renders ovarian and breast cancer cells transiently susceptible to second-phase synthetic lethal approaches targeting the senescence state using senolytic drugs. The combination of PARPi and a senolytic is effective in preclinical models of ovarian and breast cancer suggesting that coupling these synthetic lethalities provides a rational approach to their clinical use and may together be more effective in limiting resistance.

Exploiting interconnected synthetic lethal interactions between PARP inhibition and cancer cell reversible senescence

Senescence is a tumor suppression mechanism defined by stable proliferation arrest. Here we demonstrate that the known synthetic lethal interaction between poly(ADP-ribose) polymerase 1 inhibitors (PARPi) and DNA repair triggers p53-independent ovarian cancer cell senescence defined by senescence-associated phenotypic hallmarks including DNA-SCARS, inflammatory secretome, Bcl-XL-mediated apoptosis resistance, and proliferation restriction via Chk2 and p21 (CDKN1A). The concept of senescence as irreversible remains controversial and here we show that PARPi-senescent cells re-initiate proliferation upon drug withdrawal, potentially explaining the requirement for sustained PARPi therapy in the clinic. Importantly, PARPi-induced senescence renders ovarian and breast cancer cells transiently susceptible to second-phase synthetic lethal approaches targeting the senescence state using senolytic drugs. The combination of PARPi and a senolytic is effective in preclinical models of ovarian and breast cancer suggesting that coupling these synthetic lethalities provides a rational approach to their clinical use and may together be more effective in limiting resistance.

Niraparib Maintenance Therapy in Patients With Recurrent Ovarian Cancer After a Partial Response to the Last Platinum-Based Chemotherapy in the ENGOT-OV16/NOVA Trial

PURPOSE

In the ENGOT-OV16/NOVA trial (ClinicalTrials.gov identifier: NCT01847274), maintenance therapy with niraparib, a poly(ADP-ribose) polymerase inhibitor, prolonged progression-free survival in patients with platinum-sensitive, recurrent ovarian cancer who had a response to their last platinum-based chemotherapy. The objective of the study was to assess the clinical benefit and patient-reported outcomes in patients who had a partial response (PR) and complete response (CR) to their last platinum-based therapy.

PATIENTS AND METHODS

A total of 553 patients were enrolled in the trial. Of 203 patients with a germline BRCA mutation (gBRCAmut), 99 had a PR and 104 had a CR to their last platinum-based therapy; of 350 patients without a confirmed gBRCAmut (non–gBRCAmut), 173 had a PR and 177 had a CR. Post hoc analyses were carried out to evaluate safety and the risk of progression in these patients according to gBRCAmut status and response to their last platinum-based therapy. Ovarian cancer–specific symptoms and quality of life were assessed using the Functional Assessment of Cancer Therapy–Ovarian Symptom Index.

RESULTS

Progression-free survival was improved in patients treated with niraparib compared with placebo in both the gBRCAmut cohort (PR: hazard ratio [HR], 0.24; 95% CI, 0.131 to 0.441; P < .0001; CR: HR, 0.30; 95% CI, 0.160 to 0.546; P < .0001) and the non–gBRCAmut cohort (PR: HR, 0.35; 95% CI, 0.230 to 0.532; P < .0001; CR: HR, 0.58; 95% CI, 0.383 to 0.868; P = .0082). The incidence of any-grade and grade 3 or greater adverse events was manageable. No meaningful differences were observed between niraparib and placebo in PR and CR subgroups with respect to patient-reported outcomes.

CONCLUSION

Patients achieved clinical benefit from maintenance treatment with niraparib regardless of response to the last platinum-based therapy.

Paraffin-embedding lithography and micro-dissected tissue micro-arrays: tools for biological and pharmacological analysis of ex vivo solid tumors

There is an urgent need and strong clinical and pharmaceutical interest in developing assays that allow for the direct testing of therapeutic agents on primary tissues. Current technologies fail to provide the required sample longevity, throughput, and integration with standard clinically proven assays to make the approach viable. Here we report a microfluidic micro-histological platform that enables ex vivo culture of a large array of prostate and ovarian cancer micro-dissected tissue (MDT) followed by direct on-chip fixation and paraffination, a process we term paraffin-embedding lithography (PEL). The result is a high density MDT-Micro Array (MDTMA) compatible with standard clinical histopathology that can be used to analyse ex vivo tumor response or resistance to therapeutic agents. The cellular morphology and tissue architecture are preserved in MDTs throughout the 15 day culture period. We also demonstrate how this methodology can be used to study molecular pathways involved in cancer by performing in-depth characterization of biological and pharmacological mechanisms such as p65 nuclear translocation via TNF stimuli, and to predict the treatment outcome in the clinic via MDT response to taxane-based therapies.

Efficacy and safety of niraparib as maintenance treatment in older patients (≥ 70 years) with recurrent ovarian cancer: Results from the ENGOT-OV16/NOVA trial

OBJECTIVE

To analyze the safety and efficacy of niraparib in patients aged ≥70 years with recurrent ovarian cancer in the ENGOT-OV16/NOVA trial.

METHODS

The trial enrolled 2 independent cohorts with histologically diagnosed recurrent ovarian, fallopian tube, or peritoneal cancer who responded to platinum rechallenge, on the basis of germline breast cancer susceptibility gene mutation (gBRCAmut) status. Patients were randomized 2:1 to receive niraparib (300 mg) or placebo once daily until disease progression. The primary endpoint was progression-free survival (PFS) by blinded independent central review. Adverse events (AEs) of special interest were based on the known safety profile of poly(ADP-ribose) polymerase inhibitors.

RESULTS

Patients aged ≥70 years in the gBRCAmut cohort receiving niraparib (n = 14) had not yet reached a median PFS compared with a median PFS of 3.7 months for the same age group in the placebo arm (hazard ratio [HR], 0.09 [95% confidence interval (CI), 0.01 to 0.73]). Non-gBRCAmut patients aged ≥70 years receiving niraparib (n = 47) had a median PFS of 11.3 months compared with 3.8 months in the placebo arm (HR, 0.35 [95% CI, 0.18 to 0.71]). Median duration of follow-up in the niraparib arm was 17.3 months in patients ≥70 years and 17.2 months in patients <70 years. Frequency, severity of AEs, and dose reductions in the niraparib arm were similar in patients aged <70 and ≥ 70 years population. The most common grade ≥ 3 AEs in patients ≥70 years were hematologic: thrombocytopenia event (34.4%), anemia event (13.1%), and neutropenia event (16.4%).

CONCLUSIONS

For patients ≥70 years of age receiving niraparib as maintenance treatment in the ENGOT-OV16/NOVA trial, PFS benefits and incidence of any grade or serious treatment-emergent AEs were comparable to results in the younger population. Use of niraparib should be considered in this population.

Evolution of genetic assessment for BRCA-associated gynaecologic malignancies: a Canadian multisociety roadmap

The landscape of genetic testing in ovarian cancer patients has changed dramatically in recent years. The therapeutic benefits of poly ADP-ribose polymerase (PARP) inhibitors in treatment of BRCA1/2-related ovarian cancers has resulted in an increased demand and urgency for genetic testing results, while technological developments have led to widespread use of multi-gene cancer panels and development of tumour testing protocols. Traditional genetic counselling models are no longer sustainable and must evolve to match the rapid evolution of genetic testing technologies and developments in personalized medicine. Recently, representatives from oncology, clinical genetics, molecular genetics, pathology, and patient advocacy came together to create a national multi-disciplinary Canadian consortium. By aligning stakeholder interests, the BRCA Testing to Treatment (BRCA TtoT) Community of Practice aims to develop a national strategy for tumour and germline BRCA1/2 testing and genetic counselling in women with ovarian cancer. This article serves to provide an overview of the recent evolution of genetic assessment for BRCA1/2-associated gynecologic malignancies and outline a Canadian roadmap to facilitate change, improve genetic testing rates, and ultimately improve outcomes for hereditary ovarian cancer patients and their families.