Efficacy and Safety of Avutometinib ± Defactinib in Recurrent Low-Grade Serous Ovarian Cancer: Primary Analysis of ENGOT-OV60/GOG-3052/RAMP 201

TPS5615 Background: Low-grade serous ovarian cancer (LGSOC) constitutes up to 10% of all ovarian cancer and has clinical and molecular characteristics distinct from high-grade serous ovarian cancer. Approximately a third of patients (pts) with recurrent LGSOC harbor KRAS mutations (mt) and pts with KRAS wild-type (wt) LGSOC may have mutations in NRAS, BRAF, or other RAS pathway-associated genes. Prior clinical studies with single agent MEK inhibitors have shown response rates of 16-26% in recurrent LGSOC. VS-6766 is a unique small molecule RAF/MEK clamp that inhibits both RAF and MEK activities by trapping them in inactive complexes. This mechanism of blockade has been shown to limit compensatory MEK activation, thereby potentially enhancing efficacy of MEK inhibition. Focal adhesion kinase (FAK) activation is a putative resistance mechanism to RAF and MEK inhibition, and defactinib, a small molecule inhibitor of FAK, has shown synergistic anti-tumor activity with VS-6766 in preclinical models, including organoids from LGSOC pts. Furthermore, FAK inhibition combined with VS-6766 induces tumor regression in a KRAS mt ovarian cancer xenograft model. The combination of VS-6766 and defactinib is currently being evaluated in the ongoing Investigator Sponsored FRAME study (NCT03875820). In this proof-of-concept study, durable objective responses (ORR = 46%; 11/24) have been reported in recurrent LGSOC pts, including pts who have had a prior MEK inhibitor (Banerjee ESMO 2021) and the combination of VS-6766 + defactinib has received FDA Breakthrough Therapy Designation for recurrent LGSOC. These initial preclinical and clinical results support the ongoing phase 2 ENGOT-ov60/GOG-3052 in recurrent LGSOC. Methods: This is an international phase 2, adaptive, multicenter, randomized, open label study designed to evaluate the efficacy and safety of VS-6766 vs VS-6766 in combination with defactinib currently open to enrollment (NCT04625270). The study will be conducted in two parts. Part A will determine the optimal regimen based on confirmed overall response rate (independent radiology review) in KRAS mt and KRAS wt LGSOC. Part B will determine the efficacy of the optimal regimen identified in Part A in KRAS mt and KRAS wt LGSOC. The minimum expected enrollment is 104 pts, 52 pts with KRAS mt and 52 KRAS wt (64 pts in Part A and 40 pts in Part B). Pts will be randomized to receive VS-6766 (4.0 mg orally (PO), twice weekly 3 wks on, 1 wk off) or VS-6766 with defactinib (VS-6766 3.2 mg PO, twice weekly + defactinib 200 mg PO BID 3 wks on, 1 wk off) till progression. Key inclusion criteria include histologically confirmed LGSOC, known KRAS mutation status, prior systemic therapy including platinum for metastatic disease and up to 1 prior line of MEK inhibitor therapy permitted. Part A of this study has completed enrollment and Part B is currently enrolling pts. Clinical trial information: NCT04625270.

Background: VS-6766 is a unique small molecule inhibitor that blocks MEK kinase activity and RAF phosphorylation of MEK. This mechanism of blockade has been shown to limit compensatory MEK activation, thereby potentially enhancing efficacy of MEK inhibition. Defactinib, (VS-6063), an orally active small molecule, is a potent adenosine 5'- triphosphate (ATP) competitive, reversible inhibitor of focal adhesion kinase (FAK). Defactinib has shown synergistic activity with BRAF and MEK inhibitors in both in vitro and in vivo solid tumor models. Prior molecularly unselected studies with single agent MEK inhibitors have shown response rates up to 26% in recurrent LGSOC. A third of patients with recurrent LGSOC harbor somatic KRAS mutations. FAK inhibition has been shown to induce tumor regression when combined with RAF, MEK or RAF/MEK inhibitors in in vivo models of KRAS mutant ovarian cancer. The combination of VS-6766 and defactinib is currently being evaluated in the ongoing Investigator Sponsored FRAME study (NCT03875820). In this proof of concept study, durable objective responses have been reported in recurrent LGSOC patients, particularly those with KRAS mutations including patients who have had a prior MEK inhibitor (Banerji et al AACR 2020). Based on preclinical studies demonstrating efficacy of both VS-6766 and the VS-6766/defactinib combination and preliminary results of the FRAME study, the phase II ENGOT-ov60/GOG3052 has been developed in recurrent LGSOC. Methods: This is a Phase II, adaptive, two-part, multicenter, parallel cohort, randomized, open label study designed to evaluate the efficacy and safety of VS-6766 versus VS-6766 in combination with defactinib (NCT04625270). The study will be conducted in two parts. Part A will determine the optimal regimen based on confirmed overall response rate (independent radiology review) in KRAS-mutated LGSOC. Part B will determine the efficacy of the optimal regimen identified in Part A in KRAS-mutated and KRAS wild-type LGSOC. The minimum expected enrollment is 52 subjects with KRAS-mutated tumors (32 subjects in Part A and 20 in Part B) and 36 with KRAS wild-type tumors in Part B. Patients will be randomized to receive VS-6766 (4.0 mg PO, twice weekly 3 weeks on, 1 week off) or VS6766 with defactinib (VS-6766 3.2 mg PO, twice weekly + defactinib 200 mg PO BID 3 weeks on, 1 week off) till progression. Key inclusion criteria include histologically confirmed LGSOC, presence of KRAS mutation (Part A), prior systemic therapy for metastatic disease and up to 1 prior line of MEK/RAF inhibitor therapy permitted. This international study is open to enrollment. Citation Format: Susana N. Banerjee, Bradley J. Monk, Els Van Nieuwenhuysen, Kathleen N. Moore, Ana Oaknin, Michel Fabbro, Nicoletta Columbo, David M. O’Malley, Robert L. Coleman, Jonathan Pachter, Andrew Koustenis, Gloria Patrick, Lorna Leonard, Rachel Grisham. ENGOT-ov60/GOG3052/RAMP 201: A phase 2 study of VS-6766 (dual RAF/MEK inhibitor) alone and in combination with defactinib (FAK inhibitor) in recurrent low-grade serous ovarian cancer (LGSOC) [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P046.

ObjectiveRetrospective series have shown secondary cytoreductive surgery improves oncological outcomes in recurrent low-grade serous ovarian cancer. We aim to compare surgical procedures and complications between patients with low-grade and high-grade...

TPS5603 Background: VS-6766 is a unique small molecule inhibitor that blocks MEK kinase activity and RAF phosphorylation of MEK. This mechanism of blockade has been shown to limit compensatory MEK activation, thereby potentially enhancing efficacy of MEK inhibition. Defactinib, (VS-6063), an orally active small molecule, is a potent adenosine 5'- triphosphate (ATP) competitive, reversible inhibitor of focal adhesion kinase (FAK). Defactinib has shown synergistic activity with BRAF and MEK inhibitors in both in vitro and in vivo solid tumor models. Prior molecularly unselected studies with single agent MEK inhibitors have shown response rates up to 26% in recurrent LGSOC. A third of patients with recurrent LGSOC harbor somatic KRAS mutations. FAK inhibition has been shown to induce tumor regression when combined with RAF, MEK or RAF/MEK inhibitors in in vivo models of KRAS mutant ovarian cancer. The combination of VS-6766 and defactinib is currently being evaluated in the ongoing Investigator Sponsored FRAME study (NCT03875820). In this proof of concept study, durable objective responses have been reported in recurrent LGSOC patients, particularly those with KRAS mutations including patients who have had a prior MEK inhibitor (Banerji et al AACR 2020). Based on preclinical studies demonstrating efficacy of both VS-6766 and the VS-6766/defactinib combination and preliminary results of the FRAME study, the phase II ENGOT-ov60/GOG3052 has been developed in recurrent LGSOC. Methods: This is a Phase II, adaptive, two-part, multicenter, parallel cohort, randomized, open label study designed to evaluate the efficacy and safety of VS-6766 versus VS-6766 in combination with defactinib (NCT04625270). The study will be conducted in two parts. Part A will determine the optimal regimen based on confirmed overall response rate (independent radiology review) in KRAS-mutated LGSOC. Part B will determine the efficacy of the optimal regimen identified in Part A in KRAS-mutated and KRAS wild-type LGSOC. The minimum expected enrollment is 52 subjects with KRAS-mutated tumors (32 subjects in Part A and 20 in Part B) and 36 with KRAS wild-type tumors in Part B. Patients will be randomized to receive VS-6766 (4.0 mg PO, twice weekly 3 weeks on, 1 week off) or VS6766 with defactinib (VS-6766 3.2 mg PO, twice weekly + defactinib 200 mg PO BID 3 weeks on, 1 week off) till progression. Key inclusion criteria include histologically confirmed LGSOC, presence of KRAS mutation (Part A), prior systemic therapy for metastatic disease and up to 1 prior line of MEK/RAF inhibitor therapy permitted. This international study is open to enrollment. Clinical trial information: NCT04625270.

Introduction/BackgroundRetrospective series have shown secondary cytoreductive surgery (SCS) improves oncological outcomes in recurrent low-grade serous ovarian cancer (LGSOC), a relatively chemoresistant subtype. We aim to describe surgical procedures and complications,...

Low-grade serous ovarian cancer accounts for approximately 10% of epithelial ovarian cancer cases and is histologically, clinically, and molecularly distinct from high-grade serous ovarian cancer. Patients often present at a younger age and can have a protracted clinical course with median survival approaching 10 years. Prior retrospective studies have shown lower response rates to chemotherapy than are typically seen for patients with high-grade serous ovarian cancer in both the upfront and recurrent setting. However, patients with low-grade serous ovarian cancer also tend to be hormone receptor positive, with approximately 90% of patients being estrogen receptor and/or progesterone receptor positive. This has led to considerable interest in the use of hormonal therapies such as aromatase inhibitors and tamoxifen. Based on prior retrospective studies showing response, hormonal therapies are now routinely used for treatment of recurrent low-grade serous ovarian cancer. Given the generally well-tolerated side effect profile of hormonal therapies, the limited response rates to chemotherapy, and the high prevalence of hormone receptor positivity in low-grade serous ovarian cancer, there has also been considerable interest in the use of hormonal therapies in the first-line treatment of this disease. Dr. Gershenson and colleagues presented a large retrospective study showing a significant improvement in progression-free survival for patients with advanced low-grade serous ovarian cancer treated with maintenance hormonal therapy following upfront surgery and adjuvant chemotherapy. Hormonal therapy is now a standard-of-care management option following surgery and chemotherapy. These findings have led others to question if chemotherapy could potentially be omitted from upfront treatment altogether. The upcoming randomized phase III study, NRG-GY019, seeks to answer this question by randomizing patients with stage II-IV low-grade serous ovarian cancer treated with primary debulking surgery to either 6 cycles of carboplatin and paclitaxel chemotherapy followed by letrozole maintenance therapy or to letrozole maintenance therapy alone. With the recent FDA approval of bevacizumab in the front-line setting for treatment of all patients with advanced ovarian cancer, triplet therapy with carboplatin, paclitaxel, and bevacizumab has recently also become an option for selected patients with advanced low-grade serous ovarian cancer, a strategy specifically supported in low-grade serous ovarian cancer based on retrospective studies showing activity of bevacizumab in combination with chemotherapy in the recurrent setting. There has also been considerable interest in the use of targeted therapies for the treatment of recurrent low-grade serous ovarian cancer, with most efforts thus far targeting the MAP kinase pathway. Thirty-five to 45% of patients with advanced disease harbor a hotspot KRAS mutation and a smaller percentage a BRAF V600E mutation. Following promising results seen in a phase II study of selumetinib, two large phase III studies randomized patients with recurrent disease to treatment with single-agent MEK inhibitor vs. either standard-of-care chemotherapy or hormonal therapy, with results of both studies expected to be reported soon. Additional early-stage studies have shown promising results with targeted therapy combinations, but further development has been limited by toxicity and associated compliance issues. Newer strategies and trials currently in development concentrate on novel hormonal therapies such as the progesterone antagonist onapristone, and hormonal combination strategies such as CDK 4/6 inhibitors in combination with letrozole or fulvestrant. Citation Format: Rachel N. Grisham. Low-grade serous ovarian cancer: Recent advances and future directions [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr IA24.

We describe a phase II clinical trial evaluating the safety and efficacy of the oral CDK4/6 inhibitor palbociclib in patients with recurrent ovarian cancer. Eligible patients with Response Evaluation Criteria in Solid Tumors (RECIST) and/or CA-125 measurable recurrent ovarian cancer were treated with oral palbociclib 125 mg daily for 21 days of a 28-day cycle. Patients with hormone receptor-positive tumors were allowed to concurrently receive an aromatase inhibitor. The primary endpoint was the biochemical response rate, determined by CA-125 response based on Gynecologic Cancer InterGroup criteria. Genomic analyses were performed using targeted next-generation sequencing. The biochemical response rate among 40 patients was 8.3% (95% CI 2.2 to 23.6), and the objective response rate by CA-125 criteria and/or RECIST was 10.5% (95% CI 3.4 to 25.7). Median progression-free survival was 3.2 months. Progression-free survival rates at 6 and 12 months were 25% and 7.5%, respectively. Two patients diagnosed with recurrent low-grade serous ovarian cancer experienced long-term disease stabilization for more than 37 and 9 months, triggering a review of 12 additional low-grade serous ovarian cancer patients treated outside of the phase II trial. Exploratory tumor genomic profiling revealed potential predictors of sensitivity (CDKN2A deletion) or resistance (CCNE1 amplification or RB1 deletion), which require additional independent validation. Palbociclib demonstrated only modest clinical activity in unselected patients with ovarian cancer. However, cyclin-dependent kinases 4/6 inhibition showed promising clinical activity in low-grade serous ovarian cancer, warranting further study in this subtype. Further biomarker analyses may facilitate patient selection in high-grade serous ovarian cancer.

High level of estrogen in the blood of women has been linked to the progression and possibly development of ovarian cancer. Almost all low-grade serous ovarian cancer (LGSOC) expresses estrogen receptor alpha (ERα protein encoded by the gene ESR1) and develops during reproductive age of women. However, recent studies suggested that a higher expression of ERα correlates with better survival. In a phase II clinical trial, hormonal therapies have been shown to be associated with a clinical benefit rate of 61% for recurrent ER-positive LGSOC patients. The study also indicated that women with recurrent LGSOC who received hormonal therapies had a significantly longer progression-free survival but not overall survival. Endocrine therapies have proven to be effective in treating breast cancer. Unfortunately, in ovarian cancer clinical trials (GOG0281 and PARAGON), these treatments have not achieved comparable results, with an objective response rate of only approximately 14%. To understand the ESR1 regulation in LGSOC, we have performed RNAseq and ChIPseq analyses of LGSOC tumor tissues. We also forced over-expression of ESR1 in LGSOC cell lines. Using RNAseq data, we aligned the sequencing reads to all the known ESR1 transcript variants. We found that ESR1 transcript variant 1, 2, 3 and X11 were the major transcripts expressed. Variants 1, 2 and 3 encode the regular 66 kDa ESR1 protein, while the X11 variant encodes a 52 kDa ESR1 protein. Both 66 kDa and 52 kDa ESR1 proteins were also detected in LGSOC tumor tissues by western blots. To further explore the function of ESR1 66kDa in LGSOC, we over-expressed ESR1 variant 1 in two LGSOC cell lines (HOC-7 and HCC5075) by transfecting with an expression plasmid. Total proteins were extracted from the mock control and transfected cells for functional proteomic analysis by reverse phase protein arrays (RPPA). From the RPPA data, overexpressing ESR1 in LGSOC cell lines suppressed DNA repair pathways but activated cell cycle and mitosis pathways. To further delineate the ESR1 DNA binding sites in LGSOC, we performed ChIPseq analysis of these tumor samples as well as two ovarian cancer cell lines that express ESR1 protein. Our results demonstrated that ESR1 regulated “cistromes” in ER positive ovarian carcinoma is very different from that in ER positive breast cancer as much less ESR1 binding sites were found in LGSOC. There are ESR1 binding sites common to both types of cancers, but we found quite a few unique ESR1 binding sites. We are trying to integrate the ChIPseq and RNAseq data and hopefully identify, for the first time, an ovarian cancer specific ERα cistrome. ER expression may not always correlate with activation of ESR1 signaling pathways, which may be one of the reasons underlying endocrine therapy resistance in ovarian cancer. The results of an integrated analyses will also give us insight on the management of ER positive LGSOC by identifying new genetic targets that may be used in combination with endocrine therapy. Citation Format: Yvonne TM Tsang, Chun Wai Oscar Ng, David Gershenson, K-Kwok wong. Estrogen signaling in low-grade serous ovarian carcinoma [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 6279.

Introduction/BackgroundLGSOC, a RAS/MAPK driven cancer, constitutes ≤10% of ovarian cancer, with no FDA-approved treatments. Avutometinib is a novel small molecule RAF/MEK clamp. Focal adhesion kinase (FAK) activation is a resistance...

5515 Background: LGSOC is a RAS/MAPK pathway driven cancer that constitutes ≤10% of ovarian cancer. There are no FDA approved treatments specifically for LGSOC. Avutometinib is a novel small molecule RAF/MEK clamp. Focal adhesion kinase (FAK) activation is a resistance mechanism to RAF/MEK inhibition, and defactinib, a small molecule inhibitor of FAK, has shown synergistic antitumor activity with avutometinib in preclinical models. The combination of avutometinib and defactinib has demonstrated a high rate of confirmed and durable responses (overall response rate [ORR] = 46%) in recurrent LGSOC (Banerjee S, ESMO 2021). Methods: A registration-directed phase 2, adaptive, multicenter, randomized study was initiated to evaluate avutometinib ± defactinib in patients with KRAS mutant (mt) and KRAS wild-type (wt) recurrent LGSOC to identify the optimal regimen based on confirmed ORR by blinded independent central review (Part A) and determine the efficacy of the optimal regimen (Part B) (NCT04625270). Pts were randomized to avutometinib 4 mg orally (PO), twice weekly, 3 weeks on, 1 week off (mono) or avutometinib 3.2 mg PO twice weekly + defactinib 200 mg PO BID 3 weeks on, 1 week off (combo). Key inclusion criteria include histologically confirmed recurrent LGSOC, known KRAS status and prior systemic therapy with platinum chemotherapy. Unlimited additional prior lines, including prior MEK inhibitor, were permitted. Here we present efficacy results from Part A (evaluable patients, N=59) and safety data from all pts enrolled (N=121). Results: In Part A, the median number of prior systemic regimens was 3 for mono, and 4 for combo. In evaluable patients, a confirmed ORR of 7% (2/30) was observed for mono (13% KRAS mt, 0% KRAS wt), and an ORR of 28% (8/29) was observed for combo (27% KRAS mt, 29% KRAS wt). Two of 4 patients previously treated with a MEK inhibitor showed a confirmed partial response (PR) on the combination arm. A high disease control rate (PR or SD ≥ 8 weeks) was observed for both mono (90%) and combo (93%). The majority of treatment related adverse events (AEs, any grade) for combo (N=57) were mild to moderate. The most common Grade ≥3 AEs for combo were blood CPK increase (15.8%), fatigue (5.3%), diarrhea (3.5%), dermatitis acneiform (1.8%), and rash (1.8%). A similar AE profile was observed for mono (N=64). Most AEs were manageable/reversible. On the combo arm, 90.6% (±20%) of planned doses were given and 9% (n=5) of pts discontinued due to AEs [asymptomatic elevated blood CPK (n=3) and fatigue (n=2)]. Conclusions: The interim data support avutometinib + defactinib as an active go-forward regimen in heavily-pretreated recurrent LGSOC, regardless of KRAS status. No new safety signals were observed, and most AEs were mild to moderate. Enrollment continues in Part B for the combination of avutometinib and defactinib. Clinical trial information: NCT04625270 .

TPS5613 Background: Low-grade serous ovarian cancer (LGSOC) represents a minority within the group of invasive epithelial ovarian malignancies. Recent analyses showed a very limited responsiveness to chemotherapy in LGSOC. Since bevacizumab many years ago, none other agents have been approved in LGSOC. There is a high demand of new therapy combinations with modern substances to improve the response rate and prognosis in this group of patients. Immune check-point inhibitors provide a new possibility which showed to be effective in different malignant diseases as well as in selected ovarian cancer patients. In this study, the standard chemotherapy is going to be combined with pembrolizumab in recurrent LGSOC cases with therapy free interval (TFI) over 6 months after last platinum-based chemotherapy. To the authors knowledge no comparable studies have been performed or planned. If our trial should show pembrolizumab effectivity in LGSOC, it would be a signal and impulse for future clinical studies in this rare disease. Methods: PERCEPTION/NOGGO-ov44 (NCT04575961) clinical trial is a multi-center, single-arm phase 2 study to evaluate pembrolizumab therapy concomitant to platinum-based chemotherapy (carboplatin plus pegylated liposomal doxorubicin, carboplatin plus gemcitabine or carboplatin monotherapy) and as maintenance in recurrent low-grade serous ovarian cancer cases. LGSOC patients with progression or recurrence at least six months after most previous platinum-containing therapy and in good general performance (ECOG 0 or 1) are eligible to participate in this clinical trial. The primary objective is the 12 months progression free survival (PFS) rate. Secondary end-points include overall survival, response rate (RR), PFS and RR according to Ki67 expression levels, time to first subsequent therapy (TFST) and its response, safety and quality of life. The trial is planned according to Simon’s two-stage design with total sample size up to 33 patients. The null hypothesis is PFS-rate after 12 months of 20%. In the first phase 18 patients will be enrolled and if at least 5 patients show PFS after 12 months the study is going to be continued with an additional 15 patients. The trial is claimed successful, if at least 11 patients show PFS after 12 months. Assuming a true PFS-rate of 40%, this trial has 5% type I error rate and 80% power. Clinical trial information: NCT04575961.

Background: The Australian Ovarian Cancer Assortment Trial (ALLOCATE) was designed as a pilot study to demonstrate feasibility of molecularly profiling patients with recurrent ovarian cancer with the aim of allocating patients to targeted therapies based on the genomic profile of their tumors. Materials and Methods: Two next-generation sequencing (NGS) panels, as well as a BRCA1 methylation assay, were used for molecular profiling of most common subtypes of ovarian cancer. A custom Illumina TruSeq Amplicon Low Input (v2) panel with dual-strand coverage was designed to target 38 genes commonly mutated and clinically important in ovarian cancer. The second assay was a NGS modification of the Multiplex Ligation-dependent Probe Amplification (MLPA) assay that was designed to target 11 genes with common copy number alterations (CNA) in ovarian cancer, including extensive BRCA1/2 coverage for large exonic deletions (Kondrashova et al., 2015). A thorough analytic validation was performed to ensure that both tests were fit for diagnostic use. Patients with recurrent epithelial ovarian cancer were eligible for the study. Where feasible, patients underwent biopsies of recurrent tumor that were snap frozen. Otherwise, archival FFPE tumor blocks were retrieved. Sequencing was performed using Illumina Miseq and HiSeq 2500 with target median coverage of 2000x (amplicon panel) and 800x (MLPA-Seq). Data were analyzed using an internally built pipeline, an upgraded version of AmpliVar (Hsu et al 2015), with Variant Effect Predictor (Mclaren et al., 2016) used for variant annotation. Results: Between December 2013 and October 2016, 113 patients with recurrent ovarian cancer were recruited from two tertiary hospitals, with 15 cases (13%) excluded due to insufficient tumor material or poor-quality DNA. Ninety-eight cases (87%) were analyzed and reports issued back to the referring clinician. Fifty-six patients (61%) in the study had recurrent high-grade serous ovarian cancer (HGSC). Of these, TP53 mutations were identified in 91%. Events in genes other than TP53 were detected in 44 cases, most commonly MYC and CCNE1 amplifications and BRCA1/2 mutations. BRCA1/2 reversions were identified in two cases, explaining their lack of response to platinum/PARPi. Fifteen patients (16%) had recurrent low-grade serous ovarian cancer (LGSC), with KRAS or BRAF mutations identified in four cases. Two HGSC tumors were reclassified as LGSC on the basis of a lack of TP53 mutation, presence of KRAS mutation, and subsequent pathology review. Other cases in the study included mucinous, clear cell, and mixed-histology carcinomas and a metastatic carcinosarcoma. In terms of clinical utility, 6 patients (7%) received a matched therapy. Three HGSC patients with somatic BRCA1/2 mutations were treated with PARP inhibitors. Another HGSC patient with ERBB2 amplification was treated with trastuzumab. One LGSC patient with a BRAF mutation was enrolled on a BRAF inhibitor clinical trial. A second LGSC patient was enrolled in a trial of anastrazole. Furthermore, 7 patients (14%) with HGSC who were previously untested were found to have a germline BRCA1/2 mutation and were subsequently referred to a familial cancer clinic for further management and cascade testing. The limitations in the study included the turnaround time and advanced stage of disease at enrolment, which significantly affected the clinical utility of the test. Conclusion: We demonstrated that molecular profiling of recurrent ovarian cancer using the ALLOCATE panel was feasible and reflected the known genomic characteristics of the different subtypes. However, challenges remain, including appropriate patient selection and efficient turnaround time for reporting. Furthermore, improved access to targeted therapies or clinical trials will also enhance the clinical utility of the ALLOCATE panel. Citation Format: Olga Kondrashova, George Au-Yeung, Leakhena Leas, Gwo-Yaw Ho, Sebastian Lunke, Kathryn Alsop, Clare Scott, Anne Hamilton, Sumitra Ananda, Alison Freimund, Michael Quinn, Orla McNally, Nadia Traficante, Tiffany Cowie, Matthew Wakefield, Arthur Hsu, Alex Dobrovic, Michael Christie, Graham Taylor, David Bowtell, Linda Mileshkin, Paul Waring. Australian Ovarian Cancer Assortment Trial–Allocating ovarian cancer patients into clinical trials based on molecular profiling. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr B35.

Recurrent low-grade serous ovarian cancer (LGSOC) is considered relatively chemoresistant; until more effective chemotherapy approaches become available, surgical management remains the mainstay of treatment. However, some subtypes of LGSOC behave distinctly differently from high-grade SOC. The upregulation of estrogen and progesterone receptors in ovarian cancer suggests hormone therapy as a possible treatment modality. Our patient was a 75-year-old woman with advanced low-grade papillary serous ovarian cancer. In consultation, supported by appropriate histopathological examination and immunohistochemical study to guide the treatment decisions, our Gynaecological Oncology Multi-Disciplinary Team recommended primary debulking surgery. The patient underwent surgery followed by hormone therapy with letrozole, after declining bevacizumab-containing adjuvant chemotherapy. Eighteen months of ongoing monitoring has shown no signs of progressive disease and stable tumor markers. This case highlights the importance of initial assessment by a multidisciplinary team experienced in gynecological oncology, together with knowledge of the tumor biology, to determine effective treatment strategies for the management of advanced LGSOC.

Recurrent low-grade serous ovarian cancer (LGSOC) is considered relatively chemoresistant; until more effective chemotherapy approaches become available, surgical management remains the mainstay of treatment. However, some subtypes of LGSOC behave distinctly differently from high-grade SOC. The upregulation of estrogen and progesterone receptors in ovarian cancer suggests hormone therapy as a possible treatment modality. Our patient was a 75-year-old woman with advanced low-grade papillary serous ovarian cancer. In consultation, supported by appropriate histopathological examination and immunohistochemical study to guide the treatment decisions, our Gynaecological Oncology Multi-Disciplinary Team recommended primary debulking surgery. The patient underwent surgery followed by hormone therapy with letrozole, after declining bevacizumab-containing adjuvant chemotherapy. Eighteen months of ongoing monitoring has shown no signs of progressive disease and stable tumor markers. This case highlights the importance of initial assessment by a multidisciplinary team experienced in gynecological oncology, together with knowledge of the tumor biology, to determine effective treatment strategies for the management of advanced LGSOC.

Low-grade serous ovarian cancer (LGSC) represents 5% of all epithelial ovarian cancers. They are characterized by indolent growth and KRAS and BRAF mutations, differing from high-grade serous ovarian cancer both clinically and molecularly. LGSC has low response rates to traditional systemic therapies, including chemotherapy and hormonal therapy. The objective of this systematic review was to appraise the literature describing the efficacy of MEK inhibitors in the treatment of LGSC. A comprehensive search was conducted of the following databases: Medline ALL, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Sciences, ClinicalTrials.gov, International Clinical Trials Registry Platform (ICFRP), and International Standard Randomized Controlled Trials Number (ISRCTN) Registry. All studies investigating MEKi in the treatment of LGSC in the adjuvant or recurrent setting for patients 18 years of age or older were included. All titles/abstracts were then screened by 2 independent reviewers (A.K. and C.C.). The full-text articles were then screened. All disagreements were resolved by a third independent reviewer (T.Z.). Two independent reviewers (A.K. and C.C.) extracted data from the studies deemed eligible for final review. A total of 2108 studies were identified in the initial search. Of these, a total of 4 studies met the eligibility criteria for systematic review. In these studies, 416 patients were treated with an MEKi alone. All patients included in the studies were being treated for LGSC in the recurrent setting. Varied results and efficacy of the MEKi were reported in each study. The results highlighted in this systematic review demonstrate varied responses to MEKi for recurrent LGSC. Further research is needed in this field comparing the efficacy to current therapies, as well as to further evaluate the safety and toxicity profile with long-term use of MEKi.