Platinum-resistant Epithelial Ovarian Cancer Research Articles

Efficacy of birinapant in combination with carboplatin in targeting platinum‑resistant epithelial ovarian cancers.

Patients diagnosed with epithelial ovarian cancers (EOCs) often suffer from disease relapse associated with the emergence of resistance to standard platinum-based chemotherapy. Treatment of patients with chemo-resistant disease remains a clinical challenge. One mechanism of chemoresistance includes overexpression of pro-survival proteins called inhibitors of apoptosis (IAP) which enable cancer cells to evade apoptosis. Due to their anti-apoptotic activity, association with poor prognosis, and correlation with therapy resistance in multiple malignancies, IAP proteins have become an attractive target for development of anticancer therapeutics. Second mitochondrial activator of caspase (SMAC) mimetics are the most widely used IAP antagonists currently being tested in clinical trials as a monotherapy and in combination with different chemotherapeutic drugs to target different types of cancer. In the present study, the antitumor efficacy of combination therapy with birinapant, a bivalent SMAC mimetic compound, and carboplatin to target platinum-resistant EOC cells was investigated. A 3D organoid bioassay was utilized to test the efficacy of the combination therapy in a panel of 7 EOC cell lines and 10 platinum-resistant primary patient tumor samples. Findings from the in vitro studies demonstrated that the birinapant and carboplatin combination was effective in targeting a subset of ovarian cancer cell lines and platinum-resistant primary patient tumor samples. This combination therapy was also effective in vitro and in vivo in targeting a platinum-resistant patient-derived xenograft (PDX) model established from one of the patient tumors tested. Overall, our study demonstrated that birinapant and carboplatin combination could target a subset of platinum-resistant ovarian cancers and also highlights the potential of the 3D organoid bioassay as a preclinical tool to assess the response to chemotherapy or targeted therapies in ovarian cancer.

Poly(ADP-ribose) polymerase (PARP) inhibitors for the treatment of ovarian cancer.

Poly(ADP-ribose) polymerase (PARP) inhibitors for the treatment of ovarian cancer.

The potential feasibility of nab-paclitaxel as the first-line chemotherapy for ovarian cancer: clinical development and future perspectives.

Optimal first-line chemotherapy regimens are crucial for epithelial ovarian cancer (EOC) treatment. Nab-paclitaxel has showed its considerable survival and low toxicity profiles in first-line treatment for three solid tumors and is recommended as a treatment for recurrent EOC. We focus on clinical efficacy and safety outcomes of nab-paclitaxel in current clinical studies of EOC treatment and aim to explore the potential feasibility of nab-paclitaxel as the first-line treatment for EOC. We searched for eligible studies up to January 2020 in Pubmed. Outcomes of interests included drug regimes, objective response rate (ORR), median progression free survival (PFS), median overall survival (OS) and main adverse events to determine feasibility of nab-paclitaxel. This review included nine eligible studies. One study about nab-paclitaxel with carboplatin as first-line therapy in ten cases after hypersensitivity to paclitaxel had an ORR of 100%, median PFS of 16.7months and median OS of 65.4months. Evidence of nab-paclitaxel activity in platinum-sensitive EOC demonstrated an ORR of 64%, a median time to response of 1.3months and PFS of 8.5months. The ORR, median PFS and median OS range in patients with recurrent platinum-resistant EOC from 23%-72%, 4.0-8.5months, 16.8-17.4months, respectively. All studies demonstrated manageable toxicity profile in EOC patients. Nab-paclitaxel presents potentials as the first-line chemotherapy for considerable survival and safety in EOC compared to conventional paclitaxel. However, there is no prospective trial in EOC so far. Therefore, more studies about nab-paclitaxel are needed.

Safety and efficacy of the tumor-selective adenovirus enadenotucirev with or without paclitaxel in platinum-resistant ovarian cancer: a phase 1 clinical trial

BackgroundTreatment outcomes remain poor in recurrent platinum-resistant ovarian cancer. Enadenotucirev, a tumor-selective and blood stable adenoviral vector, has demonstrated a manageable safety profile in phase 1 studies in epithelial solid...

Identification of Patients with Recurrent Epithelial Ovarian Cancer Who Will Benefit from More Than Three Lines of Chemotherapy.

PurposeThis study aimed to identify patients who would benefit from third and subsequent lines of chemotherapy in recurrent epithelial ovarian cancer (EOC).Materials and MethodsRecurrent EOC patients who received third, fourth, or fifth-line palliative chemotherapy were retrospectively analyzed. Patients’ survival outcomes were assessed according to chemotherapy lines. Based on the best objective response, patients were divided into good-response (stable disease or better) and poor response (progressive disease or those who died before response assessment) groups. Survival outcomes were compared between the two groups, and factors associated with chemotherapy responses were investigated.ResultsA total of 189 patients were evaluated. Ninety-four and 95 patients were identified as good and poor response group respectively, during the study period of 2008 to 2021. The poor response group showed significantly worse progression-free survival (median, 2.1 months vs. 9.7 months; p < 0.001) and overall survival (median, 5.0 months vs. 22.9 months; p < 0.001) compared with the good response group. In multivariate analysis adjusting for clinicopathologic factors, short treatment-free interval (TFI) (hazard ratio [HR], 5.557; 95% confidence interval [CI], 2.403 to 12.850), platinum-resistant EOC (HR, 2.367; 95% CI, 1.017 to 5.510), and non-serous/endometrioid histologic type (HR, 5.045; 95% CI, 1.152 to 22.088) were identified as independent risk factors for poor response. There was no difference in serious adverse events between good and poor response groups (p=0.167).ConclusionThird and subsequent lines of chemotherapy could be carefully considered for palliative purposes in recurrent EOC patients with serous or endometrioid histology, initial platinum sensitivity, and long TFIs from the previous chemotherapy regimen.

CXCL2-mediated ATR/CHK1 signaling pathway and platinum resistance in epithelial ovarian cancer

Tumor microenvironment and chemokines play a significant role in cancer chemoresistance. This study was designed to reveal the important role of CXCL2 in platinum resistance in epithelial ovarian cancer (EOC). Differently expressed (DE) genes were screen out based on analysis of GSE114206 dataset in GEO database. The expression of DE chemokines was further validated in platinum- resistant and sensitive EOC. Cell viability assay and cell apoptosis assay were performed to explore the roles of CXCL2 in EOC. Cell stemness characteristics and the signaling pathway regulated by CXCL2 were also investigated in this study. As the results showed, CXCL2 was identified up-regulated in platinum-resistant EOC. The functional assays showed overexpressing CXCL2 or co-culturing with recombinant human CXCL2 promoted cell resistance to cisplatin. Conversely, knocking down CXCL2 or co-culturing with neutralizing antibody to CXCL2 increased cell response to cisplatin. CXCL2 overexpressing maintained cell stemness and activated ATR/CHK1 signaling pathway in EOC. Moreover, we further demonstrated that CXCL2-mediated resistance to cisplatin could be saved by SB225002, the inhibitor of CXCL2 receptor, as well as be rescued by SAR-020106, the inhibitor of ATR/CHK1 signaling pathway. This study identified a CXCL2-mediated mechanism in EOC platinum resistance. Our findings provided a novel target for chemoresistance prevention in EOC.

Puerarin induces platinum-resistant epithelial ovarian cancer cell apoptosis by targeting SIRT1.

ObjectivePrevious investigations indicated the anticancer activity of puerarin. The current study aimed to evaluate the effect and molecular mechanisms of puerarin in chemotherapy-resistant ovarian cancer cells.MethodsWe examined the effects of puerarin in platinum-resistant epithelial ovarian cancer cells in vitro and in vivo. We also analyzed the molecular mechanism underlying Wnt/β-catenin inhibition and sirtuin 1 (SIRT1) regulation following puerarin treatment.ResultsOur study demonstrated that puerarin effectively inhibited cell growth in vitro and in vivo by increasing apoptosis in ovarian cancer cells. More importantly, puerarin sensitized cisplatin-resistant ovarian cancer cells to chemotherapy. Puerarin treatment decreased SIRT1 expression, which attenuated the nuclear accumulation of β-catenin to inhibit Wnt/β-catenin signaling. In addition, SIRT1 overexpression diminished the effects of puerarin treatment on cisplatin-resistant ovarian cancer cells. Further analysis supported SIRT1/β-catenin expression as a candidate biomarker for the disease progression of epithelial ovarian cancer.ConclusionsPuerarin increased the apoptosis of platinum-resistant ovarian cancer cells. The mechanism is partly related to the downregulation of SIRT1 and subsequent inhibition of Wnt/β-catenin signaling.

Predicting response to platinum and non-platinum drugs through bioluminescence resonance energy transfer (BRET) based bio-molecular interactions in platinum resistant epithelial ovarian cancer

Therapy induced rewiring of signalling networks often lead to acquirement of platinum-resistance, thereby necessitating the use of non-platinum agents as second-line treatment particularly for epithelial ovarian cancer (EOC). A prior subject-specific assessment can guide the choice of optimal non-platinum agent/s and possible targeted therapeutic/s. Assessment of protein-protein interactions are superior to simple cytotoxicity assays to determine therapeutic efficacy and associated molecular responses. Utilizing improved PIP3-AKT and ERK1/2 activation Bioluminescence Resonance Energy Transfer (BRET) sensors, we report chemotherapy-induced ERK1/2 activation predominantly in cisplatin-paclitaxel resistant EOC cells and increased activation of both ERK1/2 and AKT in malignant ascites derived cancer cells from platinum-resistant patients but not from treatment-naive or platinum-sensitive relapse patients. Further, majority of the non-platinum drugs except irinotecan increased ERK1/2 activation in platinum-taxol resistant cells as observed by live-cell BRET assessment which were associated with p90RSK1/2 and BAD activation along with upregulation of multidrug transporter gene ABCC1 and cell survival genes like cyclin D1 and Bcl2. Interestingly, only irinotecan was able to sensitize these resistant cells. Altogether, this first report of BRET based sensing of molecular pathway activations in platinum resistant cell lines and patient's derived cancer cells highlight the clinical potential of BRET sensors in management of therapy resistant cancer.

Phase I study of mirvetuximab soravtansine (MIRV) and rucaparib for recurrent endometrial, platinum-resistant ovarian, fallopian tube or primary peritoneal cancer

Phase I study of mirvetuximab soravtansine (MIRV) and rucaparib for recurrent endometrial, platinum-resistant ovarian, fallopian tube or primary peritoneal cancer

Anlotinib combined with pemetrexed as a further treatment of patients with platinum-resistant ovarian cancer: A single-arm, open-label, phase II study

<h3>Objectives:</h3> Anlotinib is a novel multi-target tyrosine kinase inhibitor for tumor angiogenesis and proliferative signaling. A previous retrospective study achieved the overall response rate (ORR) of 14.3% and the disease control rate (DCR) of 85.7% in platinum-resistant ovarian cancer (PROC) patients (pts) treated with anlotinib monotherapy, and the ORR of 33.3% and the DCR of 100% with anlotinib plus chemotherapy. The current prospective clinical trial (ChiCTR1800018192) aimed to further assess the efficacy and safety of anlotinib combined with pemetrexed and continued as maintenance therapy for PROC. <h3>Methods:</h3> Pts who had received at least two different chemotherapy regimens (including the first line platinum-based regimen), with histologically proven recurrent platinum-refractory or platinum-resistant epithelial ovarian cancer (including fallopian tube carcinoma and primary peritoneal carcinoma), ECOG 0-2, were considered eligible for enrollment to receive six 21-days cycles of anlotinib (12 mg QD from day 1 to 14) orally plus pemetrexed intravenously (0.5 g/m² on day 1). Anlotinib monotherapy was subsequently performed up to 1 year in patients without disease progression or intolerable toxicity. The primary endpoint was ORR, and the secondary endpoints included DCR, progression-free survival (PFS) and safety. <h3>Results:</h3> As of October 2020, 22 pts were enrolled. The median prior lines of chemotherapy was 4 (range, 2-10) and 55% of pts had ever received antiangiogenic therapy. A total of 17 pts had the confirmed best overall response assessments which inferred the ORR of 41.2% (PR in 7 pts; 95% CI, 18.4-67.1) and the DCR of 100% (PR in 7 pts and SD in 10 pts; 95% CI, 80.5-100). The median PFS was 9.3 months (95% CI, 6.0-12.6). Any grades of adverse events (AEs) were observed in 91% (20/22) of pts, containing frequent hand-foot syndrome (36%), hypertension (32%), allergic eruption (27%), fatigue (23%) and oral ulcer (14%). High grade AEs occurred in 3 pts, including 1 with grade III proteinuria, 1 with grade III ascites increase, and 1 with grade IV hemoglobin reduction. <h3>Conclusions:</h3> The treatment of anlotinib plus pemetrexed showed encouraging efficacy and satisfactory safety for platinum-resistant and -refractory, recurrent ovarian cancer pts who were previously treated with chemotherapy.

Melphalan as a Promising Treatment for BRCA-Related Ovarian Carcinoma.

IntroductionMelphalan, as a bifunctional alkylating agent has been shown to be selectively efficient in BRCA-deficient case reports of epithelial ovarian cancer (EOC). The clinical benefit of melphalan on unselected platinum-resistant EOC population and stratified by BRCA status has not been clearly elucidated. We aimed to determine the response to melphalan in patients with recurrent EOC after platinum-based therapy.Material and MethodsThis retrospective observational study included patients with recurrent EOC treated with melphalan between February 2007 to July 2020. Eligibility criteria included having a histological confirmation of EOC, previous treatment with carboplatin plus paclitaxel regimens, and disease recurrence during treatment with or within 6 months of the end of the platinum-based chemotherapy.ResultsA total of 75 platinum-resistant EOC patients were enrolled. Median age was 69 years (range 41-82). Median of previous therapies before melphalan was 4 (range 1-7). We observed a median follow-up of 32 months (range 1-62), progression-free survival (PFS) and overall survival (OS) of 3.6 months (range 2.9-4.7) and 9.5 months (range 8.0-14.1), respectively. In the whole population, 1 complete response, 6 partial responses and 37 stable diseases were registered with an overall clinical benefit rate of 58.7%. In BRCA1/2 mutant patients, we showed a significant longer PFS compared to BRCA1/2 wild type patients (6.2 versus 2.6 months; hazard ratio (HR) 0.25, 95% confidence interval (CI) 0.10-0.61; p=0.002). Moreover, a trend was seen for BRCA1/2 mutants to have a better OS (25.9 versus 8.0 months; HR 0.38; 95% CI 0.12-1.19; p=0.097).ConclusionsOur study represents the largest cohort of heavily-pretreated EOC patients receiving melphalan treatment. Here, we report a considerable clinical activity of melphalan chemotherapy, more evident in a subset of BRCA1/2 mutated patients. Prospective studies to validate these findings are warranted.

Phase I evaluation of lenvatinib and weekly paclitaxel in patients with recurrent endometrial, ovarian, fallopian tube, or primary peritoneal Cancer

ObjectivesTo estimate the maximally tolerated dose (MTD) and describe toxicities associated with lenvatinib and weekly paclitaxel in patients with recurrent endometrial and platinum resistant epithelial ovarian cancer. MethodsUsing a 3 + 3 design patients were given weekly paclitaxel 80 mg/m2 IV day 1, 8, 15 and oral levantinib daily on a 28-day cycle. Lenvatinib dose levels were 8 mg, 12 mg, 16 mg, 20 mg. Toxicities were recorded using CTCAE v4.03 and response was determined with imaging after cycle 2, then every 3rd cycle, using RECIST 1.1 criteria. Results26 patients were enrolled; 19 with ovarian cancer (14 high grade serous, 1 low grade serous, 2 clear cell, 1 endometrioid, and 1 carcinosarcoma), and 7 with endometrial cancer (3 serous, and 4 endometrioid). The MTD was established at lenvatinib 16 mg and weekly paclitaxel 80 mg/m2. Toxicities (all grades) occurring in ≥25% of patients included anemia, neutropenia, lymphopenia, mucositis, nausea, diarrhea, anorexia, hypertension, fatigue, proteinuria, epistaxis, hoarseness.Twenty-three patients were evaluable for response and PFS; 15 (65%) had a partial response, 7 (30%) stable, 1 (4%) progressive disease with an objective response rate of 65%; 71% in ovarian and 50% in endometrial cancer. Median progression free survival (PFS) is 12.4 months; 14.0 months in endometrial cancer, 7.2 months in ovarian cancer; 54% had a PFS > 6 months. The median duration of response for PR patients (n = 15) was 10.9 months. ConclusionsThe regimen was tolerable with manageable side effects. Encouraging activity was observed in endometrial and ovarian cancer, and warrants further development.

Deregulation of Exo70 Facilitates Innate and Acquired Cisplatin Resistance in Epithelial Ovarian Cancer by Promoting Cisplatin Efflux.

Simple SummaryInnate and acquired platinum resistance are the leading causes of epithelial ovarian cancer (EOC) mortality. However, the mechanisms remain elusive. Here we found that Exo70, a key subunit of the exocyst, is upregulated in EOC and promotes cisplatin efflux to facilitate innate resistance. More interestingly, cisplatin could downregulate Exo70 to sustain cell sensitivity. However, this function was hampered during prolonged cisplatin treatment, which in turn stabilized Exo70 to facilitate the acquired cisplatin resistance of EOC cells. Our study potentiates Exo70 as a promising target to overcome cisplatin resistance in EOC.Whilst researches elucidating a diversity of intracellular mechanisms, platinum-resistant epithelial ovarian cancer (EOC) remains a major challenge in the treatment of ovarian cancer. Here we report that Exo70, a key subunit of the exocyst complex, contributes to both innate and acquired cisplatin resistance of EOC. Upregulation of Exo70 is observed in EOC tissues and is related to platinum resistance and progression-free survival of EOC patients. Exo70 suppressed the cisplatin sensitivity of EOC cells through promoting exocytosis-mediated efflux of cisplatin. Moreover, cisplatin-induced autophagy-lysosomal degradation of Exo70 protein by modulating phosphorylation of AMPK and mTOR, thereby reducing the cellular resistance. However, the function was hampered during prolonged cisplatin treatment, which in turn stabilized Exo70 to facilitate the acquired cisplatin resistance of EOC cells. Knockdown of Exo70, or inhibiting exocytosis by Exo70 inhibitor Endosidin2, reversed the cisplatin resistance of EOC cells both in vitro and in vivo. Our results suggest that Exo70 overexpression and excessive stability contribute to innate and acquired cisplatin resistance through the increase in cisplatin efflux, and targeting Exo70 might be an approach to overcome cisplatin resistance in EOC treatment.

Abstract 1211: Anti-LSR mAb with carboplatin shows the synergistic effect in epithelial ovarian cancer

Abstract Objectives : Previously, we demonstrated anti-cancer effect of our newly developed monoclonal antibody (mAb) targeting lipolysis-stimulated lipoprotein receptor (LSR) in LSR-positive epithelial ovarian cancer (EOC) in vitro and in vivo. In EOC treatment, platinum agents which induce apoptosis are the key drugs over the decades, therefore, we aimed to demonstrate the synergistic effect of anti-LSR mAb and platinum agent against LSR-positive EOC cells. Methods : We administrated anti-LSR mAb and carboplatin to RMG-I cells (platinum resistant and LSR-positive EOC cell line) and evaluated cell proliferation in vitro and in vivo. We also investigated whether anti-LSR mAb reverse platinum resistance of RMG-I in vitro. In addition, we analyzed changes in protein expression related to MAPK/ERK and apoptosis using western blotting after treatment. Results : In RMG-I, anti-LSR mAb inhibited phosphorylation of MAPK pathway-related proteins including MEK and ERK, and activated apoptosis-related proteins. Although RMG-I showed the refractory for carboplatin, anti-LSR mAb reversed its platinum resistance and decreased IC50 value of carboplatin. As a result, anti-LSR mAb induced the apoptotic effect of carboplatin in RMG-I. Finally, the combination therapy of anti-LSR mAb and carboplatin significantly inhibited the tumor growth of RMG-I in a synergistic manner in vitro and in vivo (p&amp;lt;0.05). The combination therapy caused strong apoptotic changes in tumor. Conclusions : We confirmed the synergistic effect of the combination therapy of anti-LSR mAb and platinum agent against LSR-positive EOC cells via apoptotic pathway. Our findings demonstrated that this combination therapy might be a new treatment option of EOC. Citation Format: Masashi Funauchi, Kosuke Hiramatsu, Satoshi Serada, Minoru Fujimoto, Tetsuji Naka. Anti-LSR mAb with carboplatin shows the synergistic effect in epithelial ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1211.

Pembrolizumab in combination with bevacizumab and pegylated liposomal doxorubicin in patients with platinum-resistant epithelial ovarian cancer.

5522 Background: There is a medical unmet need for effective treatments in platinum resistant ovarian cancer patients. We assessed the safety and efficacy of a combination of pembrolizumab with bevacizumab and pegylated liposomal doxorubicin (PLD). Methods: This is an open-label phase 1b trial in patients ECOG 0 or 1 with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. The safety of the dual combinations of pembrolizumab with bevacizumab or with PLD were previously evaluated in 6 patients respectively. In the absence of dose limiting toxicities (DLT) the triple combination was evaluated at a maximum tolerated dose (MTD)-1 for PLD in 3 patients and in the absence of DLT at MTD. The sample size was calculated according to the modified toxicity probability interval design. The primary evaluation criteria was the safety, the secondary endpoint was the outcome. Pharmacokinetics of the flat dose of bevacizumab will be evaluated. Results: 22 patients were enrolled from September 2019 until June 2020 in six French centers. 3 initial patients have been treated at 20mg/m2 of PLD (MTD-1) and 19 patients were treated at the dose of 30mg/m2 of PLD (MTD) combined with 200mg of pembrolizumab until progression, unacceptable toxicity, or withdrawal of consent and 400mg of bevacizumab for a total of six cycles. The patients’ characteristics are reported in the table. No DLT occurred. Grade 3 palmar-plantar erythrodysesthesia were reported in 4 patients. The recommended phase II dose of PLD was 30mg/m2 in combination with pembrolizumab and bevacizumab. For patients treated at MTD, the overall response rate was 32% (6 partial responses) with 74% of clinical benefit with a durable response in 10 patients (53%). Median number of cycles was 7.5 (2 to not reached). Two patients are still on treatment. Correlative studies are ongoing. Conclusions: The combination was well tolerated and demonstrated clinical benefit in 74% platinum resistant ovarian cancer patients with durable response (&gt;6 months) in 53% of patients. Clinical trial information: NCT03596281. [Table: see text]

Patient self-reporting of tolerability using PRO-CTCAE: A randomized double-blind placebo controlled phase II trial comparing gemcitabine in combination with adavosertib or placebo in women with platinum resistant epithelial ovarian cancer.

5541 Background: A 4 month improvement in OS was demonstrated when Wee1 inhibitor adavosertib (Ad) and gemcitabine (G; arm A) was compared to G and placebo (P; arm B) in a phase 2 trial in recurrent ovarian cancer (NCT02151292). The patient reported outcome version of the CTCAE (PRO-CTCAE) was used to capture self-report of the frequency, severity and/or interference (scored 0-4; higher scores indicating worse symptomatic adverse events [syAEs]). Methods: Ad/P was given orally on D1-2, D8-9, D15-16 with G D1, D8, D15 in a 28-day cycle. English speaking pts in 2 centres completed PRO-CTCAE items electronically in clinic at baseline, D1 and D15 of each cycle and off treatment. An exploratory objective was to characterize syAEs in the first 3 months of therapy. We calculated 12-week area under the curve (AUC12w) as a measure of syAE over time and incremental AUC12w (iAUC12w) for adjustment to baseline syAEs and compared arms A and B using an independent samples t-test. We assessed proportion of scores 3-4 at 6 time-points and compared them using Fisher’s Exact Test at each survey. Results: 51 pts were enrolled and completed ≥1 survey, 47 were evaluable for primary outcome (arm A: 28, B: 19). ECOG status was ≤1 in 44/47 pts. Median number of cycles of therapy were 5 (1-16) in arm A, and 2 (1-16) in B. Survey completion rates were high (arm A 93%, B 95%). Mean AUC12w fatigue severity (A 152 [standard error 9] vs B 112 [10]; p = 0.005) and interference (A 144 [11] vs 98 [15]; p = 0.018), diarrhea frequency (A 70 [12] vs B 33 [9]; p = 0.014), mucositis (A 23 [6] vs B 6 [3]; p = 0.012) and difficulty swallowing severity (A 10 [3] vs B 2 [2]; p = 0.023) were higher in arm A (any grade). There were no statistically significant between-arm differences in abdominal pain, bloating, nausea, vomiting and anxiety. The iAUC12w was significantly higher in arm A vs B for difficulty swallowing severity (A 10.1 [3] vs B -2.7 [4.7]; p = 0.02), mucositis severity (A 19.9 [6.6] vs B -3.1 [6.9]; p = 0.02) and fatigue severity (A 35.2 [8.2] vs B -3.1 [9.8]; p = 0.005). Proportions with high scores (3-4) were only significantly higher at C1D15 for fatigue severity in arm A (A 55% vs B 19%, p = 0.044). No significant differences were seen in other 3-4 scores per survey time. Conclusions: This is the first study evaluating pts self-reported toxicity with adavosertib in a randomized setting, allowing pts self-evaluation of toxicity in the context of improved PFS and OS. Greater fatigue, diarrhea, mucositis and difficulty swallowing were experienced by pts receiving adavosertib and gemcitabine, but score 3-4 reached significance on C1D15 fatigue only. No significant differences were detected in syAE profile for nausea, vomiting, abdominal pain, bloating and anxiety. This approach allows objective assessment of pts perception of toxicity with complex therapy. Clinical trial information: NCT02151292.

Phase 1 dose-escalation study of STRO-002, an antifolate receptor alpha (FRα) antibody drug conjugate (ADC), in patients with advanced, progressive platinum-resistant/refractory epithelial ovarian cancer (EOC).

5550 Background: STRO-002-GM1 is a Phase 1, open-label study in patients (pts) with advanced, platinum resistant or refractory EOC. STRO-002 is a novel FRα-targeting ADC with a precise DAR of 4 using site-specific conjugation technology to circumvent limitations of current ADCs. STRO-002 induces immunogenic cell death and contains the tubulin-targeting 3-aminophenyl hemiasterlin warhead SC209, a potent cytotoxin that is a weak substrate for P-gp. Methods: STRO-002 is given IV on Day 1 of each 21-day cycle until disease progression. Ocular exams are performed at baseline and every other cycle. Prophylactic corticosteroid eyedrops are not administered. FRα expression was not required for eligibility and retrospective analysis of FRα expression in archival tumor tissue is ongoing. Results: Enrollment has been completed with 39 pts treated at 9 dose levels (0.5 to 6.4 mg/kg). Data cut-off is Jan 30, 2021. Median age was 61 years (range 48-79). Median number of prior systemic therapies was 6 (range 2-11). 86% of treatment emergent adverse events (AEs) were Grade 1-2. The most common treatment related Grade 3 and 4 AEs were reversible neutrophil count decreased (36%) and neutropenia (33%), Grade 3 arthralgia (12.8%) and neuropathy (7.7%). Two pts developed neutropenic fever that resolved with antibiotic therapy. 34 pts were treated at clinically active doses (≥ 2.9 mg/kg) and 31/34 are evaluable for RECIST 1.1 response. Objective responses were seen in 10/31 pts - 1 CR, 4 confirmed PR, and 5 unconfirmed PR (imaging studies under review in 1 pt with uPR). Disease control rate (CR+PR+SD) is 74% at ≥ 12 weeks and 61% at ≥ 16 weeks. 5 pts remain on treatment with 3 ongoing at &gt; 74 weeks. FRα-expression results are available in 14 pts treated at ≥ 2.9 mg/kg with 50% low, 21% medium and 29% high FRα-expressing tumors per PS2+ scoring algorithm. 12/13 pts with H-scores of ≥ 105 achieved disease control with PR or SD. Maximum plasma concentrations of STRO-002 were achieved at the end of the 1 hour infusion and exposure increased in an apparent dose proportionate/linear manner. Conclusions: STRO-002 is a novel FRα-targeting ADC with an encouraging emerging safety and efficacy profile in heavily pretreated relapsed/refractory EOC. No ocular toxicity signals have been observed. Durable responses and anti-tumor activity have been demonstrated across a broad range of FRα expression levels in evaluable pts treated at ≥ 2.9 mg/kg. 48% (15/31) of pts were on treatment without disease progression for ≥ 24 weeks and 13% (4/31) remain on treatment for over a year, suggesting that STRO-002 is well tolerated in long-term responding patients. A randomized expansion cohort comparing STRO-002 at 4.3 mg/kg vs 5.2 mg/kg dose levels in less heavily pretreated EOC pts is ongoing. Clinical trial information: NCT03748186.

Anlotinib in combination with TQB2450 in patients with recurrent ovarian cancer (ACTION): A multicenter, single-arm, open-label, phase Ib trial.

5557 Background: Combination of antiangiogenic therapy and immune checkpoint inhibitor therapy is reported as an effective antitumor strategy. TQB2450 is a humanized IgG1 monoclonal antibody against programmed death-ligand 1 (PD-L1). We aimed to assess the activity and safety of TQB2450 plus the antiangiogenic multi-target tyrosine kinase inhibitor anlotinib in patients with recurrent advanced ovarian cancer. Methods: The study with ClinicalTrials.gov identifier NCT04236362 is an open-label, multicohort, and multicenter phase Ib trial evaluating the efficacy and safety of anlotinib combined with TQB2450 in patients with advanced gynecologic cancer. The present study (ACTION study) reports the ovarian cancer cohort. We enrolled patients aged 18–70 years with platinum-resistant or platinum-refractory epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer, an Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease according to the Response Evaluation Criteria in Solid Tumors (RECIST). Eligible patients received anlotinib 12 mg per day orally on days 1 to 14 and TQB2450 1200 mg intravenously on day 1, every three weeks. Treatment continued until disease progression, unacceptable toxicity, and withdrawal of consent. The primary endpoint was objective response rate (ORR) assessed by investigators according to RECIST version 1.1. Secondary endpoints included progression-free survival (PFS), duration of response (DOR), overall survival (OS) and safety. Results: Between 21 Feb 2020 and 15 Jan 2021, 33 patients with a median age of 55 years (range, 26-71) were enrolled and received study treatment. Patients had received at least once platinum-based chemotherapy, and the median number of previous chemotherapy lines was 3 (range, 1–6). 30.3% patients had bevacizumab therapy before enrollment. At data cutoff (15 Jan 2021), the median follow-up was 5.1 months (range, 0.1–10.8). In the 25 efficacy-evaluable patients, 13 of them achieved partial response, yielding the ORR of 52.0% (95% CI, 30.4%–71.6%). The median PFS was 6.7 months (95% CI, 4.5 months to not reached). The median duration of response and the median OS were not reached. The treatment-related grade 3 or 4 adverse events (AEs) occurred in 54.5% patients, and the most common ones were palmar-plantar erythrodysesthesia syndrome (21.2%) and hypertension (18.2%). The most potential immune-related AEs included grade 1 to 2 hypothyroidism (24.2%) and fatigue (9.1%). No treatment-related death was recorded. Conclusions: Anlotinib plus TQB2450 showed encouraging antitumor activity and tolerable toxicity in patients with recurrent advanced ovarian cancer. Clinical trial information: NCT04236362.

Clinical trial in progress: Pivotal study of VB-111 combined with paclitaxel versus paclitaxel for treatment of platinum-resistant ovarian cancer (OVAL, VB-111-701/GOG-3018).

TPS5599 Background: Ofranergene obadenovec (VB-111) is a targeted anti-cancer gene therapy with a dual mechanism of action that includes a broad antiangiogenic effect and induction of a tumor directed immune response. A phase II trial in patients with platinum resistant ovarian cancer showed that VB-111 in combination with weekly paclitaxel was well tolerated and associated with a CA-125 Objective Response Rate (ORR) of 58% with a trend for improved survival. The favorable outcomes were associated with induction of an immunotherapeutic effect of tumor infiltration with CD-8 T cells. Based on these observations, a phase III study was initiated in collaboration with the GOG Foundation, Inc. Methods: Study NCT03398655 is an international, randomized, double-blind, placebo-controlled, phase III study. Eligible patients have recurrent platinum-resistant epithelial ovarian cancer with measurable disease (RECIST 1.1), and may have been previously treated with up to 5 prior lines of therapy. Patient are randomized 1:1 to receive VB-111 (1x1013 VPs) with weekly paclitaxel (80mg/m2), or weekly paclitaxel with placebo. Randomization is stratified by number of prior treatment lines, prior antiangiogenic therapy and platinum refractory disease status. The efficacy endpoints are OS, PFS and ORR by RECIST 1.1 and by CA-125 (GCIG criteria). A pre-planned interim analysis was performed by the DSMC in the first 60 patients evaluable for CA-125 response. The analysis met the pre-defined criteria of a CA-125 ORR (GCIG) in the treatment arm at least 10% higher than in the control arm. Study enrolment is ongoing and over 220 patients were enrolled in the US, EU, and Israel. Enrolment of the full sample size of 400 patients is expected to complete by the end of 2021. Clinical trial information: NCT03398655.

Phase III, randomized trial of mirvetuximab soravtansine versus chemotherapy in patients with platinum-resistant ovarian cancer: primary analysis of FORWARD I

Mirvetuximab soravtansine (MIRV) is an antibody-drug conjugate comprising a folate receptor alpha (FRα)-binding antibody, cleavable linker, and the maytansinoid DM4, a potent tubulin-targeting agent. The randomized, open-label, phase III study FORWARD I compared MIRV and investigator's choice chemotherapy in patients with platinum-resistant epithelial ovarian cancer (EOC). Eligible patients with 1-3 prior lines of therapy and whose tumors were positive for FRα expression were randomly assigned, in a 2 : 1 ratio, to receive MIRV (6 mg/kg, adjusted ideal body weight) or chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan). The primary endpoint was progression-free survival [PFS, Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, blinded independent central review] in the intention-to-treat (ITT) population and in the prespecified FRα high population. A total of 366 patients were randomized; 243 received MIRV and 109 received chemotherapy. The primary endpoint, PFS, did not reach statistical significance in either the ITT [hazard ratio (HR), 0.98, P= 0.897] or the FRα high population (HR, 0.69, P= 0.049). Superior outcomes for MIRV over chemotherapy were observed in all secondary endpoints in the FRα high population including improved objective response rate (24% versus 10%), CA-125 responses (53% versus 25%), and patient-reported outcomes (27% versus 13%). Fewer treatment-related grade 3 or higher adverse events (25.1% versus 44.0%), and fewer events leading to dose reduction (19.8% versus 30.3%) and treatment discontinuation (4.5% versus 8.3%) were seen with MIRV compared with chemotherapy. In patients with platinum-resistant EOC, MIRV did not result in a significant improvement in PFS compared with chemotherapy. Secondary endpoints consistently favored MIRV, particularly in patients with high FRα expression. MIRV showed a differentiated and more manageable safety profile than chemotherapy.