Platinum-sensitive Disease Research Articles

Efficacy of a platinum-based chemotherapy rechallenge for platinum-sensitive recurrence after PARP inhibitor maintenance

ObjectivePlatinum-free interval (PFI) is the period from the end of platinum-based chemotherapy to the date of recurrence. If the PFI is > 6 months, a platinum-based chemotherapy rechallenge is considered; however, its efficacy after poly adenosine 5′-diphosphate-ribose polymerase (PARP) inhibitor maintenance therapy is unknown. This study aimed to examine the efficacy of a platinum-based chemotherapy rechallenge after PARP inhibitor therapy. MethodsWe retrospectively evaluated patients with ovarian cancer with a PFI≥6 months with PARP inhibitor maintenance therapy, receiving platinum-based chemotherapy. Duration of PARP inhibitor therapy, best response to subsequent platinum chemotherapy rechallenge, and clinical characteristics were collected from medical records. Tumor response was assessed according to RECIST 1.1. Correlations were calculated using Spearman’s correlation coefficients. ResultsAmong the 10 included patients, seven (70 %) received PARP inhibitors after primary chemotherapy, and three (30 %) received chemotherapy for platinum-sensitive relapse. One and five patients harbored a germline BRCA1 and BRCA wild-type mutations, respectively, and two had homologous recombination proficiency. The median PFI was 303.5 (182–602) days, and PARP inhibitor therapy duration was 249 (147–570) days. Platinum chemotherapy rechallenge efficacy was complete and partial response and stable disease in one (10 %), six (60 %), and three (30 %) patients, respectively. The longer the duration of PARP inhibitor treatment, better the response to platinum agents (Spearman correlation coefficient 0.284, p = 0.0288). ConclusionPlatinum-based chemotherapy rechallenge is reasonable for patients with platinum-sensitive disease, using the traditional PFI cutoff of 6 months, even when the PFI is obtained with a maintenance PARP inhibitor.

How Progesterone Receptor Expression Impacts Platinum Sensitivity in Ovarian Clear Cell Carcinoma: Insights from Clinical and Experimental Perspectives.

Ovarian clear cell carcinoma (OCCC) is often considered a relatively platinum-resistant malignancy. The aim of this study was to explore the influence of progesterone receptor (PR) expression levels on platinum sensitivity and survival outcomes in people with OCCC. A retrospective analysis was conducted with 80 people with OCCC who underwent surgery followed by adjuvant chemotherapy. PR expression was assessed via immunohistochemical (IHC) staining and quantified using the H score. The platinum sensitivity and survival outcomes of patients with weak and strong PR expression were compared. Additionally, cisplatin viability and migration experiments were conducted with OCCC cell lines (ES-2 and TOV-21G) with varying PR isoform expressions. Among the 80 patients, 62 were classified as having platinum-sensitive disease, while 18 had platinum-resistant disease. The mean total PR H- score of platinum-sensitive tumors was significantly higher than that of platinum-resistant tumors (p = 0.002). Although no significant differences in progression-free and overall survival were observed between patients with high and low PR expression, those with high PR expression tended to have longer survival. While PR protein was only weakly detectable in ES-2 and TOV-21G cells, a transfection of the PR-A or PR-B gene resulted in a strong expression of PR-A or PR-B, which led to significantly reduced proliferation and migration in ES-2 and TOV-21G cells. Furthermore, overexpression of PR-A or PR-B enhanced cisplatin cytotoxicity in these cell lines. In conclusion, strong PR expression was associated with improved platinum sensitivity and survival outcomes, consistent with our experimental findings. The potential of PR as a tumor sensitizer to cisplatin in OCCC warrants further investigation.

High pre-treatment NLR and PLR predict poor prognosis of patients with recurrent/metastatic head and neck squamous cell carcinoma treated with immune checkpoint inhibitors.

e18001 Background: The treatment landscape of unresectable recurrent and/or metastatic (R/M) Head and Neck Squamous cell Carcinoma (HNSCC) has profoundly changed with the introduction of Immune checkpoint inhibitors (ICIs). High neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been associated with poor outcome in several tumor types. The aim of the present study was to investigate the role of pre-treatment NLR and PLR in predicting overall survival (OS) of patients treated with ICIs. Materials and Methods: We retrospectively reviewed the clinical records of 106 consecutive patients with R/M-HNSCC who received ICIs (single-agent or ICIs-based treatment) between January 2018 and June 2023 at the Istituto Oncologico Veneto of Padua. Patients were grouped into platinum-refractory (patients progressed within 6 months from the last platinum dose) and platinum-sensitive. The cut-off values of pre-treatment NLR and PLR were determined based on percentile distribution (75th percentile). OS was estimated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used to compare survival outcomes. Results: A total of 102 patients were analyzed. Four patients were excluded because of incomplete data. Primary tumor sites were oropharynx (37%), oral cavity (24%), hypopharynx (19%), larynx (15%), nasopharynx (5%) and nasal cavity (1%). 63 patients (62%) with platinum-refractory disease received nivolumab single-agent. All 39 patients (38%) with platinum-sensitive disease were PD-L1 positive (CPS≥1) and received pembrolizumab-based treatment. Median OS was 8.0 months (95% CI 5.8-10.1) in the platinum-refractory cohort and 13.3 months (95% CI 7.3-19.3) in the platinum-sensitive cohort. At the univariate analysis high NLR (≥7) and PLR (≥345) correlated with poor OS in the overall population and in both the platinum-refractory and the platinum-sensitive cohorts (Table1). At the multivariate analysis PLR was an independent predictor of OS. Conclusions: The efficacy results reported in this retrospective series were in line with the literature data. High PLR was an independent predictor of poor outcome regardless of the platinum sensitivity. Prospective studies are needed to better explore the predictive role of easily obtainable blood biomarkers in this poor prognostic population. Univariate analysis for OS [Table: see text]

Correlation between irAEs and treatment efficacy of anti-PD-1 single agent in patients with recurrent/metastatic head and neck squamous cell carcinoma: A monocentric real-world observational study.

6029 Background: Immune-related adverse events (irAEs) are associated with efficacy of ICIs-based treatment in various cancer types. The aim of this retrospective study was to assess the relationship between irAEs and outcomes in patients with recurrent/metastatic Head and Neck squamous cell carcinoma (R/M-HNSCC) treated with immune checkpoint inhibitors (ICIs) monotherapy. Methods: We retrospectively reviewed data from patients with R/M HNSCC treated with ICIs single-agent between January 2018 and June 2023 at the Istituto Oncologico Veneto of Padua. Common Terminology Criteria for Adverse Events v.5.0 was used to assess irAEs evaluation. Patients were stratified into irAEs (any grade) and non-irAEs groups. Overall survival (OS) and progression free survival (PFS) were assessed using the Kaplan-Meier method. Univariate and multivariate Cox-regression were used to compare survival outcomes. The chi-square test was used to assess the association between irAEs and objective responses (ORR). Results: A total of 89 patients were eligible for the analysis. Patients with platinum-refractory disease received nivolumab (64 patients, 72%). All the 25 patients (28%) with platinum-sensitive disease were PD-L1 positive (CPS≥1) and received pembrolizumab as first line treatment for R/M disease. Median follow-up was 8.7 months. IrAEs (any grade) were observed in 60 patients (67%), including 9 patients (10%) with grade ≥3 AEs. The most common irAEs were endocrinopathies (35%), skin events (15%), hepatic events (13%), diarrhea/colitis (10%) and lipase/amylase elevation (10%). The ORR was higher in the irAEs group than in the non-irAEs group (19.5% vs 2%, p=0.017). PFS and OS were also significantly longer in the irAEs group: median PFS was 3.9 months vs 2.1 months (HR 0.48 95% CI 0.30-0.77; p=0.003) and median OS was 12.5 months vs 4.3 months (HR 0.36 95% CI 0.21-0.60; p=0.000). The statistically significant benefit for both PFS and OS was confirmed at the multivariate analysis (Table1). Patients who experienced endocrine-related irAEs (p=0.004), diarrhea/colitis (p=0.040) and lipase/amylase increase (p=0.005) had significantly longer OS than those without the corresponding toxicity. A positive trend was observed for skin toxicity (p=0.051). Conclusions: The occurrence of irAEs was a predictor of response and survival outcomes in patients with R/M HNSCC treated with ICIs single-agent.[Table: see text]

The Poor Prognosis of Acquired Secondary Platinum Resistance in Ovarian Cancer Patients

Objective: The goal of this study was to evaluate response to treatment and survival in epithelial ovarian cancer patients with acquired secondary platinum resistance (SPR) compared to patients with primary platinum resistance (PPR). Methods: Patients were categorized as PPR (patients with disease recurrence occurring during or <6 months after completing first-line platinum-based chemotherapy) and SPR (patients with previously platinum-sensitive disease that developed platinum resistance on subsequent treatments). Clinico-pathological variables and treatment outcomes were compared. Results: Of the 118 patients included in this study, 60 had PPR and 58 developed SPR. The SPR women had a significantly higher rate of optimal debulking during their upfront and interval operations, significantly lower CA-125 levels during their primary treatment, and a significantly higher complete and partial response rate to primary chemotherapy. Once platinum resistance appeared, no significant difference in survival was observed between the two groups. The median PFS was 2 months in the PPR group and 0.83 months in the SPR group (p = 0.085). Also, no significant difference was found in post-platinum-resistant relapse survival, with a median of 17.63 months in the PPR and 20.26 months in the SPR group (p = 0.515). Conclusions: Platinum resistance is an important prognostic factor in women with EOC. Patients with SPR acquire the same poor treatment outcome as with PPR. There is a great need for future research efforts to discover novel strategies and biological treatments to reverse resistance and improve survival.

Poly (ADP-ribose) polymerase inhibitor therapy and mechanisms of resistance in epithelial ovarian cancer.

Advanced epithelial ovarian cancer is the commonest cause of gynaecological cancer deaths. First-line treatment for advanced disease includes a combination of platinum-taxane chemotherapy (post-operatively or peri-operatively) and maximal debulking surgery whenever feasible. Initial response rate to chemotherapy is high (up to 80%) but most patients will develop recurrence (approximately 70-90%) and succumb to the disease. Recently, poly-ADP-ribose polymerase (PARP) inhibition (by drugs such as Olaparib, Niraparib or Rucaparib) directed synthetic lethality approach in BRCA germline mutant or platinum sensitive disease has generated real hope for patients. PARP inhibitor (PARPi) maintenance therapy can prolong survival but therapeutic response is not sustained due to intrinsic or acquired secondary resistance to PARPi therapy. Reversion of BRCA1/2 mutation can lead to clinical PARPi resistance in BRCA-germline mutated ovarian cancer. However, in the more common platinum sensitive sporadic HGSOC, the clinical mechanisms of development of PARPi resistance remains to be defined. Here we provide a comprehensive review of the current status of PARPi and the mechanisms of resistance to therapy.

Subsequent chemotherapy with paclitaxel plus cetuximab-based chemotherapy following immune checkpoint inhibitor in recurrent or metastatic squamous cell carcinoma of the head and neck

BackgroundImmune checkpoint inhibitors (ICIs) are essential in treating recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). However, the overall response rate (ORR) is limited to 10-20%, and subsequent chemotherapy is critical to maximizing the subjects’ prognosis.MethodsWe retrospectively reviewed 59 patients with R/M SCCHN treated with paclitaxel+cetuximab (PE)-based chemotherapy (PCE, paclitaxel+carboplatin+cetuximab; or PTX+Cmab, paclitaxel+cetuximab) following disease progression after either pembrolizumab or nivolumab monotherapy.ResultsOf 59 patients, 15 were treated with pembrolizumab, with an ORR of 13.3%, and the remaining 44 with nivolumab, with an ORR of 11.4%. All patients in the pembrolizumab cohort had platinum-sensitive disease. Following ICI treatment, 19 patients were treated with PCE and the remaining 40 with PTX+Cmab. PE-based chemotherapy induced favorable and prompt tumor shrinkage even in cases where ICI was not effective, with a median change in the summed dimensions of target lesions of -43.4%, resulting in an ORR of 62.7%. Median time to response was 1.8 months. The patients in the pembrolizumab cohort appeared to have a numerically higher response rate than those receiving nivolumab (80.0% vs. 56.8%). For the 59 patients, progression-free survival and overall survival, calculated from the initiation of PE-based chemotherapy, were 4.6 months and 17.1 months, respectively. Grade ≥3 adverse events occurred in 40.7%, and no treatment-related death was observed.ConclusionPE-based chemotherapy following ICI is encouraging for its robust antitumor efficacy in R/M SCCHN.

Prognosis Following Surgery for Recurrent Ovarian Cancer and Diagnostic Criteria Predictive of Cytoreduction Success: A Systematic Review and Meta-Analysis.

For women achieving clinical remission after the completion of initial treatment for epithelial ovarian cancer, 80% with advanced-stage disease will develop recurrence. However, the standard treatment of women with recurrent platinum-sensitive diseases remains poorly defined. Secondary (SCS), tertiary (TCS) or quaternary (QCS) cytoreduction surgery for recurrence has been suggested to be associated with increased overall survival (OS). We searched five databases for studies reporting death rate, OS, cytoreduction rates, post-operative morbidity/mortality and diagnostic models predicting complete cytoreduction in a platinum-sensitive disease recurrence setting. Death rates calculated from raw data were pooled based on a random-effects model. Meta-regression/linear regression was performed to explore the role of complete or optimal cytoreduction as a moderator. Pooled death rates were 45%, 51%, 66% for SCS, TCS and QCS, respectively. Median OS for optimal cytoreduction ranged from 16-91, 24-99 and 39-135 months for SCS, TCS and QCS, respectively. Every 10% increase in complete cytoreduction rates at SCS corresponds to a 7% increase in median OS. Complete cytoreduction rates ranged from 9-100%, 35-90% and 33-100% for SCS, TCS and QCS, respectively. Major post-operative thirty-day morbidity was reported to range from 0-47%, 13-33% and 15-29% for SCS, TCS and QCS, respectively. Thirty-day post-operative mortality was 0-6%, 0-3% and 0-2% for SCS, TCS and QCS, respectively. There were two externally validated diagnostic models predicting complete cytoreduction at SCS, but none for TCS and QCS. In conclusion, our data confirm that maximal effort higher order cytoreductive surgery resulting in complete cytoreduction can improve survival.

Pegylated liposomal doxorubicin for relapsed epithelial ovarian cancer.

Pegylated liposomal doxorubicin for relapsed epithelial ovarian cancer.

Clinical predictors of survival in advanced epithelial ovarian cancer: Can we foresee the long-term survivors and develop a personalized treatment approach?

e17605 Background: While women with recurrent disease have a poor prognosis, a subset of women are long term survivors (LTS). We aimed to characterize the demographic and clinical characteristics associated with long and short-term survival of patients with advanced epithelial OC (EOC). Methods: We conducted a retrospective descriptive analysis of 822 patients diagnosed with advanced EOC (FIGO stage III/IV) and treated at a single institution, between 2002-2020. Characteristics of short-term survivors (STS), women who survived less than 2 years, were compared to LTS, patients who lived beyond 7 and 10 years from diagnosis. Descriptive statistics of the clinical, oncologic, and treatment parameters were performed using t-test, chi-square. We assessed the contribution of age and stage, BRCA carrier status, interval or primary debulking, optimal debulking, platinum sensitivity, and treatment scheduling upon oncological outcomes. Results: Among 822 patients with advanced EOC, 112 women (13.6%) died withing 24 months from diagnosis, while 139 (16.9%), and 64 (7.8%) survived beyond 7 and 10 years, respectively. Histology, CA125 level at diagnosis, and interval or primary debulking approach, were not significant among the STS and LTS. LTS were younger at diagnosis, (median age of 57, and 56.5 among women who lived > 7 and 10 years, respectively vs. 70 in STS, p < 0.0001). The majority of LTS were diagnosed with stage III disease, (95%, and 97%, > 7 and > 10 years, respectively vs. 67% of STS), in contrast to a greater proportion of STS diagnosed with stage IV (33.0% of STS vs. 5.0%, 3.1% of LTS > 7 and > 10 years, respectively, p < 0.0001). BRCA mutation status was the strongest prognostic factor for LTS ( > 7 and 10 years, OR = 17.8, 21.2 respectively, p < 0.001). Almost half of LTS who were carriers of a deleterious BRCA mutation, (47.3%, 46.2% of LTS > 7 and 10 years, respectively, p < 0.0001), whereas most STS were not carriers of BRCA mutations (89.8%). LTS were predominantly platinum sensitive (99.3%, 98.4% > 7 and > 10 year, vs. 21.6% of STS, P < 0.0001). Optimal cytoreductive surgery was performed in a smaller number of STS compared to the LTS (41.9% of STS vs. 83.5% and 88.7% of LTS > 7 and 10 years, respectively, p < 0.0001). A greater proportion of LTS received weekly treatment scheduling of paclitaxel and carboplatin compared to STS (50.8% and 49.2% of LTS > 7 and 10 years, respectively vs. 31.6% of STS, p < 0.01). Conclusions: The long and short-term survivors of advanced EOC may be identified early in the clinical assessment, based on distinct patient characteristics associated with survivorship, which are critical in developing a personalized treatment approach. Our work demonstrated that LTS are a distinct group of women diagnosed at a younger age, lower stage, optimally debulked, platinum sensitive disease, and BRCA mutation carriers.

Luveltamab tazevibulin (STRO-002), an anti-folate receptor alpha (FolRα) antibody drug conjugate (ADC), safety and efficacy in a broad distribution of FolRα expression in patients with recurrent epithelial ovarian cancer (OC): Update of STRO-002-GM1 phase 1 dose expansion cohort.

5508 Background: Luveltamab tazevibulin (luvelta) is a novel FolRα-targeting ADC with a stable cleavable linker and a 3-aminophenyl hemiasterlin warhead (DAR of 4) that induces cytotoxic and immunologic cell death. Using site-specific conjugation technology, luvelta is designed to target a broad range of FolRα expressing OC. STRO-002-GM1 is a global phase 1 study evaluating luvelta in patients with relapsed OC. We provide updated data from the initial ovarian expansion cohort. Methods: The study enrolled advanced OC pts who had progressive platinum resistant (PROC) after 1-3 prior lines or platinum sensitive disease after 2-3 prior lines of platinum chemotherapy. Pts were randomized 1:1 to received luveltamab at 4.3 or 5.2 mg/kg given IV every 3 weeks until disease progression. Prophylactic corticosteroid eyedrops were not required/administered. FolRα expression was not required for study entry but was analyzed retrospectively in archival tissue using the FOLR1 IHC assay (Ventana Medical Systems). The scoring paradigm assessed percentage of cells with any intensity expression (TPS). TPS >25% was selected for further analysis. Results: 44 pts were enrolled (23 pts at 4.3 mg/kg and 21 pts at 5.2 mg/kg). For pts with a TPS >25% (n=35), the median prior lines of therapy was 2.5 (range 1-3), 69% had prior bevacizumab treatment, and 83% prior PARP inhibitor treatment. Investigator assessed efficacy data for pts with a TPS >25% are presented in the table. The most common grade ≥ 3 treatment emergent adverse events (TEAEs) included neutropenia (70.5%), arthralgia (18.2%), and anemia (13.6%). G3/4 neutropenia had a higher incidence at 5.2 mg/kg than 4.3 mg/kg (76% vs 65%); most notable for G4 neutropenia (52% vs 22%). 1 pt at each dose level had febrile neutropenia. TEAEs led to dose delay in 80% of pts with a higher incidence at 5.2 mg/kg (95% vs. 65%). TEAEs led to dose reduction in 61% of pts with a higher incidence at 5.2 mg/kg (76% vs. 48%). 1 pt had a G5 sepsis with G4 neutropenia. Neutropenia, arthralgia and anemia were managed with standard medical treatment and dose reductions. Conclusions: These dose expansion data confirm activity of luvelta at starting doses ranging from 4.3-5.2 mg/kg in recurrent OC with FolRα expression as low as TPS>25% and supports further clinical study in this population. The global phase 2/3 REFRaME registration study will evaluate luvelta in PROC pts with TPS >25%. Clinical trial information: NCT03748186 . [Table: see text]

Real-world overall survival in second-line maintenance niraparib monotherapy vs active surveillance in BRCA wild-type patients with recurrent ovarian cancer.

5592 Background: The Phase 3NOVA trial assessed niraparib versus placebo as a maintenance treatment (tx) for patients (pts) with recurrent ovarian cancer (OC) who were platinum-sensitive after ≥2 regimens; progression-free survival was the primary endpoint and overall survival (OS) was a secondary endpoint (NCT01847274). The aim of this real-world study was to compare OS in a breast cancer gene wild-type ( BRCAwt) population of pts with recurrent OC and who received second-line maintenance (2Lm) niraparib monotherapy or were under active surveillance (AS). Methods: This study used the US nationwide Flatiron Health de-identified electronic health record (EHR)-derived database. Pts diagnosed with epithelial OC between 1Jan2011–31May2021 who completed 2L therapy between 1Jan2017–2Mar2022 were eligible for inclusion. Pts were BRCAwt, had an ECOG PS score 0–1, epithelial histology, and platinum-sensitive disease with ≥6 months between end of first-line tx and start of 2L tx. Pts were assigned to 2Lm niraparib or AS cohorts based on their management following 2L non-maintenance therapy (≤120 days). Follow-up was measured from the index date (end of 2L non-maintenance therapy) until end of study (31May2022), last activity, or death, whichever came first. A target trial emulation cloned inverse probability of censoring weighting (IPCW) methodology was selected a priori to minimize bias. IPCW median OS and hazard ratios (HR) for 2Lm versus AS were estimated with Kaplan-Meier curves and Cox regression models. Results: Overall, 266 BRCAwt pts were included and received niraparib 2Lm (N=123) or were under AS (N=143). Across 2Lm and AS cohorts, prior to cloning and IPCW, 23.6% and 34.3% of pts were aged ≥75 years, and 26.0% and 16.8% had an EHR value for race as other than White, respectively. The majority of pts were from community practice (80.5% and 90.2%, respectively), had serous OC (79.7% and 81.1%) and had Stage III disease (53.7% and 60.8%). Homologous recombination deficiency status was unknown for 92.7% and 86.0% of pts in 2Lm and AS cohorts, respectively. Median follow-up for 2Lm and AS cohorts was 16.8 (Quartile [Q] 1, Q3: 10.4, 28.7) and 10.2 (Q1, Q3: 4.1, 23.7) months, respectively. IPCW median OS was 28.1 (95% confidence interval [CI]: 22.5, 43.2) and 21.5 (95% CI: 14.7, 27.0) months (HR: 0.63 [95% CI: 0.45, 0.88]) for niraparib 2Lm and AS cohorts, respectively and survival rates at 24 months were 58.2% (95% CI: 47.5, 67.6) and 46.1% (95% CI: 33.6, 57.7). Conclusions: This analysis provides real-world data on OS among pts with OC receiving niraparib 2Lm or under AS in the 2L setting following chemotherapy. Funding: GSK study (219306). Editorial support was provided by Fishawack Health, funded by GSK.

Abstract 966: Exploration of a novel HRD signature (HRDsig) as a biomarker for rucaparib benefit in ARIEL2

Abstract Introduction: The ARIEL2 (Parts 1 and 2) all-comers study tested the effectiveness of the PARP inhibitor rucaparib in patients (pts) with platinum-sensitive or resistant/refractory relapsed high-grade ovarian cancer. Pre-specified analyses identified associations of BRCA1/2 mutation status and genomic LOH (gLOH) with prolonged PFS. Recently, a novel scar-based measure of HRD was described [HRDsig; AACR #1249], and we retrospectively examined its predictive value in the ARIEL2 study. Methods: ARIEL2 (CO-338-017; NCT01891344) was an international multicenter, two-part, phase 2 open-label study conducted across 64 sites. Tumor tissues were profiled with comprehensive genomic profiling for all classes of alterations in at least 287 genes (FoundationOne®). HRDsig was called using a machine learning based algorithm with a broad set of genome-wide copy number and short variant features, independent of gLOH (AACR 2022 #1249). Survival analysis was limited to samples where both gLOH and HRDsig could be evaluated (n=394). Hazard ratios were estimated using a univariate Cox proportional hazards model and objective response rates (ORR) were compared using Fisher’s exact test. gLOH high was defined using a cutoff of 16%, based on ARIEL2 and subsequently FDA approved as a complementary diagnostic. BRCA1 promoter methylation was quantified by digital droplet PCR. Results: HRDsig(+) was identified in 56% (251/449) of cases, including 92% (108/117) of those with deleterious BRCA1/2 alterations and 43% (143/332) of BRCAwt. In the intention to treat (ITT) and in pts with platinum sensitive (plat-sen) disease, HRDsig(+) was predictive of PFS benefit on rucaparib (ITT HR = 0.63 [0.50-0.80], p<0.001; plat-sen HR = 0.44 [0.32-0.60]; p<0.001), similar to gLOH-high (ITT HR = 0.70 [0.56-0.87], p=0.0016; plat-sen HR 0.55 [0.41-0.74], p<0.001). In BRCAwt pts with plat-sen disease (n=179), HRDsig was predictive of objective response and PFS on rucaparib, (ORR 28% in HRDsig(+) vs 10% in HRDsig(-), p=0.002; PFS HR = 0.66 [0.48-0.91]; p=0.012). Tumors with RAD51C/D alterations (5/5; 100%) were identified as HRDsig(+). Most other HRR alterations showed little association with HRDsig, including ATM (0/5 HRDsig(+)), and CHEK2 (0/4 HRDsig(+)). Additionally, 33 BRCAwt pts were identified as BRCA1 methylation positive in the cohort, with 32/33 (97%) identified as HRDsig(+), similar to gLOH-high (30/33; 91%). Conclusions: HRDsig(+) was associated with rucaparib benefit overall and in BRCAwt pts with platinum-sensitive ovarian cancer in this study. HRDsig(+) status exhibited strong association with deficiency caused by both epigenetic (BRCA1 methylation) and genetic (HRR mutation) mechanisms. Additional studies should further explore the utility of this biomarker for pt selection in ovarian cancer and other relevant cancer types to inform the use of PARP inhibitors or other DNA damaging agents. Citation Format: Ethan S. Sokol, Russell W. Madison, Dexter X. Jin, Kuei Ting Chen, Zoe Fleischmann, Justin Newberg, Alexa Shrock, David Fabrizio, Jie He, Neeru Bhardwaj, Kevin K. Lin, Iain A. McNeish, Elizabeth M. Swisher. Exploration of a novel HRD signature (HRDsig) as a biomarker for rucaparib benefit in ARIEL2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 966.

Ovarian Cancer-Insights into Platinum Resistance and Overcoming It.

Ovarian cancer is the most lethal gynecologic malignancy. Platinum-based chemotherapy is the backbone of treatment for ovarian cancer, and although the majority of patients initially have a platinum-sensitive disease, through multiple recurrences, they will acquire resistance. Platinum-resistant recurrent ovarian cancer has a poor prognosis and few treatment options with limited efficacy. Resistance to platinum compounds is a complex process involving multiple mechanisms pertaining not only to the tumoral cell but also to the tumoral microenvironment. In this review, we discuss the molecular mechanism involved in ovarian cancer cells' resistance to platinum-based chemotherapy, focusing on the alteration of drug influx and efflux pathways, DNA repair, the dysregulation of epigenetic modulation, and the involvement of the tumoral microenvironment in the acquisition of the platinum-resistant phenotype. Furthermore, we review promising alternative treatment approaches that may improve these patients' poor prognosis, discussing current strategies, novel combinations, and therapeutic agents.

Efficacy of gemcitabine in combination with nanoparticle albumin-bound paclitaxel in the treatment of recurrent ovarian cancer: A retrospective single institution review.

The objective of this study was to evaluate the efficacy of gemcitabine plus nab-paclitaxel in patients with recurrent ovarian cancer. We performed a single institution retrospective review of patients with recurrent ovarian cancer who were treated with gemcitabine plus nab-paclitaxel from 2012 to 2018 at the Mayo Clinic in Florida. Twenty patients were identified and the median PFS for patients treated with gemcitabine plus nab-paclitaxel was 9months (95% CI, 5.7-20.7). Overall, 17 of the 20 patients (85%) achieved a clinical benefit (complete response 5%, partial response 55%, or stable disease at 3months 25%). For platinum-sensitive disease and platinum-resistant disease, the median OS were 38.7months (95% CI, 5.8-63.1) and 31.2months (95% CI, 12.8-51.8), respectively (p= 0.4306). This well-tolerated regimen shows promising activity in recurrent ovarian cancer and is a viable option for patients who are intolerant to paclitaxel or carboplatin because of allergic reactions.

Phase II Trials of Iniparib (BSI-201) in Combination with Gemcitabine and Carboplatin in Patients with Recurrent Ovarian Cancer.

Iniparib (BSI-201), a novel anticancer agent thought to have poly(ADP-ribose) polymerase (PARP) inhibitory activity and synergy with both gemcitabine and carboplatin (GC) was evaluated in 2 cohorts with GC. Parallel multicenter, single-arm, phase II studies using a Simon two-stage design. Eligible patients had a histological diagnosis of epithelial ovarian carcinoma, fallopian tube cancer, or primary peritoneal carcinoma and demonstration of platinum-sensitive (≥6 months [mo]) or -resistant disease (relapse 2-6 mo post-platinum). Carboplatin (AUC 4 IV day 1), gemcitabine (1000 mg/m2 IV days 1 and 8), and iniparib (5.6 mg/kg IV days 1, 4, 8, and 11) were given on a 21-day cycle. The overall response rate (ORR RECIST 1.0) in platinum sensitive disease was 66% (95% CI, 49-80) with a higher response rate in the 15 pts with germline BRCA mutations (gBRCAmut) (73%). Median PFS was 9.9 (95% CI, 8.2-11.3) months. In the platinum resistant population the ORR was 26% (95% CI, 14-42), however in the 11 pts for whom BRCA mutation was present, the best overall response was PR in 5 (46%). Median PFS was 6.8 months (range, 5.7-7.7 months). Notably, among the 17 CA-125-response-evaluable patients who did not achieve tumor response, 7 (41.2%) patients had a CA125 response, and 93% has clinical benefit (CR + PR + SD). The GCI combination was generally well tolerated despite a high incidence of thrombocytopenia and neutropenia, with no new toxicities. Given the subsequent lack of efficacy demonstrated for iniparib in breast cancer, these are studies of GC and demonstrate a higher than traditionally appreciated activity in patients with platinum-sensitive and -resistant recurrent ovarian cancer, especially in patients that harbor a BRCA mutation, resetting the benchmark for efficacy in phase II trials. (ClinicalTrials.gov Identifiers: NCT01033292 & NCT01033123).

Development of Homologous Recombination Functional Assays for Targeting the DDR.

Identification of tumours that have homologous recombination deficiency (HRD) has become of increasing interest following the licensing of PARP inhibitors. Potential methods to assess HRD status include; clinical selection for platinum sensitive disease, mutational/methylation status, genomic scars/signature and functional RAD51 assays. Homologous recombination (HR) is a dynamic process with the potential to evolve over a disease course, particularly in relation to previous treatment. This is one of the major drawbacks of genomic scars/signatures, as they only demonstrate historic HR status. Functional HR assays have the benefit of giving a real time HR status readout and therefore have the potential for clearer identification of patients who may benefit from PARP inhibitors at that specific time point. However, the development of RAD51 foci assays ready for clinical practice has been challenging. Pre-clinical considerations have included; controlling for variation in tumour proliferation, tissue type and whether DNA damage induction is required. Furthermore, the assays require correlation with clinical outcomes, an understanding of how they complement current testing modalities and validation of test performance in large cohorts. Despite these challenges, given the profound benefit from PARP inhibitors seen in those with an HRD phenotype to date, the ongoing development and validation of these functional HR assays remains of high clinical importance.

Timing and duration of bevacizumab treatment and survival in patients with recurrent ovarian, fallopian tube, and peritoneal cancer: a multi-institution study.

Bevacizumab has demonstrated significant benefit in recurrent ovarian, fallopian tube and peritoneal cancer (OC), but its optimal position within the sequence of systemic therapies remains controversial. Since rebound progression after bevacizumab has been observed in other cancers, and because bevacizumab is incorporated in several regimens used in the recurrent setting, the duration of treatment may impact survival. We sought to identify whether earlier bevacizumab exposure is associated with prolonged bevacizumab therapy and survival by conducting a multi-institution retrospective study of recurrent OC patients treated with bevacizumab from 2004-2014. Multivariate logistic regression identified factors associated with receiving more than six bevacizumab cycles. Overall survival by duration and ordinal sequence of bevacizumab therapy were evaluated using logrank testing and Cox regression. In total, 318 patients were identified. 89.1% had stage III or IV disease; 36% had primary platinum resistance; 40.5% received two or fewer prior chemotherapy regimens. Multivariate logistic regression demonstrated that primary platinum sensitivity (Odds Ratio (OR) 2.34, p = 0.001) or initiating bevacizumab at the first or second recurrence (OR 2.73, p < 0.001) were independently associated with receiving more than six cycles of bevacizumab. Receiving more cycles of bevacizumab was associated with improved overall survival whether measured from time of diagnosis (logrank p < 0.001), bevacizumab initiation (logrank p < 0.001), or bevacizumab discontinuation (logrank p = 0.017). Waiting one additional recurrence to initiate bevacizumab resulted in a 27% increased hazard of death (Hazard Ratio (HR) 1.27, p < 0.001) by multivariate analysis. In conclusion, patients with primary platinum sensitive disease who received fewer prior lines of chemotherapy were able to receive more cycles of bevacizumab, which was associated with improved overall survival. Survival worsened when bevacizumab was initiated later in the ordinal sequence of therapies.

Novel inflammatory markers and prognostic importance of platinum-sensitive ovarian carcinoma relapse

Introduction/Objective. Ovarian carcinomas are the deadliest gynecological tumors. Despite advances in treatment options, survival rates are still not at the desired level. Since clinical signs are not typical in early-stage disease, two-thirds of patients are diagnosed late. Carbohydrate Antigen 125 (CA125) does not have sufficient sensitivity and specificity in early-stage disease and early post-relapse progression. There is a need for a simple and cost-effective marker that correlates with CA125. For this purpose, we aimed to evaluate the potential of systemic inflammatory markers? as diagnostic aids. Methods. Patients with platinum-sensitive recurrent ovarian carcinomas were preferred because the treatment options were more diverse than the resistant group. Using retrospective data collection, 105 patients with platinum-sensitive recurrent ovarian carcinoma, admitted in the last four years were included in the study. Complete blood count data was recorded based on recurrence and progression periods. Results. When the systemic immune inflammatory index (SII) values were evaluated in combination with CA125 in terms of progression during the control visits after platinum-sensitive disease recurrence treatment, progression detection proportions increased to 97.5%, which was 82.9% when only CA125 was used. On the other hand, false positivity, which was 18.5% for CA125 alone, decreased to 2.5% when combined with SII. Furthermore, neutrophil lymphocyte ratio, white blood cells, and neutrophil values showed correlations with high CA125 values. Conclusion. The SII value could be used together with CA125 because it is easy to use, accessible, and has low cost in clinical practice, as well as to increase the accuracy rate and make precise corrections in the false positivity rate.

The role of PARP inhibitor combination therapy in ovarian cancer.

The use of PARP inhibitors (PARPi) has transformed the care of advanced high-grade serous/endometrioid ovarian cancer. PARPi are now available to patients in both the first-line and recurrent platinum-sensitive disease settings; therefore, most patients will receive PARPi at some point in their treatment pathway. The majority of this expanding population of patients eventually acquire resistance to PARPi, in addition to those with primary PARPi resistance. We discuss the rationale behind developing combination therapies, to work synergistically with PARPi and overcome mechanisms of resistance to restore drug sensitivity, and clinical evidence of their efficacy to date.