Antitumor activity and safety of pembrolizumab in patients with advanced recurrent ovarian cancer: results from the phase II KEYNOTE-100 study

Identification of TTLL8, POTEE, and PKMYT1 as immunogenic cancer-associated antigens and potential immunotherapy targets in ovarian cancer

Most high-grade serous ovarian cancers (OC) do not respond to current immunotherapies. To identify potential new actionable tumor antigens in OC, we performed immunopeptidomics on a human OC cell line expressing the HLA-A02:01 haplotype, which is commonly expressed across many racial and ethnic groups. From this dataset, we identified TTLL8, POTEE, and PKMYT1 peptides as candidate tumor antigens with low expression in normal tissues and upregulated expression in OC. Using tissue microarrays, we assessed the protein expression of TTLL8 and POTEE and their association with patient outcomes in a large cohort of OC patients. TTLL8 was found to be expressed in 56.7% of OC and was associated with a worse overall prognosis. POTEE was expressed in 97.2% of OC patients and had no significant association with survival. In patient TILs, increases in cytokine production and tetramer-positive populations identified antigen-specific CD8 T cell responses, which were dependent on antigen presentation by HLA class I. Antigen-specific T cells triggered cancer cell killing of antigen-pulsed OC cells. These findings suggest that TTLL8, POTEE, and PKMYT1 are potential targets for the development of antigen-targeted immunotherapy in OC.

Tertiary lymphoid structures achieve 'cold' to 'hot' transition by remodeling the cold tumor microenvironment

Immune checkpoint blockade (ICB) therapies have demonstrated significant clinical efficacy in immune-infiltrated tumors such as melanoma and non-small cell lung cancer. However, "cold tumors"-including ovarian cancer, pancreatic cancer, and gliomas-exhibit insufficient immune infiltration, leading to poor therapeutic responses to ICBs and limited improvement in patient prognosis. Recent studies have shown that tumor-associated tertiary lymphoid structures (TLSs) can induce strong local immune responses within the tumor microenvironment (TME), serving as important biological markers for predicting ICB therapy efficacy. Notably, preclinical and clinical studies on cold tumors have confirmed that TLSs can potently enhance ICB efficacy through TME remodeling-a breakthrough that has attracted considerable attention. Here, we systematically examine the immunological profile of cold tumors and decipher the mechanistic basis for their impaired immune cell infiltration. We further delineate the distinctive features of tumor-associated TLSs in generating antitumor immunity and establish criteria for their identification. Significantly, we emphasize the unique capability of TLSs to reprogram the immunosuppressive tumor microenvironment characteristic of cold tumors. Based on these insights, we evaluate clinical evidence supporting TLS-mediated enhancement of ICB efficacy and discuss emerging strategies for exogenous TLSs induction.

Antibody drug conjugate targets are highly differentially expressed across the major types of ovarian cancer

BACKGROUND

Antibody-drug conjugates (ADCs) are emerging anti-cancer agents. The folate receptor alpha (FOLRα)-directed ADC mirvetuximab soravtansine recently demonstrated clinical activity in platinum-resistant ovarian cancer, with other ADCs currently in development. The relative expression of FOLRα and other ADC targets is largely unknown across ovarian cancer histotypes.

METHODS

Expression levels of the ADC targets FOLRα, TROP2 and B7-H4 were assessed by immunohistochemistry in patient cohorts using tumour tissue microarrays of the major ovarian cancer histotypes: high grade serous (HGSOC, n = 331); endometrioid (EnOC, n = 101) and clear cell ovarian carcinoma (CCOC, n = 60). Degree of expression was quantified by membrane histoscore.

RESULTS

We observed differences in ADC target expression patterns across ovarian cancer histotypes. FOLRα expression was highest in HGSOC, with few EnOC or CCOC demonstrating positivity (HGSOC: 70.9 % FOLRα histoscore ≥50 vs 21.1 % and 29.3 % in EnOC and CCOC). B7-H4 was expressed in HGSOC, EnOC and CCOC (99.7 %, 89.8 % and 80.7 % with histoscore ≥50). CCOC were mostly TROP2 negative (89.3 % with histoscore <50); a subset of HGSOC and EnOC expressed TROP2 (54.8 % and 57.7 % with histoscore ≥50, respectively). There was no significant association between ADC target expression and molecular subtypes of HGSOC (BRCA1/2-mutant, CCNE1-gained, other) or EnOC (TP53-mutant, CTNNB1-mutant, POLE-mutant, MMR deficient, no specific molecular profile). In CCOC, ARID1A/B mutation was associated with lower B7-H4 expression (P-adj=0.024).

CONCLUSION

EnOC and CCOC are usually FOLRα negative, while HGSOC, EnOC and CCOC frequently express B7-H4. TROP2 positivity is limited to HGSOC and EnOC. Careful consideration of histotype and ADC target expression levels is warranted when designing and analysing clinical studies of ADCs.

Proteomics analysis and immune profiling reveal regulators of PD-L1 in oesophageal squamous cell carcinoma

BACKGROUND

Proteomics studies have advanced our comprehension of cancer biology, accelerated targeted therapy, and improved patient outcomes.

METHODS

High-resolution mass spectrometry and immune profiling based on immunohistochemistry and multiple immunohistochemistry were employed to investigate proteomic and immune landscapes in oesophageal squamous cell carcinoma (ESCC) and explore the regulators of PD-L1 in ESCC. Molecular validation was performed using qRT-PCR, western blotting, and in vitro functional assays.

RESULTS

Proteomic profiling of 89 treatment-naive ESCC specimens identified over 9300 proteins, with 6900 proteins detected across most samples. Proteome-based stratification identified three subtypes related to diverse clinical and molecular features. Combined proteomics and immune analyses revealed core proteins associated with the immune landscape in ESCC. Further, integrated proteomics, transcriptomics, and immune profiling nominated COTL1 as a potential regulator of PD-L1 in ESCC. Overexpression of COTL1 upregulated both mRNA and protein levels of PD-L1 and promoted cell proliferation in ESCC. Patients with high COTL1 protein expression were likely to have a poor prognosis, along with increased infiltration of CD4+CD8+ and CD4+GrB+ cells.

CONCLUSIONS

Collectively, our integrative analysis enables a more comprehensive understanding of the proteomic and immune landscape of ESCC and implicates COTL1 as a potential modulator of PD-L1 and immune cell infiltration.

Antigen presentation potential is variable among human ovarian tumour and syngeneic murine models and dictates pre-clinical outcomes of immunotherapy

High grade serous ovarian carcinoma (HGSC) is a fatal gynaecological malignancy with limited therapeutic options. Immunotherapies targeting MHC-I-dependent antigen presentation offer potential. Currently, the antigen presentation machinery (APM) of widely used syngeneic murine HGSC models remains poorly characterised, limiting translational relevance. Here, we systematically evaluate APM gene expression in syngeneic murine and patient samples. Tap1 and Psmb8 were identified as critical APM markers, deficient in murine models and strongly correlating with MHC-I expression. Hierarchical clustering correlation analysis using these markers revealed that ID8-p53⁻/⁻BRCA1⁻/⁻ was the most strongly correlated model and aligned with the largest patient subset. Moreover, ID8-ip1 correlated to the smaller second patient subset strongly. The low MHC-I expressing IG10 model was unique clustering alongside patient derived LP28 tumour and not fitting either patient subset. In vivo test of a novel combination immune therapy consisting of Flt3L, Poly(I:C), and paclitaxel therapy demonstrated significantly reduced tumour burden in high APM models (p53⁻/⁻BRCA1⁻/⁻, ID8-ip1; p < 0.01), but not IG10. Furthermore, high expressing MHC-I models were linked to enhanced DC expansion, CD8⁺ T-cell infiltration, and effector differentiation (131 % increase in ID8-ip1), alongside improved CD8⁺ T-cell activation and CD86⁺ B-cell co-stimulation. These findings establish MHC-I as a predictive biomarker for immunotherapy response and underscore the need for APM-enhancing strategies in antigen-poor tumours. By bridging murine models to human APM heterogeneity, this work provides a framework for optimising preclinical immunotherapy evaluation and patient stratification, advancing tailored therapeutic approaches for HGSC.

Molecular Interplay Between PTEN, ARID1A, PD-L1, and MMR in Asian Ovarian Clear Cell Carcinoma: Implications for Immunotherapy Response and Patient Stratification

Ovarian clear cell carcinoma (OCCC) represents a distinct histological subtype with a high prevalence in Asian populations and poor chemotherapy response. This study investigated molecular interactions between phosphatase and tensin homolog (PTEN), AT-rich interactive domain 1A (ARID1A), programmed death-ligand 1 (PD-L1), and mismatch repair (MMR) proteins in Asian patients with OCCC. Immunohistochemical analysis was performed on tissue microarrays from 69 OCCC cases. The expression of PTEN, ARID1A, PD-L1, and four MMR proteins was evaluated alongside clinical data. A high prevalence of PTEN loss (78.3%) and ARID1A deficiency (48.8%), with PD-L1 expression in 26.1% and MMR deficiency in 10.1% of cases, was observed. All PD-L1-positive tumors demonstrated concurrent PTEN loss (p = 0.007). MMR deficiency was significantly associated with ARID1A loss (p = 0.049). PTEN loss correlated with worse progression-free survival (PFS) in early-stage disease (p = 0.039). PTEN and ARID1A alterations represent early pathogenic events in Asian OCCC, with PTEN loss significantly impacting PFS in early-stage disease. The correlation between PTEN loss and PD-L1 expression, alongside ARID1A-MMR deficiency association, provides insights into OCCC's immunological landscape and therapeutic vulnerabilities.

Effectiveness and safety of pembrolizumab for the treatment of Japanese patients with microsatellite instability-high tumors excluding colorectal cancer: a post-marketing surveillance

BACKGROUND

We aimed to assess the real-world effectiveness and safety of pembrolizumab monotherapy in Japanese patients with high-frequency microsatellite instability (MSI-H) solid tumors except colorectal cancer.

METHODS

This multicenter, observational, post-marketing surveillance had a 12-month observation period. We included all patients with locally advanced or metastatic MSI-H solid tumors, except colorectal cancer, in whom standard treatment was difficult or who had shown tumor progression after conventional chemotherapies and had started treatment with pembrolizumab by 31 December 2019.

RESULTS

In total, 403 patients were enrolled, and 396 and 376 patients were included in the safety and effectiveness analysis sets, respectively. The numbers of patients and frequencies of tumor types occurring in ≥20 cases were: endometrial, 162/403 (40.2%); gastric, 61/403 (15.1%); biliary tract, 42/403 (10.4%); pancreatic, 29/403 (7.2%); and ovarian, 20/403 (5.0%). The objective response rate was 50.3% (189/376) and the disease control rate was 71.5% (269/376). The 12-month progression-free survival (PFS) rate was 42.1% and the median PFS was 8.8 months (95% confidence interval, 6.4-11.5). The 12-month overall survival (OS) rate was 75.1%, and median OS was not reached. Treatment-related adverse events (AEs) of special interest of any grade occurred in 128/396 (32.3%) patients, and those of Grade ≥ 3, in 54/396 (13.6%) patients. One patient with esophageal cancer experienced a Grade 5 AE. No new safety signals were observed.

CONCLUSIONS

This study confirmed the real-world effectiveness and safety of pembrolizumab monotherapy in patients with MSI-H solid tumors except colorectal cancer in Japan.

Neoadjuvant Chemotherapy with Dual Immune Checkpoint Inhibitors for Advanced-Stage Ovarian Cancer: Final Analysis of TRU-D Phase II Nonrandomized Clinical Trial

PURPOSE

This open-label, investigator-initiated, phase II study was conducted to evaluate the safety, survival, and neoadjuvant outcomes of neoadjuvant chemotherapy (NAC) combined with dual immune checkpoint inhibitors in advanced-stage epithelial ovarian cancer (EOC).

PATIENTS AND METHODS

Between June 2019 and July 2021, 45 patients with unresectable stage III to IV EOC were enrolled. The patients received three cycles of NAC combined with durvalumab and tremelimumab. All patients underwent interval debulking surgery and received three cycles of durvalumab and adjuvant chemotherapy, followed by 12 cycles of durvalumab as maintenance therapy. The primary endpoint was the 12-month progression-free survival (PFS) rate; the secondary endpoints were the objective response rate after NAC, a chemotherapy response score, pathologic complete response, overall survival, and safety. The preplanned exploratory analyses assessed the lymphocyte infiltration, PD-L1 expression, and genomic profiles of pretreatment tumors.

RESULTS

The 12-month PFS rate was 65.9% [95% confidence interval (CI), 52.8-not estimated (NE)], whereas the 24- and 30-month PFS rates were 38.6% (95% CI, 26.7-NE) and 36.4% (95% CI, 24.7-NE), respectively. After NAC, the objective response rate was 86.7%, whereas 14 patients (31.1%) had a chemotherapy response score of three, and five (11.1%) achieved pathologic complete response. The 30-month overall survival rate was 87.7%. The most common grade ≥3 adverse event was neutropenia (26.7%). In an exploratory analysis, patients with pre-NAC tumors showing PD-L1 (combined positive score) ≥1, high Mutation Signature 3, and a high extracellular matrix signature demonstrated improved PFS outcomes.

CONCLUSIONS

NAC combined with dual immune checkpoint inhibitors is feasible for advanced-stage EOC and shows promising activity with a durable clinical response.

Frequency of microsatellite instability in gynecologic cancers and the efficacy of immune checkpoint inhibitors treated: real-world data from a single gynecologic center

Objective

This study evaluated the incidence of Microsatellite Instability-High (MSI-H) in patients with gynecologic cancers in a single gynecologic center and investigated the effect of immune checkpoint inhibitors (ICIs) in treating MSI-H in advanced or recurrent gynecologic cancers.

Methods

We conducted a retrospective study of patients diagnosed with gynecological cancers between June 2021 and May 2024. We investigated their clinicopathological information, the results of microsatellite instability (MSI), the immunohistochemistry staining PD-L1 analyses, the molecular classification testing, and the tumor response to treatment with ICIs.

Results

Among 1333 patients included in the analysis, the frequency of MSI-H was 1.3% (3/223) in cervical cancer, 25.7% (280/1091) in endometrial cancer, and 10.5% (2/19) in ovarian or tubal and peritoneal cancer. When the patients were evaluated by histologic type, the frequency of MSI-H was 26.1% (241/921) in endometrioid adenocarcinoma and 35.1% (20/57) in mixed adenocarcinoma. Molecular classification results for the 1020 cases that successfully underwent the tests were 71 for the POLE mutation (POLEmut) subtype, 271 for MMR-deficiency (MMRd) subtype, 571 for the non-specific molecular profile (NSMP) subtype, and 107 for the p53 abnormality (p53abn) subtype. Thirty-five patients were treated with ICIs for at least one cycle. The objective response rate (ORR) was 34.3% (95% CI, 19.1% to 52.2%). Among the patients who achieved an objective response, the median time to respond was 2.65 months, and the median duration of response had not been reached. The median progression-free survival (PFS) was 9 months (95% CI, 4 to 10), and the median overall survival (OS) had not been reached. Additionally, in the patients with endometrial cancer, the median PFS in MSI-H patients was 5 months versus 3 months in microsatellite stable (MSS) patients (Δ = 2 months; p=0.92), and the median OS in both MSI-H and MSS patients had not been reached (p=0.89).

Conclusion

This study had shown the MSI-H frequencies for the three major types of gynecological tumors and demonstrated the clinical benefit of treatment with ICIs in patients with advanced or recurrent gynecologic cancer. Among endometrial cancer patients, the effects of immunotherapy may be consistent regardless of MSI status.

Mitigating T cell DNA damage during PARP inhibitor treatment enhances antitumor efficacy

Poly(ADP-ribose) polymerase inhibitors (PARPis) are a class of agents targeting DNA damage repair that have become standard therapy for epithelial ovarian cancer (EOC) and multiple other solid tumors. In addition to targeting DNA damage repair, PARPis actively modulate antitumor immune responses, with efficacy being partially dependent on T cell activity. Here, we found that patient T cells sustain DNA damage during PARPi treatment, which reduces treatment efficacy. Leveraging paired pre- and posttreatment tumor samples from a clinical trial of patients with EOC treated with neoadjuvant niraparib as monotherapy, we showed that the PARPi caused DNA damage, slowed proliferation, and increased apoptosis in T cells, which we validated both in vitro and in mouse models. A genome-wide CRISPR (clustered regularly interspaced short palindromic repeats) knockout screen in primary human T cells identified PARP1 as the principal mediator of PARPi-induced T cell death. T cell-specific deletion of PARP1 or mutating Parp1 at its binding sites in transgenic mice led to reduced T cell DNA damage during PARPi treatment, resulting in improved efficacy of PARPis, alone or in combination with immune checkpoint inhibition. We then engineered PARPi-tolerant CAR T cells using cytosine base editing, which decreased PARPi-induced PARP1 trapping and led to reduced PARPi-induced DNA damage, resulting in superior antitumor efficacy in xenograft models compared with parental CAR T cells. This study highlights the relevance of PARPi-induced DNA damage to T cells and suggests opportunities to improve the efficacy of PARPis as monotherapy or in combination with immunotherapy.

TLR5 Signaling Causes Dendritic Cell Dysfunction and Orchestrates Failure of Immune Checkpoint Therapy against Ovarian Cancer

Ovarian cancer accounts for more deaths than any other cancer of the female reproductive system. Patients who have ovarian tumors infiltrated with high frequencies of T cells are associated with a greater survival probability. However, therapies to revitalize tumor-associated T cells, such as PD-L1/PD-1 or CTLA4 blockade, are ineffective for the treatment of ovarian cancer. In this study, we demonstrate that for ovarian cancer, Toll-like receptor 5 (TLR5) signaling, for which the only known ligand is bacterial flagellin, governed failure of PD-L1 and CTLA4 blockade. Mechanistically, chronic TLR5 signaling on CD11c+ cells in vivo and in vitro impaired the differentiation of functional IL-12-producing XCR1+CD103+ conventional type 1 dendritic cells, biasing CD11c+ precursor cells toward myeloid subsets expressing high levels of PD-L1. This culminated in impaired activation of CD8+ T cells, reducing CD8+ T-cell function and ability to persist within the ovarian tumor microenvironment. Expansion of XCR1+CD103+ conventional type 1 dendritic cells in situ using Flt3L-Ig in combination with PD-L1 blockade achieved significant survival benefit in TLR5 knockout mice bearing ovarian tumors, whereas no benefit was observed in the presence of TLR5 signaling. Thus, we have identified a host-intrinsic mechanism leading to the failure of PD-L1 blockade for ovarian cancer, demonstrating that chronic TLR5 signaling on CD11c+ cells is a barrier limiting the efficacy of checkpoint therapy.

Adaptive immune response and PD-1/ PD-L1 status in chemotherapy treated high grade serous carcinoma is dependent on chemotherapy response score

BACKGROUND

Platinum-based chemotherapy and debulking surgery is the standard of care for patients with advanced tubo-ovarian high-grade serous carcinoma (HGSC). The chemotherapy response scoring (CRS) system is a histopathologic scoring system developed to measure response to neoadjuvant chemotherapy with prognostic implications. Omental samples with high CRS have greater inflammatory cell infiltrates, but the immunophenotype of infiltrating immune cells and PD-L1 expression of the residual tumor has not been well-defined.

DESIGN

Twenty cases of patients with FIGO stage IIIA to IIIC HGSC undergoing interval debulking after receiving 3-4 rounds of chemotherapy were selected. 6/20 cases of omental samples were graded as CRS 1, 7/20 were graded CRS 2, and 7/20 were graded CRS 3. The following immunohistochemical stains were performed: CD8, CD4, Foxp3, PD1, and PD-L1. The total number of tumor-infiltrating lymphocytes was recorded, and each case was given a PD-L1 combined positive score (CPS) and tumor proportion score (TPS).

RESULTS

There was a significantly greater number of CD8+ T cells, PD-1+ T cells, CD4+ T cells, and Foxp3+ T cells in CRS 3-scored cases compared to CRS 1 scored cases (p-values: 0.0018, 0.0224, 0.0071, and 0.0136, respectively). CRS 3-scored cases had a greater PD-L1 CPS (CRS 3 CPS 13 ± 8.2 versus CRS 1 CPS 0 ± 0; p-value: 0.0485).

CONCLUSIONS

Tubo-ovarian high-grade serous carcinoma with greater response to neoadjuvant treatment have significantly greater T cell infiltrate and greater PD-L1 combined positive score, highlighting a potential role of the CRS as a predictive biomarker for immune checkpoint blockade therapy.

The dynamic immune behavior of primary and metastatic ovarian carcinoma

Patients with high-grade serous ovarian carcinoma (HGSC) are usually diagnosed with advanced-stage disease, and the tumors often have immunosuppressive characteristics. Together, these factors are important for disease progression, drug resistance, and mortality. In this study, we used a combination of single-cell sequencing and spatial transcriptomics to identify the molecular mechanisms that lead to immunosuppression in HGSC. Primary tumors consistently showed a more active immune microenvironment than did omental tumors. In addition, we found that untreated primary tumors were mostly populated by dysfunctional CD4 and CD8 T cells in later stages of differentiation; this, in turn, was correlated with expression changes in the interferon α and γ pathways in epithelial cells, showing that cross-communication between the epithelial and immune compartments is important for immune suppression in HGSC. These findings could have implications for the design of clinical trials with immune-modulating drugs.

Transforming treatment paradigms: Focus on personalized medicine for high-grade serous ovarian cancer

High-grade serous ovarian cancer (HGSOC) is the most common and aggressive subtype of ovarian cancer, accounting for approximately 70% of all ovarian cancer cases and contributing significantly to the high mortality rates associated with this disease. Because of the asymptomatic nature of early stage disease, most patients are diagnosed at advanced stages when the cancer has already spread into the abdominal cavity, requiring complex and intensive surgical and chemotherapeutic interventions followed by maintenance therapies. Although a minority of cases are associated with well defined genetic syndromes, specific risk factors and a clear etiology in many cases remain elusive. HGSOC tumors are characterized by a high frequency of somatic gene copy number alterations, often associated with defects in homologous recombination repair of DNA. All attempts to introduce an effective screening for HGSOC to date have been unsuccessful. This review elucidates the complexities surrounding HGSOC and encompasses its etiology, epidemiology, classification, pathogenesis, and the current array of treatment strategies. Understanding molecular underpinnings is crucial for the development of targeted therapies and personalized multimodal treatment approaches in centralized therapeutic structures. This review also examines the importance of the tumor microenvironment. In addition, the authors' objective is to underscore the critical importance of placing the patient's perspective and diversity at the forefront of therapeutic strategies, thereby fostering a genuinely participatory decision-making process and ultimately improving patient quality of life.

Activated immune infiltrates expand opportunities for targeted therapy in p53-abnormal endometrial carcinoma

Tumor protein p53 mutated/abnormal (p53abn) endometrial carcinomas account for over 50% of deaths but comprise only 15% of all endometrial carcinomas. Most patients show limited response to standard-of-care chemotherapy with or without radiotherapy, and only a minority of cases are amenable to targeted therapies like poly-ADP ribose polymerase (PARP) inhibitors and HER2-directed therapies. Recent immunotherapy clinical trials have demonstrated remarkable efficacy, not only in mismatch repair deficient (MMRd) tumors but also in a subset of mismatch repair-proficient (MMRp) tumors. However, the immune microenvironment and its relationship to other therapeutic targets in MMRp endometrial carcinoma remains poorly understood. Here, we characterize the immune microenvironment of p53abn endometrial carcinoma, the most clinically aggressive subtype of MMRp endometrial carcinoma, and correlate antitumor immune signatures with other targetable alterations. We accrued 256 treatment-naïve p53abn endometrial carcinomas and systemically profiled T-cell, B-cell, myeloid, and tumor-cell populations with multiplex immunofluorescence to assess the tissue localization and functional status of immune cells. Shallow whole-genome sequencing was performed on a subset of 126 cases. Patterns of immune infiltration were compared to survival outcomes and mutational signatures. Mixture modeling divided p53abn endometrial carcinoma into tumor-infiltrating lymphocyte (TIL)-rich and TIL-poor subsets. Over 50% of tumors were TIL-rich. TIL-rich cases overexpressed targetable immune evasion molecules and were associated with longer overall and disease-specific survival in multivariate analysis. This effect was particularly pronounced in advanced stage disease and in patients who did not receive adjuvant chemotherapy. TIL did not associate with homologous recombination deficient mutational signatures or HER2 amplification. Our findings demonstrate a biological rationale for immunotherapy in a substantial subset of patients with p53abn endometrial cancer and may help inform combination therapies with immune checkpoint inhibition, PARP inhibitors, and anti-HER2 agents. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Neo-adjuvant pembrolizumab in stage IV high-grade serous ovarian cancer: the phase II Neo-Pembro trial

While immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, their efficacy in high-grade serous ovarian cancer (HGSOC) remains limited. Some patients, however, achieve lasting responses, emphasizing the need to understand how tumor microenvironment and molecular characteristics influence ICI response. The phase 2 Neo-Pembro study (NCT03126812) included 33 untreated stage IV HGSOC patients, who were scheduled for 6 cycles of carboplatin-paclitaxel and interval cytoreductive surgery. Pembrolizumab (pembro) was added from cycle two and continued for one year. The primary objective was to assess intratumoral immune activation using multiplexed immunofluorescence and immune-related gene expression. Our findings show immune activation, evidenced by an increase in CD3 + , CD8 + , CD8 + /FOXP3+ ratio, TNF-α and interferon-γ signaling. Treatment was well-tolerated. We observed major pathologic responses in 9/33 patients (27%, 95%CI 14-46), with pathologic response strongly associated with immune activation and OS. At a median follow-up of 52.8 months, 8/9 major responders were alive, with 6 patients recurrence-free. In contrast, 4/24 minor responders survived, including one recurrence-free. ctDNA clearance was observed in all major responders and was associated with prolonged PFS and OS. PD-L1 expression and homologous recombination deficiency were predictive of major response and may serve as biomarkers, warranting further exploration. These results suggest major responders may benefit from neo-adjuvant pembro.

Advances in the relationship of immune checkpoint inhibitors and DNA damage repair

Cancer immunotherapy, alongside surgery, radiation therapy, and chemotherapy, has emerged as a key treatment modality. Immune checkpoint inhibitors (ICIs) represent a promising immunotherapy that plays a critical role in the management of various solid tumors. However, the limited efficacy of ICI monotherapy and the development of primary or secondary resistance to combination therapy remain a challenge. Consequently, identifying molecular markers for predicting ICI efficacy has become an area of active clinical research. Notably, the correlation between DNA damage repair (DDR) mechanisms and the effectiveness of ICI treatment has been established. This review outlines the two primary pathways of DDR, namely, the homologous recombination repair pathway and the mismatch repair pathway. The relationship between these key genes and ICIs has been discussed and the potential of these genes as molecular markers for predicting ICI efficacy summarized.

Pembrolizumab in Patients With Advanced Clear Cell Gynecological Cancer: A Phase 2 Nonrandomized Clinical Trial

Importance

Advanced clear cell gynecological cancers (CCGCs) have a poor prognosis, with response rates to second-line chemotherapy less than 8%. Preliminary clinical activity with programmed cell death 1 protein (PD-1) inhibitors reported in CCGC merits further investigation.

Objective

To assess the clinical benefit of pembrolizumab in patients with previously treated advanced CCGC.

Design, Setting, and Participants

The PEACOCC trial is a single-arm multicenter phase 2 trial conducted at 5 UK centers investigating the clinical benefit and safety of pembrolizumab. PD-1 inhibitor-naive patients with histologically confirmed advanced CCGC, radiological disease progression following 1 or more prior courses of chemotherapy, and an Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of 0 to 1 were included. Patients were enrolled from March 2019 to October 2021, with data collected until July 2024.

Interventions

Pembrolizumab, 200 mg, intravenously every 21 days up to 2 years until progression, discontinuation due to toxic effects, or patient/clinician decision. Up to 1 year of retreatment on diseases progression, if stable disease, partial response, or complete response at 2 years.

Main Outcomes and Measures

The primary end point was progression-free survival (PFS) rate at 12 weeks using Response Evaluation Criteria in Solid Tumors version 1.1 to detect a 12-week PFS rate of 33% or greater and exclude a PFS rate of less than 15%, with 90% power and 1-sided 5% significance level. Secondary end points included objective response rate, duration of response, PFS, overall survival, safety, and quality of life.

Results

A total of 48 patients were eligible. The median (range) age was 58.5 (32-77) years, and 26 (54%) had an ECOG PS score of 0 and 22 (46%) had an ECOG PS score of 1; 41 (85%) had ovarian, 6 (13%) had endometrial, and 1 (2%) had cervical advanced CCGC. The median (range) courses prior therapy was 3 (1-6); 19 patients (40%) received prior anti-angiogenic therapy, and 19 (40%) had a platinum-free interval of more than 12 months. Grade 3 treatment-related adverse events were observed in 9 patients (19%), and no patients had grade 4 or 5 adverse events. A total of 45 of 46 patients (98%) had mismatch repair-proficient tumors. The 12-week PFS rate was 42% (95% CI, 28-57), and the best objective response rate was 25% (95% CI, 14-40), with 12 partial responses. After a median follow-up of 46.9 months (95% CI, 43.4-55.0), the median PFS was 2.7 months (95% CI, 1.3-5.4), and the median overall survival was 14.8 months (95% CI, 6.7-28.2).

Conclusions and Relevance

The PEACOCC trial showed clinical benefit with pembrolizumab in patients with previously treated advanced CCGC, of whom all except 1 had MMR-proficient disease. Clinical outcomes were durable with an overall tolerable safety profile, justifying further evaluation of pembrolizumab monotherapy for advanced CCGC in a randomized clinical trial.

Trial Registration

ClinicalTrials.gov Identifier: NCT03425565.

The multiple facets of ovarian high grade serous carcinoma: A review on morphological, immunohistochemical and molecular features

High-grade serous ovarian carcinoma (HGSOC) is the most aggressive subtype of epithelial ovarian cancer and a leading cause of mortality among gynecologic malignancies. This review aims to comprehensively analyze the morphological, immunohistochemical, and molecular features of HGSOC, highlighting its pathogenesis and identifying biomarkers with diagnostic, prognostic, and therapeutic significance. Special emphasis is placed on the role of tumor microenvironment (TME) and genomic instability in shaping the tumor's behavior and therapeutic vulnerabilities. Key advancements, such as the identification of TP53 and BRCA mutations, the classification of homologous recombination repair (HRR) deficiencies, and the clinical implications of biomarkers like folate receptor alpha (FRα) and PD-L1 are discussed. These findings reveal actionable insights into targeted therapies, including immune checkpoint inhibitors and PARP inhibitors, which hold promise for improving outcomes in HGSOC. This synthesis of knowledge aims to bridge gaps in understanding HGSOC's multifaceted biology, enhance clinical decision-making, and foster the development of precision therapies.

Mature cystic teratoma and their malignant transformation

Mature cystic teratomas (MCT) are benign germ cells tumors which are fairly common and are often diagnosed incidentally. In most cases they don't present a significant risk to survival, but in some rare cases they can progress to a malignant phenotype. In such cases the treatment must be adjusted to the new conditions and tailored to suit the malignant phenotype. In this review, we aim to describe the main clinical and biological features of various types of recorded malignant transformations and/or complications, as well as stress their differences in clinical behavior and therapeutic options. The management of benign vs. malignant MCT differs greatly and a specific subtype of transformation should be taken into consideration when designing therapy, as it can greatly improve the survival and quality of life.

Preclinical study of inetetamab combined with atezolizumab to synergistically inhibit HER2 and PD-L1 in the treatment of ovarian cancer

Epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy. Precision treatments are crucial for improving patient survival. This research explored the potential anti-tumor effects of combining inetetamab and atezolizumab for HER2+ EOC patients. The expressions of human epidermal growth factor receptor 2 (HER2) and programmed cell death ligand 1 (PD-L1) in EOC cells were evaluated. EOC cell-derived subcutaneous and peritoneal dissemination mouse models were used to evaluate the anti-tumor effects of inetetamab, with or without atezolizumab. The correlations between the expressions of HER2 and PD-L1 as well as the infiltration of T cells in tumors from patients and mice were analyzed by immunohistochemistry. Inetetamab suppressed the growth of HER2+ tumors in mouse models. HER2 overexpression increased PD-L1 levels in EOC cells. The expression level of HER2 is positively related to that of PD-L1 in the tumors of EOC patients as well as the infiltration of both CD4+ and CD8+ T cells. The combination of inetetamab and atezolizumab impeded the growth of HER2+ EOC tumors in vivo and induced a long-term anti-tumor effect with the elevated infiltration of CD103+CD8+ cells. These findings suggest that the combination of inetetamab and atezolizumab could be a promising precision treatment strategy for HER2+ EOC patients.

Unlocking the potential of organopalladium complexes for high-grade serous ovarian cancer therapy

High-Grade Serous Ovarian Cancer (HGSOC) is the most common and lethal subtype of ovarian cancer, known for its high aggressiveness and extensive genomic alterations. Typically diagnosed at an advanced stage, HGSOC presents formidable challenges in drug therapy. The limited efficacy of standard treatments, development of chemoresistance, scarcity of targeted therapies, and significant tumor heterogeneity render this disease incurable with current treatment options, highlighting the urgent need for novel therapeutic approaches to improve patient outcomes. In this study we report a straightforward and stereoselective synthetic route to novel Pd(II)-vinyl and -butadienyl complexes bearing a wide range of monodentate and bidentate ligands. Most of the synthesized complexes exhibited good to excellent in vitro anticancer activity against ovarian cancer cells. Particularly promising is the water-soluble complex bearing two PTA (1,3,5-triaza-7-phosphaadamantane) ligands and the Pd(II)-butadienyl fragment. This compound combines excellent cytotoxicity towards cancer cells with substantial inactivity towards non-cancerous ones. This derivative was selected for further studies on ex vivo tumor organoids and in vivo mouse models, which demonstrate its remarkable efficacy with surprisingly low collateral toxicity even at high dosages. Moreover, this class of compounds appears to operate through a ferroptotic mechanism, thus representing the first such example for an organopalladium compound.

A clinical study of tremelimumab, alone or in combination with olaparib, for recurrent epithelial ovarian cancer

OBJECTIVE

PARP inhibitors may work synergistically to improve the efficacy of immunotherapy in patients with epithelial ovarian cancer (EOC). We performed a parallel-arm study of tremelimumab, alone or with olaparib, in patients with recurrent EOC.

METHODS

Eligibility criteria included measurable disease and progression <12 months from last platinum. Participants were randomized to Arm A (tremelimumab monotherapy, 10 mg/kg/dose intravenously [IV]) or Arm B (dose level 1 [DL1] olaparib orally 150 mg twice daily with tremelimumab IV 3 mg/kg/dose and DL2 olaparib orally 150 mg twice daily with tremelimumab IV 10 mg/kg/dose). Primary objectives were safety, change in peripheral ICOS+ T cells, and identification of optimal dose combination.

RESULTS

Among 24 total patients (12 on Arm A, 6 on Arm B-DL1, 6 on Arm B-DL2), the most common grade 3 toxicities were rash (13 %), immune-mediated hepatitis (8 %), and colitis (8 %). No grade ≥ 4 toxicities were identified. No dose-limiting toxicities were identified. One patient (Arm B-DL2) experienced a partial response; no complete responses were observed. Ten patients (7 on Arm A, 2 on Arm B-DL2, and 1 on Arm B-DL1) had a best response of stable disease. There was a significant increase in CD4+ICOS+ and CD8+ICOS+ T cells at both C1D15 and C1D22 in groups treated with tremelimumab IV 10 mg/kg/dose, but not in those treated with tremelimumab 3 mg/kg/dose.

CONCLUSIONS

Tremelimumab IV 10 mg/kg/dose with olaparib 150 mg orally twice daily was safe and feasible. Tremelimumab 10 mg/kg/dose (as opposed to 3 mg/kg/dose) was required for immune activation, although this did not translate into clinical responses.

Tumor Cell-Expressed Herpesvirus Entry Mediator Regulates Proliferation and Adaptive Immunity in Ovarian Cancer

BACKGROUND

Ovarian cancer (OvCa) is a prevalent gynecological malignancy with an increasing incidence and high mortality rate. Although the role of the herpesvirus entry mediator (HVEM), encoded by the TNFRSF14 gene, is currently considered pivotal in various types of cancer, the regulation of tumor cell-expressed HVEM in OvCa remains inadequately understood.

METHODS

Specimens were used to detect HVEM expression via quantitative RT-PCR and flow cytometry. The proliferation of the murine OvCa cell line ID8 was determined using the Cell Counting Kit-8, colony formation, and EdU staining assays. The immune constituents within the ascites fluid and spleen of tumor-bearing mice were analyzed by flow cytometry. Bioinformatics analysis was performed to explore cytokines, chemokines, and signaling pathways regulated by HVEM, and differential expression levels were confirmed via quantitative RT-PCR and western blot analysis.

RESULTS

Herein, we identified a significant upregulation of HVEM in OvCa tissues compared with that in benign tissues and observed dominant expression of HVEM in CD45⁻EpCAM⁺ subsets in OvCa specimens. Tumor cell-expressed HVEM was found to promote OvCa cell proliferation by partly activating spliced X-box-binding protein 1 (XBP1s)-c-Myc signaling. In mouse models, knockdown of Tnfrsf14 in ID8 cells alleviated OvCa progression and specifically affected the frequency and function of T cells in the ascites fluid and spleen. In addition, tumor cell-expressed HVEM altered chemokine expression (CXCL1/9/10/11 and CCL2/4/5) and STAT signal activation (STAT5 and STAT6) in ID8 cells.

CONCLUSION

This study investigated the effects of HVEM on OvCa and validated its potential as a therapeutic marker for treating OvCa.

Targeting mesothelin-CD24 axis repolarizes tumor-associated macrophages to potentiate PD-1 blockade therapy in high-grade serous ovarian cancer

BACKGROUND

High-grade serous ovarian cancer (HGSOC) is a highly aggressive malignancy marked by an immunosuppressive tumor microenvironment that hinders effective immune responses. A key feature of this environment is the extensive infiltration of myeloid cells, which contributes to immune evasion. This study explored how mesothelin (MSLN), a tumor-associated antigen, modulates the expression of CD24, an emerging target for immune modulation, and its role in promoting immune evasion in HGSOC. Understanding these underlying mechanisms is crucial for enhancing the efficacy of immune checkpoint blockade (ICB) therapies and improving outcomes in patients with HGSOC.

METHODS

We analyzed the expression of MSLN in HGSOC samples and examined its correlation with clinical outcome. In vitro and in vivo models were used to explore how MSLN influences CD24 expression and the polarization of tumor-associated macrophages (TAMs). We also investigated the role of MSLN in the activation of Wnt/β-catenin signaling and its impact on T-cell function and antitumor immunity. The effects of Msln knockdown on CD24 expression and the response to anti-programmed cell death protein-1 (PD-1) therapy were evaluated in syngeneic mouse models.

RESULTS

MSLN expression was found to be significantly elevated in HGSOC, with high MSLN levels correlating with poor prognosis and resistance to ICB. MSLN upregulated CD24 and promoted the protumorigenic polarization of TAMs, contributing to T-cell dysfunction. Mechanistically, MSLN activated Wnt/β-catenin signaling, which in turn enhanced CD24 expression. This activation forms a positive feedback loop that further promotes MSLN transcription. In contrast, Msln knockdown reduced CD24 expression, relieved cytotoxic T-cell suppression, and significantly improved the efficacy of anti-PD-1 therapy in syngeneic models.

CONCLUSIONS

This study elucidates the critical role of MSLN in immune evasion in HGSOC and its underlying mechanisms. Targeting MSLN in combination with ICB is a promising strategy to enhance the efficacy of immunotherapy and improve patient outcomes in HGSOC.

A Critical Role of Intracellular PD-L1 in Promoting Ovarian Cancer Progression

Disrupting the interaction between tumor-cell surface PD-L1 and T cell membrane PD-1 can elicit durable clinical responses. However, only about 10% of ovarian cancer patients respond to PD-1/PD-L1 blockade. Here, we show that PD-L1 expression in ovarian cancer-patient tumors is predominantly intracellular. Notably, PARP inhibitor treatment highly increased intracellular PD-L1 accumulation in both ovarian cancer-patient tumor samples and cell lines. We investigated whether intracellular PD-L1 might play a critical role in ovarian cancer progression. Mutating the PD-L1 acetylation site in PEO1 and ID8Brca1-/- ovarian cancer cells significantly decreased PD-L1 levels and impaired colony formation, which was accompanied by cell cycle G2/M arrest and apoptosis induction. PEO1 and ID8Brca1-/- tumors with PD-L1 acetylation site mutation also exhibited significantly reduced growth in mice. Furthermore, targeting intracellular PD-L1 with a cell-penetrating antibody effectively decreased ovarian tumor-cell intracellular PD-L1 level and induced tumor-cell growth arrest and apoptosis, as well as enhanced DNA damage and STING activation, both in vitro and in vivo. In conclusion, we have shown the critical role of intracellular PD-L1 in ovarian cancer progression.

Optimal early endpoint for second-line or subsequent immune checkpoint inhibitors in previously treated advanced solid cancers: a systematic review

BACKGROUND

The administration of second-line or subsequent immune checkpoint inhibitors (ICIs) in previously treated patients with advanced solid cancers has been clinically investigated. However, previous clinical trials lacked an appropriate primary endpoint for efficacy assessment. This systematic review aimed to explore the most optimal early efficacy endpoint for such trials.

METHODS

Phase 2 or 3 clinical trials involving patients with advanced solid cancers with disease progression following standard first-line therapy receiving second-line or subsequent ICI administration, with adequate survival outcome data, were included from PubMed, Embase, Web of Science, and Cochrane Library databases before February 2023. Quality assessment was conducted using the Cochrane tool and Newcastle-Ottawa Quality Assessment Scale for Cohort Studies for randomized controlled trials (RCTs) and non-randomized trials, respectively. Objective response rate (ORR) and progression-free survival (PFS) at 3, 6, and 9 months were investigated as potential early efficacy endpoint candidates for 12-month overall survival (OS), with a strong correlation defined as Pearson's correlation coefficient r ≥ 0.8.

RESULTS

A total of 64 RCTs comprising 22,725 patients and 106 non-randomized prospective trials involving 10,608 participants were eligible for modeling and external validation, respectively. RCTs examined 15 different cancer types, predominantly non-small-cell lung cancer (NSCLC) (17, 28%), melanoma (9, 14%), and esophageal squamous cell carcinoma (5, 8%). The median sample size of RCTs was 124 patients, and the median follow-up time was 3.2-57.7 months. The ORR (r = 0.38; 95% confidence interval [CI], 0.18-0.54) and PFS (r = 0.42; 95% CI, 0.14-0.64) exhibited weak trial-level correlations with OS. Within ICI treatment arms, the r values of ORR and 3-, 6-, and 9-month PFS with 12-month OS were 0.61 (95% CI, 0.37-0.79), 0.78 (95% CI, 0.62-0.88), 0.84 (95% CI, 0.77-0.90), and 0.86 (95% CI, 0.79-0.90), respectively. External validation of 6-month PFS indicated an acceptable discrepancy between actual and predicted 12-month OS.

CONCLUSIONS

In non-randomized phase 2 trials on second-line or subsequent ICI therapy in patients with advanced solid cancers, 6-month PFS could serve as an early efficacy endpoint. However, early efficacy endpoints are not recommended in RCTs to replace OS.

The UBA1-STUB1 Axis Mediates Cancer Immune Escape and Resistance to Checkpoint Blockade

SIGNIFICANCE

Our study reveals UBA1 as a predictive biomarker for clinical outcomes in ICB cohorts, mediating cancer immune evasion and ICB resistance. We further highlight JAK1 stabilization as a key mechanism of UBA1 inhibition and nominate the UBA1-STUB1 axis as an immuno-oncology therapeutic target to improve the efficacy of ICB.

The oncolytic adenovirus TILT-123 with pembrolizumab in platinum resistant or refractory ovarian cancer: the phase 1a PROTA trial

Immune checkpoint inhibitors have demonstrated modest efficacy as a monotherapy in ovarian cancer. Originally developed to improve efficacy of T-cell therapies such as immune checkpoint inhibitors and adoptive cell transfer, TILT-123 (Ad5/3-E2F-D24-hTNFα-IRES-hIL-2) is a serotype chimeric oncolytic adenovirus encoding tumor necrosis factor alpha and interleukin-2. Here we report results from phase 1a of PROTA, a single-arm, multicentre dose escalation trial with TILT-123 and pembrolizumab in female patients with platinum resistant or refractory ovarian cancer (NCT05271318). The primary endpoint was safety. Secondary endpoints included efficacy, tolerability, virus persistence and anti-viral immunity. Patients (n = 15) received intravenous and intraperitoneal and/or intratumoral injections of TILT-123 as well as intravenous pembrolizumab. Treatment was well tolerated, and no dose-limiting toxicities were observed. The most frequent adverse events were fever (40%), fatigue (40%) and nausea (40%). Disease control was achieved in 64% of evaluable patients (9/14). Median progression-free survival and overall survival were 98 and 190 days respectively. Clinical responses were associated with higher serum anti-adenovirus neutralizing antibody titer at baseline and post-treatment. The phase 1b investigating TILT-123, pembrolizumab and PEGylated liposomal doxorubicin in a similar patient population is underway.

Targeting of Tumoral NAC1 Mitigates Myeloid-Derived Suppressor Cell-Mediated Immunosuppression and Potentiates Anti-PD-1 Therapy in Ovarian Cancer

Epithelial ovarian cancer is the most common type of ovarian cancer with a low rate of response to immunotherapy such as immune checkpoint blockade therapy. In this study, we report that nucleus accumbens-associated protein 1 (NAC1), a putative driver of epithelial ovarian cancer, has a critical role in immune evasion. We showed in murine ovarian cancer models that depleting or inhibiting tumoral NAC1 reduced the recruitment and immunosuppressive function of myeloid-derived suppressor cells (MDSC) in the tumor microenvironment, led to significant increases of cytotoxic tumor-infiltrating CD8+ T cells, and promoted antitumor immunity and suppressed tumor progression. We further showed that tumoral NAC1 directly enhanced the transcription of CXCL16 by binding to CXCR6, thereby promoting MDSC recruitment to the tumor. Moreover, lipid C20:1T produced by NAC1-expressing tumor cells fueled oxidative metabolism of MDSCs and promoted their immune-suppressive function. We also showed that NIC3, a small-molecule inhibitor of NAC1, was able to sensitize mice bearing NAC1-expressing ovarian tumors to anti-PD-1 therapy. Our study reveals a critical role for NAC1 in controlling tumor infiltration of MDSCs and in modulating the efficacy of immune checkpoint blockade therapy. Thus, targeting of NAC1 may be exploited to sensitize ovarian cancer to immunotherapy.

PARP Inhibitors Differentially Regulate Immune Responses in Distinct Genetic Backgrounds of High-Grade Serous Tubo-Ovarian Carcinoma

SIGNIFICANCE

This work highlights how different PARPis, especially talazoparib, modulate immune-related gene expression in ovarian cancer cells, independent of the cGAS-STING pathway. These findings may improve our understanding of how different PARPis affect the immune system in various genetic backgrounds.

Prognostic significance of serum complement activation, neutrophil extracellular traps and extracellular DNA in newly diagnosed epithelial ovarian cancer

PURPOSE

We observed that the tumor microenvironment (TME) in metastatic epithelial ovarian cancer (EOC) and in other solid tumors can reprogram normal neutrophils to acquire a complement-dependent suppressor phenotype characterized by inhibition of stimulated T cell activation. This study aims to evaluate whether serum markers of neutrophil activation and complement at diagnosis of EOC would be associated with clinical outcomes.

EXPERIMENTAL DESIGN

We conducted a two-center prospective study of patients with newly diagnosed EOC (N = 188). Blood and ascites fluid were collected at diagnosis for biomarker analysis. Patients were evaluated for progression-free survival (PFS) and overall survival (OS).

RESULTS

The median OS was 47 months (95 % CI: 34-58) and the median PFS was 12 months (95 % CI: 11-15). Pre-treatment serum levels of genomic DNA (gDNA), markers of neutrophil degranulation (myeloperoxidase [MPO]) and neutrophil extracellular traps (NETs) (citrullinated histone H3 [CitH3]), and complement activation (C3b/c) were each associated with worse OS in univariate analysis. In multivariate analyses controlling for age, stage, and optimal debulking, serum gDNA, MPO, and CitH3 remained associated with worse OS, while C3b/c levels were not. In an exploratory analysis, the largest magnitude of difference in 2-year OS occurred in patients with low C3b/c and low CitH3 compared to all other patients (87 % vs 46 % survival, respectively). In ascites fluid, increased factor H, a negative regulator of complement activation, was associated with improved OS in univariate analysis.

CONCLUSIONS

These results point to serum gDNA, NETs, and complement activation as potential prognostic biomarkers in patients with newly diagnosed EOC.

Incorporating immune checkpoint inhibitors in epithelial ovarian cancer

OBJECTIVE

Therapeutic interventions for epithelial ovarian cancer (EOC) have increased greatly over the last decade but improvements outside of biomarker selected therapies have been limited. There remains a pressing need for more effective treatment options that can prolong survival and enhance the quality of life of patients with EOC. In contrast to the significant benefits of immunotherapy with immune checkpoint inhibitors (CPI) seen in many solid tumors, initial experience in EOC suggests limited efficacy of CPIs monotherapy.

METHODS

A systematic review of phase III studies testing the role of CPIs in ovarian cancer was performed.

RESULTS

Seven randomized trials testing CPIs in newly diagnosed (n = 3) and recurrent (n = 4) EOC are evaluated. Overall, those trials included data of 5671 patients. Single-agent PD-L1 inhibitor trials have not shown significant efficacy in newly diagnosed ovarian cancer. Triplet maintenance with bevacizumab plus olaparib and durvalumab is associated with longer progression-free survival than maintenance with bevacizumab alone in patients without tumor BRCA mutations. CPIs were not effective in platinum-sensitive (n = 1031) and platinum-resistant (n = 1420) EOC.

CONCLUSIONS

The value of adding CPI to standard treatment including poly (ADP-ribose) polymerase (PARP) inhibitors with or without bevacizumab remains unclear and is being addressed in ongoing clinical trials. The combination of cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) inhibitors may enhance the efficacy of immunotherapy in EOC and studies are underway to investigate the combination of CPI with other emerging treatment modalities. PROSPERO registration ID: CRD42024536017.

Immunotherapy in Recurrent Ovarian Cancer

BACKGROUND/OBJECTIVES

It remains challenging to treat recurrent ovarian cancer effectively as traditional interventions like chemotherapy and surgery have limited long-term efficacy, highlighting an urgent need for innovative approaches. Immunotherapy offers potential advantages in modulating the immune response against tumor cells and has emerged as a promising strategy in ovarian cancer management. This review discusses various immunotherapy modalities, including active and passive immune strategies, for recurrent ovarian cancer.

METHODS

We systematically reviewed recent immunotherapy advances for recurrent ovarian cancer, including the efficacy and mechanisms of single and dual immune checkpoint inhibitors, checkpoint inhibitor combinations with chemotherapy or radiotherapy, anti-angiogenic agents, PARP inhibitors, antibody-drug conjugates (ADC), tumor vaccines, and adoptive cell therapies (ACT). Additionally, we assessed emerging research on biomarkers predictive of immunotherapy responsiveness in ovarian cancer.

RESULTS

The findings indicate that immunotherapy, particularly combinations involving immune checkpoint inhibitors and other agents, demonstrates promising efficacy in recurrent ovarian cancer, with some therapies showing enhanced benefits in specific subtypes. The immune microenvironment in platinum-sensitive and -resistant cases exhibits distinct immunological profiles, influencing therapy outcomes. Several potential biomarkers have been identified, potentially aiding in patient stratification and treatment optimization.

CONCLUSIONS

Immunotherapy significantly advances recurrent ovarian cancer treatment, with various combinations potentially improving outcomes. Further research on predictive biomarkers and immune microenvironment characteristics is crucial for personalizing immunotherapy approaches and enhancing their efficacy in managing recurrent ovarian cancer.

First-in-human phase I trial of the bispecific CD47 inhibitor and CD40 agonist Fc-fusion protein, SL-172154 in patients with platinum-resistant ovarian cancer

BACKGROUND

SL-172154 is a hexameric fusion protein adjoining the extracellular domain of SIRPα to the extracellular domain of CD40L via an inert IgG4-derived Fc domain. In preclinical studies, a murine equivalent SIRPα-Fc-CD40L fusion protein provided superior antitumor immunity in comparison to CD47- and CD40-targeted antibodies. A first-in-human phase I trial of SL-172154 was conducted in patients with platinum-resistant ovarian cancer.

METHODS

SL-172154 was administered intravenously at 0.1, 0.3, 1.0, 3.0, and 10.0 mg/kg. Dose escalation followed a modified toxicity probability interval-2 design. Objectives included evaluation of safety, dose-limiting toxicity, recommended phase II dose, pharmacokinetic (PK) and pharmacodynamic (PD) parameters, and antitumor activity.

RESULTS

27 patients (median age 66 years (range, 33-85); median of 4 prior systemic therapies (range, 2-9)) with ovarian (70%), fallopian tube (15%), or primary peritoneal (15%) cancer received SL-172154. Treatment-emergent adverse events (TEAEs) were reported for 27 patients (100%), with 24 (88.9%) having a drug-related TEAE and infusion-related reactions being the most common. 12 patients (44.4%) had grade 3/4 TEAEs, and half of these patients (22.2%) had a drug-related grade 3/4 TEAE. There were no fatal adverse events, and no TEAEs led to drug discontinuation. SL-172154 Cmax and area under the curve increased with dose with greater than proportional exposure noted at 3.0 and 10.0 mg/kg. CD47 and CD40 target engagement on CD4+ T cells and B cells, respectively, approached 100% by 3.0 mg/kg. Dose-dependent responses in multiple cytokines (eg, interleukin 12 (IL-12), IP-10) approached a plateau at ≥3.0 mg/kg. Paired tumor biopsies demonstrated a shift in macrophages from an M2- to an M1-dominant phenotype and increased infiltration of CD8 T cells. PK/PD modeling showed near maximal margination of B cells and a dose-dependent production of IL-12 nearing a plateau at >3.0 mg/kg. The best response was stable disease in 6/27 (22%) patients.

CONCLUSIONS

SL-172154 was tolerable as monotherapy and induced, dose-dependent, and cyclical immune cell activation, increases in multiple serum cytokines, and trafficking of CD40-positive B cells and monocytes following each infusion. The safety, PK, and PD activity support 3.0 mg/kg as a safe and pharmacologically active dose.

TRIAL REGISTRATION NUMBER

NCT04406623.

Pembrolizumab plus chemotherapy in frontline treatment of advanced ovarian cancer: Clinical and translational results from a phase 2 trial

BACKGROUND

The efficacy and feasibility of pembrolizumab combined with chemotherapy in frontline management of advanced high-grade epithelial ovarian cancer (EOC) is unknown. Additionally, modification of the tumor microenvironment following neoadjuvant therapy is not well understood.

METHODS

In this single-arm phase 2 trial (this study was registered at ClinicalTrials.gov: NCT02520154), eligible patients received up to 4 cycles of neoadjuvant chemotherapy followed by interval cytoreduction, 3 cycles of adjuvant intravenous carboplatin/weekly paclitaxel/pembrolizumab, and finally maintenance pembrolizumab until progression or toxicity (maximum 20 cycles). The primary endpoint was progression-free survival (PFS). Secondary endpoints included feasibility, toxicity, and overall survival (OS). PD-L1 staining, multiplex immunofluorescence staining, RNA sequencing, reverse-phase protein array analyses were performed on pre- and post-chemotherapy samples.

FINDINGS

Thirty-one eligible patients were enrolled. Median PFS and OS was 14.88 (95% CI 12.39-23.00) and 57.43 months (95% CI 30.88-not reached), respectively. Among those with PD-L1 combined positive score (CPS) ≥10, the median PFS and OS were not reached compared to those with CPS <10 (10.50 and 30.90 months, respectively). Feasibility was met, with all patients completing their planned adjuvant cycles. Treatment discontinuation due to immune-related toxicity occurred in 6 patients (20%). Chemotherapy resulted in an infiltration of anti-tumor immune cells in the tumor microenvironment. Samples of patients with the best PFS demonstrated increased expression of NF-κB, TGF-β, and β-catenin signaling.

CONCLUSIONS

Pembrolizumab with chemotherapy was feasible and resulted in PFS within the historical range for this EOC population. Patients with CPS ≥10 may benefit more from this regimen, and future studies should investigate this potential biomarker.

FUNDING

This investigator-initiated trial was funded by Merck.

A Phase I Trial of Trebananib, an Angiopoietin 1 and 2 Neutralizing Peptibody, Combined with Pembrolizumab in Patients with Advanced Ovarian and Colorectal Cancer

Ovarian cancers and microsatellite stable (MSS) colorectal cancers are insensitive to anti-programmed cell death 1 (PD-1) immunotherapy, and new immunotherapeutic approaches are needed. Preclinical data suggest a relationship between immunotherapy resistance and elevated angiopoietin 2 levels. We performed a phase I dose escalation study of pembrolizumab and the angiopoietin 1/2 inhibitor trebananib (NCT03239145). This multicenter trial enrolled patients with metastatic ovarian cancer or MSS colorectal cancer. Trebananib was administered intravenously weekly for 12 weeks with 200 mg intravenous pembrolizumab every 3 weeks. The toxicity profile of this combination was manageable, and the protocol-defined highest dose level (trebananib 30 mg/kg weekly plus pembrolizumab 200 mg every 3 weeks) was declared the maximum tolerated dose. The objective response rate for all patients was 7.3% (90% confidence interval, 2.5%-15.9%). Three patients with MSS colorectal cancer had durable responses for ≥3 years. One responding patient's colorectal cancer harbored a POLE mutation. The other two responding patients had left-sided colorectal cancers, with no baseline liver metastases, and genomic analysis revealed that they both had KRAS wild-type, ERBB2-amplified tumors. After development of acquired resistance, biopsy of one patient's KRAS wild-type ERBB2-amplified tumor showed a substantial decline in tumor-associated T cells and an increase in immunosuppressive intratumoral macrophages. Future studies are needed to carefully assess whether clinicogenomic features, such as lack of liver metastases, ERBB2 amplification, and left-sided tumors, can predict increased sensitivity to PD-1 immunotherapy combinations.

Promising new drugs and therapeutic approaches for treatment of ovarian cancer-targeting the hallmarks of cancer

Ovarian cancer remains the most lethal gynecological malignancy. Despite the approval of promising targeted therapy such as bevacizumab and PARP inhibitors, 5-year survival has not improved significantly. Thus, there is an urgent need for new therapeutics. New advancements in therapeutic strategies target the pivotal hallmarks of cancer. This review is giving an updated overview of innovative and upcoming therapies for the treatment of ovarian cancer that focuses specific on the hallmarks of cancer. The hallmarks of cancer constitute a broad concept to reenact complexity of malignancies and furthermore identify possible targets for new treatment strategies. For this purpose, we analyzed approvals and current clinical phase III studies (registered at ClinicalTrials.gov (National Library of Medicine, National Institutes of Health; U.S. Department of Health and Human Services, 2024)) for new drugs on the basis of their mechanisms of action and identified new target approaches. A broad spectrum of new promising drugs is currently under investigation in clinical phase III studies targeting mainly the hallmarks "self-sufficiency in growth signals," "genomic instability," and "angiogenesis." The benefit of immune checkpoint inhibitors in ovarian cancer has been demonstrated for the first time. Besides, targeting the tumor microenvironment is of growing interest. Replicative immortality, energy metabolism, tumor promoting inflammation, and the microbiome of ovarian cancer are still barely targeted by drugs. Nevertheless, precision medicine, which focuses on specific disease characteristics, is becoming increasingly important in cancer treatment.

Tertiary lymphoid structures in high-grade serous tubo-ovarian carcinoma: anatomical site matters

Tertiary lymphoid structures (TLS) in the tumor microenvironment are prognostically beneficial in many solid cancer types. Reports on TLS in high-grade serous tubo-ovarian carcinoma (HGSC) are few, and the prognostic impact is unclear. We investigated mature TLS (mTLS), immature TLS (iTLS) and lymphoid aggregates (LA) in primary adnexal tumors (PTs) and synchronous omental/peritoneal metastases (pMets) of HGSC. Whole H&E slides were scrutinized for mTLS and LA in a population-based cohort of 130 cases with stage III-IV HGSC. The immune cell tumor infiltration was evaluated with single chromogenic immunohistochemistry (IHC) on a tissue microarray (TMA) from the same cases. Selected whole slides (PT n = 11, pMet n = 10) of the cases most abundant in mTLS and LA were further investigated with multiplex IHC and immunofluorescence using digital image analysis (QuPath), to confirm TLS status and map the T and B lymphocyte subtypes. The results showed that mTLS were more common in pMets than in PTs but did not have an independent prognostic impact on overall or progression-free survival. The presence of mTLS correlated with intratumoral infiltration of CD8+ cytotoxic T cells, FOXP3+ regulatory T cells and PD-1+ lymphocytes in pMets only. Although overall mTLS cell composition was similar between PTs and pMets, the outer zones of mTLS in PTs were more immune cell-rich. In conclusion, our results indicate differences in TLS presence and cellular elements between primary adnexal tumors and synchronous peritoneal metastases, which are important to consider when conducting studies of the immune environment in HGSC.

Phase II randomized study of dostarlimab alone or with bevacizumab versus non-platinum chemotherapy in recurrent gynecological clear cell carcinoma (DOVE/APGOT-OV7/ENGOT-ov80)

BACKGROUND

Recurrent gynecological clear cell carcinoma (rGCCC) has a low objective response rate (ORR) to chemotherapy. Previous preclinical and clinical data suggest a potential synergy between immune checkpoint inhibitors and bevacizumab in rGCCC. Dostarlimab, a humanized monoclonal antibody targeting programmed cell death protein 1 (PD-1), combined with the anti-angiogenic bevacizumab, presents a novel therapeutic approach. This study will investigate the efficacy of dostarlimab +/- bevacizumab in rGCCC.

METHODS

DOVE is a global, multicenter, international, open-label, randomized phase 2 study of dostarlimab +/- bevacizumab with standard chemotherapy in rGCCC. We will enroll 198 patients with rGCCC and assign them to one of three groups in a 1:1:1 ratio: arm A (dostarlimab monotherapy), B (dostarlimab + bevacizumab), and C (investigator's choice of chemotherapy [weekly paclitaxel, pegylated liposomal doxorubicin, doxorubicin, or gemcitabine]). Patients with disease progression in arm A or C will be allowed to cross over to arm B. Stratification factors include prior bevacizumab use, prior lines of therapy (1 vs. >1), and primary site (ovarian vs. non-ovarian). Key inclusion criteria are histologically proven recurrent or persistent clear cell carcinoma of the ovary, endometrium, cervix, vagina, or vulva; up to five prior lines of therapy; disease progression within 12 months after platinum-based chemotherapy; and measurable disease. Key exclusion criteria are prior treatment with an anti-PD-1, anti-programmed death-ligand 1, or anti-programmed death-ligand 2 agent. The primary endpoint is progression-free survival determined by investigators. Secondary endpoints are ORR, disease control rate, clinical benefit rate, progression-free survival 2, overall survival, and toxicity. Exploratory objectives include immune biomarkers.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT06023862.

Immune checkpoint inhibitors in gynecological cancers: a narrative review on the practice-changing trials

During the last decades, the introduction of immune checkpoint inhibitors has radically changed the treatment landscape of several cancer types, improving the prognosis and the quality of life of cancer patients. Even for gynecological cancers, where the prognosis has historically been poor despite advancements in surgery, radiotherapy and oncological treatment, immunotherapy has represented a significant leap forward. In cervical and endometrial cancer, the introduction of immunotherapy has radically changed the treatment algorithm, especially for advanced disease. However, the scenario remains less promising for ovarian cancer, where, despite extensive research efforts, no consistent positive results have been achieved with immune checkpoint inhibitors, except for a few cases in rarer histological subtypes Here, we present a narrative review summarizing the most important practice-changing studies involving immune checkpoint inhibitors in gynecological cancers, particularly in cervical, endometrial, ovarian and vulvar cancer.

Integrated proteomics and scRNA-seq analyses of ovarian cancer reveal molecular subtype-associated cell landscapes and immunotherapy targets

BACKGROUND

Epithelial ovarian cancer (EOC) represents the most lethal gynaecological malignancy, yet understanding the connections between its molecular subtypes and their therapeutic implications remains incomplete.

METHODS

We conducted mass spectrometry-based proteomics analyses of 154 EOC tumour samples and 29 normal fallopian tubes, and single-cell RNA sequencing (scRNA-seq) analyses of an additional eight EOC tumours to classify proteomic subtypes and assess their cellular ecosystems and clinical significance. The efficacy of identified therapeutic targets was evaluated in patient-derived xenograft (PDX) and orthotopic mouse models.

RESULTS

We identified four proteomic subtypes with distinct clinical relevance: malignant proliferative (C1), immune infiltrating (C2), Fallopian-like (C3) and differentiated (C4) subtypes. C2 subtype was characterized by lymphocyte infiltration, notably an increased presence of GZMK CD8+ T cells and phagocytosis-like MRC+ macrophages. Additionally, we identified CD40 as a specific prognostic factor for C2 subtype. The interaction between CD40+ phagocytosis-like macrophages and CD40RL+ IL17R CD4+ T cells was correlated with a favourable prognosis. Finally, we established a druggable landscape for non-immune EOC patients and verified a TYMP inhibitor as a promising therapeutic strategy.

CONCLUSIONS

Our study refines the current immune subtype for EOC, highlighting CD40 agonists as promising therapies for C2 subtype patients and targeting TYMP for non-immune patients.

Ovarian cancer-derived IL-4 promotes immunotherapy resistance

Ovarian cancer is resistant to immunotherapy, and this is influenced by the immunosuppressed tumor microenvironment (TME) dominated by macrophages. Resistance is also affected by intratumoral heterogeneity, whose development is poorly understood. To identify regulators of ovarian cancer immunity, we employed a spatial functional genomics screen (Perturb-map), focused on receptor/ligands hypothesized to be involved in tumor-macrophage communication. Perturb-map recapitulated tumor heterogeneity and revealed that interleukin-4 (IL-4) promotes resistance to anti-PD-1. We find ovarian cancer cells are the key source of IL-4, which directs the formation of an immunosuppressive TME via macrophage control. IL-4 loss was not compensated by nearby IL-4-expressing clones, revealing short-range regulation of TME composition dictating tumor evolution. Our studies show heterogeneous TMEs can emerge from localized altered expression of cancer-derived cytokines/chemokines that establish immune-rich and immune-excluded neighborhoods, which drive clone selection and immunotherapy resistance. They also demonstrate the potential of targeting IL-4 signaling to enhance ovarian cancer response to immunotherapy.

Amitriptyline revitalizes ICB response via dually inhibiting Kyn/Indole and 5-HT pathways of tryptophan metabolism in ovarian cancer

Reprogramming tryptophan metabolism (TRP) may be able to overcome immunosuppression and restore the immune checkpoint blockade (ICB) response in patients with epithelial ovarian cancer (EOC) resistant to ICB therapy because TRP metabolism is involved in the kynurenine/indole and serotonin pathways of tryptophan metabolism. Herein, employing amitriptyline (AMI), an antagonist of TLR4 and serotonin transporter (SERT), we revealed that AMI remodels the immunological landscape of EOC. In particular, AMI lowered the expression of IDO1, IL-4I1, and PD-L1, the quantity of KYN and indoles, and the level of immunosuppressive immune cells MDSC, Tregs, and CD8+CD39+/PD-1+ T cell. AMI boosted the killing potential of anti-PD-1-directed CD8+T cells and worked in concert with PD-1 inhibitors to suppress tumor growth and to prolong the survival of EOC-bearing mice. This work highlights AMI as an effective regulator of ICB response by manipulating EOC cell TRP metabolism, indicating it could be a potential strategy for improving EOC ICB therapy.

Challenges in Implementing Comprehensive Precision Medicine Screening for Ovarian Cancer

Precision medicine has revolutionised targeted cancer treatments; however, its implementation in ovarian cancer remains challenging. Diverse tumour biology and extensive heterogeneity in ovarian cancer can limit the translatability of genetic profiling and contribute to a lack of biomarkers of treatment response. This review addresses the barriers in precision medicine for ovarian cancer, including obtaining adequate and representative tissue samples for analysis, developing functional and standardised screening methods, and navigating data infrastructure and management. Ethical concerns related to patient consent, data privacy and health equity are also explored. We highlight the socio-economic complexities for precision medicine and propose strategies to overcome these challenges with an emphasis on accessibility and education amongst patients and health professionals and the development of regulatory frameworks to support clinical integration. Interdisciplinary collaboration is essential to drive progress in precision medicine to improve disease management and ovarian cancer patient outcomes.

Chemotherapy induces myeloid-driven spatially confined T cell exhaustion in ovarian cancer

Anti-tumor immunity is crucial for high-grade serous ovarian cancer (HGSC) prognosis, yet its adaptation upon standard chemotherapy remains poorly understood. Here, we conduct spatial and molecular characterization of 117 HGSC samples collected before and after chemotherapy. Our single-cell and spatial analyses reveal increasingly versatile immune cell states forming spatiotemporally dynamic microcommunities. We describe Myelonets, networks of interconnected myeloid cells that contribute to CD8+ T cell exhaustion post-chemotherapy and show that M1/M2 polarization at the tumor-stroma interface is associated with CD8+ T cell exhaustion and exclusion, correlating with poor chemoresponse. Single-cell and spatial transcriptomics reveal prominent myeloid-T cell interactions via NECTIN2-TIGIT induced by chemotherapy. Targeting these interactions using a functional patient-derived immuno-oncology platform demonstrates that high NECTIN2-TIGIT signaling in matched tumors predicts responses to immune checkpoint blockade. Our discovery of clinically relevant myeloid-driven spatial T cell exhaustion unlocks immunotherapeutic strategies to unleash CD8+ T cell-mediated anti-tumor immunity in HGSC.

Interferon response and epigenetic modulation by SMARCA4 mutations drive ovarian tumor immunogenicity

Cell-intrinsic mechanisms of immunogenicity in ovarian cancer (OC) are not well understood. Damaging mutations in the SWI/SNF chromatin remodeling complex, such as SMARCA4 (BRG1), are associated with improved response to immune checkpoint blockade; however, the mechanism by which this occurs is unclear. We found that SMARCA4 loss in OC models resulted in increased cancer cell-intrinsic immunogenicity, characterized by up-regulation of long-terminal RNA repeats, increased expression of interferon-stimulated genes, and up-regulation of antigen presentation machinery. Notably, this response was dependent on STING, MAVS, and IRF3 signaling but was independent of the type I interferon receptor. Mouse ovarian and melanoma tumors with SMARCA4 loss demonstrated increased infiltration and activation of cytotoxic T cells, NK cells, and myeloid cells in the tumor microenvironment. These results were recapitulated in BRG1 inhibitor-treated SMARCA4-proficient tumor models, suggesting that modulation of chromatin remodeling through targeting SMARCA4 may serve as a strategy to overcome cancer immune evasion.

Integrative multi-omics analysis uncovers tumor-immune-gut axis influencing immunotherapy outcomes in ovarian cancer

Recurrent ovarian cancer patients, especially those resistant to platinum, lack effective curative treatments. To address this, we conducted a phase 2 clinical trial (NCT02853318) combining pembrolizumab with bevacizumab, to increase T cell infiltration into the tumor, and oral cyclophosphamide, to reduce the number of regulatory T cells. The trial accrued 40 heavily pretreated recurrent ovarian cancer patients. The primary endpoint, progression free survival, was extended to a median of 10.2 months. The secondary endpoints demonstrated an objective response rate of 47.5%, and disease control in 30% of patients for over a year while maintaining a good quality of life. We performed comprehensive molecular, immune, microbiome, and metabolic profiling on samples of trial patients. Here, we show increased T and B cell clusters and distinct microbial patterns with amino acid and lipid metabolism are linked to exceptional clinical responses. This study suggests the immune milieu and host-microbiome can be leveraged to improve antitumor response in future immunotherapy trials.

Harnessing Antitumor Immunity in Ovarian Cancer

Despite progress in other tumor types, immunotherapy is not yet part of the standard of care treatment for high-grade serous ovarian cancer patients. Although tumor infiltration by T cells is frequently observed in patients with ovarian cancer, clinical responses to immunotherapy remain low. Mechanisms for immune resistance in ovarian cancer have been explored and may provide insight into future approaches to improve response to immunotherapy agents. In this review, we discuss what is known about the immune landscape in ovarian cancer, review the available data for immunotherapy-based strategies in these patients, and provide possible future directions.

Intraperitoneal immunotherapy with denileukin diftitox (ONTAK) in recurrent refractory ovarian cancer

BACKGROUND

Denileukin diftitox (ONTAK) is a diphtheria/IL-2R fusion protein able to deplete regulatory T cells in peripheral blood. Regulatory T cells in the local immune microenvironment have been shown to be associated with poor prognosis in ovarian cancer. This study examined whether denileukin diftitox (ONTAK) could be safely administered intraperitoneal in patients with advanced refractory ovarian cancer and assessed its effects on regulatory T cells and tumor associated cytokines in ascites and peripheral blood.

PATIENTS AND METHODS

A phase I dose escalation study of intraperitoneal denileukin diftitox (ONTAK) enrolled 10 patients with advanced, refractory ovarian carcinoma at 3 doses (5 μg/kg, 15 μg/kg, and 25 μg/kg). Serial CA-125 measurements assessed clinical response. Regulatory T cells were quantified using RT-PCR and cytokine levels measured by Luminex.

RESULTS

The maximum tolerated dose was 15 μg/kg with a dose limiting toxicity observed in 1 out of 6 patients in the expansion group. The majority of adverse events were transient grades 1-2. One patient treated at the 25 μg/kg dose experienced cytokine storm with prolonged hospitalization. 3 patients had decreases in CA-125 after treatment but none met criteria for partial response. Treatment with denileukin diftitox (ONTAK) decreased regulatory T cells in peripheral blood and ascites. Treated patients did not show any significant changes in IL-8, TGF-β, sIL2Ra in ascites or peripheral blood.

CONCLUSIONS

Denileukin diftitox (ONTAK) can be safely administered intraperitoneally to recurrent refractory ovarian cancer patients. Regulatory T cells were reduced in ascites and peripheral blood, but there were no significant changes in cytokine levels.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov # NCT00357448.