First-line maintenance therapy with niraparib in advanced platinum-sensitive ovarian cancer: two 'long responder' case reports and review of the current literature

The standard of care for newly diagnosed advanced ovarian cancer is surgical cytoreduction plus platinum-based chemotherapy; however, recurrent disease frequently occurs after treatment. Poly(ADP-ribose) polymerase (PARP) inhibitors as first-line maintenance therapy have been demonstrated to significantly reduce the risk of disease progression or death in patients with advanced ovarian cancer who have a complete or partial response to first-line platinum-based chemotherapy. Niraparib is the only PARP inhibitor that offers a significant progression-free survival benefit compared with placebo in this patient population regardless of the homologous recombination status. However, predictive factors for treatment responses and approaches to dose optimization remain to be investigated. In this study, two Chinese patients with newly diagnosed advanced ovarian cancer exhibited long-term responses to niraparib treatment, and hematological toxicity was successfully managed by dose adjustment. The literature on clinical trials and real-world experience on the efficacy, tolerability, and dose individualization of niraparib treatment in Western and Chinese patients was also reviewed. Future research is warranted to identify the characteristics of 'long responders' to niraparib treatment.

The evolving role of DNA damage response in overcoming therapeutic resistance in ovarian cancer

Epithelial ovarian cancer (EOC) is treated in the first-line setting with combined platinum and taxane chemotherapy, often followed by a maintenance poly (ADP-ribose) polymerase inhibitor (PARPi). Responses to first-line treatment are frequent. For many patients, however, responses are suboptimal or short-lived. Over the last several years, multiple new classes of agents targeting DNA damage response (DDR) mechanisms have advanced through clinical development. In this review, we explore the preclinical rationale for the use of ATR inhibitors, CHK1 inhibitors, and WEE1 inhibitors, emphasizing their application to chemotherapy-resistant and PARPi-resistant ovarian cancer. We also present an overview of the clinical development of the leading drugs in each of these classes, emphasizing the rationale for monotherapy and combination therapy approaches.

Trabectedin plus pegylated liposomal doxorubicin in patients with disease progression after PARP inhibitor maintenance: a real-life case-control study

OBJECTIVE

Poly (ADP-ribose) polymerase (PARP) inhibitor resistance is problematic in epithelial ovarian cancer management and sequencing strategies may be performed to overcome this issue. In this context, our study evaluated the role of non-platinum doublet pegylated liposomal doxorubicin/trabectedin in ovarian cancer platinum-sensitive patients who experienced disease progression under PARP inhibitor maintenance.

METHODS

This case-control study includes patients with recurrent epithelial ovarian cancer treated between March 2016 and April 2021 who progressed under PARP inhibitor maintenance. Data of patients treated with pegylated liposomal doxorubicin/trabectedin (experimental group) were matched 1:1 with a series of patients who received platinum-based treatment (control group). The study outcomes were overall clinical benefit (including complete, partial, and stable response), progression-free survival, and overall survival. The safety of both treatments was also evaluated.

RESULTS

A total of 26 patients in both groups were analyzed. Clinical benefit was achieved in 15 (57%) patients in the study group and 17 (65%) patients in the control group (p=0.38). Patients receiving pegylated liposomal doxorubicin/trabectedin had 5 months of progression-free survival, compared with 5 months in patients treated with platinum-based treatment (p=0.62). Patients in the experimental group achieved a median overall survival of 16 months compared with 19 months in the control group (p=0.26) There was no difference concerning severe toxicities (G3-G4) between groups, except for hepatic toxicity, which was experienced in 30% of the patients receiving pegylated liposomal doxorubicin/trabectedin and none in the control group (p<0.009).

CONCLUSIONS

Pegylated liposomal doxorubicin/trabectedin might be an alternative option to platinum-based treatment in patients experiencing disease progression during PARP inhibitor maintenance with an acceptable toxicity profile. This might be a therapeutic option in this setting, sparing platinum compounds for subsequent relapse.

Advancing antibody-drug conjugates in gynecological malignancies: myth or reality?

Antibody-drug conjugates (ADCs) represent a new class of therapeutic agents designed to target specific antigens on tumor cells, combining the specificity of monoclonal antibodies to the cytotoxicity of classic chemotherapy agents. These drugs have been extensively studied both in solid and hematologic malignancies, leading to substantial improvement in the therapeutic landscape for several tumors. Despite no ADC have been yet approved for the treatment of gynecological malignancies, some agents have shown promising results and might have the potential to become part of the standard of care. Among them, mirvetuximab soravtansine has shown activity in platinum-resistant ovarian cancer with high folate-α receptor expression, as a single agent and in combination. Tisotumab vedotin is active in patients with pre-treated cervical cancer, and further investigation is ongoing. The purpose of this review is to summarize the structural and functional characteristics of ADCs and analyze the most recent and promising data regarding the clinical development of ADCs in gynecological malignancies. The available data on the efficacy of the more studied ADCs in ovarian, endometrial, and cervical cancers will be discussed along with toxicities of special interest, the mechanisms of resistance, and future possible drugs combination.

Perspectives on PARP Inhibitor Combinations for Ovarian Cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors constitute an important treatment option for ovarian cancer nowadays. The magnitude of benefit from PARP inhibitors is influenced by the homologous recombination status, with greater benefit observed in patients with BRCA mutated or BRCA wild-type homologous recombination deficient (HRD) tumors. Although some PARP inhibitor activity has been shown in homologous recombination proficient (HRP) ovarian tumors, its clinical relevance as a single agent is unsatisfactory in this population. Furthermore, even HRD tumors present primary or secondary resistance to PARP inhibitors. Strategies to overcome treatment resistance, as well as to enhance PARP inhibitors' efficacy in HRP tumors, are highly warranted. Diverse combinations are being studied with this aim, including combinations with antiangiogenics, immunotherapy, and other targeted therapies. This review discusses the rationale for developing therapy combinations with PARP inhibitors, the current knowledge, and the future perspectives on this issue.

[Hereditary breast and ovarian cancer syndrome: Diagnosis and therapeutic implications]

Patients who carry the BReast Cancer 1 or 2 (BRCA) gene mutations have an underlying hereditary predisposition for breast and ovarian cancers. These deleterious genetic mutations are the most common ones implicated in hereditary breast and ovarian cancers. Oncogenetic counselling plays a key role in identifying patient for BRCA testing and for mutation identification. BRCA1/2 carriers have to be followed up regularly and may justify breast and/or adnexal prophylactic surgery, according to the French National Cancer Institute guidelines (INCa). Poly- (DNA-riboses) polymerases inhibitors, notably olaparib, have a major role in the management of epithelial ovarian cancer in patients with BRCA mutation and many studies are ongoing to expand their indications in a near future.