Immune checkpoint blockades in gynecological cancers: A review of clinical trials

Advanced and recurrent gynecological cancers are associated with a poor prognosis and there is still a lack of effective treatments. Immune checkpoint blockade (ICB) therapy is an important element of cancer-targeted therapy and immunotherapy. The programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) pathways are the two main targets of ICB. In this study, we provide a comprehensive review of clinical evidence concerning ICB therapy in gynecological cancers and discuss future implications. All clinical trials of ICB therapy in gynecological cancers were reviewed. We searched ClinicalTrials.gov to collect data from completed and ongoing clinical trials. The clinical evidence regarding the efficacy of ICB agents in gynecological cancers were discussed. Six phase III clinical trials have reported their results of primary outcomes, and a total of 25 phase II clinical trials have been completed. As revealed in phase III trials, pembrolizumab (a PD-1 antibody) improved the overall survival and progression-free survival in endometrial cancer patients with mismatch repair deficiency and cervical cancer patients with expressions of PD-L1. Based on these findings, pembrolizumab was approved by the Food and Drug Administration and European Medicines Agency as a cancer medication used to treat certain patients with endometrial cancer or cervical cancer. Other PD-1 antibodies, including dostarlimab and cemiplimab, also showed antitumor efficacy in clinical trials. Dostarlimab treatment showed an encouraging response rate in endometrial cancer patients with mismatch repair deficiency. Cemiplimab treatment led to a longer overall survival and a lower risk of death than chemotherapy among patients with recurrent cervical cancer. Three completed phase III trials investigated anti-PD-L1 agents (atezolizumab and avelumab) in the treatment of ovarian cancer. The results were not encouraging. Other strategies of ICB therapy which had showed potential clinical benefit in the treatment of gynecological cancers in early-phase trials need to be further evaluated in late-stage trials. The antitumor efficacy of ICB therapy is promising, and the key to making further progress in the treatment of gynecological cancers is to identify more biomarkers and explore innovative combination treatments with other targeted therapies.

Targeted therapies in gynecological cancers: a comprehensive review of clinical evidence

Advanced and recurrent gynecological cancers are associated with poor prognosis and lack of effective treatment. The developments of the molecular mechanisms on cancer progression provide insight into novel targeted therapies, which are emerging as groundbreaking and promising cancer treatment strategies. In gynecologic malignancies, potential therapeutic targeted agents include antiangiogenic agents, poly (ADP-ribose) polymerase (PARP) inhibitors, tumor-intrinsic signaling pathway inhibitors, selective estrogen receptor downregulators, and immune checkpoint inhibitors. In this article, we provide a comprehensive review of the clinical evidence of targeted agents in gynecological cancers and discuss the future implication.

Current Possibilities of Gynecologic Cancer Treatment with the Use of Immune Checkpoint Inhibitors

Despite the ongoing progress in cancer research, the global cancer burden has increased to 18.1 million new cases and 9.6 million deaths in 2018. Gynecological cancers, such as ovarian, endometrial, and cervical cancers, considerably contribute to global cancer burden, leading to $5,862.6, $2,945.7, and $1,543.9 million of annual costs of cancer care, respectively. Thus, the development of effective therapies against gynecological cancers is still a largely unmet medical need. One of the novel therapeutic approaches is to induce anti-cancer immunity by the inhibition of the immune checkpoint pathways using monoclonal antibodies. The molecular targets for monoclonal antibodies are cytotoxic T lymphocyte-associated protein-4 (CTLA-4), programmed cell death protein-1 (PD-1), and programmed death-ligand 1 (PD-L1). The rationale for the use of immune checkpoint inhibitors in patients with gynecological cancers was based on the immunohistological studies showing high expression levels of PD-1 and PD-L1 in those cancers. Currently available immune checkpoint inhibitors include nivolumab, pembrolizumab, atezolizumab, avelumab, durvalumab, and ipilimumab. The efficacy and safety of these inhibitors, used as monotherapy and with combination with chemotherapy, is being currently evaluated in several clinical studies. As the results are promising, more clinical trials are being planned, which may lead to the development of efficient therapies for gynecological cancer patients.

Immunotherapy: Checkpoint Inhibitors in Lynch-Associated Gynecologic Cancers

OPINION STATEMENT

Research into novel therapies for gynecologic cancers is underfunded, and as a result, we are still playing catchup with other solid tumors in the realm of immune checkpoint inhibition. This is despite the fact that two of the most common gynecologic cancers in the USA have strong biologic rationales for response to these agents. Work is now underway to demonstrate safe and effective therapies for our patients. As we better understand the immune system, and more specifically the tumor microenvironment, we will be able to achieve complete responses. The immune system can learn, adapt, and provide ongoing surveillance; if only we could mimic its abilities.