Systemic therapy for advanced cervical cancer: Leveraging the historical threshold of overall survival

Cervical cancer (CC) is a worldwide problem, especially in low- and middle-income countries, where patients are often diagnosed with locally advanced disease. Until recently, all chemotherapy drugs achieved low ORR and 12-month overall survival (12- month OS) for advanced CC after failure for platinum compounds. Advances in systemic therapy with immunotherapy, targeted therapy, and antibody-drug conjugates (ADC) have leveraged the 12-month OS limit. Recently, immunotherapy (pembrolizumab) has become the standard of care in first-line advanced CC combined with platinum and taxane and in second-line after platinum doublet failure.

Monoclonal antibodies in cervical malignancy-related HPV

Despite many efforts to treat HPV infection, cervical cancer survival is still poor for several reasons, including resistance to chemotherapy and relapse. Numerous treatments such as surgery, radiation therapy, immune cell-based therapies, siRNA combined with various drugs, and immunotherapy are being studied and performed to provide the best treatment. Depending on the stage and size of the tumor, methods such as radical hysterectomy, pelvic lymphadenectomy, or chemotherapy can be utilized to treat cervical cancer. While accepted, these treatments lead to interruptions in cellular pathways and immune system homeostasis. In addition to a low survival rate, cervical neoplasm incidence has been rising significantly. However, new strategies have been proposed to increase patient survival while reducing the toxicity of chemotherapy, including targeted therapy and monoclonal antibodies. In this article, we discuss the types and potential therapeutic roles of monoclonal antibodies in cervical cancer.

Balstilimab and other immunotherapy for recurrent and metastatic cervical cancer

Recurrent and metastatic cervical cancer is generally treated by cisplatin, paclitaxel, and bevacizumab with limited benefit this constituting an unmet need. Immune checkpoint inhibitors, namely the inhibitors of programmed death 1 and programmed death ligand 1 have been proved to be efficacious in the treatment of patients with advanced cervical cancer. Recently, a PD-1 inhibitor, pembrolizumab was approved for such cancer. However, there is much scope of improvement of current outcome. Dual blockade of cytotoxic T lymphocyte-associated protein 4 and PD-1 is an attractive therapeutic approach. It is used in other cancers and is currently proposed for cancer cervix also. Search is on for single or combined regimen showing efficacy in multiple pathological conditions of cancer cervix irrespective presence of PD-L1 in malignant tissue. An effort to meet such unmet need has culminated in inventing new immune checkpoint inhibitors namely PD-1 inhibitor, AGEN2034 (Balstilimab) and CTLA-4 inhibitor, AGEN1884 (Zalifrelimab).They have shown meaningful and durable activity as single-agent therapy in previously treated patients with persistent R/M CC in a large phase II trial (NCT03104699) in PD-L1 + and PD-L1- tumour. Responses were found both in squamous cell carcinoma & adenocarcinoma cell types. Balstilimab plus zalifrelimab combination (NCT03495882) produced improved clinical benefit over monotherapy as evidenced by higher relative response rates and longer response duration, as well as a manageable safety profile. Interesting development of this combination and other immunotherapies in R/M CC are discussed in this ensuing review.

The Role of Immunotherapy in the Treatment of Advanced Cervical Cancer: Current Status and Future Perspectives

Cervical cancer remains one of the most common cancers in women around the world however therapeutic options in the advanced and recurrent setting are limited. Immune checkpoint inhibitors (ICI) have been considered an attractive option given the viral etiology of cervical cancer although the majority of patients do not benefit from their use. This review summarises current knowledge and use of immune checkpoint blockade in cervical cancer as well as discussing the challenges faced in their clinical application, namely, the role of biomarker-driven ICI use, potential mechanisms of resistance, strategies to overcome such resistance and additional immunotherapy options beyond ICI.

Phase II study of the safety and efficacy of the anti-PD-1 antibody balstilimab in patients with recurrent and/or metastatic cervical cancer

OBJECTIVE

This phase II clinical trial evaluated the safety and antitumor activity of balstilimab, an anti-PD-1 antibody, in patients with previously-treated, recurrent/metastatic cervical cancer.

METHODS

Eligible patients were 18 years or older with recurrent and/or metastatic cervical cancer and who had relapsed after a prior platinum-based treatment regimen for advanced disease. Balstilimab was administered intravenously at 3 mg/kg once every two weeks, for up to 24 months. The primary endpoint was objective response rate (ORR, RECIST v1.1) as assessed by an independent review committee.

RESULTS

At data cutoff, 161 women (median age, 53 years [range 25-81]) were enrolled and treated with balstilimab. Of these, 140 had measurable disease at baseline and one prior line of platinum-based therapy in the metastatic, persistent, or recurrent setting; these patients were included in the efficacy analyses. The ORR was 15% (95% CI, 10.0%-21.8%) and included 5 patients with a complete response and 16 with a partial response. The median duration of response was 15.4 months. In patients with PD-L1-positive tumors the ORR was 20%, however patients with PD-L1-negative tumors also responded to balstilimab (ORR, 7.9%). Responses were not restricted to tumors of squamous cell histology, and an ORR of 12.5% was seen in the subset of patients with cervical adenocarcinoma. The disease control rate was 49.3% (95% CI, 41.1%-57.5%). Immune-mediated enterocolitis (3.1%) and diarrhea (1.9%) were the most common grade 3 or higher treatment-related adverse events.

CONCLUSION

Balstilimab demonstrated meaningful and durable clinical activity, with manageable safety, in patients with previously-treated, recurrent/metastatic cervical cancer.

RaPiDS (GOG-3028): randomized Phase II study of balstilimab alone or in combination with zalifrelimab in cervical cancer

Balstilimab (anti-programmed death 1) and zalifrelimab (anti-CTLA-4) are two new checkpoint inhibitors that have emerged as promising investigational agents for the treatment of cervical cancer, particularly in the setting of previously-treated, recurrent/metastatic disease. Here we describe the rationale and design of RaPiDS (NCT03894215), a two-arm Phase II study evaluating the safety, tolerability and efficacy of balstilimab administered alone or in combination with zalifrelimab in patients with advanced cervical cancer who progressed after first-line, platinum-based chemotherapy. Patients will be randomized in a 1:1 ratio. The primary end point is objective response rate, and key secondary objectives include safety, duration of response, progression-free survival, overall survival and quality of life outcomes.