Perspectives on the future of urothelial carcinoma therapy: chemotherapy and beyond

INTRODUCTION

Despite recent developments in the landscape of urothelial carcinoma (UC) treatment, platinum combination chemotherapy still remains a milestone. Recently immunotherapeutic agents have gained ever-growing attractivity, particularly in the metastatic setting. Novel chemotherapeutic strategies and agents, such as antibody-drug conjugates (ADCs), and powerful combination regimens have been developed to overcome the resistance of most UC to current therapies.

AREAS COVERED

Herein, we review the current standard-of-care chemotherapy, the development of ADCs, the rationale for combining therapy regimens with chemotherapy in current trials, and future directions in UC management.

EXPERT OPINION

Immunotherapy has prompted a revolution in the treatment paradigm of UC. However, only a few patients experience a long-term response when treated with single-agent immunotherapies. Combination treatments are necessary to bypass resistance mechanisms and broaden the clinical utility of current options. Current evidence supports the intensification of standard-of-care chemotherapy with maintenance immunotherapy. However, the optimal sequence, combination, and duration must be determined to achieve individual longevity with acceptable health-related quality of life. In that regard, ADCs appear as a promising alternative for single and combination strategies in UC, as they specifically target the tumor cells, thereby, theoretically improving treatment efficacy and avoiding extensive off-target toxicities.

Elucidation of Novel Molecular Targets for Therapeutic Strategies in Urothelial Carcinoma: A Literature Review

Urothelial carcinoma therapy is a rapidly evolving and expanding field. Traditional cytotoxic chemotherapy regimens have not produced optimal long-term outcomes, and many urothelial cancer patients have comorbidities that disqualify them as chemotherapy candidates. In recent years, a plethora of novel therapeutic agents that target diverse molecular pathways has emerged as alternative treatment modalities for not only metastatic urothelial carcinoma, but also for muscle-invasive bladder cancer and non-muscle invasive bladder cancer in adjuvant and definitive settings. This review paper aims to discuss the various categories of therapeutic agents for these different types of urothelial cancer, discussing immunotherapy, antibody-drug conjugates, kinase inhibitors, CAR-T cell therapy, peptide vaccination, and other drugs targeting pathways such as angiogenesis, DNA synthesis, mTOR/PI3K/AKT, and EGFR/HER-2.

RX-3117 (fluorocyclopentenyl cytosine): a novel specific antimetabolite for selective cancer treatment

INTRODUCTION

RX-3117 is an oral, small molecule cytidine analog anticancer agent with an improved pharmacological profile relative to gemcitabine and other nucleoside analogs. The agent has excellent activity against various cancer cell lines and xenografts including gemcitabine-resistant variants and it has excellent oral bioavailability; it is not a substrate for the degradation enzyme cytidine deaminase. RX-3117 is being evaluated at a daily oral schedule of 700 mg (5 days/week for 3 weeks) which results in plasma levels in the micromolar range that have been shown to be cytotoxic to cancer cells. It has shown clinical activity in refractory bladder cancer and pancreatic cancer. Areas covered: The review provides an overview of the relevant market and describes the mechanism of action, main pharmacokinetic/pharmacodynamic features and clinical development of this investigational small molecule. Expert opinion: RX-3117 is selectively activated by uridine-cytidine kinase 2 (UCK2), which is expressed only in tumors and has a dual mechanism of action: DNA damage and inhibition of DNA methyltransferase 1 (DNMT1). Because of its tumor selective activation, novel mechanism of action, excellent oral bioavailability and candidate biomarkers for patient selection, RX-3117 has the potential to replace gemcitabine in the treatment of a spectrum of cancer types.