Pharm'Up 
Antibody-drug conjugates (ADCs) merge monoclonal antibodies with potent cytotoxic agents to precisely target cancer cells, minimizing damage to healthy tissues and enhancing treatment outcomes.
Enfortumab vedotin (EV) emerges as a highly effective ADC for urothelial carcinoma, outperforming traditional chemotherapy in key efficacy metrics.
Ongoing research and clinical trials continue to expand the role of ADCs in managing bladder cancer and other malignancies.
The urgent need for innovative cancer treatments is more pressing than ever as various cancer types continue to affect communities worldwide. Traditional chemotherapy, while a cornerstone in cancer care, often leads to significant toxicity in healthy tissues and delivers suboptimal responses for many patients. Enter antibody-drug conjugates (ADCs), a promising new class of therapeutics designed to deliver targeted treatment with reduced harm to non-cancerous cells and fewer side effects. This approach represents a significant leap forward in oncology, particularly for challenging cancers like urothelial carcinoma (UC).
Understanding Urothelial Carcinoma and the Promise of ADCs
Urothelial carcinoma, the predominant form of bladder cancer, originates in the urothelial cells lining the bladder and other parts of the urinary tract, including the ureter and urethra. This cancer poses a substantial health risk, with the potential to progress into muscle-invasive bladder cancer (MIBC), where tumors invade the bladder’s muscle layer, complicating treatment efforts. The quest for effective therapies has led to the development of ADCs, which combine the precision of monoclonal antibodies (mAbs) with the cell-killing power of cytotoxic agents.
ADCs operate by leveraging the antigen-specific targeting capabilities of mAbs to deliver cytotoxic payloads directly to tumor cells, sparing healthy tissues. This is facilitated by linker agents that ensure the controlled release of the drug payload. As noted by Di Maria Jiang, MD, MSc, FRCPC, from Princess Margaret Hospital, University Health Network, during her presentation at the 2025 ASCO Genitourinary Cancers Symposium, “ADCs aim to improve efficacy, reduce toxicity, and expand the therapeutic index.” A notable feature of some ADCs is their bystander effect, where released payloads can eliminate adjacent tumor cells, enhancing overall tumor control.
Enfortumab Vedotin: A Breakthrough in UC Treatment
Among the ADCs making waves in urothelial carcinoma treatment, enfortumab vedotin (EV) stands out. This novel agent, marketed as Padcev by Pfizer, comprises a humanized anti-nectin-4 antibody, a cleavable linker, and monomethyl auristatin E. Approved by the FDA in 2019 for use as a monotherapy or in combination with pembrolizumab (Keytruda; Merck & Co) for patients with locally advanced or metastatic UC, EV has since been the subject of extensive research to optimize its application.
The global, open-label, phase 3 EV-301 clinical trial (NCT03474107) provided critical evidence supporting EV’s approval. This trial randomized 608 patients to receive either EV or chemotherapy, revealing that EV offered longer overall survival (OS) and superior progression-free survival (PFS) compared to chemotherapy. Importantly, the incidence of treatment-related adverse events (TRAEs) was comparable between the two groups, underscoring EV’s safety profile.
Further validation came from the KEYNOTE-A39 trial (NCT03223856), presented at the 2025 ASCO Genitourinary Cancers Symposium. This trial reaffirmed the effectiveness of first-line EV combined with pembrolizumab, demonstrating superior PFS and OS compared to chemotherapy in patients with previously untreated, locally advanced, or metastatic UC. Notably, EV achieved a higher overall response rate, irrespective of cisplatin eligibility or the presence of liver metastases. However, the combination of EV with pembrolizumab showed a higher incidence of grade 3 or higher TRAEs compared to EV monotherapy in EV-301, though still lower than chemotherapy, indicating a balanced safety profile with slightly increased risks.
The Expanding Role of ADCs in Oncology
The success of EV highlights the growing potential of ADCs in transforming cancer care, particularly for UC and other malignancies. Ongoing research aims to deepen our understanding of ADCs, including their mechanisms, optimal combinations, and long-term effects. Pharmacists and healthcare providers play a pivotal role in this evolution, tasked with selecting the appropriate ADC, determining optimal dosages, and managing TRAEs to ensure the best outcomes for patients. As clinical trials continue to explore new ADC candidates and combinations, the treatment landscape for urothelial carcinoma is poised for a revolutionary shift, offering hope for improved survival and quality of life.
About the Author
