Panel Discusses ASCO GU Data Released on Sacituzumab Govitecan: Real-World Findings, UNITE Trial

A roundtable discussion, moderated by Vadim Koshkin, MD, discussed the post-EV-302 world for metastatic urothelial carcinoma, as well as recent trial data from the American Society of Clinical Oncology Genitourinary Cancers Symposium 2024. Dr. Koshkin was joined by Petros Grivas, MD, PhD; Karine Tawagi, MD; Terence Friedlander, MD; and Guru Sonpavde, MD.

In the fifth segment of the roundtable series, the panel highlighted new data released on sacituzumab govitecan (SG), including real-world findings and relevant results from the UNITE trial.

Watch the next segment in this series.

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Dr. Koshkin: We’ll now delve into some data from this conference concerning SG. Dr. Tawagi, perhaps you could elaborate on the SG abstract.

Dr. Tawagi: Certainly. There was an intriguing abstract discussing the real-world toxicity of SG. They examined approximately 86 patients, with about two-thirds having received EV in the immediate prior line of therapy. A total of 71 percent of patients received EV at some point before SG, and they found the toxicity to be very similar to what was reported in the TROPHY-U-01 trial. This included general neutropenia, GI toxicity, with about 25% of patients receiving primary GCSF prophylaxis, and none of those experiencing severe neutropenia. This study suggests a case for considering GCSF in treatment plans as primary prophylaxis.

Another noteworthy finding was that about half of the patients did not require dose reduction, maintaining the same 10 mg/kg dosage throughout their sacituzumab treatment. While this retrospective study lacked efficacy data, it provided valuable insights into the safety profile of SG.

Dr. Koshkin: Very interesting data, indeed. Is this consistent with current practice regarding GCSF?

Dr. Friedlander: I have encountered challenges with insurance regarding primary GCSF prophylaxis, needing to advocate for its approval. From my recollection of the TROPHY-U-01 study, around 20% of patients experienced grade 3 neutropenia, potentially higher, with a lower rate of febrile neutropenia, approximately 10%. To me, these numbers warrant considering primary GCSF. Financial concerns aside, preventing neutropenic infections in advanced bladder cancer patients seems crucial. This data should support providers considering this approach.

Dr. Grivas: I wholeheartedly agree. I routinely use GCSF as primary prophylaxis to reduce neutropenia. This retrospective data reinforces this approach. I take into account patient demographics, such as older age, prior therapies, comorbidities, and performance status, to justify this upfront. It has helped maintain dose consistency and treatment adherence, which is crucial.

Regarding response rates, in TROPHY-U-01 Cohort 1, it was 28% as monotherapy, aligning with what we observed in the real-world cohort. This underscores the potential efficacy of SG even in patients with variant histology. Dr. Koshkin, you mentioned data from the UNITE registry addressing SG activity in variant histology.

Dr. Koshkin: Indeed, that’s the next abstract we will discuss. SG is a potent drug, widely used, especially post-platinum and post-immunotherapy. The analysis of the UNITE study, focusing on patients with variant histology treated with SG, revealed response rates consistent with clinical trials, even in heavily pretreated populations. This suggests the potential for efficacy in variant histologies, which is further supported by Dr. Grivas’ trial specifically investigating SG in these patients.

Dr. Grivas: Our experience from the TROPHY-U-01 Cohort 1 study and ongoing research at the University of Washington emphasize the relevance of SG in variant histologies. Our prospective neoadjuvant trial aims to explore SG’s activity further in this context.

Dr. Friedlander: It’s exciting to consider deeper histological analysis in responders versus non-responders, particularly in understanding neuroendocrine markers. Small-cell tumors present a challenge, but recent developments offer hope, as seen with DLL3-targeted therapies.

Dr. Koshkin: Agreed. Small-cell bladder cancer remains a therapeutic challenge, underscoring the need for continued research and better treatment options.