Personalised peptide vaccination promising in bladder cancer

By Shreeya Nanda, Senior medwireNews Reporter

Metastatic bladder cancer patients who have progressed on first-line platinum-based chemotherapy could derive survival benefits from personalised peptide vaccination (PPV), according to phase II trial results.

The authors explain that PPV is a “novel immunotherapeutic approach” that involves the administration of four human leukocyte antigen-matched antigens chosen from a pool of 31 peptides in 12 injectable doses.

In this open-label trial, the primary endpoint of median progression-free survival was comparable for the 39 patients with metastatic urothelial carcinoma of the bladder randomly assigned to receive PPV plus best supportive care and their 41 counterparts treated with best supportive care alone (median 2.0 vs 1.8 months).

But overall survival was longer for the PPV group than for the control group, at a median of 7.9 and 4.1 months, respectively, equating to a significant hazard ratio of 0.58.

And 23% of patients in the PPV treatment arm achieved a partial response compared with none of those in the best supportive care alone arm.

Researcher Masanori Noguchi (Kurume University School of Medicine, Japan) and colleagues note that the survival curves diverged late, attesting to “a slow onset of clinical benefit in several patients, some of whom initially experienced disease progression”.

They speculate in Clinical Cancer Research that this could be because it takes longer to mount an effective immune response, unlike chemotherapy or small molecule agents, which can cause immediate tumour shrinkage.

The most common adverse event in the PPV arm was dermatological reactions at injection sites, experienced by 91% of patients, followed by abdominal pain (34%), elevated creatinine (34%) and anaemia (29%).

However, “[a]lmost all adverse events were of grade 1 or 2 and resolved in 2 to 3 days”, say the researchers, adding that PPV treatment was well tolerated.

Highlighting the small scale of the study, Noguchi et al conclude that “further investigation of PPV in advanced or metastatic urothelial cancer is warranted.”

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