Cisplatin patch explores surgery-free treatment for oral lesions: 21 of 22 trial patients achieve pathological complete response

For patients with oral carcinoma in situ or high-grade dysplasia, treatment involves both removing lesions and preserving the tissue needed for speech and swallowing. If lesions recur, repeated excisions may lead to accumulated scarring and functional burdens. An investigational patch that delivers cisplatin directly into local tissue is exploring the possibility of reducing surgery for these patients.

On October 5, Privo Technologies announced updated results from the first cohort of the Phase 2 CLN-004 trial of PRV111: after one treatment course, 21 of 22 evaluable patients achieved a pathological complete response confirmed by central review, a rate of 95.5%; the remaining patient's lesion was downgraded from oral carcinoma in situ to low-grade dysplasia. The company said that none of these 22 patients underwent their originally scheduled surgery.

The scope of these results needs to be made clear. The patients initially had biopsy-confirmed non-invasive oral cancer or high-grade dysplasia, so the efficacy findings cannot be directly extrapolated to oral cancer that has invaded deeper tissue. Targeted Oncology reported that pathological complete response in this update meant that specimens obtained by punch biopsy after treatment showed no residual dysplastic cells on histopathological examination; it describes the sampling results and does not mean that a permanent cure has been proven.

PRV111 is a nanoengineered topical patch that adheres to the surface of a lesion, allowing cisplatin to enter the affected tissue and adjacent mucosa, and is then removed after treatment. The development concept is to provide a higher drug concentration at the lesion while reducing systemic exposure. OncLive's overview of the trial procedures also noted that one treatment course includes multiple treatment visits; “one treatment course” should not be understood as a single patch application.

The company reported a median follow-up of 14 months from the start of treatment, with a range of 8 to 21 months. As of this update, no recurrence had been observed in the treated areas. OncLive also reported that the treated mucosa had healed completely, function was preserved, and no clinically apparent scarring was observed. These observations make the concept of preserving tissue through local drug delivery more tangible, but they are not yet sufficient to determine the risk of recurrence years later.

Regarding safety, Privo said that systemic cisplatin exposure was extremely low, with no reported systemic toxicity, dose-limiting toxicity, or serious treatment-related adverse events; 85% of treatment-related adverse events were mild, mainly transient local oral symptoms. This percentage refers to the distribution of adverse events by severity, rather than indicating that 85% of patients experienced side effects; a small cohort also makes it difficult to rule out less common risks.

This update expanded the number of evaluable patients from 12 in the early analysis to 22; according to Targeted Oncology's summary, 11 patients had achieved a pathological complete response in the early analysis. However, the latest efficacy figures reported by multiple outlets still come from the same company announcement and cannot be regarded as replication by independent studies. These data also did not provide results from a direct comparison with surgery. PRV111 remains in development. Whether it can become a reliable non-surgical option still requires larger studies, comprehensive pathological assessment, and longer follow-up to confirm whether disease control and preservation of tissue function can both be achieved.