By Bruce Sylvester
CHICAGO -- June 9, 2010 -- Chemoablation with an injectable 10% solution of rose bengal disodium (PV-10), an iodinated fluorescein derivative, induces a robust response in a majority of patients with metastatic melanoma, researchers reported at the 2010 Annual Meeting of the American Society of Clinical Oncology (ASCO).
"What's really interesting is that we are seeing responses not only in the injected lesions, but in lesions that we are not injecting. So we think the systemic effect is based on the immune system," said lead investigator Sanjiv Agarwala, MD, St. Luke's Hospital and Health Network, Bethlehem, Pennsylvania, speaking here on June 6.
The authors noted that PV-10 had shown a signal for melanoma efficacy in an earlier, safety study. The current phase 2 trial was organised to enrol a total of 80 subjects with measurable stage III-IV melanoma. Enrolment was completed in May 2009.
Subjects received initial treatment of 1 to 20 cutaneous, subcutaneous, or nodal lesions. Then, new or incompletely responsive lesions were retreated at weeks 8, 12, or 16, with follow-up to 52 weeks.
For assessment of bystander response, another 1 to 2 lesions, including visceral lesions, were left untreated.
Target lesions were 0.2 cm or greater in diameter, with a biopsy confirmation of at least 1 target lesion.
The primary endpoint of the ongoing study is overall survival of injected target lesions.
The investigators reported that 40 subjects (median age 75 years, range 37 to 92 years) had completed the study so far, and they had received PV-10 treatment in 486 lesions. Of these subjects, 26 are male; the median age was 74.5 years at enrolment.
Subjects had a median of 36 months between first diagnosis of metastatic myeloma and enrolment.
Among the 40 completers, 33% achieved complete remission, 28% achieved partial remission, and 18% achieved stable disease in their target lesions. Additionally, 33% of 21 subjects with evaluable bystander lesions achieved complete remission in these lesions, along with 10% achieving partial remission and 14% achieving stable disease.
Mean progression-free survival for all subjects was 8.5 months. Subjects with an overall response achieved significantly longer progression-free survival (11.1 months) than those with stable disease or partial disease (2.8 and 2.7 months, respectively).
Adverse events were predominantly mild to moderate, with no grade 4 or 5 adverse events attributed to PV-10.
The investigators concluded that PV-10 offers potential locoregional control of metastatic disease, and the response of injected lesions appears to be unrelated to disease stage or prior treatment.
Funding for this study was provided by Provectus Pharmaceuticals, Inc.
[Presentation title: Chemoablation of Metastatic Melanoma With Rose Bengal (PV-10). Abstract 8534]
E-Mail this DGDispatch to a colleague
