Safety and Efficacy of 188-Rhenium-Labeled Antibody to Melanin in Patients with Metastatic Melanoma

Abstract EN

There is a need for effective “broad spectrum” therapies for metastatic melanoma which would be suitable for all patients.

The objectives of Phase Ia/Ib studies were to evaluate the safety, pharmacokinetics, dosimetry, and antitumor activity of 188Re-6D2, a 188-Rhenium-labeled antibody to melanin.

Stage IIIC/IV metastatic melanoma (MM) patients who failed standard therapies were enrolled in both studies.

In Phase Ia, 10 mCi 188Re-6D2 were given while unlabeled antibody preload was escalated.

In Phase Ib, the dose of 188Re-6D2 was escalated to 54 mCi.

SPECT/CT revealed 188Re-6D2 uptake in melanoma metastases.

The mean effective half-life of 188Re-6D2 was 12.4 h.

Transient HAMA was observed in 9 patients.

Six patients met the RECIST criteria for stable disease at 6 weeks.

Two patients had durable disease stabilization for 14 weeks and one for 22 weeks.

Median overall survival was 13 months with no dose-limiting toxicities.

The data demonstrate that 188Re-6D2 was well tolerated, localized in melanoma metastases, and had antitumor activity, thus warranting its further investigation in patients with metastatic melanoma.