Elesclomol study shows significant improvement in progression-free survival for chemotherapy-naïve patients with metastatic melanoma

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GlaxoSmithKline and Synta Pharmaceuticals Corp. today announced positive Phase II clinical data for elesclomol (formerly STA-4783), an investigational agent currently in development for metastatic melanoma. A retrospective analysis showed that stage IV metastatic melanoma patients treated with elesclomol and paclitaxel who had not previously received chemotherapy had a statistically significant improvement in progression-free survival (PFS) compared to patients who received paclitaxel alone.1 These data will be presented at the 44th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago. Elesclomol is not yet approved for any indication in any market.

“The incidence of melanoma has continued to rise in recent years and there is an undeniable need to identify effective treatments for patients with metastatic disease,” said Paolo Paoletti, M.D., Senior Vice President of the Oncology Medicine Development Center at GSK. “GSK is at the forefront of research to improve the lives of cancer patients, including those with limited treatment options, and we are dedicated to conducting ongoing trials in metastatic melanoma.”

“The preliminary clinical data for elesclomol in metastatic melanoma patients are encouraging and underscore the urgent need for new treatments,” said Eric Jacobson, MD, Senior Vice President and Chief Medical Officer, Synta. “These data, combined with earlier clinical and pre-clinical data we have presented for elesclomol, support our belief that oxidative stress induction is a promising new approach to cancer therapy in melanoma and, potentially, other cancer types.”

Metastatic melanoma occurs when melanoma – a cancer that begins in melanocytes, the cells that make skin pigment, or melanin – spreads to other parts of the body.2,3 In the U.S. alone, the percentage of people who develop melanoma – the deadliest form of skin cancer – has more than doubled in the past 30 years, and about 60,000 people are diagnosed with melanoma and 8,000 will die from it in 2008.4,5,6 Worldwide, approximately 132,000 new diagnoses are made each year.7 Currently, there are no approved therapies that have been shown to improve survival for patients with metastatic melanoma.8

Phase II Trial of Elesclomol and Paclitaxel in Stage IV Metastatic Melanoma: A Subgroup Analysis By Prior Chemotherapy (Abstract # 9036) Presentation Date/Time: 31 May 2008, 2:00 PM – 6:00 PM

This retrospective subgroup analysis of a randomised, double-blind, active-controlled, Phase II trial in patients with stage IV metastatic melanoma evaluated the rates of progression free survival and overall survival for the combination of elesclomol and paclitaxel versus paclitaxel alone in patients who received one prior chemotherapy treatment with those who were chemotherapy-naive. A total of 81 patients evaluated in this analysis either received 213 mg/m2 of elesclomol co-infused with 80 mg/m2 paclitaxel or 80 mg/m2 of paclitaxel alone in four-week cycles (once weekly for three weeks and one week’s rest) until disease progression.1

Patients who had not received prior chemotherapy and were given a combination of elesclomol and paclitaxel (n=24), compared to patients who were given paclitaxel alone (n=8):

Experienced a 69 percent reduction in the risk of progression or death
Lived an average of almost six months longer (15.9 months versus 10.0 months)
Had a longer median progression-free survival (7.1 months versus 1.8 months; p=0.020).1
“Metastatic melanoma is an aggressive disease, and patients currently have few treatment options,” said investigator David Lawson, M.D., Emory University School of Medicine. “Identifying novel therapies like elesclomol represent the future of treating this hard-to-treat disease.”

Data for patients on the elesclomol and paclitaxel arm who had one prior chemotherapy showed a trend toward results similar to patients who had received no prior chemotherapy; however these data were not statistically significant. Specifically, after receiving one prior chemotherapy, the median PFS was 2.8 months for patients receiving elesclomol and paclitaxel (n=29) versus 1.8 months for patients on paclitaxel alone (n=20; p=0.552), and OS was 9.0 months for patients on elesclomol and paclitaxel versus 7.8 months for patients on paclitaxel alone.1

Regardless of prior chemotherapy, the most common adverse events in the elesclomol plus paclitaxel group included fatigue, alopecia, constipation, nausea, hypoaesthesia, arthralgia, insomnia, diarrhoea and anaemia. The most serious adverse events (Grade 3 or higher) for the combination arm were similar to those seen in the paclitaxel-only arm and included neutropenia, back pain, fatigue and neuropathy.1