By Bill Berkrot
NEW YORK, May 30 (Reuters) - An experimental vaccine combined with the immunotherapy drug Interleukin-2 showed promise against advanced melanoma -- one of the deadliest of cancers, according to data from a late stage clinical trial.
The vaccine, developed by the National Cancer Institute (NCI) and called gp 100:209-217, or gp 100, helped shrink tumors and delay worsening of the disease in the study.
In the 185-patient trial, those who received the vaccine had a statistically significant response rate of 22.1 percent, meaning 22.1 percent of patients had their tumor shrink by at least half. That compared with a 9.7 percent response rate in those who received only Interleukin-2 (IL-2), researchers said.
Patients in the vaccine plus IL-2 arm also experienced progression-free survival -- the time before the disease starts to worsen -- of 2.9 months compared with 1.6 months in the control group, according to results presented at the American Society of Clinical Oncology (ASCO) meeting in Orlando on Saturday.
There was also a trend toward overall survival benefit seen in those receiving the vaccine. But the extension of life did not reach statistical significance and so could have been by chance, though researchers found it to be encouraging.
'The findings represent a significant step forward for treatment of advanced melanoma,' Dr. Douglas Schwartzentruber, one of the study's lead investigators who will present the data at the ASCO meeting, said in a statement.
Gp 100 and Provenge from Dendreon Corp are among the first therapeutic cancer vaccines to show positive results in late stage clinical trials after years of vaccine failures.
'While more follow-up is needed, this study serves as a proof-of-principle for vaccines' role in melanoma and in cancer therapy overall,' said Dr. Patrick Hwu, chairman of M.D. Anderson's Department of Melanoma Medical Oncology and a study co-investigator.
The gp 100 vaccine activates patients' immune response controlling T cells to recognize antigens on the surface of the tumor. The T cells secrete enzymes that poke holes in the tumor cell's membrane, causing it to disintegrate.
'If we can use the body's own defense system to attack tumor cells, we provide a mechanism for ridding the body of cancer without destroying healthy tissue,' Hwu said.
Some 8,650 Americans will likely die from melanoma in 2009, according to the American Cancer Society. Only 16 percent of patients with metastatic melanoma survive five years and the median survival is less than one year.
There are currently few approved treatments for advanced melanoma, which strikes people of all ages and spreads very quickly. They include an older chemotherapy agent that does not work very well and IL-2.
'IL-2 has dramatic effects in some patients, but precious few,' said Hwu, highlighting the need for new therapies.
While the gp 100/IL-2 combination looks to be a promising advance, Hwu said, 'a 22 percent response means 78 percent of our patients did not respond, and that's not OK.'
Researchers said conducting the study was challenging due to complications associated with administering IL-2, which is sold by Swiss drugmaker Novartis, a co-sponsor of the trial with NCI.
The immunotherapy is typically given in intensive care units and is associated with significant side effects, such as low blood pressure and capillary leak syndrome, which poses risks to the heart and lungs but is reversible upon stopping therapy, Hwu said.
He added that only about half of those with advanced melanoma are eligible for the vaccine as it must match a patient's tissue type.
'A major priority for us is to figure out ways to broaden our approach and use mixtures of peptides so that more patients are eligible,' Hwu said.
(Reporting by Bill Berkrot, editing by Matthew Lewis) Keywords: CANCER MELANOMA/VACCINE (bill.berkrot@thomsonreuters.com; + 1 646 223-6030; Reuters Messaging: bill.berkrot.reuters.com@reuters.net) COPYRIGHT Copyright Thomson Reuters 2009. All rights reserved. The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.
NEW YORK, May 30 (Reuters) - An experimental vaccine combined with the immunotherapy drug Interleukin-2 showed promise against advanced melanoma -- one of the deadliest of cancers, according to data from a late stage clinical trial.
The vaccine, developed by the National Cancer Institute (NCI) and called gp 100:209-217, or gp 100, helped shrink tumors and delay worsening of the disease in the study.
In the 185-patient trial, those who received the vaccine had a statistically significant response rate of 22.1 percent, meaning 22.1 percent of patients had their tumor shrink by at least half. That compared with a 9.7 percent response rate in those who received only Interleukin-2 (IL-2), researchers said.
Patients in the vaccine plus IL-2 arm also experienced progression-free survival -- the time before the disease starts to worsen -- of 2.9 months compared with 1.6 months in the control group, according to results presented at the American Society of Clinical Oncology (ASCO) meeting in Orlando on Saturday.
There was also a trend toward overall survival benefit seen in those receiving the vaccine. But the extension of life did not reach statistical significance and so could have been by chance, though researchers found it to be encouraging.
'The findings represent a significant step forward for treatment of advanced melanoma,' Dr. Douglas Schwartzentruber, one of the study's lead investigators who will present the data at the ASCO meeting, said in a statement.
Gp 100 and Provenge from Dendreon Corp are among the first therapeutic cancer vaccines to show positive results in late stage clinical trials after years of vaccine failures.
'While more follow-up is needed, this study serves as a proof-of-principle for vaccines' role in melanoma and in cancer therapy overall,' said Dr. Patrick Hwu, chairman of M.D. Anderson's Department of Melanoma Medical Oncology and a study co-investigator.
The gp 100 vaccine activates patients' immune response controlling T cells to recognize antigens on the surface of the tumor. The T cells secrete enzymes that poke holes in the tumor cell's membrane, causing it to disintegrate.
'If we can use the body's own defense system to attack tumor cells, we provide a mechanism for ridding the body of cancer without destroying healthy tissue,' Hwu said.
Some 8,650 Americans will likely die from melanoma in 2009, according to the American Cancer Society. Only 16 percent of patients with metastatic melanoma survive five years and the median survival is less than one year.
There are currently few approved treatments for advanced melanoma, which strikes people of all ages and spreads very quickly. They include an older chemotherapy agent that does not work very well and IL-2.
'IL-2 has dramatic effects in some patients, but precious few,' said Hwu, highlighting the need for new therapies.
While the gp 100/IL-2 combination looks to be a promising advance, Hwu said, 'a 22 percent response means 78 percent of our patients did not respond, and that's not OK.'
Researchers said conducting the study was challenging due to complications associated with administering IL-2, which is sold by Swiss drugmaker Novartis, a co-sponsor of the trial with NCI.
The immunotherapy is typically given in intensive care units and is associated with significant side effects, such as low blood pressure and capillary leak syndrome, which poses risks to the heart and lungs but is reversible upon stopping therapy, Hwu said.
He added that only about half of those with advanced melanoma are eligible for the vaccine as it must match a patient's tissue type.
'A major priority for us is to figure out ways to broaden our approach and use mixtures of peptides so that more patients are eligible,' Hwu said.
(Reporting by Bill Berkrot, editing by Matthew Lewis) Keywords: CANCER MELANOMA/VACCINE (bill.berkrot@thomsonreuters.com; + 1 646 223-6030; Reuters Messaging: bill.berkrot.reuters.com@reuters.net) COPYRIGHT Copyright Thomson Reuters 2009. All rights reserved. The copying, republication or redistribution of Reuters News Content, including by framing or similar means, is expressly prohibited without the prior written consent of Thomson Reuters.