Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Phase I clinical trial shows drug shrinks melanoma brain metastases

18.05.2012
3-pronged study reveals high response rate in other advanced melanoma patients and activity in multiple cancers

An experimental drug targeting a common mutation in melanoma successfully shrank tumors that spread to the brain in nine out of 10 patients in part of an international phase I clinical trial report in the May 18 issue of The Lancet.

The drug dabrafenib, which targets the Val600 BRAF mutation that is active in half of melanoma cases, also cut the size of tumors in 25 of 36 patients with late-stage melanoma that had not spread to the brain. The drug also showed activity in other cancer types with the BRAF mutation.

"Nine out of 10 responses among patients with brain metastases is really exciting. No other systemic therapy has ever demonstrated this much activity against melanoma brain metastases," said study co-lead author Gerald Falchook, M.D., assistant professor in the Department of Investigational Cancer Therapeutics at The University of Texas MD Anderson Cancer Center.

Melanoma patients whose disease has spread to their brains have a median overall survival of four or five months, the researchers noted. Drugs used to treat brain metastases have response rates of 10 percent or lower. Surgery and stereotactic or whole-brain radiation also are used.

Tumor shrinkage in the nine responders ranged from 20 percent to 100 percent. In four cases, the brain metastases disappeared.

Drug's reach into brain a surprise

These results will need to be validated in additional clinical trials with larger groups of patients, Falchook said. "This changes how we think of this drug and exclusion criteria for future trials."

"Most clinical trials exclude patients with brain metastases because the drugs are assumed not to cross the blood-brain barrier," Falchook said. "These are the patients most in need of a clinical trial because their treatment options are so limited."

Dabrafenib, made by GlaxoSmithKline, was not designed to cross the blood-brain barrier, which protects the brain from toxic substances in the blood.

The drug's activity against brain metastases was initially a serendipitous finding at one study site. In one patient, a research PET scan performed just before starting dabrafenib revealed a brain metastasis, but this result was not available until after treatment began. The institution's ethics board approved the patient to continue treatment because a follow-up PET scan two weeks later showed decreased metabolic activity in the brain metastasis and subsequent MRIs showed a reduction in its size.

The team then designed a sub-study for 10 patients with untreated brain metastases, Falchook said. The mechanism by which dabrafenib reaches tumors in the brain is under investigation.

"In all of these patients with melanoma brain metastases, the tumors eventually progressed," Falchook said. Prevention of drug resistance remains a challenge in advanced cancers.

High response rate for those without brain metastases

184 patients enrolled at eight sites in the United States and Australia. Of these, 156 patients had melanoma that had spread to other organs. MD Anderson enrolled 64 patients.

The main purpose of a phase I clinical trial is to gradually escalate an experimental drug's dosage to evaluate side effects and establish the highest possible dose that can be safely given.

The researchers never reached a maximum-tolerated dose limit. No patients had to discontinue the drug due to side effects, and few patients experienced severe toxicity. "This is a very non-toxic drug, which is common with these newer, targeted therapies," Falchook said.

Based on response rates and the drug's pharmacokinetics – how the body metabolizes it – the team recommended an oral dose of 150 mg twice daily for future phase II and phase III trials. In the second stage of the phase I trial, they tested that dose in:

36 patients with melanoma with the Val600 BRAF mutation without brain metastases,

10 patients with untreated melanoma brain metastases, and

28 patients with other BRAF-mutant cancers.
Among the 36 melanoma patients without untreated brain metastases:
25 (69 percent) had a partial or complete response, which is shrinkage of at least 30 percent as determined by measuring tumor shrinkage with radiographic imaging,

18 (50 percent) had a confirmed response, meaning the reduction in size was observed in a second imaging scan at least one month later,

17 (47 percent) stayed on the trial for more than six months, and

Responses were seen in the less common Val600Lys BRAF mutation.
The confirmed response rate was similar to that in a phase III study of vemurafenib, the first drug approved for treatment of BRAF-mutant melanoma.

Among those with other types of cancers, patients with papillary thyroid, non-small cell lung and colorectal cancers had partial responses.

"This is further evidence that a tumor's molecular profile is as important, and possibly more important, than the organ where the cancer begins," Falchook said.

"We need to screen for BRAF and other molecular abnormalities in our patients' tumors," he said. "In many other tumor types BRAF mutations occur in small percentages of patients. If we're not testing for it routinely, these patients might never be treated with a promising targeted agent for their cancer."

Falchook has six melanoma patients still receiving dabrafenib, including five who are in complete remission. In addition, Falchook is still treating six papillary thyroid patients and one colorectal cancer patient whose tumors have not progressed on the treatment.

GlaxoSmithKline sponsored and funded the clinical trial. Phase II and phase III trials of dabrafenib for melanoma are under way.

Co-authors with Falchook are Razelle Kurzrock, M.D., of MD Anderson's Department of Investigational Cancer Therapeutics, and Kevin Kim, M.D. of MD Anderson's Department of Melanoma Medical Oncology; co-lead author Georgina Long, M.D., Ph.D., and senior author Richard Kefford, M.D., Ph.D., of Melanoma Institute Australia, Westmead Institute for Cancer Research and Westmead Hospital, University of Sydney, in Sydney, Australia; Tobias Arkenau, M.D., Ph.D., Prince of Wales Hospital, Randwick, Australia; Michael Brown, M.D., Ph.D., Royal Adelaide Hospital and University of Adelaide, Adelaide, Australia; Omid Hamid, M.D., and Steven O'Day, M.D., of The Angeles Clinic and Research Institute. Los Angeles, Calif.; Jeffrey Infante, M.D., Sarah Cannon Research Institute, Nashville, Tenn.; Michael Millward, M.D., Cancer Council of Western Australia, Sir Charles Gairdner Hospital and University of Western Australia, Perth, Australia; Anna Pavlick, M.D., New York University School of Medicine; and Samuel Blackman, M.D., Ph.D., C. Martin Curtis, Peter Lebowitz, M.D., Ph.D., Bo Ma, Ph.D., and Daniele Ouellet, Ph.D., of GlaxoSmithKline Research and Development, Philadelphia.

Scott Merville | EurekAlert!
Further information:
http://www.mdanderson.org

More articles from Studies and Analyses:

nachricht Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>