09 April 2003
Immune therapy shows potential vs. melanoma, ovarian cancer
An immune therapy discovered at Berkeley can boost the benefit of some cancer vaccines, according to a small, preliminary study led by researchers at Dana-Farber Cancer Institute and Brigham and Women’s Hospital in Boston.
The experimental therapy blocks a key protein on immune system T cells, releasing a natural brake on the immune system and unleashing an assault on the cancer.
The study tested the effect of a single injection of an antibody, MDX-CTLA4, in nine patients who had previously been treated with cancer vaccines for either metastatic melanoma or metastatic ovarian cancer. The result, in every patient who had received a particular kind of vaccine, was widespread death of cancer cells and an increase in the number of immune system cells within the tumors — evidence of a potent immune system attack.
The technique was inspired by the laboratory work of study co-author James P. Allison, a Berkeley professor of immunology, director of the campus’s Cancer Research Laboratory, and a Howard Hughes Medical Institute investigator. He and his colleagues discovered that a protein called CTLA-4, an antigen found on T cells, restrains the immune system from attacking cancer cells. In a series of laboratory and animal experiments, Allison’s team showed that combining a cancer vaccine with an antibody able to block CTLA-4 resulted in an especially potent immune attack on tumors.
“There is a lot of excitement about this,” said Allison, a member of Berkeley’s Health Sciences Initiative, which fosters collaboration among researchers in the biological and physical sciences, “because you usually don’t see any signs of drug activity in these early, Phase I trials, which are designed to look only at a drug’s safety.”
Previous clinical trials have shown that vaccines can be at least temporarily effective in treating metastatic melanoma and ovarian cancer, but most patients eventually succumb to their diseases. One of the reasons for this may be that the CTLA-4 molecule gradually weakens the immune system’s ability to recognize and respond to tumor cells.
“By blockading CTLA-4 with antibodies, we had hoped to strengthen the immune response produced by cancer vaccines,” remarked the study’s senior author, Glenn Dranoff, M.D., of Dana Farber. “Work in the laboratory and in animal models suggested that this approach could be effective. The new study offers the first evidence that the technique has promise in human patients, although much more study will be needed to demonstrate that this is the case.”
Charter schools suffer from ill-prepared teachers, unequal funding
The nation’s ballooning number of charter schools rely heavily on uncredentialed teachers, fail to acquire federal monies to aid low-achieving or disabled children, and display the same financial disparities that beset regular public schools, according to an unprecedented study led by scholars with Policy Analysis for California Education (PACE), an institute based at Stanford University and UC Berkeley,
More than 2,600 charter schools have sprouted since 1991, serving just under 700,000 students in 36 states and Washington, D.C. Each operates with public funding but independent of its local school board and most government rules.
Among the report’s highlights:
• Forty-eight percent of charter- school teachers lack a teaching certificate, compared with 9 percent in a typical public school. In schools serving a predominantly black student population, nearly 60 perent of teachers lack a teaching credential.
• Charter schools have spartan staffing: Most teachers instruct 20-plus percent more students each day than do teachers in regular schools.
• Fewer than 5 percent of all charter school students are helped by federal programs for low-income students, even though 43 percent of the children qualify for assistance.
• Black children attending charter schools are more isolated racially than those attending regular public schools. In charter schools serving the largest number of black students, enrollments are 80-percent black, on average. In comparable public schools, the highest percentage of blacks enrolled is 54 percent.
• Charter schools run by private firms rely heavily on less-experienced, uncredentialed teachers, who make up 55 percent of their staffs, compared with charter schools run by local parents or educators, where 45 percent of teachers are uncredentialed.
• Teacher quality and instructional resources vary dramatically across states. In California, the ratio of children per full-time teacher is 30-to-1, more than twice the 14-to-1 level observed among charter schools in North Carolina. Eighty percent of all charter school teachers are uncredentialed in the District of Columbia, compared to 32 percent in California.