Testing Expands In Gene Therapy, Gene Transfer vector. The now neomycin-resistant TILs were stimulated with interleukin-2 before being reinfused into the patient. TILs later recovered from tumor biopsies are identified by their survival in the presence of neomycin. In January 1992, Michael T. Lotze, M.D., of the University of Pittsburgh, received approval from NIH's Recombinant DNA Advisory Committee (RAC) to conduct a similar TIL-tracking trial in patients with melanoma. Lotze will use a combination of interleukin-4 and IL-2 to boost growth of the TILs before their reinfusion. In another set of gene transfer trials, the neomycin resistance gene tags bone marrow cells used in autologous bone marrow transplants after myeloablative
Children and Adults The Brenner trials, started in January 1992, involve children with acute myelogenous leukemia and neuroblastoma. If the autologous transplant proves to be the source of relapse in these patients, it would call for more rigorous purging of the bone marrow before it is reinfused. Deisseroth's trial applies the same strategy to adults undergoing autologous bone marrow transplants for chronic myelogenous leukemia.
Tracking Cells Many of the cancer trials using genes as markers, called gene transfer trials, are variations of an earlier Rosenberg trial, started in May 1989 - the first trial to introduce cells transfected with a foreign gene into humans. In that original gene transfer trial, Rosenberg tracked tumor-infiltrating lymphocytes in patients with advanced melanoma. TILs removed from a patient's tumor received a bacterial neomycin resistance gene via a retroviral
380
L)r. Midiaet i .
Journal of the National Cancer Institute
Downloaded from http://jnci.oxfordjournals.org/ at University of Michigan on July 12, 2015
Only 1 year after gene therapy made its debut in clinical trials as a cancer treatment, eight cancer protocols involving transfer of genes into patients have been launched, with four more cancer protocols nearing final government approval. The two patients who received gene therapy for melanoma at the National Institutes of Health in a trial initiated in January 1991 by Steven A. Rosenberg, M.D., Ph.D., have been joined by more than 20 cancer patients participating in trials across the country involving either gene transfer or gene therapy. The nine cancer trials under way represent two-thirds of all gene transfer/ gene therapy trials being conducted in the United States for all diseases. And cancer protocols account for all four additional trials edging toward final approval. While the majority of the cancer trials use the added genes as markers for tracking cells, some of the latest protocols are breaking new ground in strategies for delivery and deployment of genes as part of therapy.
treatment for leukemia and neuroblastoma. The trials are designed to determine if the reinfused bone marrow is the source of cancer cells responsible for relapse that can occur in these patients. Gene transfer trials in this group include three conducted by Malcolm T. Brenner, M.D., of St. Jude Children's Research Hospital in Memphis, and one by Albert P. Deisseroth, M.D., Ph.D., of The University of Texas M. D. Anderson Cancer Center in Houston.
News News
Two Vectors Another gene transfer trial granted RAC approval in February adds a new twist to the tracking strategy. The trial, proposed by UCLA investigator James S. Economou, M.D., Ph.D., is designed to compare trafficking patterns of TILs and peripheral blood leukocytes (PBLs) in a patient being treated for melanoma or renal cell carcinoma. Both types of cells will be transfected with the neomycin resistance gene, but with slightly different vectors: the TILs with LNL6 and the PBLs with the related vector GINa. The vectors can be distinguished by polymerase chain reaction to help quantify the two cell types infiltrating the tumor.
In two subsequent trials started in October 1991, Rosenberg is inserting the TNF or IL-2 gene in malignant cells biopsied from a patient's tumor. The patient is then vaccinated with the altered tumor cells, which are expected to spark a more potent immune response specific to the tumor. Another gene therapy trial, approved by the RAC in February, seeks to stimulate the immune response against a tumor in a different way. The protocol, proposed by Gary Nabel, M.D., Ph.D., of the Uni-
Stat Bite
Potential Reductions in Tobacco-Related Cancers Researchers in France estimated potential worldwide reductions in cancer incidence if tobacco use, including chewing and smoking, were eliminated entirely. An estimated 1 million to 1.5 million cancer cases per year are attributable to tobacco use. Site
Area
Possible Reduction
oo-sqj^^
Gene Therapy
Oral Cavity
Asia, Europe
Immunotherapy is a dominant focus for trials introducing new genes as therapy in cancer patients. In gene therapy trials being conducted by NCI's Rosenberg, the genes for cytokines are employed to stimulate immune responses to tumors locally. The strategy is designed to overcome the sometimes severe systemic effects of cytokines, such as tumor necrosis factor and IL-2, while concentrating their immunostimulatory effects at the tumor site. The first such trial, launched in January 1991 in melanoma patients, equipped TILs removed from a patient's tumor with the gene coding for TNF. Reinfused into the patient, the cytokinestimulated TILs are expected to mount a more potent attack against the tumor.
Esophagus*
U.S.. S. Europe India
Pancreas
World
Larynx*
World
Vol. 84, No. 6, March 18, 1992
versity of Michigan, involves introducing the gene for HLA-B7, a major transplantation antigen, into melanoma cells. Nabel's protocol is the first RACapproved gene therapy trial to use a gene delivery system other than a retroviral vector as well as the first to transfect cells without removing them from the body. The HLA-B7 gene will be spliced into bacterial plasmids, or rings of DNA, which are then loaded into liposomes. Once injected into a tumor, the liposomes are taken up by the cancer cells
i
ng
Cervix Bladder Kidne>
World (Men) World (Women) 'Western" Countries World
7 5 1
3
^ ^
35 %;^J
80-90% 60-80%
|
20-25% 30-70** 30-401
•
NEWS 381
Downloaded from http://jnci.oxfordjournals.org/ at University of Michigan on July 12, 2015
A similar trial approved by the RAC in February, now waiting final government approval, will extend the bone marrow tracking technique to adults with acute leukemia. The trial is proposed by Kenneth Cornetta, M.D., of Indiana University.
News News cer cells will render them susceptible to the antiviral drug gancyclovir. Irradiated ovarian cancer cells with the added gene will be injected into the peritoneum to deliver the gene to the ovarian tumor. Gancyclovir will thus be expected to kill the cancer cells receiving the gene.
—ByJMWaalen
Gene Therapy for ADA Takes Next Step The Recombinant DNA Advisory Committee has approved an amended gene therapy protocol for two children who have already benefited from their pioneering gene treatments for an extremely rare, inherited immune system disorder, adenosine deaminase (ADA) deficiency. "We are exceptionally pleased with our patients' progress so far," Michael Blaese, M.D., of the National Cancer Institute, told members of the RAC, citing significant improvements in lymphocyte counts and immune responses since (he initial gene therapy studies began in 1990 and 1991. However, supplemental therapy is needed, Blaese said, because there are still "holes" in the children's immune repertoire that leave them vulnerable to potentially life-threatening infections. According to both Blaese and W. French Anderson, M.D., of the National Heart, Lung, and Blood Institute, the amended gene therapy protocol is designed to plug up these holes by inserting a healthy ADA gene into a population of blood stem cells, which are far more primitive than the T cells now being used, and from which, in theory, the missing ADA enzyme would be churned out indefinitely. By adding a gene to these early stem cells (CD 34+ cells) - the parent cells of T lymphocytes - "the benefit could be profound," Anderson said. "Basically, we're talking about a cure... on the basis of a minute risk." Some RAC members were not convinced. Although the proposed study won approval by an 1 l-to-3 margin (with 2 abstentions), several RAC members felt the use of a new target cell system as well as a new retroviral vector went far beyond the original protocol, and required a review from scratch. Others were concerned about the proposed treatment's anticipated efficacy, given the lack of a good animal model for ADA, and the safety risks associated with an increasing number of potentially mutagenic events. Finally, there were ethical reservations about simultaneously initiating a second gene therapy protocol in children who are reportedly "doing so well" on their present therapy. Anderson told the RAC that no matter how well the children are doing, there is uncertainty about how long their immunologic protection may last, and the investigators see stem cell therapy as the best hope for a normal life. But Anderson stressed the protocol would not be limited solely to these patients and will be made available to other ADA children "as they come along." —By Susan Jenks
382
Researchers Struggle To Get Fetal Tissue For Cancer Research While the federal ban on the use of fetal tissue from induced abortions in human therapeutic transplants continues, cancer researchers are using fetal tissue in laboratory systems to study oncogenes, cancer formation, and immune system development. Many are uncomfortable talking about their work with fetal tissue because of misconceptions about the extent of the ban. Some say they could not do their research without it. Others have developed alternative systems, rather than deal with difficulties in obtaining fetal tissue and the stigma surrounding its use. 'This research is continuing because it's important," although some people are mistakenly concerned that it's not allowable, according to Faye Austin, Ph.D., associate director for the extramural research program in NCI's Division of Cancer Biology, Diagnosis, and Centers. "Many don't understand that the ban is just on transplantation [of fetal tissue] to patients for therapeutic purposes," Austin said. "The ban is very restricted." Since the ban, many NCI grantees have stopped using fetal tissue or significantly dropped the percentage of their grants that cover fetal tissue work, according to Harry Canter, chief of NCI's Research Analysis Evaluation Branch.
Access Not Easy "We have extraordinary trouble getting [fetal tissue]," said Dennis J. Slamon, M.D., Ph.D., associate professor of medicine at the University of California at Los Angeles. He uses tissue collected 5 or 6 years ago, before the ban. Slamon is using fetal tissue to study oncogenes and tumor suppressor genes.
Journal of the National Cancer Institute
Downloaded from http://jnci.oxfordjournals.org/ at University of Michigan on July 12, 2015
and the plasmid incorporated into the cell's genome, ultimately resulting in expression of HLA-B7. In perhaps the most exotic gene therapy trial approved by the RAC to date, Scott Freeman, M.D., and colleagues at the University of Rochester have devised a protocol for ovarian cancer in which a gene added to ovarian can-
Children and Adults The Brenner trials, started in January 1992, involve children with acute myelogenous leukemia and neuroblastoma. If the autologous transplant proves to be the source of relapse in these patients, it would call for more rigorous purging of the bone marrow before it is reinfused. Deisseroth's trial applies the same strategy to adults undergoing autologous bone marrow transplants for chronic myelogenous leukemia.
Tracking Cells Many of the cancer trials using genes as markers, called gene transfer trials, are variations of an earlier Rosenberg trial, started in May 1989 - the first trial to introduce cells transfected with a foreign gene into humans. In that original gene transfer trial, Rosenberg tracked tumor-infiltrating lymphocytes in patients with advanced melanoma. TILs removed from a patient's tumor received a bacterial neomycin resistance gene via a retroviral
380
L)r. Midiaet i .
Journal of the National Cancer Institute
Downloaded from http://jnci.oxfordjournals.org/ at University of Michigan on July 12, 2015
Only 1 year after gene therapy made its debut in clinical trials as a cancer treatment, eight cancer protocols involving transfer of genes into patients have been launched, with four more cancer protocols nearing final government approval. The two patients who received gene therapy for melanoma at the National Institutes of Health in a trial initiated in January 1991 by Steven A. Rosenberg, M.D., Ph.D., have been joined by more than 20 cancer patients participating in trials across the country involving either gene transfer or gene therapy. The nine cancer trials under way represent two-thirds of all gene transfer/ gene therapy trials being conducted in the United States for all diseases. And cancer protocols account for all four additional trials edging toward final approval. While the majority of the cancer trials use the added genes as markers for tracking cells, some of the latest protocols are breaking new ground in strategies for delivery and deployment of genes as part of therapy.
treatment for leukemia and neuroblastoma. The trials are designed to determine if the reinfused bone marrow is the source of cancer cells responsible for relapse that can occur in these patients. Gene transfer trials in this group include three conducted by Malcolm T. Brenner, M.D., of St. Jude Children's Research Hospital in Memphis, and one by Albert P. Deisseroth, M.D., Ph.D., of The University of Texas M. D. Anderson Cancer Center in Houston.
News News
Two Vectors Another gene transfer trial granted RAC approval in February adds a new twist to the tracking strategy. The trial, proposed by UCLA investigator James S. Economou, M.D., Ph.D., is designed to compare trafficking patterns of TILs and peripheral blood leukocytes (PBLs) in a patient being treated for melanoma or renal cell carcinoma. Both types of cells will be transfected with the neomycin resistance gene, but with slightly different vectors: the TILs with LNL6 and the PBLs with the related vector GINa. The vectors can be distinguished by polymerase chain reaction to help quantify the two cell types infiltrating the tumor.
In two subsequent trials started in October 1991, Rosenberg is inserting the TNF or IL-2 gene in malignant cells biopsied from a patient's tumor. The patient is then vaccinated with the altered tumor cells, which are expected to spark a more potent immune response specific to the tumor. Another gene therapy trial, approved by the RAC in February, seeks to stimulate the immune response against a tumor in a different way. The protocol, proposed by Gary Nabel, M.D., Ph.D., of the Uni-
Stat Bite
Potential Reductions in Tobacco-Related Cancers Researchers in France estimated potential worldwide reductions in cancer incidence if tobacco use, including chewing and smoking, were eliminated entirely. An estimated 1 million to 1.5 million cancer cases per year are attributable to tobacco use. Site
Area
Possible Reduction
oo-sqj^^
Gene Therapy
Oral Cavity
Asia, Europe
Immunotherapy is a dominant focus for trials introducing new genes as therapy in cancer patients. In gene therapy trials being conducted by NCI's Rosenberg, the genes for cytokines are employed to stimulate immune responses to tumors locally. The strategy is designed to overcome the sometimes severe systemic effects of cytokines, such as tumor necrosis factor and IL-2, while concentrating their immunostimulatory effects at the tumor site. The first such trial, launched in January 1991 in melanoma patients, equipped TILs removed from a patient's tumor with the gene coding for TNF. Reinfused into the patient, the cytokinestimulated TILs are expected to mount a more potent attack against the tumor.
Esophagus*
U.S.. S. Europe India
Pancreas
World
Larynx*
World
Vol. 84, No. 6, March 18, 1992
versity of Michigan, involves introducing the gene for HLA-B7, a major transplantation antigen, into melanoma cells. Nabel's protocol is the first RACapproved gene therapy trial to use a gene delivery system other than a retroviral vector as well as the first to transfect cells without removing them from the body. The HLA-B7 gene will be spliced into bacterial plasmids, or rings of DNA, which are then loaded into liposomes. Once injected into a tumor, the liposomes are taken up by the cancer cells
i
ng
Cervix Bladder Kidne>
World (Men) World (Women) 'Western" Countries World
7 5 1
3
^ ^
35 %;^J
80-90% 60-80%
|
20-25% 30-70** 30-401
•
NEWS 381
Downloaded from http://jnci.oxfordjournals.org/ at University of Michigan on July 12, 2015
A similar trial approved by the RAC in February, now waiting final government approval, will extend the bone marrow tracking technique to adults with acute leukemia. The trial is proposed by Kenneth Cornetta, M.D., of Indiana University.
News News cer cells will render them susceptible to the antiviral drug gancyclovir. Irradiated ovarian cancer cells with the added gene will be injected into the peritoneum to deliver the gene to the ovarian tumor. Gancyclovir will thus be expected to kill the cancer cells receiving the gene.
—ByJMWaalen
Gene Therapy for ADA Takes Next Step The Recombinant DNA Advisory Committee has approved an amended gene therapy protocol for two children who have already benefited from their pioneering gene treatments for an extremely rare, inherited immune system disorder, adenosine deaminase (ADA) deficiency. "We are exceptionally pleased with our patients' progress so far," Michael Blaese, M.D., of the National Cancer Institute, told members of the RAC, citing significant improvements in lymphocyte counts and immune responses since (he initial gene therapy studies began in 1990 and 1991. However, supplemental therapy is needed, Blaese said, because there are still "holes" in the children's immune repertoire that leave them vulnerable to potentially life-threatening infections. According to both Blaese and W. French Anderson, M.D., of the National Heart, Lung, and Blood Institute, the amended gene therapy protocol is designed to plug up these holes by inserting a healthy ADA gene into a population of blood stem cells, which are far more primitive than the T cells now being used, and from which, in theory, the missing ADA enzyme would be churned out indefinitely. By adding a gene to these early stem cells (CD 34+ cells) - the parent cells of T lymphocytes - "the benefit could be profound," Anderson said. "Basically, we're talking about a cure... on the basis of a minute risk." Some RAC members were not convinced. Although the proposed study won approval by an 1 l-to-3 margin (with 2 abstentions), several RAC members felt the use of a new target cell system as well as a new retroviral vector went far beyond the original protocol, and required a review from scratch. Others were concerned about the proposed treatment's anticipated efficacy, given the lack of a good animal model for ADA, and the safety risks associated with an increasing number of potentially mutagenic events. Finally, there were ethical reservations about simultaneously initiating a second gene therapy protocol in children who are reportedly "doing so well" on their present therapy. Anderson told the RAC that no matter how well the children are doing, there is uncertainty about how long their immunologic protection may last, and the investigators see stem cell therapy as the best hope for a normal life. But Anderson stressed the protocol would not be limited solely to these patients and will be made available to other ADA children "as they come along." —By Susan Jenks
382
Researchers Struggle To Get Fetal Tissue For Cancer Research While the federal ban on the use of fetal tissue from induced abortions in human therapeutic transplants continues, cancer researchers are using fetal tissue in laboratory systems to study oncogenes, cancer formation, and immune system development. Many are uncomfortable talking about their work with fetal tissue because of misconceptions about the extent of the ban. Some say they could not do their research without it. Others have developed alternative systems, rather than deal with difficulties in obtaining fetal tissue and the stigma surrounding its use. 'This research is continuing because it's important," although some people are mistakenly concerned that it's not allowable, according to Faye Austin, Ph.D., associate director for the extramural research program in NCI's Division of Cancer Biology, Diagnosis, and Centers. "Many don't understand that the ban is just on transplantation [of fetal tissue] to patients for therapeutic purposes," Austin said. "The ban is very restricted." Since the ban, many NCI grantees have stopped using fetal tissue or significantly dropped the percentage of their grants that cover fetal tissue work, according to Harry Canter, chief of NCI's Research Analysis Evaluation Branch.
Access Not Easy "We have extraordinary trouble getting [fetal tissue]," said Dennis J. Slamon, M.D., Ph.D., associate professor of medicine at the University of California at Los Angeles. He uses tissue collected 5 or 6 years ago, before the ban. Slamon is using fetal tissue to study oncogenes and tumor suppressor genes.
Journal of the National Cancer Institute
Downloaded from http://jnci.oxfordjournals.org/ at University of Michigan on July 12, 2015
and the plasmid incorporated into the cell's genome, ultimately resulting in expression of HLA-B7. In perhaps the most exotic gene therapy trial approved by the RAC to date, Scott Freeman, M.D., and colleagues at the University of Rochester have devised a protocol for ovarian cancer in which a gene added to ovarian can-
