The New York Times - April 26, 1984
Harold M. Schmeck Jr.

That feat is considered a major step toward artificial commercial production of the human blood substance, which is crucial to the lives and health of about 20,000 American hemophiliacs.

The protein, produced through gene- splicing techniques, is known as factor VIII. It is missing or deficient in hemophiliacs, who might bleed to death without it, and who now must obtain it as a substance extracted from donated blood.

Not Expected So Soon

Previously, scientists said production of the complete protein was probably years in the future. But several research teams have been striving to speed the research and recently produced part of the gene for factor VIII.

The feat announced yesterday by Genentech Inc. of South San Francisco, was the cloning of the entire gene and transplantation of that gene into animal cells that then produced the human blood substance.

In a telephone interview, Dr. David Martin, vice president of research at the biotechnology company, said he was confident the laboratory experiment could be translated, in time, into large-scale production of the pure substance for use in patients. He said the material produced in the company's experiments was "clearly biologically active."

"With some luck," he said, the first clinical trials in patients may begin either late next year or early in 1986.

An announcement from the company said, "Several years of development, including clinical trials, remain before the product will be commercially available." Meanwhile, the announcement said, scientists will be better able to study the molecular basis of hemophilia and possibly develop techniques for prenatal diagnosis of the hereditary disease.

When informed of the development, Dr. Anne P. Ball, chief of the blood diseases branch of the National Heart, Lung and Blood Institute, said she considered it "tremendously important" because of the difficulty of the task it represents and the potential value of having large quantitites of the blood factor in pure form.

In addition to its potential use for treating patients, and for research on the disease, she said, availability of large quantities of the pure substance should help scientists develop better tests for carriers of the disease and for detecting it in the fetus.

In the absence of enough functioning factor VIII, Dr. Ball said, blood clots extremely slowly. As a result hemophiliacs bleed easily and at length and the hemorrhages damage joints and other tissues.

Today the only source of the protein is natural factor VIII extracted from human blood. Many hemophiliacs take from 30 to 50 infusions of the blood protein a year at a total cost ranging from $5,000 to $10,000, according to the National Hemophilia Foundation. Most patients administer it to themselves by injection when needed to control bleeding.

Use of the natural factor carries some risk of infection, notably with the hepatitis B virus and the virus or viruses that cause acquired immune deficiency syndrome, or AIDS.

Eliminating Risk of Infection

Use of an artificially produced substance would eliminate the risk of such infections and would probably be substantially less expensive in the long run.

Dr. Martin said the research that led to production of factor VIII took a team of about 30 people a little more than a year.

"It was an amazing amount of work by some very clever people," he said.

The project started with samples of partly purified human factor VIII from a British company, Speywood Laboratories and Royal Free Hospital in London. Using this, the American research workers first found, purified and made copies of the entire gene for the blood protein. Then they transplnted this gene into animal cells growing in laboratory flasks. These cells made factor VIII and secreted it into the surrounding fluid from which it could be harvested for tests.

Dr. Martin said the blood factor was present in the fluid in somewhat less quantity than it is in normal blood plasma. While this is only a very small amount, he said it is enough for current studies.

Dr. Martin said factor VIII was a large, complex protein made up of more than 2,300 subunits called amino acids.

"That is four times larger than anything that has been cloned and expressed before," he said. The next largest, so far as he knows, is human serum albumin, another blood substance, cloned by scientists of Genentech in 1981. Molecules of that protein consist of 585 amino acids.

In laboratory experiments, samples of the artificially produced human blood factor corrected the clotting defect of blood from hemophiliacs, Dr. Martin said.

The next steps in the research, he said, will be to increase the amount of factor VIII produced by the cells, scale up the system for larger production, develop a system for purifying the material to a state of homogeneity and then undertake preclinical and clinical testing of the blood factor.

'Wonderful News'

When informed of the report yesterday, Alan Brownstein, executive director of the National Hemophilia Foundation, described it as "wonderful news."

"We are seeing another advance towards a genetically manufactured product that can be used by hemophiliacs," he said. "This is of particular importance because the genetically manufactured product offers the hope of a potentially safer product as well as the potential of improved availability and reduced cost."

A preliminary report of the research was given by scientists of Genentech Tuesday at the University of California in San Francisco at a seminar on the contributions of recombinant DNA technology to blood clotting problems. The company made a public announcement yesterday. Dr. Martin said a detailed scientific report was being prepared for a scientific journal.

The cloning of a gene means that it has been obtained in pure form and has been reproduced in living cells growing in the laboratory. Cloning of the gene for human blood factor VIII was particularly difficult because of its size and the fact that the pure blood factor itself is scarce and fragile.

Dr. Martin said the entire gene was found to consist of about 200,000 of the DNA subunits called nucleotides of which all genes are made. The gene was found to be organized in 26 separate active parts called exons separated by pieces of DNA called introns that do not actually serve as parts of the coded instructions for making the gene's protein product. The working portion of this piece of the genetic material, DNA, was a total of 9,000 nucleotides long, Dr. Martin said.

The gene is found on the X chromosome and is so large that it constitutes an estimated one-tenth of 1 percent of the entire chromosome.

Blood clotting is an extremely complicated process involving a minimum of three complex steps to get to the activation of the enzyme called thrombin that actually produces a blood clot. Factor VIII is one of more than a dozen factors that take part in the process. It is the only factor missing or defective in hemophila A, the main form of that hereditary disorder.

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