Fill-in April 14, 2000

One of the things I have discovered trying to write a weekly column is that 'real life' incidents seem to have a way of intruding. Sick children. Dying cars. Work. And sometimes a good topic is hard to some by. This week seems to be one of them. Not a lot of new articles or meeting minutes. So I thought I would just do a column of short random thoughts. But as I was writing some of these down, I realized that there was a connection between the thoughts. They have to do with a project I have been working on, rather than something that has recently been published. So, let's take slow journey.

How many of us kept a close watch on the stock prices last week? We have seen an unprecedented increase in stock prices in the last 3 months so now we get to watch an unprecedented drop. Some of the genomic companies have seen their stock price drop over 70% in the last two weeks. Isn't the New Economy fun? Are the good times over? No one knows but this led to some introspection.

When I started graduate school in 1978, I was the only one who planned to go into industry. Although I love basic research, I wanted a job where I could see the direct effects of my work on the lives of other people. I did not want my work to stay in a lab. Genentech had started just a few years earlier and I figured that when I got my Ph.D. the industry would just be taking off. Well, I was a few years off. Biotechnology's first wave, including Immunex, started really taking off several years before I got my doctorate. And by the time I graduated half the other graduate students were heading for industry.

Although my involvement with TNF receptor was pretty peripheral, I get a real thrill seeing how it affects the lives of ordinary people. For example, my mother is one of our best 'unofficial' sales reps and also does market research. She brings up Enbrel every time she hears someone mention rheumatoid arthritis. Last week, she was standing in line, talking with another woman. Turns out that this woman has rheumatoid arthritis. Has had it since she was 8. Been on methotrexate since forever. My mother, in her best sales mode, mentioned Enbrel and this woman really lit up. "Enbrel is a miracle." It had completely changed her life, giving it back to her.

This is why I chose the career path I did. To be involved with an exciting company, doing cutting edge research, to discover new therapies. Therapies that actually help people. The stock options are nice, and watching the stock price go up is pretty cool, but drugs like Enbrel are what will sustain my memories years from now.

Now, being a cynical scientist, I can't blather on too much about such things or they will take away my Ph.D. license. But this is a good setup because I am directly involved with another research molecule, CD39, something we cloned a few years back. Some of the most difficult work still remains. We need to create a process to make large quantities, so that we can do further animal studies. This will help us identify just which malady this drug will be used against. Eventually, if all goes extremely well and the gods of science shine on it, CD39 will enter clinical trials. Still lots of work to do.

But not every drug gets to this point. I have worked on a lot of molecules in the many years I have been here. But sometimes hard work is not enough. The fact that we almost did not get here is one of the things that makes science so intriguing. Serendipity is sometimes a pretty important part.

I saw a movie when I was quite young that had a large effect on me. Don't remember the name but it was about one of those 'great men of Science.' He was living in the days before anesthetics. While working with ether late one night, he chanced to inhale too much and knocked himself out at his desk. When he woke up his hand had gone completely through the spindle on his desk (one of those long needle-like things that old bills were stuck on). Demonstrating, in a somewhat grotesque way, that ether could be used as an anesthetic. Surgery could be performed and modern medicine was born. But what struck me was that science might move ahead through alternate processes than simple hypothesis, experimentation, theory. Luck had a role.

Being in the right place at the right time. Making just the right connection. Fleming forgot to throw away old Petri dishes. He's a slob but we have penicillin. But it is much more complex than that. He was ready and primed to make the connection. Others might have seen mold growing on the plates and just tossed them. He saw something else.

Charlie Maliszewski and his group started working on CD39 over seven years ago. We had a project called Activation Antigens. The idea was to look at proteins expressed on activated B-cells. Try to express these proteins and see what they were. The expectation was that some might be important in regulating B-cell responses. Charlie used a then novel approach, called panning, to isolate the gene coding for human CD39. My group entered to help clone the murine form of the molecule.

Now we had a protein but no good assay. See, panning simply used a monoclonal antibody that recognized CD39. This antibody would cause B-cells expressing CD39 to stick together in a process called homotypic adhesion. That was our assay but we had no idea of what CD39 would do by itself.

The CD39 coding sequence looked unusual, with 2 apparent transmembrane regions, one at the amino terminus and one at the carboxy terminus. We spent quite some time making constructions removing one or both of the transmembrane regions. We were able to demonstrate quite a bit about the structural aspects of the protein but we could not get a handle on the activity.

Data base searches found only a single similarity in one region of the protein to a yeast GTPase. But the yeast molecule was cytoplasmic while ours was membrane bound and external. We were at a dead end. A novel molecule but no measureable activity. Now CD39 is a perfect example of why scientific publication is a necessity, even for a public company. We took our information and published it, with the hope that someone else might be able to take it further. Charlie and I turned to other projects for a couple of years.

Then we got a phone call. Dr. Aaron Marcus had worked for several years on an apyrase (an enzyme that degrades both ADP and ATP) on the surface of endothelial cells lining the inside of blood vessels. This protein is extremely important in the control of platelets during the clotting process. In fact, a potato apyrase is added to platelet preparations in order to inhibit aggregation. Well, it seemed that someone had cloned the potato apyrase and shown that it has some sequence similarity to CD39. So, Aaron was curious if CD39 had any apyrase activity.

Thus started an extremely fruitful collaboration. We had all the tools and our collaborators had a tremendous amount of expertise. We quickly showed that CD39 WAS the apyrase found on these endothelial cells. We expressed a soluble form of the molecule that could degrade both ATP and ADP. We finally had an activity for our molecule that we could actually analyze.

In addition, this protein was very special for someone who, after all, got my Ph.D. in Biochemistry. We could make a lot of it and it was very stable. We purified it on antibody columns by eluting it with pH 2 acid, although a pH 10 elution (!) worked well also. It was stable at room temperatures for almost 2 days and even at 37 °C overnight. This protein had an elimination phase in mice greater than 40 hours. And it was an enzyme. So, for the first time since I joined Immunex, I could do Michaelis-Minton kinetics on it. No Kd or binding curves. I could determine kcat/Km and show that this protein had the same specificity for either ATP or ADP.

A lot of good scientific data. But it has been some of the animal studies that have been done that really demonstrated that CD39 might be effective in certain human settings. I do not know where the next few years will take us with CD39. But it has been one of those 'once in a lifetime' molecules and I am ecstatic that we are moving ahead with it. Now chance, or serendipity, does favor the prepared mind. We had taken CD39 as far as we could. If we had just buried the information, we might never have been in a position to rediscover its usefulness. Knowledge is power but I know of pharmaceutical companies that would not have published the original work.

But I believe that one of Immunex' strengths has been the rapidity with which it can move. We have few peers when it comes to getting a protein expressed and into a clinically relevant system. We had been doing work on 'Internet' time long before there was such a concept. We freely (well sometimes not so freely but we are a public company) exchange information with other scientists. The computer industry is just now looking at a business model that incorporates 'Open Source', the idea that by allowing hundreds of powerful minds to examine the same source code, they can worry at it, making it stronger and more stable. We have built a successful company on similar ideas of free exchange of information. And CD39 is a shining example of the fruits this type of free exchange can provide.

If CD39 ever makes it into the clinic as a viable therapeutic, it will be due to a lot of hard work. Serendipity might have had a role, but only in the broadest sense, of unexpected findings. Luck may have a part in getting it started but only hard work will make it succeed. And scientists at Immunex continue to work on other molecules in the same fashion as we did with CD39. These skills will become even more important in the coming years. Because everyone else will have access to the same databases and the same information. Success will come down to how rapidly you can move once you have a useful fact. CD39 demonstrates that we can perform quite successfully under these conditions.

So let the stock market go where it may. We are not like dot com companies or most other biotechs. We not only sell a product, we still maintain the ability to discover new therapeutics. And we are attempting to generate means to discover them even faster. So let those other companies fill-in the gaps in their business models (wondering what the title came from, huh.) Or fill-in the holes in their drug portfolios. Or fill-in the missing parts of their research approaches. Or fill-in the ....fell free to add your own tortured metaphor. I am looking forward to the next molecule we move forward with.