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DBL%20Hendrix%20small.png College chemistry, 1983

Derek Lowe The 2002 Model

Dbl%20new%20portrait%20B%26W.png After 10 years of blogging. . .

Derek Lowe, an Arkansan by birth, got his BA from Hendrix College and his PhD in organic chemistry from Duke before spending time in Germany on a Humboldt Fellowship on his post-doc. He's worked for several major pharmaceutical companies since 1989 on drug discovery projects against schizophrenia, Alzheimer's, diabetes, osteoporosis and other diseases. To contact Derek email him directly: derekb.lowe@gmail.com Twitter: Dereklowe

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In the Pipeline: Don't miss Derek Lowe's excellent commentary on drug discovery and the pharma industry in general at In the Pipeline

In the Pipeline

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January 4, 2011

Detecting Single Cancer Cells

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Posted by Derek

This story on a new diagnostic method in oncology is getting a lot of attention in the press. It's a collaboration between J&J, a small company they've bought called Veridex, and several oncology centers to see if very sensitive monitoring of circulating tumor cells could be a more useful biomarker.

The press coverage has some hype in it - for one thing, all the stuff about detecting one single cancer cell in the whole body isn't too helpful. The cells have to be circulating in the blood, and they have to display the markers you're looking for, to start with. But I can't deny that this is an interesting and potentially exciting field. There's some evidence to suggest that circulating tumor cells could be a strongly predictive marker can in several kinds of cancer.

These studies are looking at the sorts of endpoints that clinicians (and patients, and the FDA) all respect: overall survival, and progression-free survival. As discussed around here before, it's widely felt in oncology that these are where the field should really be spending its time, rather than on tumor size and so on. (You'd think that tumor size or number of detectable tumors would correlate with survival, but in many cases it's a strikingly poor predictor - which is a shame, since those are easier and faster numbers to get). A blood test, on the other hand, that strongly correlates with survival would be a real advance.

The value would not just be in telling (some) patients that they're showing better chances for survival, although I'm sure that'll be greatly appreciated. It's the patients whose numbers come back worse that may well be helped out the most, because that indicates that the current therapy isn't doing the job, and that it's time to switch to something else (assuming that there is something else, of course). The more quickly and confidently you can make that call, the better.

And from a drug development perspective, the uses of such assays in clinical trials are immediately obvious. Additionally, I'd think that these would be a real help to rolling-enrollment Bayesian trial designs, since you could assign patients to (and move them between) the different study groups with more confidence.

The Veridex/J&J assay (called CellSearch) uses an ingenious magnetic immunochemical approach. Blood samples are treated with antibody-coated iron nanoparticles that recognize a common adhesion protein. The cells that get bound are separated magnetically on a diagnostic chip for further immunostaining and imaging. There are other techniques out there as well - here's an article from Technology Review on a competing one that's said to be more sensitive, and here's a San Diego company trying to enter the market with an assay that's supposed to be broader-based). The key for all of these things will be bringing the costs down (and the speed of production up, in some cases). These are tests that ideally would be run early and often, so the cheaper and faster the assay can be made, the better.

Now, of course, we just need some more therapies that work, so that when people find out that their current regimen isn't working, then they have something else to try. If these circulating-cell assays help us sort things out faster in the clinic, maybe we'll be able to make better use of our time and money to that end.

Comments (14) + TrackBacks (0) | Category: Analytical Chemistry | Cancer | Clinical Trials


COMMENTS

1. Anonymous on January 4, 2011 10:53 AM writes...

thanks for your blog. I find it useful to sort out the technologies I don't have the time to ferret out for myself. Happy New Year.

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2. anchor on January 4, 2011 11:40 AM writes...

I think there is too much hype and very little hope, when the smoke clears. J and J has gobbled it up and it is way too early. The main worry during these frugal times are not the discovery itself but the price and as to who pays for it. We shall wait.

Permalink to Comment

3. Anonymous on January 4, 2011 11:46 AM writes...

TY for your comments. Yes, this is a test to identify failed treatments early on.

And yes, onocology and its therapies have to get to the business of killing cancer and no longer be distracted by tumors.

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4. Jose on January 4, 2011 11:52 AM writes...

I'd wait until someone does a solid CBA including the massive costs of both false positives and negatives before I'd get too excited. PSA looked awfully sexy for awhile too....

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5. Xmas on January 4, 2011 12:01 PM writes...

If this works for cancers, couldn't it work for all sorts of other things as well? You coat iron nanoparticles in an antibody for N and then inject them into a person, pull them out and see what sticks.

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6. DLIB on January 4, 2011 2:37 PM writes...

A long time ago people were thinking of using this type of thing as a " magic bullet " to cure cancer. put the person in a field after tagging the cancer and the idea is that local heating would do the killing....

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7. PharmD11 on January 4, 2011 2:39 PM writes...

"I'd wait until someone does a solid CBA including the massive costs of both false positives and negatives before I'd get too excited. PSA looked awfully sexy for awhile too...."
Interesting point. Assuming this could clinically detect cancer at 1 stage earlier might prove effective for a CBA. Stage 3 vs 4 for a certain cancer could be a difference of 50k+ for costs. Not to mention life years saved. This number is usually put at ~50k/quality life year saved.

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8. pete on January 4, 2011 3:09 PM writes...

re: the degree of concordance between CTC # vs. DEGREE of progression free survival/overall survival

I'm guessing one complicating factor may be variation in patient-specific immunosurveillance of CTCs. That is, you and I may have the identical cancer subtypes + concentration of CTCs but have very different clinical outcomes, because in me, even a small number of CTCs may overwhelm my immune defenses -- and thus will be free to take root as 2ndary tumors, whereas in you, that same number of CTCs may remain below the threshold of your defenses and thus will be successfully disposed of by your circulating immune cells.

We'll see if that's the case.

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9. Andy Pierce on January 4, 2011 3:55 PM writes...

A related issue is that tumor cells getting into circulation is only half of the metastatic story. Those cells have to survive in the circulation, leave the circulatory system, and successfully set up shop elsewhere. You could well have two patients that are shedding equivalent loads of CTCs, but radically different clinical outcomes. Still lots of development work needed here, but the potential upside is very exciting.

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10. Bob Proulx on January 4, 2011 4:40 PM writes...

Thanks for the blog posting, however, I think to refer to this technology as a diagnostic method is probably a bit premature. While this technology appears to show better efficiency than the current Veridex system in terms of counting CTCs it is a highly manual process and not ready for primetime in the diagnostic laboratory. Additionally, as you point out, prognostic indicators of risk of recurrence have only so much medical benefit to the patient. The likely true market opportunity for improving patient care will come with the molecular characterization of these rare cells and not just the enumeration. There is a growing field of technologies focused on not just counting rare cells but capturing them for analysis. Expect
significant movement in the biomarker field in the coming years as these new technologies, like our DEPArray, get into the hands of clinical researchers.

Permalink to Comment

11. Bob Proulx on January 4, 2011 4:42 PM writes...

Thanks for the blog posting, however, I think to refer to this technology as a diagnostic method is probably a bit premature. While this technology appears to show better efficiency than the current Veridex system in terms of counting CTCs it is a highly manual process and not ready for primetime in the diagnostic laboratory. Additionally, as you point out, prognostic indicators of risk of recurrence have only so much medical benefit to the patient. The likely true market opportunity for improving patient care will come with the molecular characterization of these rare cells and not just the enumeration. There is a growing field of technologies focused on not just counting rare cells but capturing them for analysis. Expect
significant movement in the biomarker field in the coming years as these new technologies, like our DEPArray, get into the hands of clinical researchers.

Permalink to Comment

12. cliffintokyo on January 5, 2011 3:54 AM writes...

Post: "...assuming that there is something else, of course...."
If THAT is not a polemical pregnant pause, (stuffed full of "Xmas left-overs" brain fodder), I don't know what is!
I suspect that we are in for a *merry* new year!
Cheers Derek!

Permalink to Comment

13. Dion Madsen on January 6, 2011 2:55 PM writes...

Derek,

Love the blog. I wanted to add that there is another company out there that you missed in your review that I think is further advanced than any of the others. The company is called On-Q-ity, based in Boston and an investment of ours at Physic Ventures.

The concerns that you outlined in your post and also in the very educated comments that followed it are clearly the evidence that needs to be compiled before this methodology is used widely. The company that best addresses these issues will be able to dramatically change the cost and complexity of obtaining tumor samples which we hope will lead to more frequent monitoring of tumor response and better health outcomes

Permalink to Comment

14. Div on April 27, 2011 1:22 PM writes...

Does anyone have any ideas about the sizing of the market How much will the CTC enumeration and rare cell isolation market be any guesses?

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