Is Medarex's Prostate Cancer Drug a Success? Too Early to Tell

What's really going on with Medarex (MEDX) and ipilimumab? The company made news over the weekend with a press release from the Mayo Clinic, detailing what appears to be a substantial response in two prostate cancer patients. But the more you look at the story, the harder it is to figure out anything useful.

As this WebMD piece makes clear, this study is not a trial of ipilimumab as a single agent. The patients are undergoing prolonged androgen ablation, the testosterone-suppressing therapy that's been around for many years and is one of the standard options for prostate cancer. The trial is to see if ipilimumab has any benefit when it's added to this protocol - basically, to see if it can advance the standard of care a bit.

WebMD quotes Derek Raghavan at the Cleveland Clinic as saying that androgen ablation can sometimes have dramatic results in patients with locally advanced prostate cancer, so it's impossible to say if ipilimumab is helping or not. That's why we run clinical trials, you know, to see if there's a real effect across a meaningful number of patients. But (as this AP story notes) we don't know how many patients are in this particular study, what its endpoints are, or really anything about its design. All we know is that two patients opted out of it for surgery instead. (Credit goes to the AP's Linda Johnson for laying all this out.)

Ipilimumab is an antibody against CTLA-4, which is an inhibitory regulator of lymphocytes. Blocking it should, in theory, turn these cells loose to engage tumor cells more robustly. (It also turns them loose to engage normal tissue more robustly, too - most of the side effects seem to be autoimmune responses like colitis, which can be very severe. The antibody has been studied most thoroughly in melanoma, where it does seem to be of value, although the side effect profile is certainly complicating things.)

So overall, I think it's way too early to conclude that Medarex has hit on some miracle prostate cure. This press release, in fact, hasn't been too helpful at all, and the Mayo people really should know better.

Comments

[FoundAlpha77:]

I know that Adam P might have some difficulties using clinicaltrials.....but please it is not that hard ;-)

www.clinicaltrials.gov...

Jun 23 04:56 PM

[kenny b:]

<<the Mayo people really should know better.>> I for one think their a lot more credible than you. By the way according to the WallStreet Journal online yesterday they interviewed Dr. Kwon he confirmed that a third patient operated on ten days ago is cancer free. Also an additional 15 to 20 patients may have similar outcomes. That doesn"t sound like chance to me. The trial is scheduled to have 108 total patients with 1/2 receiving the IPI+AA combo. but not yet fully enrolled. so maybe you should do a little more DD before you dismiss a Mayo Clinic Press release.

Jun 23 05:48 PM

[jq1234:]

I agree with user 435757, you should do more DD before writing this piece.

"WebMD quotes Derek Raghavan at the Cleveland Clinic as saying that androgen ablation can sometimes have dramatic results in patients with locally advanced prostate cancer, so it's impossible to say if ipilimumab is helping or not."

I agree with the caution whether the effect was due to Ipi or not. However, to dismiss it completely is also not credible. Did you ask anyone whether they had seen patients who have inoperable prostate cancer become operable after androgen ablation only?

Jun 23 07:38 PM

[kenny b:]

<<On Monday, Eugene Kwon, a Mayo Clinic urologist and leader of the clinical trial, told Dow Jones Newswires a third patient has recently been affirmed to be cancer free after undergoing the same treatment. The operation to remove that patient's tumor occurred 10 days ago, Kwon said, adding that there may be similar results to come among another 15 to 20 patients in the trial>>

Jun 23 09:38 PM

[kenny b:]

From the MEDX MESSAGE BOARD regarding your article <<There is no doubt that these two researchers/physicians have taken considerable risk with their reputations by making this press release, not to mention that they have compromised the study, which is already open label. As a researcher myself, my reaction is that it was risky and unwise to make the press release. Having said that, if they truly believe, and are correct, that 15-20 people will have surgically resectable tumor with minimal residual cells, then their reputation will not be harmed. As pointed out, this will attract a large number of patients to the Mayo trials, and they do have something of a conflict of interest imbedded in this.
Now that I am done scolding and preaching (sorry about that - haven't had my coffee yet), I have to say that am completely hopeful that they are absolutely correct and that they have truly changed the paradigm for treatment of this disease

Jun 24 08:41 AM

[polar40:]

Biopharma is notorious for false signals which later prove to be highly exagerated. Many investors have lost fortunes when the stock falls. It is better to wait and see some real open ended statistically significant phase III results before believing these.

Jun 24 12:16 PM

[kenny b:]

Derek you should view this video.www.cbsnews.com/storie...

Jun 26 08:37 AM

[in4thelonghaul:]

You think maybe Dr. Kwon was cognizant of the unorthodox timing of his comments and thus the scrutiny which he and Mayo would be under? Now why would he take such a chance unless he had weighed the potential benefits against the serious consequences?

Think about it Derek...

Weren't you the same guy that lined up with Cramer against DNDN?

You don't exactly have a stellar track record do you?

I agree with others...you should really try and do a bit of proper DD before expressing such dismissive attitude.

Jun 26 11:31 AM