About this Author
College chemistry, 1983
The 2002 Model
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: firstname.lastname@example.org
March 24, 2014
Several years ago, the Schering-Plough cholesterol absorption inhibitor (Zetia, ezetimibe) and its combination pill with simvastatin (Vytorin) were the subject of a lot of puzzled controversy. A clinical trial (ENHANCE) looking at arterial wall thickness in patients with familial hypercholesteremia had unexpectedly shown little or no benefit, although statins themselves had worked in this population. This led to plenty of (still unresolved) speculation about the drug's mechanism of action, whether it really was going to be of benefit to the wider patient population, what this meant for the surrogate endpoint of LDL lowering (which the drug does accomplish), and so on.
Sales of both Zetia and Vytorin took a hit, naturally. But a new editorial in JAMA wonders why they're selling at all, and particularly, why they're doing so well in Canada. A new paper in the American Heart Journal shows that ezetimibe sales in the US went down 47% over the next year after the ENHANCE results came out. But in Canada, it just kept rolling along. (Even after the decline, though, it's still used more in the US).
What's causing this? Quite likely, an over-focus on cholesterol levels themselves:
Krumholz, one of the coauthors on the study with Jackevicius, remains perplexed as to the continuing popularity of ezetimibe. “The drug continues to defy gravity, and that’s probably a result of really strong marketing and the singular focus on cholesterol numbers,” he said.
Krumholz said heart health campaigns urging patients to “know your numbers” and treatment goals based on cholesterol measurements, such as getting asymptomatic individuals’ LDL-C levels below 130 mg/dL, have worked in ezetimibe’s favor at the expense of evidence-based medicine. “Is this the drug that lowers your LDL-C and helps you? We don’t know that,” he said. “The comfort of hitting a target offers little benefit if you don’t know that it is really protecting you.”
The funny thing is, all that emphasis on LDL assay numbers was supposed to be "evidence-based medicine". But that's the funny thing about science - the evidence keeps leading you in new directions.
+ TrackBacks (0) | Category: Cardiovascular Disease
January 27, 2014
A recurring theme here when I talk about cardiovascular drug discovery is how poorly we understand human lipidology. Surprise after surprise has followed on efforts to lower LDL and/or raise HDL, to the point that a person really has to wonder if the success of the statin drugs was a fluke. (And they could be a fluke in more than one way - perhaps the LDL-lowering effects are, for some reason, more beneficial through that mechanism than they might otherwise be, or as many have speculated, there might be off-target effects that are also helpful).
Everyone seems to agree, though, that raising HDL is (or would be) a good thing. Attempts to do that pharmacologically, though, have come to grief, so the evidence we have is through longitudinal studies and the occasional mutant line with unusually high HDL. Both of those have their pitfalls when it comes to drug targeting - there are, for example, people with HDL-raising mutations that don't see to show any good effect for it.
Now comes this paper in Nature Medicine that identifies an oxidized form of HDL (specifically, ApoA1 protein) in arterial plaques. This modified protein is useless for cholesterol scavenging, exacerbates inflammation, and impairs biogenesis of normal HDL. This makes it a good candidate as a diagnostic marker (which is where the paper is aimed, rightly), and also a good candidate for anyone working on HDL-raising ideas to keep an eye on.
Merck, for example, is pushing ahead with their CETP inhibitor compound anacetrapib Last report I saw on that one was on some rather alarming pharmacokinetics - the drug appears to take a long time to wash out. Long, as in "still detectable several years after the last dose". Given that it looks like something that could be used to line a nonstick frying pan (like most of the other CETP compounds), that's quite believable. As late as Merck is in the clinic, they're not going to be able to jump in and start looking for this new oxidized HDL form so easily. But it would be something to think about
+ TrackBacks (0) | Category: Cardiovascular Disease
January 16, 2014
Merck's vorapaxar, a thrombin antagonist that many had thought might never make it, has received a positive FDA advisory committee vote. I'm glad to see it - peripherally, I go way back with this compound (well, its ancestors), and I really had doubts that Merck could get things to fly. Anticoagulants are a very tricky business - we'll see (if and when it does get approved) what sort of market it can carve out. They're up for treating patient who have already had one cardiac event, which is still a good-sized market.
+ TrackBacks (0) | Category: Cardiovascular Disease | Regulatory Affairs
November 14, 2013
If you read the publications on the GSK compound (darapladib) that just failed in Phase III, you may notice something odd. These mention "odor" as a side effect in the clinical trial subjects. Say what?
If you look at the structure, there's a para-fluorobenzyl thioether in there, and I've heard that this is apparently not oxidized in vivo (a common fate for sulfides). That sends potentially smelly parent compound (and other metabolites?) into general circulation, where it can exit in urine and feces and even show up in things like sweat and breath. Off the top of my head, I can't think of another modern drug that has a severe odor liability. Anyone have examples?
Update: plenty of examples in the comments!
+ TrackBacks (0) | Category: Cardiovascular Disease | Clinical Trials | Pharmacokinetics
October 24, 2013
Here's a provocative article at the British Medical Journal on cardiovascular outcomes and diet. Now, I free admit that the BMJ has a tendency towards controversialism, but I'm hardly in a position to throw stones. The author, Aseem Malhotra, says "Saturated fat is not the issue".
Human lipidology is a very complex field, and anyone who tells you that they have the definite answers needs to be treated with caution. As has been well documented, the consensus advice about dietary fats of all kinds has varied quite a bit, and I don't think it's anywhere near settling down. The role of pharmaceutical intervention isn't settled, either, despite the huge success of the statin drugs. There's room to argue about their broad effects on cardiovascular morbidity and mortality, and how much of it is mechanism-based:
A meta-analysis of predominantly industry sponsored data reported that in a low risk group of people aged 60-70 years taking statins the number needed to treat (NNT) to prevent one cardiovascular event in one year was 345. The strongest evidence base for statins is in secondary prevention, where all patients after a myocardial infarction are prescribed maximum dose treatment irrespective of total cholesterol, because of statins’ anti-inflammatory or pleiotropic (coronary plaque stabilising) effects. In this group the NNT is 83 for mortality over five years. This doesn’t mean that each patient benefits a little but rather that 82 will receive no prognostic benefit. The fact that no other cholesterol lowering drug has shown a benefit in terms of mortality supports the hypothesis that the benefits of statins are independent of their effects on cholesterol.
You can go on from this to wonder how things are going to work out if any of the HDL-raising therapies ever make it into the general population. Do we know what we're doing there, or are we only going to find out after twenty years in the real world? On saturated fat, Malhotra says that he's not convinced by the standard recommendations, either:
Saturated fat has been demonised ever since Ancel Keys’s landmark “seven countries” study in 1970. This concluded that a correlation existed between the incidence of coronary heart disease and total cholesterol concentrations, which then correlated with the proportion of energy provided by saturated fat. But correlation is not causation. Nevertheless, we were advised to cut fat intake to 30% of total energy and saturated fat to 10%.” The aspect of dietary saturated fat that is believed to have the greatest influence on cardiovascular risk is elevated concentrations of low density lipoprotein (LDL) cholesterol. Yet the reduction in LDL cholesterol from reducing saturated fat intake seems to be specific to large, buoyant (type A) LDL particles, when in fact it is the small, dense (type B) particles (responsive to carbohydrate intake) that are implicated in cardiovascular disease.
I find this sort of thing very interesting, both as an issue in itself, and for what it says about our knowledge of medicine and human biology. You'd think that there would be nothing more well worked-out than the role of different kinds of diets in heart disease, but the closer you look, the messier the situation is. There are big public health issues here, both the obvious primary ones, and the secondary issue of causing people to become frustrated and cynical about big dietary recommendations in general.
+ TrackBacks (0) | Category: Cardiovascular Disease
October 16, 2013
Some long-awaited clinical data has appeared in the cardiovascular area: Sanofi and Regeneron have the first Phase III numbers for their PCSK9-blocking antibody alirocumab. (Here's some background on this area from John LaMattina).
This was a monotherapy trial, run head-to-head against Merck/Schering-Plough's Zetia (ezetimibe). Patients in the alirocumab arm started at a low dose, injected every two weeks, and had to the option to increase it if their LDL had not hit the target levels. Three quarters of them didn't have to. Their LDL levels went down 47% on average, compared to 15.6% in the daily Zetia group, so I think we can call that one a solid success. There are other Phase III trials ongoing in different patient populations and with different regimens (for example, taking alirocumab along with a statin), but these results bode well. No significant toxicity has been observed, which, needless to say, also bodes well.
That's the thing to watch. This is a new mechanism of action, and if there's one thing that the history of drug discovery tells us, it's that we don't know as much as we need to about mechanisms of action (both good and bad). It's good news that PCSK9-blocking therapies have been as clean as they have so far, but everyone in the field (Amgen is right behind Sanofi and Regeneron, and others are behind them) will be scrutinizing the data closely as more and more patient reports come in. These drugs could be used very widely indeed, and for many years at a time, so it's important to look for all sorts of things that might be down in the weeds. But so far, so good.
+ TrackBacks (0) | Category: Cardiovascular Disease | Clinical Trials
July 12, 2013
Hmmm. This article from Bloomberg says that the BMS/Pfizer anticoagulant Eliquis (apixaban), a Factor Xa inhibitor approved late last year by the FDA, was delayed for months because of misconduct in its Chinese clinical trials. (Its clinical trials had not been without incident even before this). Documents posted by the FDA have the details. Says the article:
In the Eliquis trial, Bristol-Myers hired Pharmaceutical Product Development Inc., a closely held, Wilmington, North Carolina, company known as PPD, to help oversee it.
The Eliquis trial was questioned on two issues, according to the FDA documents first cited by the journal Pharmaceutical Approvals Monthly. One was the improper manipulation of records at a study site for 35 patients at the Shanghai 9th Peoples Hospital in China. The second involved the high percentage of the 9,000 patients who were supposed to be getting Eliquis, and instead were either given the wrong drug, or the wrong dose.
There was a broad list of issues at the Shanghai hospital, according to FDA documents. They included failure to report four potential adverse medical events, late reports on three others and three medical outcomes that weren’t included in the data. Additionally, some patient names and dates were wrong, and Chinese and English records didn’t match in some cases. The FDA also reported that some patient records disappeared just ahead of a site visit by agency inspectors.
I wonder if the Bloomberg reporter was tipped off to this himself, because you have to dig into this PDF (which is one of many) to find the goods (do a search for the words "Shanghai" and "fraud"). Here are some quotes from the document itself:
Although BMS contracted with a Contract Research Organization, PPD, to provide site monitoring for ARISTOTLE, PPD did not have a presence in the People’s Republic of China when the trial was initiated in PRC; BMS initially used its own employees for monitoring. One BMS employee along with at least one other individual altered subject records after being notified the site would be inspected by OSI. OSI inspected eight clinical sites worldwide after becoming aware of this action. Additionally, after errors in dispensing study drug became an issue, BMS and PPD, a CRO involved in conducting and monitoring ARISTOTLE, were inspected specifically to review the issue of trial oversight and monitoring. OSI concludes that the study appears to have been conducted and monitored adequately. They did recommend that data from sites in China be excluded because the employee who committed the GCP violation in China was involved in the conduct of the trial at all Chinese sites.
This came to light because a contract worker went to his or her supervisors with a problem: this person had been asked to change data and documentation on a hard drive before an FDA inspection, and the supervisor making the request (who was later fired) had worked at 18 other trial locations in China. This led the FDA, naturally enough, to say that it was worried about what else might have been going on, and to complain about broad problems with oversight.
As shown in the FDA documents, the agency went on to run the data with that specific site excluded, and then with all the other Chinese site data excluded, and the analysis still came out in favor of apixaban (although not as robustly in some categories). So the approval of the drug seems to have been the right call; the conclusions of the trial don't seem to have been switched by the misconduct. Still, you don't want this sort of thing.
Elliot Levy of BMS is quoted several times in the Bloomberg article, generally playing down the problems mentioned by the FDA: "not exceptional", "appropriately documented and reported", and so on. But if everything was normal, why did things stall for nine months? The lead outside investigator on the trial, Christopher Granger of Duke, has a different perspective:
“There is a greater likelihood of some of this impropriety in certain regions,” Granger said in a telephone interview. “We’ve had experiences in India and China where we’ve had more than we would have expected.”
Unfortunately, I think that's a fair assessment. But it doesn't have to be that way. There are vast numbers of ethical, hard-working scientists and staff in both India and China; it's not like these entire countries are full of cheaters and corner-cutters. But international companies go to these countries to get work done for lower cost, so the incentives are there to keep those costs down by whatever means come to hand. There are underhanded shortcutters in every country in the world, but some business environments give these people more scope to exercise their talents.
I'm actually glad when this sort of thing comes to light. Although it's not like Bristol-Myers Squibb or Lilly were rushing to do that, were they? I think that the only way to clean up this kind of behavior is to make it public, so that it has as many consequences as possible. If a country's reputation for doing fast, cost-effective clinical trials is compromised by a reputation for regulatory trouble and unreliable data, well, that's another set of incentives at work, but this time in the right direction. Throwing a towel over these incidents does no one any good in the long run. Make it public; make it sting.
+ TrackBacks (0) | Category: Cardiovascular Disease | Clinical Trials | The Dark Side
May 9, 2013
Here's a drug-discovery problem that you don't often have to think about. The anticoagulant field is a huge one, with Plavix, warfarin, and plenty of others jostling for a share of a huge market (both for patients to take themselves, and for hospital use). The Factor Xa inhibitors are a recent entry into this area, with Bayer's Xarelto (rivaroxaban) as the key example so far.
But there's a problem with any Xa inhibitor: there's no antidote for them. Blood clotting therapies have a narrow window to work in - anything effective enough to be beneficial will be effective enough to be trouble under other circumstances. Anticoagulants need a corresponding way to cancel out their effects, in case of overdose or other trouble. (Vitamin K is the answer for warfarin). We don't often have to consider this issue, but it's a big one in this case.
Portola Therapeutics has developed a Factor Xa mimic that binds the inhibitors, and thus titrates their effects. They have their own Xa inhibitor coming along (bextrixaban), but if this protein makes it through, they'll have done the whole field a favor as well as themselves.
+ TrackBacks (0) | Category: Cardiovascular Disease
Vytorin's been discussed several times around here. The combination of Zetia (ezetimibe), the cholesterol absorption inhibitor discovered at Schering-Plough, with Merck's simvastatin looked as if it should be a very effective cholesterol-lowering medication, but the real-world data have been consistentlypuzzling. There's a big trial going on that people are hoping will clarify things, but so far it's had the opposite effect. It's no exaggeration to say that the entire absorption inhibitor/statin combination idea is in doubt, and we may well learn a lot about human lipidology as we figure out what's happened. It will have been an expensive lesson.
So in the midst of all this, what does Merck do but trot out anotherezetimibe/statin combination? Liptruzet has atorvastatin (generic Lipitor) in it, instead of simavastatin (generic Zocor), and what that is supposed to accomplish is a mystery to me. It's a mystery to Josh Bloom over at the American Council for Science and Health, too, and he's out with an op-ed saying that Merck should be ashamed of itself.
I can't see how he's wrong. What I'm seeing is an attempt by Merck to position itself should the ongoing Vytorin trial actually exonerate the combination idea. Vytorin, you see, doesn't have all that much patent lifetime left; its problems since 2008 have eaten the most profitable years right out of its cycle. So if Vytorin turns out to actually work out, after all the exciting plot twists, Merck will be there to tell people that they shouldn't take it. No, they should take exciting new Liptruzet instead. It's newer.
If anyone can think of a reason why this doesn't make Merck look like shady marketeers, I'd like to hear it. And (as Bloom points out) it doesn't make the FDA look all that great, either, since I'm sure that Liptruzet will count towards the end-of-the-year press release about all the innovative new drugs that the agency has approved. Not this time.
Update: John LaMattina's concerned about that last part, too.
+ TrackBacks (0) | Category: Cardiovascular Disease | Why Everyone Loves Us
April 4, 2013
I feel as if there should be some good news around here on the hiring front, so when any becomes available I want to try to mention it. So here's some: Regeneron has announced today that they're expanding their site in Westchester (NY), adding another 300,000 square feet of lab and office space, and adding over 400 new jobs in a number of areas.
The fusion protein Eylea (aflibercept) has been doing very well for them since its approval in 2011. And they're very much in the hunt for PCSK9 therapies, which could provide a completely new LDL-lowering mechanism. (Here's some good background from John LaMattina on that - Sanofi and Regeneron are running one of those humungous cardiovascular Phase III trials as we speak, and the results of it (compared to the statin standard of care) are going to be extremely interesting). If those numbers come out well, Regeneron could be looking for even more room.
+ TrackBacks (0) | Category: Business and Markets | Cardiovascular Disease
March 19, 2013
Affymax has had a long history, and it's rarely been dull. The company was founded in 1988, back in the very earliest flush of the Combichem era, and in its early years it (along with Pharmacopeia) was what people thought of when they thought of that whole approach. Huge compound libraries produced (as much as possible) by robotics, equally huge screening efforts to deal with all those compounds - this stuff is familiar to us now (all too familiar, in many cases), but it was new then. If you weren't around for it, you'll have to take the word of those who were that it could all be rather exciting and scary at first: what if the answer really was to crank out huge piles of amides, sulfonamides, substituted piperazines, aminotriazines, oligopeptides, and all the other "build-that-compound-count-now!" classes? No one could say for sure that it wasn't. Not yet.
Glaxo bought Affymax back in 1995, about the time they were buying Wellcome, which makes it seem like a long time ago, and perhaps it was. At any rate, they kept the combichem/screening technology and spun a new version of Affymax back out in 2001 to a syndicate of investors. For the past twelve years, that Affymax has been in the drug discovery and development business on its own.
And as this page shows, the story through most of those years has been peginesatide (brand name Omontys, although it was known as Hematide for a while as well). This is synthetic peptide (with some unnatural amino acids in it, and a polyethylene glycol tail) that mimics erythropoetin. What with its cyclic nature (a couple of disulfide bonds), the unnatural residues, and the PEGylation, it's a perfect example of what you often have to do to make an oligopeptide into a drug.
But for quite a while there, no one was sure whether this one was going to be a drug or not. Affymax had partnered with Takeda along the way, and in 2010 the companies announced some disturbing clinical data in kidney patients. While Omontys did seem to help with anemia, it also seemed to have a worse safety profile than Amgen's EPO, the existing competition. The big worry was cardiovascular trouble (which had also been a problem with EPO itself and all the other attempted competition in that field). A period of wranging ensued, with a lot of work on the clinical data and a lot of back-and-forthing with the FDA. In the end, the drug was actually approved one year ago, albeit with a black-box warning about cardiovascular safety.
But over the last year, about 25,000 patients got the drug, and unfortunately, 19 of them had serious anaphylactic reactions to it within the first half hour of exposure. Three patients died as a result, and some others nearly did. That is also exactly what one worries about with a synthetic peptide derivative: it's close enough to the real protein to do its job, but it's different enough to set off the occasional immune response, and the immune system can be very serious business indeed. Allergic responses had been noted in the clinical trials, but I think that if you'd taken bets last March, people would have picked the cardiovascular effects as the likely nemesis, not anaphylaxis. But that's not how it's worked out.
Takeda and Affymax voluntarily recalled the drug last month. And that looked like it might be all for the company, because this has been their main chance for some years now. Sure enough, the announcement has come that most of the employees are being let go. And it includes this language, which is the financial correlate of Cheyne-Stokes breathing:
The company also announced that it will retain a bank to evaluate strategic alternatives for the organization, including the sale of the company or its assets, or a corporate merger. The company is considering all possible alternatives, including further restructuring activities, wind-down of operations or even bankruptcy proceedings.
I'm sorry to hear it. Drug development is very hard indeed.
+ TrackBacks (0) | Category: Business and Markets | Cardiovascular Disease | Drug Development | Drug Industry History | Toxicology
February 15, 2013
You may remember that Merck and Schering-Plough took a lot of fire for the way that they released the clinical data for one of the key Vytorin trials (ENHANCE). The numbers were delayed for months, and when they were finally released, they were. . .problematic for the drug. And for the companies' stocks.
The institutional shareholders did not take that one well; and a number of them filed suit. This week it was announced that Merck has settled for $688 million, while admitting no wrongdoing. This settles the suit, but it isn't going to settle anyone's nerves, as Matthew Herper rightly observes:
Merck admitted no liability or wrongdoing in the decision, and continues to believe its handling of the study was proper. But the settlement could make investors nervous anyway. One of the reasons Vytorin has never recovered (sales of the pill are $1.5 billion, $1 billion less than before the results were released, but that partly reflects a price increase) is that Merck’s other clinical trials, so far, have never again compared Vytorin to Zocor to look for differences in real cardiovascular problems like heart attack and stroke. Instead, the other big trial of Vytorin compared it to placebo in patients who had a heart valve that did not close fully.
But Merck is doing that big Vytorin versus Zocor study, a giant clinical trial called IMPROVE-IT. Results have been delayed several times, and probably won’t come until next year. But the company has said that the independent board that is monitoring the results of the trial will meet in March. They could decide to stop the trial if it has already proved more effective, if Vytorin appears more dangerous than Zocor, or if there is no hope that Vytorin will prove more effective.
I doubt that the trial will be stopped, but at this point I'll be surprised if it yield enough strong data to vindicate Vytorin, either. The delays seen in the trial so far make that look like a very outside chance. My guess is "beneficial effect, but not as much as you'd want", which won't satisfy anyone.
+ TrackBacks (0) | Category: Cardiovascular Disease
January 25, 2013
CETP, now there's a drug target that has incinerated a lot of money over the years. Here's a roundup of compounds I posted on back last summer, with links to their brutal development histories. I wondered here about what's going to happen with this class of compounds: will one ever make it as a drug? If it does, will it just end up telling us that there are yet more complications in human lipid handling that we didn't anticipate?
Well, Merck and Lilly are continuing their hugely expensive, long-running atempts to answer these questions. Here's an interview with Merck's Ken Frazier in which he sounds realistic - that is, nervous:
Merck CEO Ken Frazier, speaking in Davos on the sidelines of the World Economic Forum, said the U.S. drugmaker would continue to press ahead with clinical research on HDL raising, even though the scientific case so far remained inconclusive.
"The Tredaptive failure is another piece of evidence on the side of the scale that says HDL raising hasn't yet been proven," he said.
"I don't think by any means, though, that the question of HDL raising as a positive factor in cardiovascular health has been settled."
Tredaptive, of course, hit the skids just last month. And while its mechanism is not directly relevant to CETP inhibition (I think), it does illustrate how little we know about this area. Merck's anacetrapib is one of the ugliest-looking drug candidates I've ever seen (ten fluorines, three aryl rings, no hydrogen bond donors in sight), and Lilly's compound is only slightly more appealing.
But Merck finds itself having to bet a large part of the company's future in this area. Lilly, for its part, is betting similarly, and most of the rest of their future is being plunked down on Alzheimer's. And these two therapeutic areas have a lot in common: they're both huge markets that require huge clinical trials and rest on tricky fundamental biology. The huge market part makes sense; that's the only way that you could justify the amount of development needed to get a compound through. But the rest of the setup is worth some thought.
Is this what Big Pharma has come to, then? Placing larger and larger bets in hopes of a payoff that will make it all work out? If this were roulette, I'd have no trouble diagnosing someone who was using a Martingale betting system. There are a few differences, although I'm not sure how (or if) they cancel out For one thing, the Martingale gambler is putting down larger and larger amounts of money in an attempt to win the same small payout (the sum of the initial bet!) Pharma is at least chasing a larger jackpot. But the second difference is that the house advantage at roulette is a fixed 5.26% (at least in the US), which is ruinous, but is at least a known quantity.
But mentioning "known quantities" brings up a third difference. The rules of casino games don't change (unless an Ed Thorp shows up, which was a one-time situation). The odds of drug discovery are subject to continuous change as we acquire more knowledge; it's more like the Monty Hall Paradox. The question is, have the odds changed enough in CETP (or HDL-raising therapies in general) or Alzheimer's to make this a reasonable wager?
For the former, well, maybe. There are theories about what went wrong with torcetrapib (a slight raising of blood pressure being foremost, last I heard), and Merck's compound seems to be dodging those. Roche's failure with dacetrapib is worrisome, though, since the official reason there was sheer lack of efficacy in the clinic. And it's clear that there's a lot about HDL and LDL that we don't understand, both their underlying biology and their effects on human health when they're altered. So (to put things in terms of the Monty Hall problem), a tiny door has been opened a crack, and we may have caught a glimpse of some goat hair. But it could have been a throw rug, or a gorilla; it's hard to say.
What about Alzheimer's? I'm not even sure if we're learned as much as we have with CETP. The immunological therapies have been hard to draw conclusions from, because hey, it's the immune system. Every antibody is different, and can do different things. But the mechanistic implications of what we've seen so far are not that encouraging, unless, of course, you're giving interviews as an executive of Eli Lilly. The small-molecule side of the business is a bit easier to interpret; it's an unrelieved string of failures, one crater after another. We've learned a lot about Alzheimer's therapies, but what we've mostly learned is that nothing we've tried has worked much. In Monty Hall terms, the door has stayed shut (or perhaps has opened every so often to provide a terrifying view of the Void). At any rate, the flow of actionable goat-delivered information has been sparse.
Overall, then, I wonder if we really are at the go-for-the-biggest-markets-and-hope-for-the-best stage of research. The big companies are the ones with enough resources to tackle the big diseases; that's one reason we see them there. But the other reason is that the big diseases are the only things that the big companies think can rescue them.
+ TrackBacks (0) | Category: Alzheimer's Disease | Cardiovascular Disease | Clinical Trials | Drug Development | Drug Industry History
December 21, 2012
Merck's Tredaptive (formerly Cordaptive) has had a long and troubled history. It's a combination of niacin and Laropiprant, which is there to try to reduce the cardiovascular (flushing) side effects of large niacin doses, which otherwise seem to do a good job improving lipid profiles. (Mind you, we don't seem to know how that works, and there's a lot of reason to wonder how well it works in combination with statins, but still).
The combination was rejected by the FDA back in 2008, but approved in Europe. Merck has been trying to shore up the drug ever since, and since the FDA told them that they would not approve without more data, the company has been running a 25,000-patient trial (oh, cardiovascular disease. . .) combining Tredaptive with statin therapy. In light of the last link in the paragraph above, one might have wondered how that was going to work out, since the NIH had to stop a large niacin-plus-statin study of their own. Well. . .
The European Medicines Agency has started a review of the safety and efficacy of Tredaptive, Pelzont and Trevaclyn, identical medicines that are used to treat adults with dyslipidaemia (abnormally high levels of fat in the blood), particularly combined mixed dyslipidaemia and primary hypercholesterolaemia.
The review was triggered because the Agency was informed by the pharmaceutical company Merck, Sharp & Dohme of the preliminary results of a large, long-term study comparing the clinical effects of adding these medicines to statins (standard medicines used to reduce cholesterol) with statin treatment alone. The study raises questions about the efficacy of the medicine when added to statins, as this did not reduce the risk of major vascular events (serious problems with the heart and blood vessels, including heart attack and stroke) compared with statin therapy alone. In addition, in the preliminary results a higher frequency of non-fatal but serious side effects was seen in patients taking the medicines than in patients only taking statins.
So much for Tredaptive, and (I'd say) so much for the idea of taking niacin and statins together. And it also looks like the FDA was on target here when they asked for more evidence from Merck. Human lipid biology, as we get reminded over and over, is very complicated indeed. The statin drugs, for all their faults, do seem to be effective, but (to repeat myself!) they also seem, more and more, to be outliers in that regard.
+ TrackBacks (0) | Category: Cardiovascular Disease | Clinical Trials | Toxicology
December 14, 2012
I wrote here in 2009 about Kynamro (mipomersen), an antisense oligonucleotide from Isis targeted LDL cholesterol levels. At the time, Isis and Genzyme were starting to look at its use in people with familial hypercholesterolaemia, and its prospects looked promising to become at least a profitable niche drug.
But the European Medicines Authority just turned down the drug, saying that its risk/benefit ratio just looks unacceptable. Efficacy was not in doubt, but a substantial number of patients stopped taking mipomersen because of side effects, including liver toxicity. That's bad enough, but the treatment groups also showed a great incidence of cardiovascular events, which is particularly worth thinking about when you're trying to lower LDL to prevent. . .cardiovascular events.
Human lipid handling continues to be a minefield for new therapies. The statins (which lower LDL through inhibiting cholesterol biosynthesis) appear, more and more, to be outliers in their safety and efficacy. That's not to say that statin drugs never have problems (they do - just ask Bayer, among others). But the risk/benefit for them does appear to be robust and positive, and how many other lipid-altering drugs can say that?
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August 31, 2012
Eli Lilly has been getting shelled with bad news recently. There was the not-that-encouraging-at-all failure of its Alzheimer's antibody solanezumab to meet any of its clinical endpoints. But that's the good news, since that (at least according to the company) it showed some signs of something in some patients.
We can't say that about pomaglumetad methionil (LY2140023), their metabotropic glutamate receptor ligand for schizophrenia, which is being halted. The first large trial of the compound failed to meet its endpoint, and an interim analysis showed that the drug was unlikely to have a chance of making its endpoints in the second trial. It will now disappear, as will the money spent on it so far. (The first drug project I ever worked on was a backup for an antipsychotic with a novel mechanism, which also failed to do a damned thing in the clinic, and which experience perhaps gave me some of the ideas I have now about drug research).
This compound is an oral prodrug of LY404039, which has a rather unusual structure. The New York Times did a story about the drug's development a few years ago, which honestly makes rather sad reading in light of the current news. It was once thought to have great promise. Note the cynical statement in that last link about how it really doesn't matter if the compound works or not - but you know what? It did matter in the end. This was the first compound of its type, an attempt at a real innovation through a new mechanism to treat mental illness, just the sort of thing that some people will tell you that the drug industry never gets around to doing.
And just to round things off, Lilly announced the results of a head-to-head trial of its anticoagulant drug Effient versus (now generic) Plavix in acute coronary syndrome. This is the sort of trial that critics of the drug industry keep saying never gets run, by the way. But this one was, because Plavix is the thing to beat in that field - and Effient didn't beat it, although there might have been an edge in long-term followup.
Anticoagulants are a tough field - there are a lot of patients, a lot of money to be made, and a lot of room (in theory) for improvement over the existing agents. But just beating heparin is hard enough, without the additional challenge of beating cheap Plavix. It's a large enough patient population, though, that more than one drug is needed because of different responses.
There have been a lot of critics of Lilly's research strategy over the years, and a lot of shareholders have been (and are) yelling for the CEO's head. But from where I sit, it looks like the company has been taking a lot of good shots. They've had a big push in Alzheimer's, for example. Their gamma-secretase inhibitor, which failed in terrible fashion, was a first of its kind. Someone had to be the first to try this mechanism out; it's been a goal of Alzheimer's research for over twenty years now. Solanezumab was a tougher call, given the difficulties that Elan (and Wyeth/Pfizer, J&J, and so on) have had with that approach over the years. But immunology is a black box, different antibodies do different things in different people, and Lilly's not the only company trying the same thing. And they've been doggedly pursuing beta-secretase as well. These, like them or not, are still some of the best ideas that anyone has for Alzheimer's therapy. And any kind of win in that area would be a huge event - I think that Lilly deserves credit for having the nerve to go after such a tough area, because I can tell you that I've been avoiding it ever since I worked on it in the 1990s.
But what would I have spent the money on instead? It's not like there are any low-risk ideas crowding each other for attention. Lilly's portfolio is not a crazy or stupid one - it's not all wild ideas, but it's not all full of attempts to play it safe, either. It looks like the sort of thing any big (and highly competent) drug research organization could have ended up with. The odds are still very much against any drug making it through the clinic, which means that having three (or four, or five) in a row go bad on you is not an unusual event at all. Just a horribly unprofitable one.
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August 30, 2012
Here's yet another chance to play the human biology game that might as well be called "Now what?" That's when we find that what we thought we knew is actually wrong, more complicated, or a sign of something else entirely.
Today's entry is niacin. As many readers know, it looks like it should be a promising therapy for patients whose lipoproteins are out of whack. It lowers LDL, raises HDL, lowers free fatty acids, and lowers triglycerides, and all those things are supposed to be good. (As came up in the comments yesterday's post, though, the evidence is pretty strong for that first proposition, but not as solid for the others). Still, if you went around to thousands of cardiologists and asked them if they'd be interested in a therapy that did those four things, you'd get a resounding "Yes".
So why hasn't niacin taken over the world? Because of the side effects. It has to be taken in rather stiff doses to show the lipid effects, and those tend to cause a nasty skin flush reaction, which is apparently unpleasant enough that most people won't put up with it. Various attempts have been made to abrogate this, with the most direct assault being Merck's (failed) Cordaptive.
The flushing is thought to be mediated through the receptor GPR109A, via a prostaglandin pathway. Unfortunately, it's also believed that niacin's beneficial effects are mediated through that receptor, too, via some mechanism that starts with the lowering of free fatty acids. If you knock out the receptor in mice, you get no skin flushing, but no FFA lowering, either.
We must now revise that idea. A new paper tests that hypothesis with two non-niacin agonists, MK-1903 (a compound via Arena Pharmaceuticals, I believe) and SCH900271, and their effects in humans. They also report niacin's effects in the receptor knockout mice, claiming that although the FFA lowering does indeed disappear, that the downstream lipid effects remain. (That surprises me; I'd thought that had already been studied).
But the human data are especially revealing. The two new agonists do indeed show FFA effects, as you'd expect from compounds hitting GPR109A. But they do not show chr