02/16/16

Nearsighted Drug Development

© Antonio Gravante | Dreamstime.com

© Antonio Gravante | Dreamstime.com

I was encouraged to hear that ALKS 5461 failed in two late-stage clinical trial studies. This isn’t because I have something against Alkermes, the pharmaceutical company developing the drug. I don’t own stock in a competing company trying to bring their new fast-acting antidepressant drug to market ahead of Alkermes. I do think antidepressants are overprescribed and have potentially harmful side effects for some people, but that’s not why I was happy to hear that ALKS 5461 is in trouble. I just don’t think that putting an antidepressant drug on the market that uses a potentially addictive opioid as its active ingredient is a good idea.

Reporting for Reuters, Amrutha Penumudi said that when news of the failed clinical trails for ALKS 5461 were made public by Alkermes, the company saw its shares fall in value by 42.8%, a $3.88 billion loss for the company. ALKS 5461 is the company’s main product, so the bad news about the clinical trials was a major financial blow. William Tanner, an analyst for Guggenheim Partners was widely quoted by Reuters and others as saying that “We believe trial failures present a major setback in the evolution of the company.” Even if ALKS 5461 succeeds in a third as-yet not completed clinical trial, more studies may be required, according to Ken Cacciatore.

ALKS 5461 is a new molecular entity (NME) that has been fast tracked by the FDA for approval as a treatment of Major Depressive Disorder (MDD) with patients who didn’t respond to standard antidepressant therapies. It is a combination of buprenorphine, a Schedule IV Controlled Substance and samidorphan, a naloxone-like substance. Suboxone, which is a combination of buprenorphine and naloxone, is commonly used as an opioid substitution medication for heroin and prescription opioid addicts. The major difference between ALKS 5461 and Suboxone as far as buprenorphine is concerned is that ALKS 5461 is currently being tested in 2 mg and .5 mg doses, where standard protocols for Suboxone as an opioid substitution drug could reach 16 mg or higher. You will find more information on ALKS 5461 and my concerns about its use to treat depression in: “The Coming Depression Apocalypse,” an article I published here a few months ago.

But it doesn’t seem Alkermes is going to give up the fight. In their press release, Richard Pops, the CEO of Alkermes said:

We are steadfast in our commitment to developing new medicines for serious CNS conditions where there is a clear and compelling need for new treatment options for patients and their families. . . . Major depressive disorder is one of these conditions. We are building a large body of evidence supporting our belief in the clinical utility and the novel mechanism of action of ALKS 5461. We await the results of FORWARD-5 and will determine our next steps along the regulatory path with those results in hand.

In one of the failed trials, Alkermes did post-hoc analyses (reanalysis of the data after the fact) that indicated the 2 mg dose was more effective than a placebo. Given the results of the two failed studies, Alkermes said they plan to increase the number of patients in the ongoing trial and “update” the planned statistical analysis for FORWARD-5, the third efficacy study in the FORWARD program. The updated analysis sounds like it means they plan to use the same analysis process applied to the 2mg dose group for FORWARD-4 after the fact. This is bit like cheating if the researchers went p-hacking or data-dredging in their post-hoc analysis. See “How to Lie About Research” for more information on p-hacking.

Another factor regarding Alkermes and ALKS 5461 that concerns me is how the company describes the drug. In their above-linked press release, Alkermes said that ALKS 5461 acted “as a balanced neuromodulator in the brain;” and was “designed to rebalance brain function that is dysregulated in the state of depression.” This sounds eerily similar to the chemical imbalance theory of depression that even psychiatrists such as Ronald Pies have said was always a kind of urban legend. In an article in Psychiatric Times, he said: “To my knowledge, no professional psychiatric organization has ever publicly promoted a ‘chemical imbalance theory’ of mental illness in general.” Look at Robert Whitaker’s response to that article by Pies and the reams of additional evidence to show how Pies’ claim was clearly wrong.

But there is now another concern with the use of opioids to treat depression. A study by Scherrer et al., published in the Annals of Family Medicine, found that people who used prescription opioids for longer than a month may have an increased risk of developing depression. Scherrer was quoted by Agata Blaszczak-Boxe for Live Science as saying the researchers rigorously controlled for pain, “and we feel strongly that these results are independent of the known contribution of pain to depression.” The longer individuals were taking opioids, the greater was their risk of depression.

Citing a 2014 study by Howe and Sullivan in General Hospital Psychiatry, Scherrer et al. said that research on the efficacy of opioids in treating depression was limited by small sample sizes, short follow-up time and lack of control groups. So they do not support opioids as effective long-term treatments for depression. “This evidence, combined with the finding from the present study, supports the conclusion that opioids may cause short-term improvement in mood, but long-term use is associated with risk of new-onset depression.”

Buprenorphine was not one of the opioids studied, but the findings of the Scherrer et al. study does give me increased concern with the fast-track status the FDA has given ALKS 5461. Recent findings do suggest the risk of new onset of depression increases with a longer duration of opioid use. A replication attempt of Scherrer’s study with buprenorphine seems needed before approving ALKS 5461. The short-term projected improvements could lead to long-term problems with depression.  “Patients and practitioners should be aware that opioid analgesic use of longer than 30 days imposes risk of new-onset depression.”

Hopefully the FDA will have the foresight to weigh all the potential adverse effects with ALKS 5461 before approving it. There is a very real potential for physical dependency to develop with ALKS 5461 given that its active ingredient is a Schedule IV controlled substance. Heroin addicts have told me buprenorphine was more difficult for them to come off of than heroin or methadone. And to top it all off, there seems to be evidence that using opioids longer than 30 days carries a risk of new-onset depression. This is not a very promising profile for a future treatment for depression.

Additionally, the initial statistical analysis done on the first two clinical trials failed to demonstrate that it was more effective than a placebo. Only after a post hoc analysis was there evidence of any statistically significant results. And then it was only with the higher, 2mg, dose. Will that lead to even higher doses of buprenorphine to increase its effectiveness? Read more on the concerns with outcome switching in clinical trials here.

Revising the statistical analysis (outcome switching) of the remaining clinical trial may produce statistically significant results, and if it does, it seems Alkermes intends to argue with the FDA to approve ALKS 5461. On the one hand, I can see where Alkermes would attempt to salvage their “lead product.” But I’m hoping their nearsighted focus on profits and the company’s market value will not blind the FDA to the long-term consequences of using opioids like buprenorphine to treat depression.