Pristiq (desvenlafaxine) information

Here’s a list of compiled links providing information on Pristiq. These links include info from my blog and others.

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Pristiq's side effects: Too close to Premarin and Prempro for comfort?

Back in January 2007, I’d mentioned that Wyeth was not only seeking to market Pristiq (desvenlafaxine) for depression but also for the use of vasomotor symptoms in menopausal women.

I just learned that Wyeth produces two major menopause drugs, Premarin and Prempro, that allegedly has produced hormones causing cancer in more than 5,000 women. This added up to a loss of 40 million users and $1 billion annually.

With Effexor going generic in 2 years and the introduction of Pristiq to the market, Wyeth hopes to lure some of those customers back and net an annual $2 billion. However, serious questions linger about Pristiq’s side effects in menopausal women.

Why did two women in the study group taking Pristiq have heart attacks
and three need procedures to repair clogged arteries compared with none
taking placebo? How can Wyeth assure long term safety when 604 of the
2,158 test subjects took Pristiq for only six months and 318 for a year
or more? And what about serious liver complications seen in the studies?

Martha Rosenberg, reporting on Pristiq’s use as a menopausal drug, culled comments from CafePharma’s message boards and found one thread rife with mixed comments on the new drug. From an Anonymous commenter:

Read the rest of this entry »

Pristiq gains ground with FDA

FDA approval for Pristiq (I'll refer to it as Pq occasionally) is contingent upon Wyeth's handling of "quality control problems… made to the satisfaction of federal inspectors." As I'd previously mentioned before, Wyeth has built an amazingly similar medication based on Effexor. Wyeth is trying to market Pristiq as an antidepressant and treatment for vasomotor symptoms (hot flashes during menopause). Wyeth is significantly banking on Pristiq since their $3.5 billion Effexor XR will lose its patent in a few years, allowing other companies to make venlafaxine generics.

Some of the "quality control" problems Wyeth is experiencing:

  • unclear whether Pq keeps depressive episodes at bay
  • efficacy at low doses and in young kids
  • severe nausea in 50 percent of patients in the clinical trials

Reuters' article notes this, though:

"But the studies do not need to be completed prior to approval of the new depression pill."

While Wyeth has admitted that Pq is "structurally related" to Effexor, it "has not yet disclosed if Pristiq has any advantages over Effexor XR, other than to say it would be an alternative to existing treatments."

But it has acknowledged the newer drug caused nausea in about one-half of patients in clinical trials.

Wyeth is banking on patients sticking out the nausea for one week (it supposedly subsides after that) or a 50 mg pill that would be more effective than the whopping 400 mg they used in earlier phases of the clinical trials.

"The company said it will not launch Pristiq until it obtains results from the low-dose trials. Moreover, Wyeth said the timing of the launch also will depend on progress of the FDA's ongoing review of Pristiq as a possible non-hormonal treatment for hot flashes. The FDA is scheduled to decide on the hot flashes indication in April."

Wyeth wants to be absolutely sure they can cover all of their bases in an effort not to lose a single portion on their market share — from those who can tolerate low doses at 50 mg to those who need to go 400 mg and up.

"A G Edwards analyst Joseph Tooley has predicted Pristiq will garner annual sales of $1.4 billion by 2011 — about $1 billion from use against depression and the remainder for menopausal symptoms."

Getting not only psychiatrists to prescribe the drug, but also OB/GYNs is a clever move on their part.

Pristiq posing as pristine

The Trouble With Spikol has linked to an article in the San Diego Union-Tribune (via Reuters) that covers Wyeth's new Effexor XR knock-off, Pristiq (desvenlafaxine succinate). Why are they launching Pristiq? Their patent on Effexor will expire in July 2010 when making generic versions of the drug will be up for grabs.

"Wyeth said in July, however, that it will not introduce Pristiq until it completes tests of a low 50-milligram dose of the drug, following trials of higher dosages in which about half the patients experienced nausea."

Too bad clinical trials don't test for withdrawal symptoms. Will Pristiq avoid the withdrawal hell issues that Effexor XR has?

“'We will wait for the results of the low-dose trials, which we've said we expect in early 2007, before making a decision' on when to launch Pristiq, company spokeswoman Gwen Fisher told Reuters on Friday.

She said nausea seen in the earlier trials was mild to moderate and generally went away within a week after treatment began.”

How long were these clinical trials and if the nausea was seen in the "earlier trials," what about the most recent trials?

Pending FDA approval, Wyeth would also like to use Pristiq for vasomotor symptoms in menopausal women.  Wyeth's unannounced strategy will be to introduce Pristiq long before Effexor's patent expires so they don't lose any of their $1 billion market share to an Effexor generic.

A Wyeth PR that went under my radar:

“Pristiq, a serotonin/norepinephrine reuptake inhibitor (SNRI) now is being studied with a specific focus on women. It initially was developed for two indications that currently are pending approval from the U.S. Food and Drug Administration (FDA) – the treatment of major depressive disorder (MDD) and vasomotor symptoms (VMS) associated with menopause. 

In the area of depression, Pristiq is expected to improve the balance of serotonin and norepinephrine as compared with serotonin reuptake inhibitors (SSRI) because of its pharmacologic profile as a dual reuptake inhibitor.”

Isn’t that what SNRIs are supposed to do?

“Clinical studies confirm that Pristiq is effective in both men and women. However, women over age 40 represent about 50 percent of the depression market and could benefit from an antidepressant that addresses their symptoms and physiology.”

No kidding – 50 percent of the depression market and the implication of all women over 40 years old? Sure, I believe that. Looks like Wall Street doesn't have much hope for the new drug either.

“Pristiq also may be a treatment option for patients who are on multiple medications. The compound has a low risk of drug-drug interactions. This is important when considering that depression often is a co-morbid condition in medically ill patients and that these patients frequently are taking multiple medications. The Company expects FDA action for the MDD indication in January 2007.”

The multiple medications thing. Um, I’m not a fan of that unless it’s absolutely necessary. It isn’t necessary in a lot of cases.

“FDA action for the second application for Pristiq for vasomotor symptoms associated with menopause is anticipated in April 2007. Pristiq is expected to provide significant relief of hot flushes (decrease in number and severity) associated with menopause.

If approved, Pristiq will be the first non-hormonal treatment indicated for relief of VMS.

The Company also plans to pursue indications for Pristiq that would include fibromyalgia syndrome and diabetic neuropathic pain.”

Wyeth certainly is attempting to milk this new drug for all it’s worth. I hope Furious Seasons or CLPsych take up on investigating this one since I simply don’t have the time, resources, or ability.