Recalls and OTC Disapproval: A Gloomy December for Merck
This is definitely not Merck’s month.
On 12 December 2007, Merck announced the voluntary recall of potentially contaminated batches of the influenza vaccines PEDVAXHIB and COMVAX. These vaccines are indicated for infants and young children for protection against the seasonal flu and hepatitis B. The affected batches were distributed in April 2007 [1].
On another front, a US FDA advisory panel voted against Merck’s application for the prescription drug Mevacor 20 mg to be sold over-the-counter. Mevacor (lovastatin) is indicated for the treatment of elevated cholesterol levels. It has been on the market as a prescription drug since 1997. The panel’s recommendation is based on concerns of the use of the drug by misinformed consumers who may not actually benefit from it. The recommendation is not binding and a final decision would be reached in January 2008 [2].
Merck News Item, 12 Dec 2007
Merck News Item, 13 Dec 2007
The STEP Trial: Discontinuation and Unblinding
The STEP Trial: The STEP study was a phase II multinational, randomized, double-blind, placebo-controlled clinical trial which was started in 2004.
The Investigational Drug: The V520 HIV vaccine candidate is a combination of 3 components made from a weakened adenovirus type 5. The vaccine serves as a vector of 3 synthetically produced HIV genes known as gag, pol and nef. These HIV genes would supposedly induce “an HIV-specific immune response through the body’s own CD8 T-cells, which become programmed to recognize and kill HIV infected cells.”
The Sponsors: The STEP trial was sponsored by Merck, the National Institute of Allergy and Infectious Diseases (NIAID), and the HIV Vaccine Trials Network (HVTN).
The The Study Population: 3,000 HIV-negative participants from different ethnic groups. They are aged between 18 and 45 years of age and at high risk of HIV infection. The trial was conducted in the United States, Peru, Brazil, Dominican Republic, Haiti, Jamaica, Australia, and South Africa.
The Efficacy Endpoints: The primary efficacy endpoints were to evaluate the ability of the vaccine to prevent HIV infection and to reduce virus proliferation in infected individuals.
The Discontinuation: On 21 September 2007, Merck announced the discontinuation of the STEP study due to poor efficacy profile. The vaccine did not prevent infection nor reduce viral loads in the bloodstream of HIV-positive individuals.
The Unblinding: In November 2007, Merck and HVTN announced their decision to unblind the trial based on concerns that the vaccine may actually have induced susceptibility to HIV infection in study participants. Sources:
HVTN Press Release 13 Nov 2007
A Promising Vaccine against Hypertension: Results from a Phase II Trial
An investigational vaccine against angiotensin II being tested by Cytos Biotechnology is showing promise. Results from an exploratory Phase IIa trial were presented at the American Heart Association Scientific Sessions 2007 [1] this month. CYT006-AngQb is a virus-like particle-based conjugate vaccine and is indicated for patients with mild to moderate hypertension. Preliminary results show “a significant reduction of daytime ambulatory blood pressure (BP) and a marked reduction in the early morning hours, when most adverse cardiovascular events occur.” [2]
Currently available antihypertensive drugs have a short half-life and must be taken on a daily basis. CYT006-AngQb has the advantage of producing extended antibody response with a half-life of about 4 months [2, 3].
In addition to a good efficacy profile, CYT006-AngQb was reported to be well-tolerated. The most common adverse events reported were pain, erythema, or edema at the injection site, and headache. All events were transient and no drug-related adverse events were reported during the 12-month follow-up period [3].
If approved, the vaccine would be a major breakthrough in the long-term management of hypertension.
Sources:
2 Medscape