Merck faces growing legal headache over Zostavax: report

Dive Brief:

  • Merck & Co. could be facing an increasing number of lawsuits alleging its shingles vaccine Zostavax has caused injury and death, reports The Legal Intelligencer, citing attorneys involved in legal action against the pharma company. 
  • Claims, so far mostly filed in state and federal courts in Pennsylvania, cover injuries ranging from rashes to chicken pox all the way up to more severe cases like fatal liver failure, according to the report.
  • In response to a request from comment, Merck said it "stands behind the demonstrated safety and efficacy of Zostavax," which was first approved by the Food and Drug Administration in 2006.

Dive Insight:

The virus behind chicken pox, varicella-zoster, can lie dormant in the nerves for years until it reactivates itself, generally when the immune system is weakened through age, stress or illness. This reactivation can result in shingles, which ranges in severity from being unpleasant to more severe long-term complications.

Vaccination with Merck’s Zostavax has been shown to reduce the risk of shingles and lower its severity. However, Zostavax is a live attenuated virus vaccine, posing a risk to immunosuppressed or immunodeficient individuals (such as patients with AIDs, leukemia or other diesases). Zostavax is contraindicated against use in such individuals. 

It's not clear whether the vaccine injury cases reported in The Legal Intelligencer are linked to people with compromised immune systems, but some of the issues reported, such as chicken pox outbreaks and rashes could be to due to infection with the varicella-zoster virus.

"Nothing is more important to Merck than the safety of our medicines and vaccines. Merck stands behind the demonstrated safety and efficacy of Zostavax, which has been licensed in over 50 countries," the company said in an emailed statement.  

"While it is difficult to determine the exact number of doses that have been administered, more than 36 million doses of Zostavax have been distributed globally since its initial approval by the FDA in 2006. The safety and efficacy of Zostavax were originally demonstrated in clinical trials involving more than 30,000 patients and since then Zostavax has been studied in hundreds of thousands of patients."

Legal headaches aside, Merck will likely be facing new competition soon from GlaxoSmithKline's shingles vaccine Shingrix nearing markets. Approvals are pending in Europe and the U.S., threatening Merck's Zostavax revenue. 

Last year, Zostavax earned $685 million in worldwide sales, but patent protection was expired in the U.S. and will lapse in Europe in 2018.

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Filed Under: Legal
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