Tuesday, April 01, 2014

Senju loses on claim preclusion

The CAFC discussed matters of claim preclusion ("res judicata") in Senju v. Apotex The outcome was that Senju's claims were barred by claim preclusion. Lawlor, 349 US 322 was cited.

As an initial matter, the CAFC used the abbreviation EDTA in the decision, although this abbreviation does not appear in the patent at issue, 6,333,045.

Of relevance, from the FDA

1. What is EDTA?

The term “EDTA” is often used to refer to two different drugs that bind to ("chelate") certain molecules within the body. This binding speeds the elimination of these molecules from the body. For example, when one type of EDTA drug is injected into the blood stream, it binds to calcium and speeds excretion of calcium through the kidneys. This type of EDTA drug has been used to treat high blood levels of calcium. The other type of EDTA drug strongly binds to lead and has been used to treat patients with lead poisoning.

2. What are the names of the two EDTA drugs?

There are two drugs approved by the FDA that have similar names are easily confused. To add to the confusion, both drugs are commonly referred to only as the abbreviation, "EDTA."

One drug is named "Calcium Disodium Versenate" and is also known by the chemical name of edetate calcium disodium. This drug is approved by the FDA to lower blood lead levels among patients with lead poisoning.

The other drug is marketed as "Endrate" and is also known by the chemical name of edetate disodium. This drug is approved by the FDA for use in selected patients with high blood calcium levels (hypercalcemia) as well as for use among patients with heart rhythm problems due to intoxication with the drug, digitalis.

3. What is the problem with the EDTA drugs?

The two EDTA drugs have established names that are easily confused and both are referred to in clinical practice as "EDTA." This confusion has resulted in medication errors in which some patients have received the wrong drug, which has been fatal in some cases or caused serious adverse reactions in others. The error is especially dangerous when edetate disodium is erroneously given to a patient who is supposed to receive edetate calcium disodium.

The two EDTA drugs have different approved uses and significantly different effects. For example, edetate disodium is more likely to cause severe decreases in blood calcium levels. A severe decrease in blood calcium levels due to the erroneous administration of edetate disodium has resulted in death, predominantly among pediatric patients, who were to be treated for lead poisoning with edetate calcium disodium. As noted below, FDA has special concerns regarding the use of edetate disodium and is reconsidering the overall risks and benefits of the drug.


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