Is amlodipine maleate a `generic' fr amlodipine besylate?

From www.deccan.com
US court rules against Dr Reddy's AmVaz
 

Hyderabad, Feb. 28: In what could be its most serious setback, a court
in the United States has ruled against Dr Reddy's Laboratories' first
specialty drug, AmVaz. The US Court of Appeals for the Federal Circuit
of New Jersey has reversed a lower court's ruling which had said that
Pfizer's patent term extension on Norvasc did not cover Dr. Reddy's
amlodipine maleate product.

The Court of Appeals in New Jersey ruled that the patent term
extension to Norvasc's amlodipine besylate was also applicate to Dr
Reddy's amlodipine maleate.
Dr Reddy's had argued that amlodipine maleate, which has one salt
different from Norvasc's amlodipine besylate but had the same
therapeutic qualities, was different in that it did not infringe on
Pfizer's patent. Norvasc, which is indicated for hypertension and
angina, is one of Pfizer's blockbuster drugs, with sales of $4.34
billion in 2003.

"We are clearly disappointed by the court's decision and had expected
that the views expressed by the Chief Judge in the dissent would have
been the position of the majority. We are considering filing a plea
against the ruling under the en banc process," G V Prasad, Dr Reddy's
CEO, told Deccan Chronicle on Saturday.

According to industry sources, Dr Reddy's had a potential market
opportunity of between $50 million-$200 million for AmVaz  in the US.
In fact, the company had been in the process of setting up a marketing
infrastructure for AmVaz in the US. Dr Reddy's is estimated to have
spent $12 million on its legal defence for AmVaz . "Obviously, there
will be some impact on the company's revenues because we were hoping
to launch the drug,"  Prasad said.