Anthra Pharmaceuticals was granted FDA approval for Valstar, indicated for the intravesical
treatment of BCG refractory carcinoma in situ in patients for whom immediate cystectomy could
not be conducted, on September 25, 1998. A special warning was included for Valstar which
stated that the product has been shown to bring about temporary disappearance of cancer in only
about 1 in 5 patients with treatment resistant bladder cancer.
Valstar was originally granted orphan drug designation and priority review. Several amendments
were made to the original NDA filing (under 505b(2)) and an ODAC Committee Review meeting
was held prior to being granted approval. The FDA had several questions in the data presented in
the NDA application, where 20 of 90 patients or 22% achieved a complete response. Of those 20,
the FDA did not take issue with 7 of them (8%); an additional 7 patients were considered
potential complete responders using non-protocol criteria; and the remaining 6 did not have a
complete response....
(That means the prescribed treatment using proper protocol was only effective in 7 out of 90 patients).
...Valstar was later removed from the market in 2002 due to impurities in the original formulation
and was placed on the FDA Drug Shortages List. The product is currently held by Indevus
Pharmaceuticals (NQ;IDEV) after the acquisition of Valera Pharmaceuticals on April 18, 2007.
Valera Pharma purchased some of the assets of Anthra Pharma during 2005.
Indevus is currently working towards the re-approval of Valstar for the same indication and the
same label. Indevus had submitted a NDA supplement detailing chemistry, manufacturing and
controls (CMC) for Valstar in May 2007. On December 19, 2008, the FDA issued a nonapprovable
letter, following a response to an approvable letter issued in August 2007. According
to Indevus, the issues related to the 2002 withdrawal of the product have been resolved, however,
the FDA identified manufacturing deficiencies with the third-party manufacturer, that require
resolution prior to granting approval. Indevus expects final approval in the coming months.
With the very limited label and the difficulties in manufacturing we question the market viability
of this product when it returns to the market.