Pharmaceutical companies have completed only 42 of the 91 post-marketing studies required under the FDA’s accelerated approval process, according to a report issued today by Rep. Edward J. Markey (D-Mass).
The incomplete studies include those for Celebrex (celecoxib), Gleevec (imatinib), and Iressa (gefitinib), said the report.
When the FDA grants accelerated approval it does so only on the condition that the drug maker agrees to conduct further studies to confirm safety and efficacy, a condition that Rep. Markey says both the FDA and drug companies are ignoring.
In the report, Markey cited Iressa as a textbook example of the value of timely post marketing studies. Iressa was approved in May 2003 on the basis of clinical trials that the FDA said demonstrated significant shrinkage in tumors in about 10% of non-small cell lung cancer patients treated.
In a statement issued December 20, 2004 the FDA said that evidence of tumor response “was thought likely to increase patients’ overall survival time,” which is why the drug received accelerated approval.
The FDA instructed the drug maker, AstraZeneca, to conduct post-marketing studies to confirm a survival benefit. But the post-marketing study in 1,700 patients demonstrated no overall survival advantage for Iressa, a finding the FDA announced December 17, 2004. (Some investigators say that they can identify by genetic testing the 10% of patients for whom Iressa is effective.)
That FDA announcement, “prevented patients from spending $1,800 a month for a drug that is ineffective,” Rep. Markey said. Other Iressa post-marketing studies are pending.
Markey said 28 companies have committed to 91 post-marketing studies for 42 different drugs, but as of March 9, 2005, only 42 of the 91 studies were completed. Moreover, half of the remaining post-marketing studies have not even been started.
He lists 16 drugs that are awaiting confirmatory post-marketing studies: Alimta, Arimidex, Celebrex, Depocyt, Ethyol, Gleevec, Iressa, Luveris, Mylotarg, Proamatine, Remodulin, Sulfamylon, Synercid, Truvada, Velcade and Viread.
Finally, Markey faults the FDA for doing too little to inform the public about “which products were given full approval and which drugs are given conditional approval.”