re: Ann: Complete Response Letter from FDA Re... Thank god CXS...

re: Ann: Complete Response Letter from FDA Re... Thank god CXS doesn't have to enroll more patients or do another trial. Even though they have said this previously it's good to get confirmation from the FDA.

Also some thoughts by Mark Sinatra from biotechdaily albeit dated after ODAC panel decision on 23 Mar..


MARC SINATRA?S BIOGUIDE BRIEF: CHEMGENEX

This morning?s US Food and Drug Administration?s Oncologic Drug Advisory Committee decision isn?t as bad as it appears. In fact, today?s trading probably represented a good buying opportunity.

ODAC?s main problem with Chemgenex?s T315I trial is whether or not the trial patients actually carried the T315I mutation.

Previously, after reviewing Chemgenex?s data, the FDA found that 35 percent of study subjects had not had their mutation status confirmed by the central laboratory at the time of enrolment.

Importantly, judging from feedback relayed back by Chemgenex from the ODAC meeting,neither safety nor efficacy is in question.

The precise nature of the problem is the quality of the T315I mutation testing Chemgenex used in its trial. It was not standardized, as different tests were used in different patients.

There is also no test for the T315I mutation that the FDA recognizes as validated. If the testing undertaken by Chemgenex in the trial has a high false positive rate, many
patients without the T315I mutation may have been included in the study.

If this is the case, the same thing is likely to occur in the real world if the drug is approved and you could end up with patients incorrectly diagnosed as carrying the T315I mutation who might be prescribed Omapro, when, in fact, until Omparo is approved for more general forms of chronic myeloid leukemia, they may be better off on another tyrosine kinase inhibitor.

If the FDA?s concerns about the T315I status of patients turn out to be unfounded, it means that few patients are likely to be misclassified once the drug is on the market and few will be at risk of receiving suboptimal therapy.

The next step will be for Chemgenex and the FDA to look at the testing procedures used in the study to determine the true mutation status of the patients enrolled in it.

The truth of the matter is that accurately identifying a point mutation is something that every medical molecular biology laboratory should be able to do. Consequently, I see little risk that Chemgenex won?t be able to satisfy the FDA?s concerns.

In my opinion, the FDA will ultimately approve Omapro for chronic myeloid leukaemia patients carrying the T315I mutation.

The question is just when.

Chemgenex deserves a big kick in the pants. Its running of this trial has been sloppy and caused undue stress to its shareholders.

It should also serve as a warning to other Australian biotechnology companies regarding the FDA?s requirements and remind them that they need to carefully design their clinical trials and actively manage them.
Marc Sinatra, analyst