The Sirtex Conundrum

So Sirtex had anounnced that is hs failed to meet the primary endpoint in the clinical trial of SIR-spheres in metastatic colorectal cancer. The somewhat overvalued shareprice proceeded to tank….from almost $40 to $17.

The stock was super over-valued but this is another story.

SIR-spheres are a way of delivering radiation treatment to cancer in the liver. In the case of the SIR-FLOX trial it was standard chemotherapy plus or minus the radiation treatment.

This was available “off-label” based on preliminary promisaring results or on trial.

The stock market release is that there was no benefit in terms of overall profression free survival but beenfit in terms of liver confined progression. There was no comment about toicity which is rumoured to be worse in the SIR-spheres arm.

This problem is not specifically a reflection on the product but the system. We have limited capacity to regulate devices at the current time. SIRT has been regulated as a device and the main requirement from a regulatory perspective is that it doesn’t kill people…..no comment about whther it helps them.

SIR-spheres almost certainly causes cancers to shrink. As a product it is manufactured according to rigid guidelines which it meets….but it doesn’t meet the standards a medication is required to meet…..actaual clinical benefit.

I will still prescribe SIR-spheres for selected situations but I have to acknowledge that the regulatory process for these products is currently flawed and it should move to a process that resembles those for medicines.In the case of the latter effectiveness not just safety is rewarded. And to be frank we need to see the full report to understand the safety of SIR-spheres.

As a Disclaimer I participated in the trial but recurited poorly and withdrew over time

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