CDX-011 versus Ixabepilone & Eribulin

乳腺癌 in PhaseIIb, an anti-boy drug, licensed from SGEN?

Interesting, Ixabepilone moved from prior therapy requirement to investigator's choice in comparator arm on 4/1. Ixabepilone was approved in 2007 and CDX-011 wasn't going head to head against it at the outset of this trial, so what are they seeing that warrants this change?
Eribulin was also added to investigator's choice comparator arm. This makes more sense since it was only approved for late stage BC in Nov 2010.

http://clinicaltrials.gov/archive/NCT011...

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What we are likely seeing is CLDX balancing the desire to speed up enrollment vs the chance of accelerated approval based on this trial.

Remember that just before this trial started, the accelerated approval filing for T-DM1 in late stage breast cancer was rejected. The FDA explained that not all approved treatment choices were exhausted for patients in that study.

It is widely believed they were referring to the omission of Ixabepilone (Ixempra) in the list of required previous treatment.

So CLDX likely included that treatment in the requirements for entry into the CDX-011 trial to keep open the possibility of accelerated approval.

But Ixempra is not a big seller. The requirement of previous treatment with this drug was probably reducing the pool of eligible patients too much.

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1. There is also an additional change in the CDX011 protocol as of 4/1/11 with an increase in prior treatments for the advanced stage breast cancer pts from 5 to 7.

2. As a brief review, this CDX011 PIIb trial is controlled, randomized and open label. So the trial investigators know what each pt is getting, and can track efficacy/safety and compare 011 head-to-head vs investigator's choice.

3. The most significant change IMO is the addition of Eribulin to the control arm. Eribulin is the first single-agent therapy to demonstrate a significant overall survival benefit (~2.5 months) in patients with advanced breast cancer. The fact that they are putting 011 against this strong competitor implies that they are seeing robust efficacy/safety results with 011 so far.

4. Finally, they are planning for the possibility of accelerated approval for CDX011 based on results so far, and are making sure that the list of prior treatments against which they compare 011 is exhaustive (which is an FDA requirement for a.a.).

My 2 cents worth: we will see an uptrend in CLDX valuation as this recent 011 trial information is incorporated into market cap, and a likely decrease in SI.