Another ASCO update

Another day of good data for melanoma.  Last year Genentech/Roche had their BRAF inhibitor (Zelboraf, or vemurafenib, or PLX40342 approved, and another company, Glaxo SmithKline (GSK) has been pushing to develop their drug.

Another day of good data for melanoma.  Last year Genentech/Roche had their BRAF inhibitor (Zelboraf, or vemurafenib, or PLX40342 approved, and another company, Glaxo SmithKline (GSK) has been pushing to develop their drug.

In data presented today, the GSK showed similar results to Zelboraf, and possibly had fewer side effects.  They also showed positive results with a different drug, a MEK inhibitor.  And they showed data of the two being used together.  The combination is somewhat more effective than either alone.  Also, the BRAF inhibitors can sometimes cause squamous cell carcinomas.  in combination, that doesn't happen.

I had heard several months ago that GSK had planned to seek approval of the drugs in combination rather that seeking approval of each drug separately.  I learned today that this is not the case, so the combination therapy may be delayed a while.

On another front, I met with a company that is developing a new approach to sentinel node biopsy.  We all know the stories of people whose sentinel node was negative for tumor, but who still progressed.  I always thought that his is because the pathologist happened to evaluate the wrong slice of tissue, or possibly just missed the tumor cells.  Turns out that the current system injects a radioactive compound, followed by a blue die.  Those compounds run through the lymph system like a cup of food dye thrown into a stream.  Surgeons have to estimate when to do the surgery, in hopes they will catch both compounds after they have gotten to the sentinel node but before they have flowed out of that node and further downstream.  This works fairly well, but every patient has different flow/clearance rates.

This new company has a compound that binds to cells in the lymph nodes.  It goes into the sentinel node and sticks there for hours.  In Phase II studies, they showed a 99% rate of identifying sentinel nodes, vs about a 90% rate using the current system.  This means that 10% of patients whose melanoma has spread to the lymph system would be staged incorrectly in the current system but may now be staged properly under the new system.

Yesterday morning I attended a poster session.  This is where about 50-75 researchers have a large display of the work they are doing tacked onto a corkboard, and everyone walks by to look at the information and ask questions.  A lot of interesting new developments, but I was particularly struck by the fact that at least five researchers were showing data on uveal or ocular melanoma.  Last year's poster session had only one poster for this form of melanoma.

One final comment.  I am hearing a lot of talk about treatments for people who do not have the BRAF mutation.  Of course the immunotherapy drugs (Yervoy, anti-PD1, etc.) are available for these patients.  Still, more options are needed for what is about 60% of the population.  Most of the work is still early stage, but some things are looking interesting.

Tim–MRF