FreeTheMice-Any chance I can get you to weigh in on this?
I certainly hope we are over 15 months on front line lung MOS but based on the likely 80% threshold before MOS is calculated anything is possible. I also believe it is likely the front line MOS should be at least 25% longer than for 2nd line given the healthier patients with less compromised immune systems.
It seems to me we have the addded complication here in not knowing how the control arm results will fare and what they will mean for the bavi arm. In the 2nd line study the control arm reaching MOS was PRed long before the two Bavi arms results were reported which gave us a nice period as time elpased to calcuate and speculate about the separation between the control arm and Bavi arms MOS. With the independent read on the front line ORR and PFS showing similar results in the control and Bavi arms isn't anyone concerned we could get a similar non-divergent result in the MOS? How would our results be perceived if the Bavi front line arm acheieved historic MOS results of say 16 months but the control arm was at 15 months? Would this invalidate the trial results and what is the liklihood of comething like this occurring given the earlier results from the independent read of ORR and PFS in this trial? Not a scientist so I would appreciate folks like FTM weighing in on this.
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Based on investigator assessments, patients treated with bavituximab plus carboplatin and paclitaxel demonstrated a current median PFS estimate of 5.8 months versus 4.6 months in patients treated with carboplatin and paclitaxel alone, a 26% improvement. These results are consistent with a prior phase II single-arm study testing the same bavituximab combination in front-line NSCLC patients which showed a 6.1 month median PFS and with several prior published studies with carboplatin and paclitaxel in front-line patients that showed approximately a 4.5 month median PFS. Based on independent central imaging reads, patients demonstrated a current median PFS estimate of 6.7 months for the bavituximab-containing arm and 6.4 months for the chemotherapy-only arm. Peregrine expects to report median overall survival (OS) from this trial in the second half of 2012.
"We are pleased that the PFS results for the bavituximab-containing arm by both local and central image interpretation actually met or exceeded our expectations going into the study. While the data from the investigator assessments were in alignment with previous published reports for carboplatin and paclitaxel and suggested an encouraging difference between the treatment arms, the unexpected long PFS estimate for the control arm based on central reads confounds our ability to fully interpret this secondary efficacy endpoint," said Joseph Shan, vice president, clinical & regulatory affairs at Peregrine. "We now await median OS data from this study which is the most clinically relevant endpoint from a drug development standpoint."
