Correct this is a hypothesis ie an educated guess. No one can know for sure untill the data is published and the curves known. But based on what we do know, I stand by my model that the 148th even will occure shortly and therefore the first IA will occur in the first quarter of 2016. Furthermore, based upon the comparision with known results from the STUPP and IMUC datasets the DCVax L will improve PFS significantly for patients treated with the experimental arm.
For Modeling data such as this with limited actual verfied data points one must use averages (ie average monthly accurals ect ect to compare the data. I develop a massive spreadsheet using the known data and model the data using historical published survival curves. Adjustments are made based on the entry requirements for the various populations. (ie in the STUPP trial, if memory serves, there were 15 to 20% of patient treated with XRT and TMZ who only could safetly have a biopsy only (ie no resection) and these patients would have worse prognosis than patients with a GTR or STR surgery... So you have to encorporate adjustments to the modelling.
Ha Ha Check my alias was born in 2000 over 15 years ago... Nope Not Pyrr. I am a clinical researcher who models survival data with statistical software. I am the real deal. Also Discloser I am long this stock.
Please reference my prior posts regarding modeling for the DCVax-L GBM trial.
IHUB POST 3433 uses the STUPP trial as the Model for the control patients.
IHUB POST 14585 used the IMUC data to further refine the model data.
IHUB POST 17001 from Flipper
FIRST Things we know ... Dec 2013 there were 66 events disclosed prior to the trial being expanded. We know the published STUPP and IMUC Control and Treated patients progression free survival (PFS) curves.
Furthermore, recently it was disclosed in August 2015 that the DCVax-L trial had accrued 300 patients randomized. This discloser gives us the average accrual rate for the trial from Dec 2013 to August 2015.
Using the above data, I then proposed the following model and thought experiment.
For the purpose of this model analysis, we make the following assumptions. Let us pretend that after the trial was expanded in Aug 2014, increasing the N to 348, that the experimental DCVax-L treated patients and non-treated, all had exactly the same progression free survival PFS, as did the control patients from the known STUPP and IMUC trials.
Using these parameters, our model would then provide us a worst case scenario in terms of when the number of events in the DCVax-L Trial would occur to give us 148 events, (first interim Analysis), 198 events (second interim analysis), and 248 events (Trial end). When one models the data in this manner, one obtains the following results.
The 149th event would have occurred in June 2015, and the 198th event would occur in Feb 2016 and the 248th event would occur on August 2016.
My Model indicates that the first IA would occur in Feb/March 2016
Therefore each month that passes after June 2015 without any announcement of the first interim analysis (148 events) has been reached, indicates that during this time period there have been less events than what would have been expected, had the patients progressed in a manner similar to historical controls