NorthWest Biotherapeutics Inc (NWBO)

[longfellow95]

On pseudo-progression.

Lots of talk on this board about pseudo-progressors and how they have been weeded out of this trial, as if they are a distinct subgroup of individuals.

Pseudo-progression, as I understand it, is a treatment response, that mimics, or could be mistaken for, disease progression. It is a known phenomenon following chemoradiation. But not only chemoradiation.

These were the ones that ended up in the info arm, along with the confirmed rapid progressors. They were originally described as either single rapid progressors or double rapid progressors. The double rapid progressors were the ones who had definite disease progression after a second scan.
I believe all bar one patient in this category are now deceased.

The single rapid progressors are the ones who showed at least some sign of disease stabilisation at the second scan, and can probably be fairly described as pseudo-progressors, though were not officially described as such. Only one patient was officially deemed to be a 'pseudo-progressor,' as he/she showed resolution of previous apparent progression.

What is not so often discussed is pseudo-progression following immunotherapy. This is potentially more significant to this trial than those who 'pseudo-progressed' following chemoradiation.
There was always the risk that the treatment arm patients who exhibited a pseudo-progression type response following L administration could possibly be wrongly deemed to have progressive disease.

On that score, my concern has been alleviated considerably, as I now feel that, in practice, this has not been a significant problem. If many such patients had been wrongly deemed to have progressed, then there is no way we would still be below 75% of patients having evented.

So many of those patients who exhibit pseudo-progression as a treatment response (the ones who tend to do better) are still in the trial.