NorthWest Biotherapeutics Inc (NWBO)

[mehitabel64]

From my limited reading, immunotherapy is a different animal and may need different measures of efficacy. Shrinking tumors do NOT necessarily correlate with pfs or os.

http://www.nature.com/nrc/journal/v12/n4/full/nrc3258.html

"Immune and clinical efficacy. Most Phase I and II studies have stumbled on two crucial issues: how to assess the clinical efficacy of cancer immunotherapy; and how to define the correlates (biomarkers) of clinical efficacy127. Initially, the Response Evaluation Criteria In Solid Tumours (RECIST) had been designed to assess chemotherapy-based trials and were considered to be crucial for assessing clinical efficacy in vaccine and immunomodulation trials127, 128. However, this has recently been challenged. A randomized Phase III clinical trial testing anti-cytotoxic T lymphocyte-associated antigen 4 (CTLA4) in patients with stage IV melanoma, showed a twofold improved overall survival in patients who received the drug129. No early tumour shrinkage was observed in treated patients, which reflects the slow build-up of anti-tumour immunity. In fact, in the early phase of treatment, tumours might increase in size and new lesions might appear; these are findings that normally call for removing the patients from the trial. However, the enlarged tumour size might instead reflect the inflammatory process that is associated with active immune responses and lymphocyte infiltration."