NorthWest Biotherapeutics Inc (NWBO)

[longfellow95]

The Role of irRC in assessing response rates in Immunotherapy.

From what I understand from reading, it is now being increasingly recognised that RECIST is not the most appropriate criteria to use in respect of measuring outcome in Immunotherapy trials, and that immune-related Response Criteria (irRC) is now increasingly finding favour.

I can see that use of irRC in respect of DCVax trials will prove the superior assessment tool.

I believe that irRC provides at least a partial solution to the problems thrown up by pseudo-progression.

iiRC allows for the fact that some patients experience progression before they respond to therapy, as well as other advantages:-

"Responses to immunotherapeutic agents can differ from those observed with conventional chemotherapy. For example, some patients can experience disease progression before they respond to therapy, and others can develop new lesions at the same time that their index lesions are shrinking. As a result, modified response criteria were proposed for use when assessing the response to ipilimumab: the immune-related response criteria (irRC). The irRC were developed from the existing World Heath Organisation (WHO) criteria and Response Evaluation Criteria in Solid Tumours (RECIST), but with some important modifications. For example, patients with new or progressing lesions can be defined as having a PR if there is an overall decrease in tumour burden of ≥50% (i.e. it is not based on the increasing size of index lesions, or the presence or absence of new lesions). The irRC also define progressive disease differently, so that patients who have progressive disease using the existing RECIST/WHO criteria may remain on therapy." My emphasis.

From Wolchok in Annals of Oncology.

I understand that irRC was used in the assessment criteria leading to approval of ipilimumab (Yervoy)