Dr Thorvardur Halfdanarson on if He Thinks There's a Future For Immunotherapy in NETs

It’s fair to say that the initial results of immunotherapy in neuroendocrine tumors (NETs) have been somewhat disappointing, explained Thorvardur Halfdanarson, MD, associate professor of medicine and consultant in medical oncology, Mayo Clinic.

Transcript

Is there a future for immunotherapy in neuroendocrine tumors?

I think there is a future for immunotherapy. The problem is that we don’t know who these patients are, who will respond. So, if we look at other cancers like lung cancer where we have a reliable biomarker, such as PD-L1, gastrointestinal malignancies where we have a reliable marker of a response, such as microsatellite instability. We don’t have that in neuroendocrine tumors. They are generally microsatellite stable tumors, and although they may and often express PD-L1, we don’t have good data to suggest that being a good marker. We know from small cell carcinoma of the lung that it probably doesn’t matter a whole lot what your PD-L1 expression is.

So, I think it’s fair to say that the initial results have been somewhat disappointing, but there are still signals and they’re suggesting to me that we need to pursue this as possible therapy. It’s just too hard to say where this will fit in. There are new trials coming down the pike for other malignancies using a combined approach with 2 immunotherapy agents with immunotherapy and cytotoxic therapy, and even immunotherapy with ablative therapies, such as the hepatic embolization or PRRT [peptide receptor radionuclide therapy] is something that I think would be very reasonable to explore.

So, immunotherapy is, I think, is still a target we should go after.