What’s in a Name?

Ipilimumab. Sipuleucel-T. Rituximab. Rindopepimut.

Say what?

Cancer immunotherapies can have some mind-boggling names. But there’s a reason for it all, and I’m here to try to elucidate the naming practices!

Monoclonal Antibodies

Monoclonal antibodies are molecules, generated in the lab, that target specific antigens on tumors. Take rituximab, otherwise known as Rituxan®, the first monoclonal antibody approved for cancer, in 1997 for non-Hodgkin lymphoma. You will probably understand the -mab portion of it—it is a monoclonal antibody. But did you know that it also tells you that it targets the tumor and that it’s a chimeric—partially mouse and partially human—monoclonal antibody? -tu- is for tumors. (Rituximab targets CD20 expressed on B cells.) And -xi- stands for chimeric. The ri- is a unique name supplied by the drug’s developer.

Rituximab:

Stem	What it Means
ri-	unique name
-tu-	tumors
-xi-	chimeric
-mab	monoclonal antibody

Checkpoint Inhibitors

Now take ipilimumab, known as Yervoy®, an anti-CTLA-4 antibody. It was the first checkpoint inhibitor approved in 2011. Checkpoint inhibitors work by “taking the brakes off” the immune response, enabling a stronger attack against cancer. You can tell ipilimumab is different from rituximab because of the -lim- involved. This means that it targets the immune system, not a tumor. The -u- is for it being a fully human antibody.

Ipilimumab:

Stem	What it Means
ipi-	unique name
-lim-	immunomodulator
-u-	fully human
-mab	monoclonal antibody

Since ipilimumab was developed, the stem for immune modulators was shortened to just -li- or -l-. Names like this include pembrolizumab, known as Keytruda®, and nivolumab, known as Opdivo®, which are anti-PD-1 antibodies that were approved in 2014.

Therapeutic Cancer Vaccines and Adoptive Cell Therapy

Okay, that was easy. Let’s get to the hard stuff now—therapeutic cancer vaccines and adoptive cell therapy. Cancer vaccines are designed to elicit an immune response against tumor-specific or tumor-associated antigens. Adoptive T cell transfer is removing T cells from the patient, genetically modifying or treating them with chemicals to enhance their activity, and then re-introducing them into the patient. There are a number of names that come with these treatments.

Let’s start with the therapeutic cancer vaccine sipuleucel-T—otherwise known as Provenge®. It was approved in 2010 for the treatment of prostate cancer. I know from the name that it takes white blood cells out of the patient, pulses it with a cancer-bearing peptide or tumor, and reinserts it. How did I know that?

The suffix is -cel, so I know that it is a cellular therapy. The hyphenated -T means it’s autologous, meaning its cells come from the patient. The white blood cells come from -leu-, and I know they get pulsed with a cancer protein by the -pu-. Only the si- is from the company!

Sipuleucel-T:

Stem	What it Means
si-	unique name
-pu-	pulsed with a cancer protein
-leu-	white blood cells
-cel	cellular therapy
-T	autologous

Now consider the adoptive cell treatment called chimeric antigen receptor (CAR) T cell therapy. This also has the suffix -cel. In tisagenleceucel-T (CTL019), it also has the -leu- and the -T hyphenated. But CAR T cells are genetically engineered immune cells. We get this from -gen and -lec.

Tisagenlecleucel-T:

Stem	What it Means
tisa-	unique name
-gen-	transfer of genetic material (transduced)
-lec-	selection and enrichment manipulation
-leu-	white blood cells
-cel	cellular therapy
-T	autologous

For non-cellular therapies, we find the suffix -imut. They are off-the-shelf cancer vaccines, which use a protein, or fragment of it, to stimulate the immune response. You might have seen rindopepimut (CDX-110) in a phase III clinical trial for brain cancer. -pep is used for peptides.

Rindopepimut:

Stem	What it Means
rindo-	unique name
-pep-	peptides
-imut	non-cellular therapy

I could go on, but I think you catch my drift. If you want to know more, go to the American Medical Association’s (AMA) website on Monoclonal Antibodies or their website on Cellular and Non-Cellular Therapies.