Obinutuzumab & Rituximab Safety Risks

Timothy Fenske, MD, MS:Comparing obinutuzumab with rituximab, there are some differences in terms of the toxicity profile. Both antibodies have a risk of infusion reactions, and anybody who’s prescribed rituximab knows that you can see significant infusion reactions. This is also true with obinutuzumab, and the rate of infusion reactions is slightly higher with obinutuzumab. The majority of those reactions, like rituximab, are grade 1 and 2. And it’s uncommon that a patient needs to discontinue either rituximab or obinutuzumab because of the infusion reaction. The management of the infusion reactions for obinutuzumab is identical to what oncologists are used to doing for rituximab.

We do see a slightly higher rate of cytopenias associated with obinutuzumab, and a slightly higher rate of infections as well. This is another thing to take into consideration. So again, if you have an older, frailer patient or someone who you think is at particularly high risk for infection at baseline, you may want to factor that information into your selection of which antibody to use.

The practice within our group as far as premedication for anti-CD20 antibodies consists of Tylenol [acetaminophen], and Benadryl [diphenhydramine], and we give everyone hydrocortisone as a premedication as well. It does reduce the rate of infusion reactions, and you get a lot fewer phone calls from the infusion room to manage subsequent reactions if you just premedicate with hydrocortisone.

When considering the different frontline options for follicular lymphoma, it’s really important to look at risk-benefit analysis, and I think as part of that you want to try to factor in how much of a threat the lymphoma is to this person’s longevity and if they are at increased risk for certain complications. On 1 end of the spectrum, if we have a person in their 40s who has no other health problems and has symptomatic follicular lymphoma, the lymphoma by far is that person’s biggest threat to their health. This was a patient that I would favor more aggressive therapy with, and I would favor an obinutuzumab therapy combination because we know that will decrease their risk of having early progression of disease.

On the other hand, if we have an older, frail patient who has a number of comorbidities and is recently diagnosed with follicular lymphoma, that patient may need treatment for their lymphoma, but the chance of the lymphoma impacting their longevity is going to be a lot less than the younger patient I referred to. So here’s a patient for whom we’re going to be more worried about toxicity, and I think we need to be more cautious with a patient like that.

Transcript edited for clarity.