At the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois, Nirav Niranjan Shah, MD, Medical College of Wisconsin, Milwaukee, Wisconsin, shared insights into a limited follow-up on he and his colleagues’ phase 2 trial of split-dose rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) for older patients with diffuse large B-cell lymphoma (DLBCL).

The trial’s goal is to explore dosing regimens that would make it more tolerable for older patients with DLBCL to receive curative intent therapy.

Transcript:

Hi, I'm here at ASCO 2023. My name is Nirav Shah, I'm an associate professor at the Medical College of Wisconsin and excited to share data from our trial: the phase 2 trial of split dose R-CHOP for older patients with diffuse large B-cell lymphoma.

The optimal management for older patients with diffuse large B-cell lymphoma remains quite variable. Some patients get sort of dose-reduced chemotherapy regimens, such as R-mini-CHOP. Others get non-curative intent regimens because of the concern that age-related comorbid conditions may make it difficult for them to tolerate standard R-CHOP21, which is one of the standard-of-cares currently used for DLBCL.

Our group studied this regimen called split dose R-CHOP, and the goal of this regimen was to be able to administer the same intensity of R-CHOP to older patients that younger patients get, by taking R-CHOP21 and splitting the doses in half. So, patients will get full-dose rituximab on day 1 with a 50% dose reduction in the CHOP chemotherapy drugs on day 1 and day 15, with a 28-day cycle having the same dose intensity equivalency to R-CHOP21. They would complete 6 months of therapy. And the idea here is if we can give these patients the same dose in a protracted and fractionated fashion, we can make it more tolerable for older patients to receive curative intent therapy.

This trial evaluated older patients; they were treatment-naive with advanced stage diffuse large B-cell lymphoma. The median age in our patient population was 81—so, highlighting that this is an older group of patients, and our oldest patient was up to age 88 years. The other interesting aspect of this work is that we looked at an interim evaluation. So after 2 months of split dose R-CHOP, we did an interim PET-CT and an interim MRD assay using a cell-free circulating tumor DNA assay to look at the depth of response.

For those patients that were interim PET negative and interim CT DNA negative, those patients were offered an abbreviated chemotherapy arm where they would complete treatment after 4 cycles, with the idea being that for older patients getting less might actually be more, by minimizing toxicity.

The primary outcome of the study was the end of treatment [complete response] (CR) rate. And this is the interim sort of feasibility endpoint, which was achieved. We actually hit that mark early, with 10 out of the first 14 patients having an end of treatment CR rate of 71%. And if you look at that number, that's actually similar to what you see with R-CHOP chemotherapy in younger patients. 

With regards to the interim endpoint, there were 6 patients that were interim MRD-negative and PET-CT negative and all of those patients remain in remission to date, and 5 of the 6 actually received abbreviated chemotherapy. Again, this is limited follow-up of only 13 months, but this suggests that there might be a group of patients that can get away with a little bit less chemo intensity. In terms of safety, there were adverse events as you would expect giving chemotherapy to an older patient population, but there were no treatment-related deaths, and we have not yet hit the median overall survival.

So what's the takeaway here? The takeaway is that split dose R-CHOP allows administration of a curative intent R-CHOP chemotherapy regimen by splitting the doses in half, giving it over a prolonged period of time, but maintaining dose intensity at the same level as our younger patients. And by doing so, we saw promising end of treatment complete remission rates, and [that] may be a signal that we can use advanced technologies, such as PET-CT and MRD, to shorten therapy for a select group of patients that are high and early responders. 

We look forward to completing accrual on this study and potentially modifying in the future with incorporation with novel drugs. Thanks again for allowing me to share this.

Source:

Shah N N, Szabo A, Rajguru S, et al. Phase II trial of split-dose R-CHOP for older patients with diffuse large B-cell lymphoma (DLBCL). Presented at ASCO Annual Meeting; June 2-6, 2023; Chicago, IL. Abstract 7554.