More Research Needed to Move CAR T-Cell Therapy Forward, Expert Says

Brian Till, MD

Brian Till, MD

Chimeric antigen receptor (CAR) T-cell therapy has generated new excitment in select hematologic malignancies. Despite recent advances, more research is necessary in order to both move these treatments to earlier settings and drive costs down, Brian Till, MD, noted.

CAR T-cell therapies are currently approved by the FDA: tisagenlecleucel (Kymriah) and axicabtagene ciloleucel (axi-cel; Yescarta). Lisocabtagene maraleucel (liso-cel; JCAR017) has also shown promise in a phase I clinical trial.

For patients with high-risk diffuse large B-cell lymphoma (DLBCL), liso-cel demonstrated a durable complete remission rate of 46% at 6 months in the multicenter TRANSCEND study.

The multicenter TRANSCEND-NHL-006 study will determine the efficacy and safety of liso-cel in adult subjects who have relapsed from or are refractory to a single line of chemoimmunotherapy for aggressive B-cell non-Hodgkin lymphoma and are ineligible for hematopoietic stem cell transplant (NCT03483103).

The primary endpoint of the study is overall response rate, with a secondary analysis on patient-reported health-related quality of life. Till says these data are not yet available.

In an interview withTargeted Oncology, Till, an associate member of the Clinical Research Division at Fred Hutchinson Cancer Research Center and professor of medicine at the University of Washington, discussed a recent presentation on the rapidly evolving field of CAR T cells.

TARGETED ONCOLOGY:You spoke about the current state of CAR T-cell therapy. What is important to highlight from your presentation?

Till:In my presentation, I spoke about the role of CAR T cells, particularly in treating pediatric and young adults with ALL and in adults with DLBCL. I gave some background on how the CAR works. There have been some pretty exciting, recent multicenter data with CAR T cells.

The key message with using CAR T cells is that these are very high-risk patients who have relapsed disease and poor outcomes. CAR T-cell therapy has shown promising results. Some relapses do occur; but in general, if patients make it past 6 months or so, they will have durable responses. We need more follow-up to really understand this.

TARGETED ONCOLOGY:What impact have tisagenlecleucel and axi-cel had on the landscape?

Till:It's still pretty early days. These agents have only been FDA approved for a short period of time, so there is a learning curve still attached to them. These agents are not widely available at every cancer center, but we're fortunate right now to have access to them [at Fred Hutchinson Cancer Research Center]. When we get into a situation where a patient has relapsed on standard treatment, we would refer in this direction [of CAR T-cell therapy]. Some of the common scenarios in which we're using this treatment are in DLBCL. These patients get their salvage therapy, and if they don't get a complete response we would put them on CAR T cells.

TARGETED ONCOLOGY:Beyond the 2 that are available, what other CAR T-cell therapies are in development?

Till:Following on the heels of the 2 FDA-approved therapies, we have liso-cel. This hasn't been FDA approved yet, but it's in the middle of a clinical trial where we have seen promising data. It hasn't been fully reported yet, but the preliminary results look great. I can see an approval forthcoming at some point. There are other CAR T cells in development, as well. We have a CD20-targeted CAR that we're looking at. Other centers are looking at CD22-targeted CARs for patients with acute lymphoblastic leukemia.

The trials we are working on at our institution are focused on lymphoma. We're participating in the TRANSCEND trial, which is a multicenter trial. All of the CAR T cells that are approved are from mouse samples. We're working on a fully human CAR T-cell product. We're also working on a CD19-targeted product that hopefully won't be as immunogenic. There is also work being done looking at targets other than CD19.

TARGETED ONCOLOGY:What are your thoughts on combining checkpoint inhibitors with CAR T-cell therapy?

Till:It makes sense because we know atezolizumab (Tecentriq) is active in other diseases and it has an impact on the immune system. We don't quite know what the mechanisms of resistance are for patients who don't respond to CAR T cells. There are data from the University of Pennsylvania that suggested if you give a patient a PD-1 inhibitor, they might respond better to CAR T cells. It could be a good combination, but there are not enough data to confirm that PD-1 is the limiting step. It's worth the try, but we need to test it further.

TARGETED ONCOLOGY:How do you see financial toxicity being addressed?

Till: