PD-1 Blockade and Transplant as a Potential New Treatment in PTCL

Mwanasha Merrill, hematology oncology clinical fellow, Department of Medical Oncology, Dana-Farber Cancer Institute, discusses results from a phase 2 study (NCT02362997) which evaluated PD-1 blockade post autologous stem cell transplantation with pembrolizumab (Keytruda) in patients with peripheral T-cell lymphoma (PTCL).

The study included 21 patients with PTCL and found that 83.6% (95% CI, 68-100) were progression-free at 18 months post-transplant. For the entire cohort, the overall survival rate for the entire cohort was 94.4% (95% CI, 84-100).

Merrill notes that larger studies are needed to investigate the use of PD-1 blockade and combination therapies in PTCL.

Transcription:

0:10 | In our study, we ended up with 21 patients and we had a few different PTCL histologies, but the most common was PTCL-NOS [not otherwise specified]. We found that at least 13 out of our 21 patients were progression-free at the 18 month post [transplant], so the study met the prespecified primary end point.

0:35 | We did also look at a second end point of PFS rate, and this was 83.6% when we looked at the entire cohort. We also looked at the PFS rate for the different histologies, and unfortunately, because the numbers are small, we didn't see any difference there. We also looked at the overall survival for the entire cohort that was about 94%. When we tried to look at the different histologies again, we didn't see any difference there, so we're not able to make any meaningful conclusions about that.

1:09 | We had 21 patients, so definitely a bigger study would be interesting. There's been quite a bit of data showing that PD-1 blockade, at least in NK T cells, has shown promising results in the relapsed and refractory setting. I think this would be a very attractive subtype to investigate further while exploring transplantation and then PD-1 blockade specifically for this subtype.

1:37 | Another interesting thing that can be looked at is seeing, what is the sequence? What is the ideal sequence of PD-1 blockade? Do we give it before transplant or after transplant? I say this because if we give it prior to transplant, potentially, this could act as a sensitizing agent. That's something that is worth looking at as well. Then the other thing I'll point out is just looking at combination studies. Brentuximab vedotin [Adcetris] has done so well, so looking at the combination of potentially brentuximab and PD-1 blockade with or without a transplant can be something that may be attractive as well.