LaQuisa C. Hill, MD, on Relapsed or Refractory T-ALL: New Data on CD5 CAR T Cells
2023 ASCO Annual Meeting
LaQuisa C. Hill, MD, of Baylor College of Medicine, Houston Methodist Hospital, discusses study findings showing that CD5 chimeric antigen receptor (CAR) T cells may induce clinical responses in heavily treated patients with relapsed or refractory T-cell acute lymphoblastic leukemia. Manufacturing CD5 CAR T cells with tyrosine kinase inhibitors seemed to improve their potency and antitumor activity (Abstract 7002).
Transcript
Disclaimer: This video transcript has not been proofread or edited and may contain errors.
LaQuisa C. Hill, MD:
The purpose of this study was a phase one clinical trial that was a dose escalation study using autologous CD5 CAR T for treatment of patients with relapse/ refractory T-cell ALL. In the initial cohort, we used our standard manufacturing practice that was overall very well-tolerated. However, in the eight patients initially treated, there were minimal responses seen with only one patient achieving a MRD positive remission.
We subsequently analyzed the cell products and determined that the CAR T cells had a significantly exhausted phenotype as a result of chronic CAR signaling. Therefore, we implemented a manufacturing change to include the use of TKI inhibitors dasatinib and ibrutinib in order to inhibit the chronic CAR signaling and saw a significant improvement in the naive T-cell repertoire and significant reduction in the number of exhausted T-cells in the final product. In the next cohort, we treated a total of seven patients, all manufactured using the TKI inhibition. And amongst those patients there was a total of four MRD negative remissions achieved out of seven patients treated.
The CAR T cell was well-tolerated in terms of CRS and ICANS. No grade-three events occurred. However, there was an increased risk of, or observation of, EBV reactivation with two patients developing PTLD. Currently it is unclear of the direct relationship to the CD5 CAR T cells manufactured with TKI. However, we plan to continue vigilant monitoring for this unexpected side effect and have instituted mitigation plans utilizing prophylactic rituximab as well as ensuring that patients have EBV-specific virus T cells available in the event that EBV reactivation occurs.
Moving forward, we will continue to try and optimize the CAR T cell product both for efficacy and safety and are looking into alternative immune effector subsets, such as virus-specific T cells as the immune factor cell of choice, as well as considering use of third-party or off-the-shelf T cells from healthy donors.
The ASCO Post Staff
Amer Methqal Zeidan, MBBS, MHS, of Yale University and Yale Cancer Center, discusses phase III findings on the first-in-class telomerase inhibitor imetelstat, which was given to patients with heavily transfusion-dependent non-del(5q) lower-risk myelodysplastic syndromes that are resistant to erythropoiesis-stimulating agents. Imetelstat resulted in a significant and sustained red blood cell (RBC) transfusion independence in 40% of these heavily transfused patients. The response was also durable and accompanied by an impressive median hemoglobin rise of 3.6 g/dL, and seen in patients with and without ring sideroblasts. Importantly, reduced variant allele frequency was observed in the most commonly mutated myeloid genes which correlated with duration of transfusion independence and hemoglobin rise, therefore suggesting a disease-modifying potential of this agent (Abstract 7004).
The ASCO Post Staff
Bobbie J. Rimel, MD, of Cedars-Sinai Medical Center, and Mansoor R. Mirza, MD, of Denmark’s Rigshospitalet and Copenhagen University Hospital, discuss new findings on dostarlimab-gxly plus carboplatin/paclitaxel, which improved progression-free survival while maintaining health-related quality of life, further supporting its use as a standard of care in primary advanced or recurrent endometrial cancer (Abstract 5504).
The ASCO Post Staff
Funda Meric-Bernstam, MD, of The University of Texas MD Anderson Cancer Center, discusses interim results from the DESTINY-PanTumor02 trial, the first tumor-agnostic global study of fam-trastuzumab deruxtecan-nxki (T-DXd) in a broad range of HER2-expressing solid tumors. This agent showed an encouraging overall response rate, particularly in patients with IHC 3+ expression; durable clinical benefit; and a manageable safety profile in these heavily pretreated patients. T-DXd may be a potential new treatment option for this population (Abstract LBA3000).
The ASCO Post Staff
Catherine C. Coombs, MD, of the University of California, Irvine, discusses prolonged pirtobrutinib therapy, which continues to demonstrate a safety profile amenable to long-term administration at the recommended dose without evidence of new or worsening toxicity signals. The safety and tolerability observed in patients on therapy for 12 months or more were similar to previously published safety analyses of all patients enrolled, regardless of follow-up (Abstract 7513).
The ASCO Post Staff
Nirav N. Shah, MD, of the Medical College of Wisconsin, discusses the efficacy and safety of pirtobrutinib, a highly selective, noncovalent BTK inhibitor, studied for more than 3 years in the BRUIN trial. The results showed that the use of pirtobrutinib continues to have durable efficacy and a favorable safety profile in heavily pretreated patients with relapsed or refractory mantle cell lymphoma and prior BTK inhibitor therapy. Responses were observed in patients with high-risk disease features, including blastoid/pleomorphic variants, elevated Ki67 index, and TP53 mutations (Abstract 7514).
