Key Points Tisagenlecleucel (CTL019) has demonstrated clinical efficacy in relapsed/refractory B-cell ALL and CLL. The cellular kinetic profile of tisagenlecleucel was consistent across the 2 diseases, with higher exposure in responding vs nonresponding patients.

Tisagenlecleucel is an anti-CD19 chimeric antigen receptor (CAR19) T-cell therapy approved for the treatment of children and young adults with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL). We evaluated the cellular kinetics of tisagenlecleucel, the effect of patient factors, humoral immunogenicity, and manufacturing attributes on its kinetics, and exposure-response analysis for efficacy, safety and pharmacodynamic endpoints in 79 patients across two studies in pediatric B-ALL (ELIANA and ENSIGN). Using quantitative polymerase chain reaction to quantify levels of tisagenlecleucel transgene, responders ( = 62) had ≈2-fold higher tisagenlecleucel expansion in peripheral blood than nonresponders ( = 8; 74% and 104% higher geometric mean Cmax and AUC0-28d, respectively) with persistence measurable beyond 2 years in responding patients. Cmax increased with occurrence and severity of cytokine release syndrome (CRS). Tisagenlecleucel continued to expand and persist following tocilizumab, used to manage CRS. Patients with B-cell recovery within 6 months had earlier loss of the transgene compared with patients with sustained clinical response. Clinical responses were seen across the entire dose range evaluated (patients ≤50 kg: 0.2 to 5.0 × 10/kg; patients >50 kg: 0.1 to 2.5 × 10 CAR-positive viable T cells) with no relationship between dose and safety. Neither preexisting nor treatment-induced antimurine CAR19 antibodies affected the persistence or clinical response. Response to tisagenlecleucel was associated with increased expansion across a wide dose range. These results highlight the importance of cellular kinetics in understanding determinants of response to chimeric antigen receptor T-cell therapy.

The anti-CD19 chimeric antigen receptor (CAR)–T cell therapy tisagenlecleucel was evaluated in the global, phase 2 JULIET study in adult patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). We correlated tisagenlecleucel cellular kinetics with clinical/product parameters in 111 patients treated in JULIET. Tisagenlecleucel persistence in responders and nonresponders, respectively, was demonstrated for 554 and 400 days maximum by flow cytometry and for 693 and 374 days maximum by quantitative polymerase chain reaction (qPCR). No relationships were identified between cellular kinetics (qPCR) and product characteristics, intrinsic/extrinsic factors, dose, or immunogenicity. Most patients with 3-month response had detectable transgene at time of response and continued persistence for ≥6 months. Expansion (maximal expansion of transgene/CAR-positive T-cell levels in vivo postinfusion [Cmax]) was potentially associated with response duration but this did not reach statistical significance (hazard ratio for a twofold increase in Cmax, 0.79; 95% confidence interval, 0.61-1.01). Tisagenlecleucel expansion was associated with cytokine-release syndrome (CRS) severity and tocilizumab use; no relationships were observed with neurologic events. Transgene levels were associated with B-cell levels. Dose was associated with CRS severity, but this was not statistically significant after adjusting for baseline tumor burden. In contrast to the results from B-cell precursor acute lymphoblastic leukemia (B-ALL) and chronic lymphocytic leukemia, similar exposure was observed in DLBCL in this study regardless of response and expansion was lower in DLBCL than B-ALL, likely from differences in cancer location and/or T-cell intrinsic factors. Relationships between expansion and CRS severity, and lack of relationships between dose and exposure, were similar between DLBCL and B-ALL. Tisagenlecleucel cellular kinetics in adult relapsed/refractory DLBCL improve current understanding of in vivo expansion and its relationships with safety/efficacy endpoints. This trial was registered at www.clinicaltrials.gov as #NCT02445248.

We assessed minimal residual disease (MRD) detection and B-cell aplasia after tisagenlecleucel therapy for acute lymphoblastic leukemia (ALL) to define biomarkers predictive of relapse (N = 143). Next-generation sequencing (NGS) MRD detection >0 in bone marrow (BM) was highly associated with relapse. B-cell recovery [signifying loss of functional chimeric antigen receptor (CAR) T cells] within the first year of treatment was associated with a hazard ratio (HR) for relapse of 4.5 [95% confidence interval (CI), 2.03-9.97; P < 0.001]. Multivariate analysis at day 28 showed independent associations of BMNGS-MRD >0 (HR = 4.87; 95% CI, 2.18-10.8; P < 0.001) and B-cell recovery (HR = 3.33; 95% CI, 1.44-7.69; P = 0.005) with relapse. By 3 months, the BMNGS-MRD HR increased to 12 (95% CI, 2.87-50; P < 0.001), whereas B-cell recovery was not independently predictive (HR = 1.27; 95% CI, 0.33-4.79; P = 0.7). Relapses occurring with persistence of B-cell aplasia were largely CD19 − (23/25: 88%). Detectable BMNGS-MRD reliably predicts risk with sufficient time to consider approaches to relapse prevention such as hematopoietic cell transplantation (HCT) or second CAR-T cell infusion. SIGNIFICANCE:Detectable disease by BMNGS-MRD with or without B-cell aplasia is highly predictive of relapse after tisagenlecleucel therapy for ALL. Clonotypic rearrangements used to follow NGS-MRD did not change after loss of CD19 or lineage switch. High-risk patients identified by these biomarkers may benefit from HCT or investigational cell therapies.

Systemic exposure to panobinostat did not increase with severity of renal impairment, and the drug was tolerated equally; thus, patients with renal impairment do not require starting dose adjustments.

Despite increased plasma exposure, patients with mild or moderate hepatic dysfunction could be safely treated with the same starting dose of panobinostat as patients with normal hepatic function, with careful monitoring and dose adjustments as required.

PurposePanobinostat, a potent pan-deacetylase inhibitor, improved progression-free survival (PFS) in patients with relapsed and refractory multiple myeloma when combined with bortezomib and dexamethasone in a phase 3 trial, PANORAMA-1. This study aims to explore exposure–response relationship for panobinostat in this combination in a phase 1 trial, B2207 and contrast with data from historical single-agent studies.MethodsPanobinostat plasma concentration–time profiles were obtained in patients from PANORAMA-1 (n = 12) and B2207 (n = 12) trials. Overall response rates (ORR) and major adverse events (AE) by panobinostat exposure were investigated in the B2207 trial. Panobinostat PK data from combination trials were contrasted with data from single-agent studies.ResultsAt maximum tolerated dose (MTD), the geometric mean of panobinostat area under curve from 0 to 24 h (AUC0-24) was 47.5 ng h/mL (77 % CV), and maximum plasma concentration (Cmax) was 8.1 ng/mL (90 % CV). These values were comparable with exposure data obtained in PANORAMA-1, but were 20 % lower than those without dexamethasone, and ∼50 % lower from single-agent trials, likely due to enzyme induction by dexamethasone. Higher levels of panobinostat exposure were associated with higher response rates and higher incidences of diarrhea and thrombocytopenia.ConclusionsApparent panobinostat exposure–AE and exposure–ORR relationships were observed when combined with bortezomib and dexamethasone in the treatment of patients with relapsed and refractory multiple myeloma. The addition of dexamethasone facilitated best response even though plasma exposure of panobinostat was reduced. Combination with a strong enzyme inducer should be avoided in future trials to prevent further reduction of panobinostat exposure.

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