Clinical and immunological responses after CD30-specific chimeric antigen receptor-redirected lymphocytes

Abstract

Background: Targeting CD30 with monoclonal antibodies in Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) has had profound clinical success. However, adverse events, mainly mediated by the toxin component of the conjugated antibodies, cause treatment discontinuation in many patients. Targeting CD30 with T cells expressing a CD30-specific chimeric antigen receptor (CAR) may reduce the side effects and augment antitumor activity.

Methods: We conducted a phase I dose escalation study in which 9 patients with relapsed/refractory HL or ALCL were infused with autologous T cells that were gene-modified with a retroviral vector to express the CD30-specific CAR (CD30.CAR-Ts) encoding the CD28 costimulatory endodomain. Three dose levels, from 0.2 × 108 to 2 × 108 CD30.CAR-Ts/m2, were infused without a conditioning regimen. All other therapy for malignancy was discontinued at least 4 weeks before CD30.CAR-T infusion. Seven patients had previously experienced disease progression while being treated with brentuximab.

Results: No toxicities attributable to CD30.CAR-Ts were observed. Of 7 patients with relapsed HL, 1 entered complete response (CR) lasting more than 2.5 years after the second infusion of CD30.CAR-Ts, 1 remained in continued CR for almost 2 years, and 3 had transient stable disease. Of 2 patients with ALCL, 1 had a CR that persisted 9 months after the fourth infusion of CD30.CAR-Ts. CD30.CAR-T expansion in peripheral blood peaked 1 week after infusion, and CD30.CAR-Ts remained detectable for over 6 weeks. Although CD30 may also be expressed by normal activated T cells, no patients developed impaired virus-specific immunity.

Conclusion: CD30.CAR-Ts are safe and can lead to clinical responses in patients with HL and ALCL, indicating that further assessment of this therapy is warranted.

Trial registration: ClinicalTrials.gov NCT01316146.

Funding: National Cancer Institute (3P50CA126752, R01CA131027 and P30CA125123), National Heart, Lung, and Blood Institute (R01HL114564), and Leukemia and Lymphoma Society (LLSTR 6227-08).

Conflict of interest statement

Conflict of interest: While this clinical trial was being conducted, the Center for Cell and Gene Therapy at Baylor College of Medicine had a Collaborative Research Agreement with Celgene Corp. and Bluebird Bio.

Figures

Figure 1. Flowchart of clinical trial NCT01316146 (CART CD30).

FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; DLCO, diffusing capacity of the lungs for carbon monoxide; AST, aspartate aminotransferase; Cr, creatinine.

Figure 2. Characteristics of CD30.CAR-Ts expanded in IL-2 or IL-7/IL-15.

(A) Total cell number at the time of transduction and clinical freeze of CD30.CAR-T products (n = 11, unpaired t test) grown in IL-2 (gray circles) or in IL-7/IL-15 (black circles). (B) Percentage of CAR+ T cells upon removal from retronectin-coated plates (day 5, squares) and at the time of freezing (day 15, circles), grown in IL-2 (gray) or in IL-7/IL-15 (black). Data in A and B are mean ± SEM. (C) Percentage of CD4+ (circles) or CD8+ (squares) T cells when grown in IL-2 (gray) or in IL-7/IL-15 (black), at the time of clinical freeze. Data are mean ± SD (n = 10, unpaired t test). (D) Cytotoxic activity of CD30.CAR-Ts (black symbols) or nontransduced, control (Ctr) T cells (white symbols) expanded in IL-2 (left graph, n = 9; paired t test) or in IL-7/IL-15 (right graph, n = 8; paired t test). Targets were CD30+ tumor cells (HDLM-2, squares) or CD30– tumor cells (Raji, circles). Data are shown as mean ± SEM for all the generated products.

Figure 3. In vivo expansion and persistence of infused CD30.CAR-Ts as assessed by qPCR in the peripheral blood.

(A) Detection of CD30.CAR-T molecular signals by qPCR. Data points represent critical postinfusion intervals after the first infusion of CD30.CAR-Ts. Lines denote each patient (legend shows universal patient identifier numbers [UPINs]). White symbols are from patients on dose level 1, gray symbols are from patients on dose level 2, and black symbols are from patients on dose level 3. (B) Detection of CD30.CAR-Ts in the peripheral blood using flow cytometry for patients treated at dose level 3. Cells were gated on T lymphocytes identified as CD45+ and CD3+ cells. Shown are zebra plots before and 1 week after infusion. (C) Pearson correlation between the cell dose of CD30.CAR-T and the peak of the CD30.CAR-T molecular signals (log transformed) for the 9 infused patients.

Figure 4. Immunological effects of infused CD30.CAR-Ts.

(A) Decrease of circulating eosinophils in the peripheral blood after CD30.CAR-T infusions. Shown are means ± SEM (n = 9; paired t test). (B) Plasma levels of inflammatory cytokines (shown are IL-6 and TNF-α) modestly increased after CD30.CAR-T infusion. Each symbol denotes a different patient (legend shows universal patient identifier numbers [UPINs]), and the dashed line represents the mean value. (C) Frequency of T cells targeting viral antigens in the peripheral blood at different time points before and after CD30.CAR-T infusions as assessed by IFN-γ ELISPOT assays. SFCs, spot-forming cells.

Figure 5. Antitumor effects of CD30.CAR-Ts.

(A) Clinical responses for the 9 infused patients. Arrows indicate ongoing remission. NR, no response; SD, stable disease; PR, partial response; CR, complete response. Asterisks indicate subsequent infusions. (B) Patient 9 had ALK+ ALCL with active disease in the right axillary, as documented in the preinfusion PET/CT scan. Six weeks after the first infusion of CD30.CAR-Ts, PET showed PR. Another PET scan obtained after a fourth infusion was consistent with CR. This patient was without evidence of disease for 9 months. (C) Patient 6 had a residual pelvic lymphadenopathy (standardized uptake value of 3.3, which was above the activity in the mediastinum blood pool) after high-dose therapy and autologous stem cell transplantation. Six weeks after the first infusion of CD30.CAR-Ts, a repeat PET scan showed resolution (no activity above mediastinum blood pool), which was also documented in a scan performed 20 weeks later.

Figure 6. Correlative biological studies after CD30.CAR-Ts.

(A) There was no significant generation of human anti-mouse antibody (HAMA) after CD30.CAR-T infusions. (B) Shown are percentages of CD4+CD25+ (top graph) and CD4+FoxP3+ (bottom graph) T cells for the 9 infused patients. Each symbol denotes a different patient (UPINs), and the dashed line indicates the mean values. (C) Pearson correlation between peak of CD30.CAR-T molecular signals (log transformed) and sCD30 cell preinfusion for the 9 infused patients. (D) CD30.CAR-T molecular signals and sCD30 levels in the peripheral blood for patient 6. (E) The graph shows the percentage of PD1+ CD30.CAR-Ts in the infused products (shown are means ± SD; n = 7). On the right, dot plots from 2 representative patients are shown.