Frontline Brentuximab Vedotin Plus Cyclophosphamide, Doxorubicin and Prednisone in Patients with Peripheral T-Cell Lymphoma with Less Than 10% CD30 Expression (SGN35-032, Trial in Progress)

Background

Brentuximab vedotin (BV) was the first antibody-drug conjugate to be approved in multiple cancer types (Gauzy-Lazo 2020). The combination of a CD30-directed monoclonal antibody, a protease-cleavable linker, and the microtubule-disrupting agent monomethyl auristatin E drives the anticancer activity of BV by inducing CD30-targeted cell cycle arrest and apoptosis as well as the bystander effect on adjacent cells (Sutherland 2006, Hansen 2016, Schönberger 2018).

In the ECHELON-2 phase 3 clinical trial, BV, cyclophosphamide, doxorubicin, and prednisone (A+CHP) showed efficacy in patients with peripheral T-cell lymphoma (PTCL) across a range of CD30 expression levels, including the lowest eligible level of 10% by immunohistochemistry when compared with patients treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) (Advani 2019).

It is hypothesized that A+CHP will demonstrate efficacy in PTCL with <10% CD30 expression because i) clinical responses to BV have occurred in patients with PTCL, cutaneous T-cell lymphoma, or B-cell lymphoma with low (<10%) and undetectable CD30 expression (Jagadeesh 2019) and ii) CD30 expression levels were not predictive of A+CHP responses in non-systemic anaplastic large cell lymphoma (sALCL) (Advani 2019).

Study Design and Methods

SGN35-032 is a dual-cohort, open-label, multicenter, phase 2 clinical trial (NCT04569032) designed to evaluate the efficacy and safety of A+CHP in patients with non-sALCL PTCL and CD30 expression of <10% on tumor cells. Up to approximately 40 patients will be enrolled in each of the CD30-negative (expression <1%) and the CD30-low (expression ≥1% to <10%) cohorts. Patients will be enrolled based on local results but only patients with CD30 expression <10% per central confirmation will be analyzed for the primary and secondary endpoints. Patients will receive 21-day cycles of A+CHP for 6-8 cycles.

Key inclusion criteria include adults with newly diagnosed PTCL, excluding sALCL, per the World Health Organization 2016 classification; CD30 expression <10% by local assessment; and fluorodeoxyglucose-avid disease by positron emission tomography (PET) and measurable disease of at least 1.5 cm by computed tomography (CT), as assessed by the site radiologist. Patients with previous exposure to BV or doxorubicin will not be eligible.

The primary endpoint of this trial is objective response rate (ORR) per blinded independent central review (BICR) using the Revised Response Criteria for Malignant Lymphoma (Cheson 2007). Secondary endpoints include ORR by BICR using the modified Lugano criteria (Cheson 2014), complete response rate, progression-free survival (PFS), and duration of response per BICR using the Revised Response Criteria for Malignant Lymphoma (Cheson 2007), overall survival, and safety and tolerability. A PET scan is required at baseline, after Cycle 4, and after the completion of study treatment. Follow-up restaging CT scans will be performed over the next 2 years.

In both the CD30-negative and the CD30-low cohorts, efficacy and safety endpoints will be summarized using descriptive statistics to describe continuous variables by cohort. Time-to-event endpoints, such as PFS, will be estimated using Kaplan-Meier (KM) methodology and KM plots will be presented. Medians for time-to-event analyses (e.g., median PFS) will be presented and two-sided 95% confidence intervals will be calculated using the log-log transformation method.

Enrollment is planned for 15 US sites and 32 sites across the Czech Republic, France, Italy, and the UK.