A Phase I Study of Romidepsin, Gemcitabine, Dexamethasone and Cisplatin Combination Therapy in the Treatment of Peripheral T-Cell and Diffuse Large B-Cell Lymphoma: Canadian Cancer Trials Group Study LY.15

Background: The outcome of peripheral T-cell lymphomas (PTCLs) remains poor and improved therapies are needed. Retrospective data suggest that integration of anthracyclines in the primary therapy may not impact outcome, providing the rationale to explore alternative regimens. Histone deacetylase inhibitors appear to have a class effect in PTCLs andromidepsin monotherapy demonstrates activity in a proportion of patients with relapsed/refractory PTCLs and can induce durable remissions. Gemcitabine is reported to be a highly active agent in PTCL, and the GDP (gemcitabine, dexamethasone, cisplatin) regimen has become a standard chemotherapy backbone for relapsed aggressive lymphomas (Crump, JCO 2014). We investigated the feasibility, safety and efficacy of GDP combined with romidepsin in a phase I dose escalation trial. Patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) were also included.

Methods: Patients with relapsed/refractory PTCL or DLBCL, PS 0-2, with measurable disease and who had received one or two prior lines of systemic therapy, were treated with standard doses of GDP (gemcitabine, 1000 mg/m2 d1, d8; dexamethasone, 40 mg po d1-4; cisplatin, 75 mg/m2 d1) every 21 days, plus escalating doses of romidepsin (6, 8, 10 and 12 mg/m2) on days 1 and 8 to a maximum of 6 cycles in a standard 3+3 design. After the first 4 patients were enrolled, based on the observed pattern of thrombocytopenia, the treatment schedule was modified so that gemcitabine and romidepsin were given on days 1 and 15 and cycles extended to every 28 days. Dose-limiting toxicities (DLTs) were assessed during the first 2 cycles and defined as requiring platelet transfusion for bleeding, grade 3 hematological toxicity lasting >10 days, grade 4 hematological toxicity lasting >7 days, febrile neutropenia, or grade 3-4 non-hematological toxicity attributable to romidepsin. Responses were as per Cheson, JCO 2007 excluding PET scans.

Results: 20 eligible patients (PTCL n=10; DLBCL n=10) were enrolled between 10/2013 and 01/2016 and treated with GDP plus romidepsin. The main PTCL subtype was PTCL, not otherwise specified (50%). Median age was 65 years (24-74); 9 were female; ECOG performance status was 0 (n=2), 1 (n=13), or 2 (n=5). Number of prior therapies was 1 (n=17) or 2 (n=3). 17 (85%) patients received >90% of the planned dose each cycle. The median number of cycles was 2 (range, 1-6); one patient is still on therapy. The reasons for treatment discontinuation were lymphoma progression (n=10), toxicity (n=2), proceeding to autologous stem cell transplant (ASCT, n=3), intercurrent illness (n=1), or completion of 6 cycles (n=3).

On the 21-day schedule at 6 mg/m2 romidepsin, there were 3 DLTs among four patients (2 with grade 3-4 thrombocytopenia, 1 venous thromboembolic event). On the 28-day schedule, there were no DLTs observed in the three patients treated at each of the 6, 8 or 10 mg/m2 dose levels. At 12 mg/m2 there were 4 observed grade 3 DLTs among six evaluable patients (hypotension, acute kidney injury, anorexia, thrombocytopenia >10 days). Notable toxicities during any cycle were: febrile neutropenia (n=2); grade 3-4 thrombocytopenia (n=9); grade 3-4 neutropenia (n=4); and grade 3-4 anemia (n=4); grade 2 atrial fibrillation (n=2); grade 2 QTc prolongation (n=1); grade 1 sinus tachycardia (n=1); grade 2-3 infections (n=16); grade 1-3 cutaneous toxicity (n=9); grade 1-3 thromboembolic events (n=2); TIA (n=2) or stroke (n=1). One patient died after cycle 1 due to sepsis. 7 other patients have died of progressive lymphoma.

The overall response rate was 9/20 (45%), all were partial remissions (PR), 3 had stable disease (SD), 4 had progressive disease (PD), and 4 were not objectively evaluable. Of the responders, 5 had PTCL and 4 had DLBCL. Four patients went on to ASCT. With a median follow-up of 5.8 months, the median duration of response was 2.8 months and median PFS is 2.2 months. For all patients, the 1 year PFS was 6% and 1 year OS was 43%

Discussion: Full doses of GDP can be combined with a recommended phase II romidepsin dose of 10 mg/m2 given on a day 1, 15 every 28 days schedule. Thrombocytopenia prohibits this combination on a 21-day schedule. Toxicity is otherwise acceptable and as expected. Further study at the recommended dose and schedule would be required to properly define the activity of this regimen in PTCLs and DLBCL.