Abstract

NF-κB is deregulated in several lymphoma subtypes, including aggressive B-NHL and T-NHL. The proteasome inhibitor, bortezomib, has the capacity to reverse some of the downstream consequences of NF-κB, but has only modest single-agent activity in aggressive NHL. Gemcitabine has a favorable toxicity profile and non-cross resistant mechanism of action with agents typically used in the first-line setting. Tumor cell lines and murine xenograft models demonstrate synergy between these two agents. Based on this data and the continued unmet clinical need for patients with relapsed/refractory aggressive NHL either ineligible for or relapsed after stem cell transplant (SCT), we conducted a phase I trial of the combination to determine a dosing regimen for phase II investigation. The phase I design was a 3+3 dose escalation of bortezomib (1.3 mg/m2 and 1.6 mg/m2, day (D) 1 and D8) with static gemcitabine dosing (800 mg/m2 D1 and D8) given on 21-day cycles. Following completion of bortezomib escalation, the phase II portion of the study was initiated. We report here the phase I study including toxicity and preliminary outcomes. 18 patients have enrolled, of whom 15 are evaluable for safety and preliminary efficacy. There were 8 women and 7 men, median age was 56 years (range 37–85 years), median prior therapies were 3 (range 2–5), and 67% had failed prior SCT. Histologies included diffuse large B-NHL (n=5) and T-NHL (1 hepatosplenic, 1 anaplastic, 2 angioimmunoblastic, 6 peripheral NOS). 11 pts accrued to the phase I portion. No dose limiting toxicity (DLT) was seen at bortezomib 1.3 mg/m2 (n=3 patients); 8 phase were tested at the next phase I dose level of bortezomib 1.6 mg/m2 since 2 patients experienced non-hematologic DLT (grade 3 hypertension and grade 3 liver function tests). The study continued to the phase II portion using bortezomib 1.6 mg/m2, in which 4 patients accrued. On planned analysis of the first 15 patients enrolled, it was noted that despite not meeting criteria for DLT, 10/15 patients experienced grade 3/4 neutropenia and/or thrombocytopenia resulting in repeated treatment delay(s). The median number of cycles delivered for all patients was 1 (range 1–3), while the median normalized dose-intensity was only 61%. Thus the trial was amended to institute a modified treatment schedule to administer gemcitabine and bortezomib on D1 and D15 on a 28-day schedule. Pre-planned analysis of the first 15 pts showed clinical activity/response allowing continuation of accrual onto the phase II portion (two partial remissions in T-NHL). In summary, our phase I study defined the safety/toxicity panel of combined bortezomib and gemcitabine dosing for patients with relapsed aggressive NHL. A planned analysis of the first 15 patients showed preliminary activity in heavily pre-treated patients allowing continuation to the 2nd stage, although repeated hematologic toxicities were seen leading to low dose intensity. Of note, data presented at ASCO 2008 (Luu et al. abstract #2563) studied the combination of bortezomib (D1, D4, D8, and D11) and gemcitabine (1,250 mg/m2 D1 and D8) in relapsed/ refractory advanced-stage solid tumors. The maximum tolerated dose of bortezomib there was 1.0 mg/m2 with gemcitabine. Furthermore, significant hematotoxicity was seen in that trial (grade 3/4 toxicity: 62% thrombocytopenia, 34% neutropenia, 17% anemia; with median of 2 cycles delivered). Accrual here continues to the phase II trial using a modified treatment schedule (gemcitabine 800 mg/m2 and bortezomib 1.6 mg/m2 both D1 and D15 on a 28-day schedule) in order allow more consistent delivery of the intended therapy.

Disclosures: Evens:Millennium: Honoraria, Research Funding. Rosen:Millennium: Honoraria. Winter:Millennium: Research Funding. Smith:Lilly: Honoraria. Off Label Use: gemcitabine/bortezomib for relapsed T-cell and aggressive B-cell lymphoma.

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