An open-label, multicenter, phase II study of AT-101 in combination with rituximab (R) in patients with untreated, grade 1-2, follicular non-Hodgkin's lymphoma (FL)

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Background: Bcl-2 family proteins are overexpressed in the majority of patients with FL and contribute to resistance to therapy. AT-101 is a pan-Bcl-2 inhibitor (Bcl-2, Bcl-XL, Bcl-W, and Mcl-1) and potent inducer of proapoptotic proteins. It is active as a single agent and in combination with R in NHL tumor models. Methods: Patients with untreated FL who did not require immediate chemotherapy were eligible. Treatment consisted of an induction cycle of AT-101 (30mg po daily × 21) and R (375 mg/m2 weekly × 4) followed by up to 4 maintenance cycles of AT-101 (30mg po daily × 21) and R (375 mg/m2) every 8 weeks in nonprogressors. Endpoints evaluated the response rate (RR) at week 8 (primary), overall response rate (ORR), molecular response rate (BCL-2JH rearrangement in blood and bone marrow), and safety of the combination. A mini-Max, 2-stage design (52 pts planned) was used to detect >70% RR with power of 90% and alpha of 0.10. Results: 23 pts enrolled: median age 64 yrs; FLIPI 0–5: 0%/17%/65%/13%/4%; Grade 1/2: 61%/39%; bulky disease (>5cm3): 35%; stage: 1–4 4%/4%/30%/61%; bone marrow + 48%. All pts received induction and 18 pts received 1 or more maintenance cycles. RR following induction was 26% (95%CI=10.2–48.4), 4% CR and the best ORR was 70% (95%CI=47.1–86.8), 35% CR. Molecular response analysis is ongoing. Grade 3/4 AEs that occurred in ≥2 pts: nausea 4(17%), vomiting 2(9%), abdominal pain 2(9%), fatigue 2(9%), and small bowel obstruction 2(9%). AT-101 was reduced to 20mg daily x 21 which improved GI tolerability. Conclusions: The combination of AT-101 and R was well tolerated. The week 8 RR did not meet statistical criteria to enroll stage II. The best ORR is at the upper limit of reported ORR for R alone; therefore a randomized trial is required to definitively determine activity of the combination.

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Alpha-difluoromethylornithine as treatment for metastatic breast cancer patients

DFMO (alpha-difluoromethylornithine) is an oral irreversible inhibitor of ornithine decarboxylase, the first rate-limiting enzyme in polyamine synthesis. DFMO has been shown to have antiproliferative effects against several human cancers, and some studies have suggested that DFMO may have pro-apoptotic and anti-invasive properties as well. DFMO is well tolerated with minimal toxicity but has been associated with ototoxicity with prolonged daily administration. We conducted a Phase I/II tolerability, pharmacokinetic, and efficacy study of high-dose DFMO in metastatic breast cancer patients. Twenty-one patients were treated with 4800 mg of DFMO p.o. three times a day for 14 days, followed by a 2-week drug holiday on a 28-day cycle. Urinary polyamine and blood DFMO levels were measured at multiple time points during therapy. High-dose DFMO was well tolerated, and no clinically significant ototoxicity was noted. No patient achieved an objective antitumor response; however, one patient with heavily pretreated liver metastases has achieved stable disease for 18 months to date on DFMO. Putrescine, spermine, and spermidine urinary levels were suppressed with DFMO treatment and remained low during the 2-week drug holiday. High-dose DFMO on a schedule of 2 weeks on treatment followed by 2 weeks off is well tolerated, is not associated with ototoxicity, and leads to sustained suppression of urinary polyamine levels. Although not an active cytotoxic agent for metastatic breast cancer, the intriguing prolonged growth arrest of liver metastases in one patient highlights the potential clinical growth inhibitory properties of DFMO. We believe that DFMO is worthy of study as adjuvant therapy in primary breast cancer patients and as a chemopreventive agent.

High-dose busulfan, melphalan and thiotepa followed by autologous peripheral blood stem cell (PBSC) rescue in patients with advanced stage III/IV ovarian cancer

The purpose of this study was to evaluate the efficacy of high-dose chemotherapy (HDC) with busulfan, melphalan and thiotepa (BUMELTT) followed by autologous PBSC infusion in treating patients with advanced ovarian cancer. Thirty-one patients, 18 with stage III/IIIc and 13 with stage IV ovarian cancer, were treated with BU (12 mg/kg), MEL (100 mg/m2) and TT (500 mg/m2) and autologous PBSC rescue. Fifteen patients were in clinical complete remission (CR) at treatment; 11 had platinum-sensitive disease. Sixteen patients were not in CR; two had platinum-sensitive disease. The probabilities of overall survival (OS), event-free survival (EFS) and relapse (R) for all patients at 18 months were 0.57, 0.30 and 0.63; for patients in CR, the rates were 0.87, 0.44 and 0.49 and for patients not in CR, 0.38, 0.13 and 0.81. Two patients (6.5%) died of treatment-related causes. Among the 13 patients with platinum-sensitive disease, all are still alive, with seven having relapsed 129-1021 days after PBSC infusion. OS, EFS and R were 1.00, 0.52 and 0.48. Of the 18 patients with platinum-resistant disease, four remain alive (two in remission). Six patients did not respond and eight relapsed from days 104-429. The OS, EFS and R were 0.33, 0.11 and 0.78. We conclude that BUMELTT is well tolerated in patients with advanced ovarian cancer and results are equivalent to other published HDC regimens.