Serum LDH predicts response rate, response duration, and survival of patients (pts) with relapsed/refractory non-Hodgkin’s lymphoma (NHL) treated with 131I-tositumomab (131I-Tab) or 90Y ibritumomab tiuxetan (90Y-Iab) radioimmunotherapy (RIT)

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Background: Although both 131I-Tab and 90Y-Iab are approved for treatment of pts with relapsed or refractory low-grade, follicular, or transformed NHL, a prospective randomized comparison of these two forms of RIT has not been performed. We retrospectively reviewed our experience using either agent in pts with NHL. Methods: Sixty-one pts with NHL who were treated with a single course of 131I-Tab (N = 22) or 90Y-Iab (N = 39) between 1999 and 2005 were included in this analysis. The median age was 61 y (range 21–83 y) and the median number of prior therapies was 5 (range 1–13). Overall, 27 pts had indolent NHL (20 follicular grade 1/2, 4 small lymphocytic, and 3 marginal zone), while 34 pts had aggressive NHL (22 diffuse large cell, 10 mantle cell, and 2 follicular grade 3). Among pts, 75% had stage III/IV disease, 52% had an elevated serum LDH, and 38% had bulky disease (>5 cm). These characteristics were similar for pts receiving either 131I-Tab or 90Y-Iab, with the exception of elevated serum LDH (64% vs. 33%, p = 0.02). Median follow up was 21 mos (range 3–55). Results: The overall response rate (ORR) was 44% with complete response (CR) in 21% of pts. The median time to progression (TTP) was 5 mos for all pts, 9 mos for responders, and 14 mos for CRs (range 4–55). Patients with indolent NHL had no difference in ORR, CR, or TTP from pts with aggressive NHL, but had a significantly longer OS (HR 0.37, p = 0.01). Elevated LDH was the only significant predictor of ORR (31% vs. 57%, p = 0.04). In multivariable analysis, elevated LDH was adversely associated with TTP (HR 2.0, p = 0.02) and OS (HR 2.7, p = 0.02) among both subgroups of NHL. We did not discern a difference in ORR, CR, TTP, or OS between 131I-Tab and 90Y-Iab, even when stratifying for serum LDH. Conclusions: RIT produced high response rates in heavily pre-treated pts with indolent or aggressive NHL. Elevated LDH is the most significant prognostic factor for ORR, TTP and OS in this population. Patients with an elevated LDH should be considered for alternative treatment approaches or clinical trials, including RIT in combination with chemotherapy or transplant.

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Prognostic value of FDG-PET scan imaging in lymphoma patients undergoing autologous stem cell transplantation

We conducted a retrospective analysis of 50 lymphoma patients (Hodgkin's disease and non-Hodgkin's lymphoma) who had an 18F-fluoro-deoxyglucose positron emission tomography (FDG-PET) scan after at least two cycles of salvage chemotherapy and before autologous stem cell transplantation (ASCT) at our institution. The patients were categorized into FDG-PET negative (N = 32) and positive (N = 18) groups. The median follow-up after ASCT was 19 months (range: 3-59). In the FDG-PET-negative group, the median progression-free survival (PFS) was 19 months (range: 2-59) with 15 (54%) patients without progression at 12 months after ASCT. The median overall survival (OS) for this group was not reached. In the FDG-PET-positive group, the median PFS was 5 months (range: 1-19) with only one (7%) patient without progression at 12 months after ASCT. The median OS was 19 months (range: 1-34). In the FDG-PET-negative group, chemotherapy-resistant patients by CT-based criteria had a comparable outcome to those with chemotherapy-sensitive disease. A positive FDG-PET scan after salvage chemotherapy and prior ASCT indicates an extremely poor chance of durable response after ASCT.

Long-term event-free survivors after high-dose therapy and autologous stem-cell transplantation for low-grade follicular lymphoma

Although follicular lymphoma (FL) is generally responsive to conventional-dose chemotherapy, improved survival in patients with this disease has been difficult to demonstrate. High-dose chemo/radiotherapy followed by autologous stem-cell transplantation (ASCT) can improve response rates, although its effects on survival remain controversial. Between 1990 and 2003, we transplanted 49 patients with low-grade FL at our institution. Twenty-two patients (45%) had undergone histologic transformation at the time of ASCT. In all, 44 patients (90%) had relapsed disease and five patients (10%) were resistant to chemotherapy at the time of transplantation. After ASCT, 30 patients (61%) were in complete remission (CR). The median overall survival (OS) has not been reached, while the median event-free survival (EFS) is 2.4 years. At a median follow-up of 5.5 years (longest 12.4 years), a plateau has been reached with 56% of patients remaining alive, and 35% event-free. ASCT was well tolerated except for two (4%) treatment-related deaths. In multivariable analysis, CR after ASCT and age less than 60 years are the best predictors of EFS and OS. ASCT is thus a safe therapeutic approach in FL, resulting in long-term EFS and OS for some patients, even with transformed disease.