Joseph P. Lynch

Regulation of BAX and BCL‐2 expression in breast cancer cells by chemotherapy

Optimizing chemotherapeutic drug delivery strategies relies, in part, on identification of the most clinically effective sequence, dose, and duration of drug exposure. The combination of dose intensive etoposide (VP‐16) followed by cyclophosphamide has clinical efficacy in the treatment of advanced breast cancer. However, molecular mechanisms that underlie the effectiveness of this combination of chemotherapeutic agents have not been investigated. In this study we investigated regulation of BAX and BCL‐2 expression by VP‐16 and cyclophosphamide as a potential mechanism for the induction of breast cancer cell death induced by this regimen.There was a dose and time dependent increase in BAX expression in the breast cancer cell lines MCF‐7, MDA‐MB‐435S, and MDA‐MB‐A231 following in vitro treatment with 50–100 μM VP‐16. Elevation of BAX protein expression in the presence of VP‐16 alone did not correlate with reduced viability or induction of apoptosis in MCF‐7, MDA‐MB‐435S, or MDA‐MB‐A231. VP‐16 did effectively block the breast cancer cell lines evaluated (MCF‐7 and MDA‐MB‐435S) at G2/M phase of the cell cycle, confirming activity of the drug in vitro. MCF‐7 and MDA‐MB‐435S cells that were pre‐treated with VP‐16 and subsequently exposed to 1.0–12.0 μg/m1 4‐hydroperoxycyclophosphamide (4HC), an active metabolite of cyclophosphamide, had markedly reduced viability when compared to matched controls treated with either VP‐16 or 4HC individually. Consistent with this loss of viability, exposure of all three cell lines to the combination of VP‐16 and 4HC resulted in higher BAX protein levels than those observed following treatment with either single agent. This combination of chemotherapeutic agents also resulted in reduced BCL‐2 expression.These observations suggest that combination chemotherapy may derive its efficacy, in part, through coordinated regulation of specific gene products associated with apoptosis. Characterization of molecular events that underlie susceptibility of specific tumor cells to combination chemotherapeutic regimens may lead to additional improvements in treatment strategies for this disease.

Recombinant human thrombopoietin augments mobilization of peripheral blood progenitor cells for autologous transplantation.

This study assessed the ability of various schedules of recombinant human thrombopoietin (rhTPO) to enhance mobilization of peripheral blood progenitor cells (PBPCs) in 134 patients with cancer undergoing high-dose chemotherapy and autologous PBPC transplantation. Patients received the study drug on days 1, 3, and 5 before initiation of granulocyte colony-stimulating factor (G-CSF) 10 microg/kg/day on day 5 and pheresis starting on day 9. Randomly assigned treatments on days 1, 3, and 5 were: group 1 (n=27) placebo, placebo, rhTPO 1.5 microg/kg; group 2 (n=27) rhTPO 1.5 microg/kg, placebo, placebo; groups 3 (n=28) and 4 (n=22) rhTPO 0.5 microg/kg on all 3 treatment days; and group 5 (n=30) placebo on all 3 treatment days. After high-dose chemotherapy and PBPC transplantation, groups 1 through 4 received rhTPO 1.5 microg/kg days 0, +2, +4, and +6 with either G-CSF 5 microg/kg/day (groups 1-3) or granulocyte-macrophage colony-stimulating factor 250 microg/m(2)/day (group 4). Group 5 received placebo plus G-CSF 5 microg/kg/day. The addition of rhTPO to G-CSF increased median CD34+ cell yield/pheresis in cohorts in which rhTPO was started before day 5, with higher yields in groups 2 (2.67 x 10(6)/kg) and groups 3 and 4 (3.10 x 10(6)/kg) than in group 1 (1.86 x 10(6)/kg) or group 5 (1.65 x 10(6)/kg) (P=.006 across groups). Comparing rhTPO to placebo, higher percentages of patients achieved the minimum yield of CD34+ > or =2 x 10(6)/kg (92% v 75%; P=.050) as well as the target yield of CD34+ > or =5 x 10(6)/kg (73% v 46%; P= .041). rhTPO-treated patients required fewer phereses to achieve minimum (P= .011) and target (P= .015) CD34+ cell values. rhTPO given after transplantation did not speed platelet recovery. No neutralizing antibodies were observed. We conclude that rhTPO can safely enhance mobilization of PBPC, reduce the number of leukapheresis, and allow more patients to meet minimal cell yield requirements to receive high-dose chemotherapy with PBPC transplantation.

A randomized phase II study of BB‐10010: a variant of human macrophage inflammatory protein‐1α for patients receiving high‐dose etoposide and cyclophosphamide for malignant lymphoma and breast cancer

Macrophage inflammatory protein‐1α (MIP‐1α) is a chemokine that can inhibit the cell cycle progression of both primitive haemopoietic and epidermal progenitor cells. This property could potentially be exploited to attenuate both the myelosuppressive effects of chemotherapy as well as mucositis. We evaluated both the biological and clinical effects of BB‐10010, a genetically engineered variant of MIP‐1α, in patients with malignant lymphoma or breast cancer receiving high‐dose etoposide (VP 3.6 g/m2) and cyclophosphamide (Cy 200 mg/kg). 52 patients were randomized to one of three cohorts. Cohort A received no BB‐10010; cohorts B and C received 10 μg/kg and 100 μg/kg of BB‐10010, respectively. All patients received post‐chemotherapy G‐CSF. BB‐10010 was well tolerated. There were no significant differences between groups in recovery to an ANC > 0.5 × 109/l, 1 × 109/l or 1.5 × 109/l, the number of days with an ANC < 0.5 × 109/l, days to a platelet count >50 × 109/l or 100 × 109/l, or the incidence and severity of mucositis. There was no evidence of any effect of BB‐10010 on colony‐forming cell (CFC) or long‐term culture‐initiating cell (LTC‐IC) mobilization, cycling activity in the marrow or on chemotherapy‐induced changes in CFC or LTC‐IC number both of which were in the normal range by 22 d after completion of the chemotherapy. To our knowledge this is the first report of a myelointensive regimen having no apparent long‐term effect on the LTC‐IC compartment. In summary, BB‐10010 is safe when used in patients receiving high‐dose therapy but has no effect on reducing the toxicity of such therapy.

Recombinant human thrombopoietin (rhTPO) after autologous bone marrow transplantation: a phase I pharmacokinetic and pharmacodynamic study

Thrombocytopenia following myelotoxic therapy is a common problem and when severe (<20 000/μl) can lead to severe morbidity and mortality. Thrombopoietin (TPO) is a naturally occurring glycosylated peptide which stimulates the differentiation of bone marrow stem cells into megakaryocyte progenitor cells, induces the expression of megakaryocyte differentiation markers, promotes megakaryocyte proliferation, polyploidization and, ultimately, the formation of increased numbers of platelets in the circulation. TPO has now been produced by recombinant technology and has entered clinical trials. This open label phase I study was designed to determine the safety, tolerance and pharmacokinetics of recombinant thrombopoietin (rhTPO) when administered to patients after undergoing high-dose chemotherapy followed by autologous bone marrow transplantation. rhTPO was administered intravenously by bolus injection at doses ranging from 0.3 to 4.8 μg/kg/day every 3 days to 30 patients and 0.6 μg/kg daily to three patients. rhTPO was begun the day after marrow infusion and continued until platelet recovery to <20 000/μl. G-CSF was concomitantly administered to promote myeloid recovery. Serious adverse events or neutralizing antibodies to rhTPO were not observed during the study. Median platelet recovery after ABMT was 19 days (range, 11–41). Neither the dose nor the schedule of rhTPO appeared to have any impact upon the time course of platelet recovery. In this phase I study, rhTPO was found to be well tolerated without the development of neutralizing antibodies and without compromising neutrophil recovery. Platelet recovery was similar for all doses studied warranting further evaluation in phase II and III trials designed to test for platelet recovery efficacy. Bone Marrow Transplantation (2001) 27, 261–268.

Complete response after high-dose chemotherapy and autologous hemopoietic stem cell transplatation in metastatic breast cancer results in survival benefit.

Abstract:  Metastatic breast cancer is an incurable disease even with high‐dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (ASCT). Even though phase III studies have not shown a survival advantage for this group as a whole, it is possible that a small subset of patients may benefit from HDC/ASCT with careful patient selection. A total of 198 patients from three different institutions were treated with HDC/ASCT. After complete staging, patients with central nervous system or bone marrow involvement were excluded. The HDC regimen consisted of: Carboplatin 600 mg/m2 IV infusion over 48 hours, Thiotepa 300 mg/m2 IV infusion over 2 hours, and Cytoxan 60 mg/kg IV infusion given over 2 hours ×3 days. The median age at the time of transplant was 46 (24–62) years and median follow‐up was 20 months. Hormone receptor status was known in 148 patients, of whom 84 had estrogen receptor (ER) and/or progestrone receptor (PgR)‐positive tumors. Eighty patients had no evidence of disease at the time of HDC/ASCT (CR1). At the completion of HDC and ASCT, complete responses (CR) were seen in an additional 57 patients (CR2). Using Kaplan–Meier analysis, the median relapse‐free survival (RFS) for the entire group was 15 months and overall survival (OS) was 27 months. The patients in CR1 had a median RFS and OS of 20.7 and 50.6 months, respectively. This was very similar to the RFS and OS in patients achieving CR2 after HDC/ASCT (p < 0.001; median: 19 and 40 months, respectively). In contrast, the patients with persistent residual disease had an RFS and OS of 7 and 12 months (p < 0.001). These data show that patients achieving a CR after HDC/ASCT have a better relapse‐free and OS, when compared to patients with persistent residual disease after HDC/ASCT. This study suggests that a subset of patients with residual metastatic breast cancer after standard chemotherapy can achieve CR with HDC and ASCT which may result in better long‐term outcome.

Protracted results of dose-intensive therapy using cyclophosphamide, carmustine, and continuous infusion etoposide with autologous stem cell support in patients with relapse or refractory Hodgkin's disease: A phase II study from the North American Marrow Transplant Group

To determine the long-term results of high-dose chemotherapy and stem cell support in relapsed or primary refractory Hodgkin disease patients. One hundred and thirty-one patients with relapsed or primary refractory Hodgkins disease were treated with a dose-intensive therapy protocol consisting of etoposide (2400 mg/m2 continuous intravenous infusion) cyclophosphamide (7200 mg/m2 intravenously), and carmustine (300-600 mg/m2 intravenously) CBVi. All patients had previously failed conventional chemoradiotherapy. Severe toxicities were related to infectious, hepatic, and pulmonary complications. Fatal, regimen-related toxicity was 19%; liver and lung dysfunction, as well as infection, were the most frequent problems. Ninety-one (69%) of the patients achieved a complete response (CR) (95% CI = 59% to 75%) after CBVi and autologous stem cell infusion. With a median follow-up of 5.1 years (range 3.0 to 9.5 years), overall and event-free survival are 44% (95% CI = 33% to 47%) and 38% (95% CI = 28% to 46%) respectively. While univariate analysis did not reveal a statistically significant variable to predict a better response, responsiveness to therapy demonstrated a trend. We conclude that CBVi is an effective therapy for relapsed or refractory Hodgkins disease, producing long-term, durable remissions.

Thiotepa and fractionated TBI conditioning prior to allogeneic stem cell transplantation for advanced hematologic malignancies: a phase II single institution trial.

Summary:Relapse of hematologic malignancies after allogeneic stem cell transplantation remains a common problem, in particular for patients who have advanced disease at the time of transplantation. Thiotepa has excellent antileukemic and immunosuppressive activity, and could therefore be a useful drug in the conditioning regimen for patients with advanced hematologic neoplasms. We retrospectively analyzed toxicity, engraftment and survival data of 41 patients who received a conditioning regimen of thiotepa (600 mg/m2) and hyperfractionated TBI (10 Gy) prior to matched related (n=25) or matched unrelated (n=16) allogeneic stem cell transplantation. The mean age at transplantation was 37.8 years (range 20–59), all but five patients had advanced hematologic malignancies at the time of transplantation. GVHD prophylaxis was with standard cyclosporine and methotrexate. Engraftment was excellent, but the regimen was associated with a high incidence of grade III renal (41%) and hepatic (15%) toxicity, and high transplant-related mortality (44% at day +90). The 3-year event-free survival was 13% and overall survival 14%. We conclude that this regimen requires modification to reduce toxicity.

High-Dose Therapy and Autologous Stem Cell Transplantation in Relapsed and Refractory Hodgkin’s Disease: Outcome Based on a Prognostic Model

We evaluated the results of high-dose therapy (HDT) and autologous hematopoietic stem cell transplantation (ASCT) in patients with relapsed or primary refractory Hodgkin’s disease (HD), using a previously reported prognostic model based on the presence of three poor prognostic factors at the start of salvage therapy/preparative regimen: B symptoms, extranodal disease and the duration of last complete response of less than 1 year. Based on this model, the patients were divided into low-risk and high-risk groups. Between 1993 and 2001, 24 patients with HD were treated with HDT and ASCT. Eighteen of the 24 patients had 0–1 risk factors (low-risk group) and 6 patients had 2–3 risk factors (high-risk group). Using Kaplan-Meier analysis, after a median follow-up of 40.5 months, the progression-free survival (PFS) was 48%, and the overall survival (OS) was 55%. PFS in the low-risk group was 56%, and in the high-risk group 17% (p < 0.001). OS in the low-risk group was 68% and in the high-risk group it was 18% (p < 0.001). The 100-day transplant-related mortality for the entire group was 16%. Our results are comparable to those reported in previous clinical trials for patients with refractory and relapsed HD treated with HDT and ASCT. The use of a prognostic model appears useful for predicting the outcome of HDT and ASCT for HD patients, and may play an important role in choosing the appropriate therapy for these patients.

Biological and clinical correlates after chemotherapy and granulocyte colony-stimulating factor administration.

Study Objective. To evaluate specific biological markers to improve understanding and use of granulocyte colony‐stimulating factor (G‐CSF) in patients receiving chemotherapy.