Effect of bexarotene on platelet counts in patients undergoing cancer treatment: An analysis of clinical trials in lung cancer and leukemia

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Background: Bexarotene (Bex) is an oral retinoid X receptor agonist with activity against cutaneous T cell lymphoma and currently under investigation for other malignancies. In patients receiving this agent for acute myeloid leukemia (AML), we noted increases in platelet counts. We therefore reviewed the available clinical trial data on Bex and its effects on platelet counts. Methods: We analyzed platelet count data from 3 Bex clinical trials encompassing non-small cell lung cancer (NSCLC) and AML. Results: In two phase III trials of Bex in NSCLC, patients underwent carboplatin + paclitaxel (CarP, n=587) or cisplatin + vinorelbine (CisV, n=613) and were randomized to receive concurrent Bex or placebo. More patients on Bex than on placebo had an increase in platelet count of at least 50 K/uL (55% vs. 27% for CarP, p<0.0001; 81% vs. 66% for CisV, p<0.0001) over pre-treatment baseline. The median increase in platelet count was higher on Bex than on placebo (69 vs 0 K/uL for CarP, p<0.0001; 168 vs. 95 K/uL for CisV, p<0.0001) and was maintained while on treatment. In both NSCLC trials, the median time to platelet increase >50 K/uL on Bex was 22 days. Similar findings were seen in a phase I monotherapy trial in AML where 5/18 (28%) patients achieved platelet transfusion independence with peak platelet counts of 40–91 K/uL. Conclusions: Clinically significant increases in platelet counts were seen in all 3 clinical trials examined. These data suggest that Bex improves platelet counts in patients with a variety of cancer types, both as monotherapy and with concurrent chemotherapy. Its effect on megakaryopoiesis and its potential role as a supportive care measure should be further evaluated.

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A phase I trial of bexarotene, a retinoid X receptor agonist, in non-M3 acute myeloid leukemia

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Background: In vitro, bexarotene inhibits the proliferation of non-M3 AML cell lines and induces differentiation of leukemic blasts. This phase I study was designed to evaluate the safety of escalating doses of bexarotene in patients with non-M3 AML and has completed enrollment. Methods: Bexarotene was administered daily until disease progression occurred. Dose escalation occurred in cohorts of 3–6 patients through 6 dose levels ranging from 100–400mg/m2. Results: 27 patients were enrolled: 19M/8F, median age 69 (range 51–82), 13 prior MDS, 12 primary refractory, median number of induction attempts 2, no prior chemotherapy 3, prior autologous stem cell transplant 5, 26 blood transfusion dependent, 18 platelet transfusion dependent, and 20 neutropenic. Despite prophylactic use of antihyperlipidemic agents, 4 patients developed grade ≥3 hypertriglyceridemia. Two patients developed a syndrome reminiscent of retinoic acid syndrome, consisting of dyspnea, pleural/pericardial effusions, and edema in the setting of a rising neutrophil count. This syndrome resolved with stopping bexarotene and initiating steroids. Evidence of activity was noted with bone marrow blasts decreasing to ≤5% in 4 patients. Seven patients showed evidence of neutrophil response (pretreatment median ANC 364/μL, range 28–1,242/μL, treatment ANC 3,540/μL, range 1,200–26,207/μL). Flow sorted peripheral blood neutrophils were collected from 3 of these patients and examined by FISH. Between 92–100% of neutrophils contained the patient's leukemic cytogenetic abnormality suggesting differentiation of the leukemic blasts. Eleven patients with platelet counts <100,000/μL had increases in their platelet counts >20,000/μL (peak range 40- 292x103/μL). Five of these patients with platelet counts <20,000/μL had improvement to 40–91,000/μL and became transfusion independent. Conclusions: Bexarotene is well tolerated at the dose levels studied. Evidence for clinical activity has been seen as exemplified by improvement in platelet counts, increased neutrophil counts and decreased bone marrow blasts. We postulate that bexarotene may induce leukemic blast differentiation in non-M3 AML and represent a novel non-cytotoxic treatment.

No significant financial relationships to disclose.

Second consensus on medical treatment of metastatic breast cancer

The present consensus manuscript defines evidence-based recommendations for state-of-the-art treatment of metastatic breast cancer depending on disease-associated and biologic variables.

Bortezomib is active in Waldenstrom’s Macroglobulinemia (WM)—Results of a National Cancer Institute of Canada (NCIC) phase II study in previously untreated or treated WM

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Background: WM is a B cell lymphoma characterized by a serum monoclonal IgM and marrow infiltration by lymphoplasmacytoid cells. Bortezomib is a proteasome inhibitor active in myeloma and other hematologic malignancies. In this 2-stage study, 27 WM pts received single agent bortezomib with RR as primary endpoint. Methods: Eligibility: symptomatic WM (Hb <110 g/L; lymphadenopathy; organomegaly; or hyperviscosity); ≤2 prior chemo regimens (± rituximab). Bortezomib 1.3 mg/m2 IV given d1, 4, 8, 11 on a 21d cycle until PD or 2 cycles beyond CR/SD. Nodal disease was included in response criteria (2nd International WM Workshop). Results: Median age 65 (46–87), M:F 14:13, no prior therapy 11 (44%). At entry, median IgM 38 g/L (11.2–83.3); median Hb 108 g/L (63–142); 18 (66%) with nodal disease on CT. At a median of 6 cycles (2–35), 11/27 (41%) patients had ≥50% decrease in IgM alone plus 10 (37%) minor responses (25–49% decrease). Using IgM + nodal criteria: 1 CR, 5 PR (≥50% decrease in IgM and bidimensional disease), 20 SD, 1 PD = overall RR 22% (95% CI 8.6–42.2%). IgM responses were prompt (median 2 cycles; range 1–8) with nodal responses lagging (median 4 cycles). Hb increased by ≥10g/L in 18 pts (66%). Bortezomib was well-tolerated with most non-hematologic toxicities Gr 1–2: fatigue (74%), nausea (63%), myalgias (51%), non-neutropenic infections (48%), diarrhea (44%), constipation (44%). 18 pts (66%) developed neuropathy (sensory): typical onset 2–4 cycles; Gr 3 in 5 pts; 15/18 (83%) improving ≥1 grade (11 complete) in 2–13 mo. Gr 3 myalgias in 2 pts resolved in <1 mo. Gr 3–4 thrombocytopenia (30%) and neutropenia (18%) led to 12 missed doses, 1 dose reduction. Conclusions: Bortezomib is active in WM with 78% pts with ≥25% fall in IgM, 41% with IgM response criteria of ≥50% decrease, 22% with composite nodal/IgM responses. Despite prompt IgM and hematologic improvement, decrease in nodal disease is slow, reflected in overall responses lower than IgM alone. Although bortezomib is generally well-tolerated, neuropathy is common but reversible. Bortezomib combinations with conventional cytotoxic or targeted agents warrant further study in WM. This is a NCIC CTG study with a grant from NCIC and funds from Canadian Cancer Society.

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Lenalidomide plus high-dose dexamethasone provides improved overall survival compared to high-dose dexamethasone alone for relapsed or refractory multiple myeloma (MM): Results of a North American phase III study (MM-009)

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Background: Lenalidomide is a novel, orally administered, immunomodulatory drug (IMiD) that has single-agent activity against MM and additive effects when combined with dexamethasone (Dex). Methods: In this phase 3, multicenter, double-blind trial, 354 patients (pts)with relapsed or refractory MM were treated with Dex 40 mg daily on days 1–4, 9–12, 17–20 every 28 days and were randomized to receive either lenalidomide (Len) 25 mg daily orally on days 1–21 every 28 days or placebo. Beginning with cycle 5, Dex was reduced to 40 mg daily on days 1–4 only, every 28 days. Patients were stratified with respect to B2M (≤ 2.5 vs. > 2.5 mg/mL), prior stem cell transplant (none vs. ≥ 1), and number of prior regimens (1 vs > 1). The treatment arms were well balanced for prognostic features. Results: The overall response rate was greater with Len-Dex than with Dex-placebo (59.4% vs. 21.1%; p < 0.001). Complete responses were achieved in 12.9% of pts treated with Len-Dex and 0.6% of pts treated with Dex-placebo. The median time to progression (TTP) for pts treated with Len-Dex was 11.1 months compared to 4.7 months for pts treated with Dex-placebo (p < 0.000001). Median overall survival was higher with Len-Dex (not reached) compared to Dex-placebo (24 months) (hazard ratio 1.76, p = .0125). Grade 3–4 neutropenia was more frequent with combination therapy than with Dex-placebo (24% vs. 3.5%), however ≥ grade 3 infections were similar in both groups. Thromboembolic events occurred in 15% of pts treated with Len-Dex and in 3.5% of pts treated with Dex-placebo. Atrial fibrillation occurred in 8 pts and CHF developed in 4 pts treated with Len-Dex. Conclusions: Considering the ease of oral administration, higher response rate, longer time to progression and overall survival benefit, the combination of lenalidomide-dexamethasone may very well represent the treatment of choice for early refractory or relapsing multiple myeloma. The relatively infrequent side effects should not detract from these improvements, but the use of prophylactic antithrombotic therapy should be considered for patients treated with the combination of lenalidomide and dexamethasone.

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Purging of autologous peripheral-blood stem cells using CD34 selection does not improve overall or progression-free survival after high-dose chemotherapy for multiple myeloma: results of a multicenter randomized controlled trial

PURPOSE

Although high-dose chemotherapy supported by autologous peripheral-blood progenitor-cell (PBPC) transplantation improves response rates and survival for patients with multiple myeloma, all patients eventually develop progressive disease after transplantation. It has been hypothesized that depletion of malignant plasma cells from autografts may improve outcome by reducing infused cells contributing to relapse.

PATIENTS AND METHODS

A randomized phase III study using the CEPRATE SC System (Cellpro, Bothell, WA) to enrich CD34(+) autograft cells and passively purge malignant plasma cells was completed in 190 myeloma patients randomized to receive an autograft of CD34-selected or unselected PBPCs.

RESULTS

After CD34 selection, tumor burden was reduced by 1.6 to 6.0 logs (median, 3.1), with 54% of CD34-enriched products having no detectable tumor. Median time to count recovery, number of transfusions, transplantation-related mortality, and days in hospital were equivalent between the two transplantation arms. With a median follow-up of 37 months, 33 patients (36%) in the selected and 34 patients (35%) in the unselected arm had died (P =.784). Median overall survival in the selected arm was reached at 50 months and is not reached at this time in the unselected arm (P =.78). Median disease-free survival was 100 versus 104 weeks (P =.82), with 67% of patients in the selected arm and 66% of patients in the unselected arm relapsing.

CONCLUSION

This phase III trial demonstrates that although CD34 selection significantly reduces myeloma cell contamination in PBPC collections, no improvement in disease-free or overall survival was achieved.

Infectious complications the year after autologous bone marrow transplantation or peripheral stem cell transplantation for treatment of breast cancer

Few studies have examined the specific incidence of infections after autologous bone marrow transplantation (BMT) or peripheral stem cell transplantation (PSCT) for treatment of breast cancer. We reviewed the medical records of 127 consecutive patients who underwent autologous BMT or PSCT for breast cancer at the University of Pennsylvania Medical Center from 1 May 1991 through 31 March 1995 and through 1 year of follow-up. The mean duration of neutropenia after transplantation was 10 days. Initial infections included catheter-site cellulitis (in 20 patients [16%]), bacteremia (17 [13%]), Clostridium difficile colitis (13 [10%]), and urinary tract infection (in 10 [8%]); there was only 1 documented invasive fungal infection (1% of patients). The mortality from infection was 2%. Infections during the 1 year follow-up included upper respiratory infections (11 patients [10%]) and dermatomal zoster (9 [8%]); neither was significantly associated with death. This group of patients who underwent BMT or PSCT for breast cancer had a low rate of infectious morbidity and mortality. Viral and fungal infections were rare despite inconsistent prophylaxis.

Soluble interleukin-2 receptor concentration as a biochemical indicator for acute graft-versus-host disease after allogeneic bone marrow transplantation

When interleukin-2 (IL-2) binds to the IL-2 receptor (IL2-R) on activated T cells, a soluble portion of the receptor (sIL2-R) is released. After allogeneic bone marrow transplantation (BMT), the serum concentration of sIL2-R may, therefore, be a useful surrogate marker for T cell activation that results in acute graft-versus-host disease (aGVHD). To determine if the sIL2-R concentration is a useful marker to help establish a diagnosis of aGVHD, serial sIL2-R concentrations were measured weekly for 4 weeks in 43 patients after allogeneic BMT. Grafts were from HLA-matched siblings (n = 33), 5/6 HLA-matched siblings (n = 3) or matched unrelated donors (n = 7). GVHD prophylaxis included cyclosporine A (CSA)/methotrexate (MTX) (n = 25), solumedrol/CSA (n = 15), or T cell depletion (n = 3). Twenty-three patients developed aGVHD (Grade I, 7; Grade II, 12; Grade III, 4) a median of 28 days after transplant. There was a significant association between a clinical diagnosis of aGVHD and an increase in the sIL2-R concentration (p < 0.001). The mean percent increase (+/-SE) over baseline for patients with a clinical diagnosis of aGVHD was 294% (+/-57%) by week 2 (n = 12), 431% (+/-116%) by week 3 (n = 14), and 650% (+/-315%) by week 4 (n = 9) after BMT. For each 100% increase over baseline, the likelihood of having aGVHD increased by 18%. Six of 20 patients without aGVHD became critically ill and exhibited marked increases in sIL2-R concentrations, similar to patients with a clinical diagnosis of aGVHD who never became critically ill. Fourteen patients without aGVHD who did not become critically ill exhibited negligible increases of sIL2-R in 2- to 4-week period after BMT. These data suggest that serial measurements sIL2-R concentration are helpful in establishing the diagnosis of aGVHD, but are not useful in the most acutely ill patients.

Human herpesvirus 8 (KSHV) contamination of peripheral blood and autograft products from multiple myeloma patients

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), has recently been identified within the bone marrow dendritic cells of multiple myeloma (MM) patients. This virus contains homologues to human cytokines such as IL-6 that could potentially stimulate myeloma cell growth and contribute to disease pathogenesis. Since mobilization chemotherapy may increase circulating dendritic cell numbers, we searched for HHV-8 in peripheral blood mononuclear cells (PBMCs) before and after mobilization chemotherapy given to MM patients. Furthermore, we determined if autograft purging using the CEPRATE SC device would reduce the percentage of HHV-8 infected stem cell products. Only two of the 39 PBMC samples collected prior to mobilization chemotherapy contained PCR detectable virus, yet nine of 37 PBMCs collected on the first day of leukapheresis had detectable HHV-8 (P = 0.016). HHV-8 was more frequently identified in autograft products before vs after Ceprate SC selection (40% vs 15%, P = 0.016). Although the role HHV-8 plays in myeloma pathogenesis remains unclear, these results imply that mobilization chemotherapy increases the numbers of circulating HHV-8-infected dendritic cells within the peripheral blood. In addition, CD34 selection of autograft products in MM patients may reduce the reintroduction of virally infected cells following high-dose chemotherapy. Bone Marrow Transplantation (2000) 25, 153-160.

Pharmacokinetics, dosimetry, and initial therapeutic results with 131I- and (111)In-/90Y-labeled humanized LL2 anti-CD22 monoclonal antibody in patients with relapsed, refractory non-Hodgkin's lymphoma

The pharmacokinetics, dosimetry, and immunogenicity of 131I- and (111)In-/90Y-humanized LL2 (hLL2) anti-CD22 monoclonal antibodies were determined in patients with recurrent non-Hodgkin's lymphoma. Fourteen patients received tracer doses of 131I-hLL2 followed 1 week later by therapeutic doses intended to deliver 50-100 cGy to the bone marrow. Another eight patients received (111)In-hLL2 followed by therapy with 90Y-hLL2 also delivering 50 or 100 cGy to the bone marrow. The blood T(1/2) (hours) for the tracer infusions of 131I-hLL2 was 44.2 +/- 10.9 (mean +/- SD) compared with 54.2 +/- 25.0 for the therapy infusions, whereas the values were 70.7 +/- 17.6 for (111)In-hLL2 and 65.8 +/- 15.0 for 90Y-hLL2. The estimated average radiation dose from 131I-hLL2 in tumors >3 cm was 2.4 +/- 1.9 cGy/mCi and was only 0.9-, 1.0-, 1.1-, and 1.0-fold that of the bone marrow, lung, liver, and kidney, respectively. In contrast, the estimated average radiation dose from 90Y-hLL2 in tumors >3 cm was 21.5 +/- 10.0 cGy/mCi and was 3.7-, 2.5-, 1.8-, and 2.5-fold that of the bone marrow, lung, liver, and kidney, respectively. No evidence of significant anti-hLL2 antibodies was seen in any of the patients. Myelosuppression was the only dose-limiting toxicity and was greater in patients who had prior high-dose chemotherapy. Objective tumor responses were seen in 2 of 13 and 2 of 7 patients given 131I-hLL2 or 90Y-hLL2, respectively. In conclusion, 90Y-hLL2 results in a more favorable tumor dosimetry compared with 131I-hLL2. This finding, combined with the initial anti-tumor effects observed, encourage further studies of this agent in therapeutic trials.

Rituximab (anti-CD20 monoclonal antibody) therapy for progressive intermediate-grade non-Hodgkin's lymphoma after high-dose therapy and autologous peripheral stem cell transplantation

We evaluated the response and toxicity of rituximab in the setting of progressive intermediate grade non-Hodgkin's lymphoma (NHL) after autologous peripheral stem cell transplantation (PSCT). Seven patients with a median age of 59 years (45-62), ECOG performance status 0-1, and CD20-positive diffuse large cell lymphoma with progression after PSCT were treated. All patients initially received 4-weekly infusions of rituximab (375 mg/m2). The maximum response was three CR and four PR. Median progression-free survival was 197 days (range 60-282). With a median follow-up of 204 (115-299) days, the patients' disease status is classified as two CR, one PR, and four PD. Four of five patients with ECOG performance status of 1 prior to treatment showed improvement to status 0 after treatment with rituximab. While follow-up is short, these results suggest that rituximab has significant activity in intermediate-grade non-Hodgkin's lymphoma that has relapsed after PSCT.

Multicenter phase III trial to evaluate CD34(+) selected versus unselected autologous peripheral blood progenitor cell transplantation in multiple myeloma

High-dose chemotherapy followed by autologous transplantation has been shown to improve response rates and survival in multiple myeloma and other malignancies. However, autografts frequently contain detectable tumor cells. Enrichment for stem cells using anti-CD34 antibodies has been shown to reduce autograft tumor contamination in phase I/II studies. To more definitively assess the safety and efficacy of CD34 selection, a phase III study was completed in 131 multiple myeloma patients randomized to receive an autologous transplant with either CD34-selected or unselected peripheral blood progenitor cells after myeloablative therapy. Tumor contamination in the autografts was assessed by a quantitative polymerase chain reaction detection assay using patient-specific, complementarity-determining region (CDR) Ig gene primers before and after CD34 selection. A median 3.1 log reduction in contaminating tumor cells was achieved in the CD34 selected product using the CEPRATE SC System (CellPro, Inc, Bothell, WA). Successful neutrophil engraftment was achieved in all patients by day 15 and no significant between-arm difference for time to platelet engraftment occurred in patients who received an infused dose of at least 2.0 x 10(6) CD34(+) cells/kg. In conclusion, this phase III trial demonstrates that CD34-selection of peripheral blood progenitor cells significantly reduces tumor cell contamination yet provides safe and rapid hematologic recovery for patients receiving myeloablative therapy.

A phase II multicenter trial of high-dose sequential chemotherapy and peripheral blood stem cell transplantation as initial therapy for patients with high-risk non-Hodgkin's lymphoma

The purpose of this study was to evaluate the safety and feasibility of front-line high-dose sequential (HDS) chemotherapy with peripheral blood stem cell (PBSC) transplantation in patients with newly diagnosed high-risk non-Hodgkin's lymphoma (NHL). Thirty-two patients with high-risk NHL (defined by the age-adjusted international index) underwent HDS chemotherapy followed by PBSC transplantation and consolidative radiotherapy. Twenty-eight patients (88%) had intermediate/high grade NHL and four patients (12%) had small noncleaved or lymphoblastic lymphoma. Twenty-four patients were classified as high-intermediate-risk (two risk factors) and eight patients were classified as high-risk (three risk factors). The five phases of HDS (see Fig. 1) consisted of Phase I (adriamycin, vincristine, and prednisone); Phase II (cyclophosphamide, filgrastim [G-CSF], and PBSC harvest); Phase III (methotrexate, leucovorin, vincristine; Phase IV (etoposide, filgrastim [G-CSF]); and Phase V (mitoxantrone, melphalan, autologous peripheral blood stem cell infusion, and filgrastim [G-CSF]). Radiation therapy was given to sites of previous bulk disease, 2400 cGy, (D + 30-100)]. Toxicity, engraftment, hospital utilization, overall survival, and relapse-free survival were evaluated. The high-dose sequential chemotherapeutic regimen was well tolerated. Treatment-related mortality was 6.25% with two deaths occurring secondary to sepsis and one death was caused by progressive disease. The major toxicity in Phase I-IV was grade 3 nausea/vomiting. The major toxicity in Phase V was grade 3 or 4 nausea/vomiting and mucositis. The median follow-up is 18.8 months (range 4-44 months). The overall survival (OS) and relapse-free survival (RFS) at 18 months for all patients were 78% (95% CI 37-90%) and 67% (95% CI 46-88%), respectively. The OS at 18 months for all patients, excluding the four patients with either small noncleaved or lymphoblastic lymphoma, was 82% (95% CI 65-98%) vs. 30% (95% CI 0-86%) (p = 0.0059). One patient in this latter group remains alive at 6 months follow-up. The RFS for all patients, excluding the four patients with either small noncleaved or lymphoblastic lymphoma, was 78% (95% CI 58-97%) vs. 0% (95% CI 0-0%) (p = 0.0004). High-dose sequential chemotherapy with initial PBSC transplantation is well tolerated and appears effective in high-risk NHL. Superior results were noted in patients with intermediate grade versus those with small noncleaved or lymphoblastic NHL.

bcl-2 gene hypomethylation and high-level expression in B-cell chronic lymphocytic leukemia

The bcl-2 gene becomes transcriptionally deregulated in the majority of low-grade non-Hodgkin lymphomas as a result of t(14;18) translocations that place the bcl-2 gene at 18q21 into juxtaposition with the Ig heavy-chain locus at 14q32. This chromosomal translocation or similar bcl-2 gene rearrangements involving the Ig light-chain genes have been reported to occur in some cases of B-cell chronic lymphocytic leukemia (B-CLL). We analyzed the structure, methylation, and expression of the bcl-2 gene in 20 cases of B-CLL or closely related variants of this lymphoproliferative disorder, including at least 16 typical examples of CD5+ B-CLL. None of the 20 specimens had evidence of bcl-2 gene rearrangements, based on Southern blot analysis using three different bcl-2 probes. However, immunoblot analysis using antibodies specific for the Bcl-2 protein showed that 14 of 20 cases (70%) contained levels of p26-Bcl-2 that were equal to or greater than those found in a t(14;18)-bearing lymphoma cell line. Furthermore, in 19 of 20 cases (95%), the Bcl-2 protein was present at levels that were 1.7- to 25-fold higher than in normal peripheral blood lymphocytes. These differences in the relative levels of Bcl-2 protein among cases of B-CLL appeared to be functionally significant, in that a preliminary analysis of 3 representative cases showed that CLL cells with higher levels of Bcl-2 protein survived longer in culture and were delayed in their onset of DNA degradation relative to CLL cells with lower Bcl-2 protein levels. Evaluation of the methylation status of the bcl-2 gene using the isoschizomers Msp I and Hpa II, and a probe corresponding to the first major exon of the gene showed complete demethylation of both copies of the bcl-2 gene in a region corresponding to a 2.4-kb Msp I fragment in all 20 cases of B-CLL. In contrast, analysis of 6 of 6 B-cell lines that harbor a t(14;18) was consistent with hypomethylation of only one of the two bcl-2 alleles. Neither copy of the bcl-2 gene was demethylated in this region in 5 of 5 lymphoid cell lines that lack this translocation. However, hypomethylation of the bcl-2 gene did not necessarily correlate with the relative levels of Bcl-2 protein present in the B-CLL cells, suggesting that additional mechanisms for regulating bcl-2 expression are involved.(ABSTRACT TRUNCATED AT 400 WORDS)