W. David Henner

Double-Blinded Randomized Study of High-Dose Calcitriol Plus Docetaxel Compared With Placebo Plus Docetaxel in Androgen-Independent Prostate Cancer: A Report From the ASCENT Investigators

PURPOSE To compare the safety and activity of DN-101, a new high-dose oral formulation of calcitriol designed for cancer therapy, and docetaxel with placebo and docetaxel. PATIENTS AND METHODS Patients with progressive metastatic androgen-independent prostate cancer and adequate organ function received weekly docetaxel 36 mg/m2 intravenously for 3 weeks of a 4-week cycle combined with either 45 microg DN-101 or placebo taken orally 1 day before docetaxel. The primary end point was prostate-specific antigen (PSA) response within 6 months of enrollment, defined as a 50% reduction confirmed at least 4 weeks later. RESULTS Two hundred fifty patients were randomly assigned. Baseline characteristics were similar in both arms. Within 6 months, PSA responses were seen in 58% in DN-101 patients and 49% in placebo patients (P = .16). Overall, PSA response rates were 63% (DN-101) and 52% (placebo), P = .07. Patients in the DN-101 group had a hazard ratio for death of 0.67 (P = .04) in a multivariate analysis that included baseline hemoglobin and performance status. Median survival has not been reached for the DN-101 arm and is estimated to be 24.5 months using the hazard ratio, compared with 16.4 months for placebo. Grade 3/4 adverse events occurred in 58% of DN-101 patients and in 70% of placebo-treated patients (P = .07). Most common grade 3/4 toxicities for DN-101 versus placebo were neutropenia (10% v 8%), fatigue (8% v 16%), infection (8% v 13%), and hyperglycemia (6% v 12%). CONCLUSION This study suggests that DN-101 treatment was associated with improved survival, but this will require confirmation because survival was not a primary end point. The addition of weekly DN-101 did not increase the toxicity of weekly docetaxel.

Common Mutation in Methylenetetrahydrofolate Reductase Correlation With Homocysteine Metabolism and Late-Onset Vascular Disease

BACKGROUND Increased homocysteine levels are a risk factor for atherosclerosis and its sequelae. A common genetic mutation in methylenetetrahydrofolate reductase (MTHFR), an enzyme required for efficient homocysteine metabolism, creates a thermolabile enzyme with reduced activity. We determined the prevalence of this mutation in many subjects with and without vascular disease and related it to homocysteine and folate levels. METHODS AND RESULTS DNA from 247 older subjects with vascular disease and 594 healthy subjects without vascular disease (in three different control groups) was screened for the MTHFR 677 C-to-T mutation. Within each group, 9% to 17% of the subjects were homozygous for this mutation, and the mutant allele frequency was 31% to 39%. The genotype distributions, homozygote frequencies, and allele frequencies did not differ significantly between the study groups. In the vascular disease subjects, despite significantly lower folate levels in MTHFR homozygotes, there was no significant difference in homocysteine levels among the MTHFR genotype groups. The negative slope of the regression line relating homocysteine and folate was significantly steeper for those with a homozygous MTHFR mutation compared with those without this mutation. CONCLUSIONS Although the thermolabile MTHFR mutation is very common, it does not appear to be a significant genetic risk factor for typical late-onset vascular disease. Because MTHFR homozygotes have increased homocysteine with low folate levels, this mutation may contribute to early-onset or familial vascular disease. The genotype dependence of the folate-homocysteine correlation further suggests that homozygotes for this mutation may have both an exaggerated hyperhomocysteinemic response to folic acid depletion and a better response to folic acid therapy.

A Phase I trial of pulse calcitriol in patients with refractory malignancies: pulse dosing permits substantial dose escalation.

Calcitriol is the principal biologically active metabolite of vitamin D. Calcitriols activity against many neoplasms is well documented, but calcitriols therapeutic application has been hampered by predictable hypercalcemia when it is given daily. Because laboratory data has suggested that intermittent exposure to high levels of calcitriol may be sufficient to produce antiproliferative effects, the authors developed a Phase I trial to determine the maximal tolerated dose, dose‐limiting toxicity, and the pharmacokinetic profile of calcitriol given weekly by mouth.

Multicenter Validation of a 1,550-Gene Expression Profile for Identification of Tumor Tissue of Origin

PURPOSE Malignancies found in unexpected locations or with poorly differentiated morphologies can pose a significant challenge for tissue of origin determination. Current histologic and imaging techniques fail to yield definitive identification of the tissue of origin in a significant number of cases. The aim of this study was to validate a predefined 1,550-gene expression profile for this purpose. METHODS Four institutions processed 547 frozen specimens representing 15 tissues of origin using oligonucleotide microarrays. Half of the specimens were metastatic tumors, with the remainder being poorly differentiated and undifferentiated primary cancers chosen to resemble those that present as a clinical challenge. RESULTS In this blinded multicenter validation study the 1,550-gene expression profile was highly informative in tissue determination. The study found overall sensitivity (positive percent agreement with reference diagnosis) of 87.8% (95% CI, 84.7% to 90.4%) and overall specificity (negative percent agreement with reference diagnosis) of 99.4% (95% CI, 98.3% to 99.9%). Performance within the subgroup of metastatic tumors (n = 258) was found to be slightly lower than that of the poorly differentiated and undifferentiated primary tumor subgroup, 84.5% and 90.7%, respectively (P = .04). Differences between individual laboratories were not statistically significant. CONCLUSION This study represents the first adequately sized, multicenter validation of a gene-expression profile for tissue of origin determination restricted to poorly differentiated and undifferentiated primary cancers and metastatic tumors. These results indicate that this profile should be a valuable addition or alternative to currently available diagnostic methods for the evaluation of uncertain primary cancers.

High-dose weekly oral calcitriol in patients with a rising PSA after prostatectomy or radiation for prostate carcinoma

In preclinical systems, calcitriol, the natural vitamin D receptor (VDR) ligand, has been found to demonstrate antiproliferative effects, although concentrations > 1 nM are required. Unlike daily dosing, weekly administration of oral calcitriol can safely achieve such blood calcitriol concentrations. This study sought to define the long‐term toxicity of this regimen and measure its effect on serum prostate specific antigen (PSA) levels in patients with hormone‐naïve prostate carcinoma.

Intermittent chemotherapy in patients with metastatic androgen-independent prostate cancer: results from ASCENT, a double-blinded, randomized comparison of high-dose calcitriol plus docetaxel with placebo plus docetaxel.

Survival in patients with metastatic, chemotherapy‐naive, androgen‐independent prostate cancer (AIPC) is improved with 10 to 12 cycles of docetaxel‐containing chemotherapy but further management is undefined. In the current study, the authors examined retreatment with the same regimen after a treatment holiday.

C-reactive protein as a prognostic marker for men with androgen-independent prostate cancer: results from the ASCENT trial.

Studies of cancer risk and molecular carcinogenesis suggest a role for inflammation in cancer development and progression. The authors sought to determine whether specific blood proteins associated with inflammation predict for outcomes in men with metastatic androgen‐independent prostate cancer (AIPC) who are initiating docetaxel‐based chemotherapy.

Weekly high-dose calcitriol and docetaxel in advanced prostate cancer☆

Novel treatment regimens for androgen-independent prostate cancer (AIPC) are needed because currently available approaches have not been shown to improve survival. Docetaxel provides a good foundation for new therapeutic combinations because of its promising single-agent activity against prostate cancer and its favorable tolerability profile, particularly when administered weekly. In both tissue culture and animal models of prostate cancer, calcitriol (the biologically active form of vitamin D) enhanced the activity of docetaxel, paclitaxel, and platinum compounds. These effects were particularly notable at supraphysiologic calcitriol concentrations. Weekly calcitriol dosing is associated with minimal toxicity and permits substantial dose escalation over the daily schedule. A weekly calcitriol dose of 0.5 microg/kg produces plasma calcitriol levels 25-fold higher than the physiologic range. In a preclinical study at the Oregon Health Sciences University, calcitriol 5 micromol/L plus docetaxel 0.15 nmol/L was at least additive in inhibiting PC-3 colony formation. A phase II study is evaluating weekly administration of 0.5 microg/kg calcitriol orally on day 1 followed by 36 mg/m(2) docetaxel intravenously on day 2 in patients with AIPC (repeated for 6 consecutive weeks of each 8-week cycle). At the time of a preliminary analysis, 11 patients had been enrolled and were actively being treated. All 5 patients who had completed 8 weeks of calcitriol/docetaxel treatment achieved prostate-specific antigen (PSA) reductions of > or =50%. Two of these patients had confirmatory assessments, both meeting the formal PSA response criteria. Treatment has been well tolerated, with 1 patient experiencing a self-limited grade 3 toxicity and no patients experiencing grade 4 or 5 toxicities.

Toxicity and efficacy of carboplatin and etoposide in conjunction with disruption of the blood-brain tumor barrier in the treatment of intracranial neoplasms

CARBOPLATIN AND ETOPOSIDE have been investigated in preclinical studies and a limited toxicity study in 13 patients; these studies have established carboplatin and etoposide as a tolerable combination when administered with blood-brain barrier disruption. The studies also found a predictable dose-limiting toxicity of myelosuppression. Subsequently, a broad efficacy trial of this regimen was carried out. A total of 34 patients, ranging in age from 7 to 72 years, underwent a combination chemotherapy regimen of carboplatin (200 mg/m2 administered intra-arterially) and etoposide (200 mg/m2 administered intravenously) administered with blood-brain barrier disruption on each of 2 consecutive days every 28 days. The diagnoses included glioblastoma multiforme (n = 3), malignant astrocytoma (n = 8), malignant astrocytoma-oligodendroglioma (n = 1), primitive neuroectodermal tumor (n = 4), disseminated germ cell tumor of the central nervous system (CNS) (n = 6), CNS lymphoma (n = 7), and metastatic carcinoma (n = 5). The major toxicity observed in patients treated with multiple courses of this regimen was the expected reversible myelosuppression and an unexpected, irreversible high-frequency hearing loss. Of these 34 patients, 22 had measurable disease, and 9 radiographic responses (50% or more decrease in enhancing tumors) were observed in these patients. Carboplatin and etoposide with blood-brain barrier disruption is an active regimen in the treatment of malignant astrocytomas and has shown dramatic responses in primitive neuroectodermal tumors and CNS lymphoma. Additionally, the durability of responses in patients with disseminated CNS germ cell tumors is encouraging. However, such therapy is associated with unexpected high-frequency hearing loss; even so, on the basis of the favorable responses in patients with primitive neuroectodermal tumors, germ cell tumors, and lymphomas, the study of this regimen for those tumors is being extended in a multiinstitutional trial that also includes cytoxan to further evaluate the potential enhanced drug delivery.

Validation and Reproducibility of a Microarray-Based Gene Expression Test for Tumor Identification in Formalin-Fixed, Paraffin-Embedded Specimens

Tumors whose primary site is challenging to diagnose represent a considerable proportion of new cancer cases. We present validation study results for a gene expression-based diagnostic test (the Pathwork Tissue of Origin Test) that aids in determining the tissue of origin using formalin-fixed, paraffin-embedded (FFPE) specimens. Microarray data files were generated for 462 metastatic, poorly differentiated, or undifferentiated FFPE tumor specimens, all of which had a reference diagnosis. The reference diagnoses were masked, and the microarray data files were analyzed using a 2000-gene classification model. The algorithm quantifies the similarity between RNA expression patterns of the study specimens and the 15 tissues on the test panel. Among the 462 specimens, overall agreement with the reference diagnosis was 89% (95% CI, 85% to 91%). In addition to the positive test results (ie, rule-ins), an average of 12 tissues for each specimen could be ruled out with >99% probability. The large size of this study increases confidence in the test results. A multisite reproducibility study showed 89.3% concordance between laboratories. The Tissue of Origin Test makes the benefits of microarray-based gene expression tests for tumor diagnosis available for use with the most common type of histology specimen (ie, FFPE).