Identifying clinically relevant prognostic subgroups of postmenopausal women with node-positive hormone receptor-positive early-stage breast cancer treated with endocrine therapy: a combined analysis of ABCSG-8 and ATAC using the PAM50 risk of recurrence score and intrinsic subtype.

BACKGROUND: In the adjuvant treatment of hormone receptor-positive (HR+) breast cancer, variables like tumour size, grade and nodal status have great impact on therapy decisions. As most node-positive patients with HR+ breast cancer currently receive adjuvant chemotherapy improved methods for characterization of individuals' metastasis risk are needed to reduce overtreatment. PATIENTS AND METHODS: Tissue specimens from node-positive patients of the ABCSG-8 and ATAC trials who received adjuvant tamoxifen and/or anastrozole were included in this study. Analysing RNA from paraffin blocks using the PAM50 test, the primary objective was to evaluate the prognostic information of the risk of recurrence (ROR) score added to combined clinical standard variables in patients with one positive node (1N+) and in patients with two or three positive nodes (2-3N+), using log-likelihood ratio tests. RESULTS: At a median follow-up of 9.6 years, distant metastases occurred in 97 (18%) of 543 node-positive patients. In a multivariate analysis, the PAM50-derived ROR score provided reliable prognostic information in addition to and beyond established clinical factors for 1N+ (P < 0.0001) and 2-3N+ patients (P = 0.0002). Ten-year distant recurrence risk was significantly increased in the high-risk compared with the low-risk group derived from ROR score for 1N+ [25.5%, 95% confidence interval (CI) 17.5% to 36.1%versus 6.6%, 95% CI 3.3% to 12.8%] and compared with the combined low/intermediate risk group for 2-3N+ patients (33.7%, 95% CI 25.5% to 43.8% versus 12.5%, 95% CI 6.6% to 22.8%). Additionally, the luminal A intrinsic subtype (IS) exhibited significantly lower risk of distant recurrence compared with the luminal B subtype in 1N+ and 2-3N+ patients. CONCLUSION: PAM50 ROR score and IS can identify node-positive patient subgroups with limited risk of metastasis after endocrine therapy, for whom adjuvant chemotherapy can be spared. The PAM50 test is a valuable tool in determining treatment of node-positive early-stage breast cancer patients.

Predicting distant recurrence in receptor-positive breast cancer patients with limited clinicopathological risk: using the PAM50 Risk of Recurrence score in 1478 postmenopausal patients of the ABCSG-8 trial treated with adjuvant endocrine therapy alone.

BACKGROUND: PAM50 is a 50-gene test that is designed to identify intrinsic breast cancer subtypes and generate a Risk of Recurrence (ROR) score. It has been developed to be carried out in qualified routine hospital pathology laboratories. PATIENTS AND METHODS: One thousand four hundred seventy-eight postmenopausal women with estrogen receptor (ER)+ early breast cancer (EBC) treated with tamoxifen or tamoxifen followed by anastrozole from the prospective randomized ABCSG-8 trial were entered into this study. Patients did not receive adjuvant chemotherapy. RNA was extracted from paraffin blocks and analyzed using the PAM50 test. Both intrinsic subtype (luminal A/B, HER2-enriched, basal-like) and ROR score were calculated. The primary analysis was designed to test whether the continuous ROR score adds prognostic value in predicting distant recurrence (DR) over and above standard clinical variables. RESULTS: In all tested subgroups, ROR score significantly adds prognostic information to the clinical predictor (P<0.0001). PAM50 assigns an intrinsic subtype to all cases, and the luminal A cohort had a significantly lower ROR at 10 years compared with Luminal B (P<0.0001). Significant and clinically relevant discrimination between low- and high-risk groups occurred also within all tested subgroups. CONCLUSION(S): The results of the primary analysis, in combination with recently published results from the ATAC trial, constitute Level 1 evidence for clinical validity of the PAM50 test for predicting the risk of DR in postmenopausal women with ER+ EBC. A 10-year metastasis risk of <3.5% in the ROR low category makes it unlikely that additional chemotherapy would improve this outcome-this finding could help to avoid unwarranted overtreatment. CLINICAL TRIAL NUMBER: ABCSG 8: NCT00291759.

Initial clinical (phase I) trial of TLC D-99 (doxorubicin encapsulated in liposomes).

A liposome-encapsulated form of doxorubicin (TLC D-99), which was shown in preclinical toxicology to be less toxic to the gastrointestinal tract and myocardium than free doxorubicin, was administered by constant infusion (1.00-1.80 h) to 38 patients in single doses of 20, 30, 45, 60, 75, and 90 mg/m2 every 3 weeks and daily for 3 days at doses of 20, 25, and 30 mg/m2/day. The dose-limiting toxicity was leucopenia: the maximum tolerated doses were one at 90 mg/m2 and three at 25 mg/m2/day. Nausea, vomiting, and stomatitis were minimal or absent at each dose; alopecia was minor. Fever and chills were noted at most of the doses, and malaise was seen in some patients, especially at the higher doses. No hepatic, renal, or other organ toxicities were observed. Clinical cardiac toxicity was not observed in any patient; however, the cumulative doxorubicin dose was greater than 400 mg/m2 in only one patient. There was large variation among patients in estimated pharmacokinetic parameters and profiles. Higher plasma levels and dose intensities were achieved with TLC D-99 than were predicted for free doxorubicin. Liposome-encapsulated doxorubicin was well tolerated and produced less nausea, vomiting, and stomatitis than would be expected with free doxorubicin administered at equally myelosuppressive doses.

New site-directed polyclonal antibody maps N-terminus of occluded region of the non-transformed glucocorticoid receptor oligomer to within BUGR epitope.

Using a 17-mer synthetic peptide for immunization, a polyclonal antibody (WS933) directed against amino acid residues 395-411 of the mouse glucocorticoid receptor (GCR) has been raised and used to probe the significance of this region in forming the receptor oligomer and to localize the truncation site of the mutant GCR of the P1798 lymphosarcoma. This region of the receptor, which encompasses the BUGR epitope, is amino-terminal of and immediately adjacent to the DNA-binding domain. The polyclonal antibody WS933 reacted with both native and denatured forms of the wild-type mouse GCR as judged by its ability to shift the transformed receptor peak on Sephacryl S300 columns, to immunoadsorb the receptor to protein A Sepharose, and by immunoblot analysis where it identified the 98 kDa receptor protein in the cortisol-sensitive line of the P1798 mouse lymphosarcoma. WS933 also reacted with rat and rabbit GCR, but not human GCR. These characteristics were shared by the BUGR-2 monoclonal antibody. Unexpectedly, there were two highly significant differences between WS933 and BUGR-2. The first was the ability of WS933 to bind to the mutant 45 kDa GCR of the cortisol-resistant P1798 lymphosarcoma as judged by its capability of shifting the receptor peak on Sephacryl S300 columns. BUGR-2, in contrast, was unable to shift this mutant receptor peak. Secondly, WS933 was unable to react with the non-DNA-binding form of the wild-type (or mutant) GCR, whereas BUGR-2 could react with the non-DNA-binding form of the wild-type GCR. The first observation suggests that the truncation site of the mutant receptor may lie within a portion of the BUGR domain. Additionally, the second observation implies that at least part of the region lying within amino acid residues 395-411 of the mouse GCR is occluded in the receptor oligomer and that this site only becomes available upon transformation of the GCR to the DNA-binding form. This data provides the first mapping of the amino-terminus of the occluded region of the non-transformed receptor, and suggests that WS933 will be a useful probe for characterizing mutant as well as wild type glucocorticoid receptors.

Initial clinical trial of the macrophage activator muramyl tripeptide-phosphatidylethanolamine encapsulated in liposomes in patients with advanced cancer.

A phase I clinical trial of the macrophage activator, muramyl tripeptide-phosphatidylethanolamine has been carried out in 37 patients (47 courses) at doses of 0.01-6.0 mg/m2 intravenously twice weekly for 4 weeks. Activation of peripheral blood monocytes and drug toxicity were used as the parameters to monitor the trial. Toxicity was acute systemic responses of fever, chills, and hypertension without a clear dose response. No major organ-related toxicity was seen. A dose of 4.0 mg/m2 biweekly produced activation of blood monocytes; a dose of 6.0 mg/m2 produced inhibition. There was one complete response of 3 months duration in a patient with renal cell carcinoma with pulmonary metastases. The optimum dose for phase II studies is in the range of 1-4 mg/m2 twice weekly for 4 weeks, a dose that is well tolerated.

DNA binding of iproplatin and its divalent metabolite cis-dichloro-bis-isopropylamine platinum (II).

The quadrivalent second-generation platinum complex iproplatin and an in vivo divalent metabolite of iproplatin, cis-dichloro-bis-isopropylamine platinum (CIP) were tested for binding to DNA in vitro. DNA binding was determined according to radioactivity measured using [14C]-iproplatin and [14C]-CIP and also by platinum content. Results indicate that (a) iproplatin shows negligible binding to DNA, (b) CIP binds to DNA in a time-dependent fashion, and (c) the isopropylamine ligand is intact when CIP is bound to DNA. Glutathione (GSH) inhibits the binding of CIP to DNA, possibly by inhibiting binding to DNA of the aquated form of CIP.

Studies on the human metabolism of iproplatin.

We have previously shown that a significant portion of the total platinum in the plasma of patients receiving iproplatin is protein-bound. We have also identified cis-dichloro-bis-isopropylamine platinum(II) (CIP) as a major metabolite of iproplatin. To understand the nature of the bound platinum, we carried out in vitro comparative protein-binding studies for iproplatin and CIP. These studies indicate that when CIP is incubated in plasma, protein binding occurs, with a 2.7-h half-life for the disappearance of CIP; the parent complex does not bind and is stable in plasma for at least 48 h. The time dependence of protein binding with CIP suggests the formation of other chemical species from CIP that may be responsible for the observed protein binding. The results indicate that in patients receiving the drug, the reduction of iproplatin to CIP must take place intracellularly and that CIP or its protein-binding derivatives must efflux from the cells into the plasma. Efflux studies carried out to explore this possibility with cells in the whole blood showed that iproplatin was taken up into cells, but the efflux of protein-binding iproplatin metabolites did not occur. To understand further the nature of the metabolites of iproplatin, we carried out 195Pt-NMR (nuclear magnetic resonance) studies with urine from two patients who received a high dose of iproplatin (500 mg/m2). The predominant signals from the 195Pt-NMR corresponded to the divalent platinum complexes and not to quadrivalent complexes, indicating that the iproplatin metabolites in urine are divalent in nature.

Uptake and metabolism of iproplatin in murine L1210 cells.

Iproplatin is structurally unique among the platinum (Pt) agents in the clinic because it is a quadrivalent complex. On the basis of the redox parameters for the Pt(IV) and Pt(II) oxidation states in a chloride system, it has been suggested that Pt(IV) complexes will be reduced to Pt(II) complexes in a biological environment. To test this hypothesis, uptake and metabolism studies of [14C]-iproplatin were carried out in L1210 cells. The L1210 cells raised in DBA2/J mice were incubated in vitro with 50 and 100 microM [14C]-iproplatin at 37 degrees C in Hanks' balanced salt solution, and total uptake and radioactivity associated with acid-insoluble fractions were measured for up to 3 h. Under these conditions, the uptake of iproplatin was linear with time and increased with increasing concentrations of iproplatin in the medium. At all times measured, greater than 35% of radioactivity was associated with the acid-insoluble fraction, suggesting binding to macromolecules. The [14C]-labelled compounds in neutralized acid extracts of cells were separated by reverse-phase high-performance liquid chromatography (HPLC). Three labelled compounds were detected; based on chromatographic elution times, they appeared to be iproplatin, cis-dichloro-bis-isopropylamine platinum(II) (CIP), the reduction product of iproplatin, and a third compound more polar than iproplatin and CIP. The finding of free CIP and the macromolecular binding of radioactivity in the cells suggests that iproplatin is reduced intracellularly.

A phase I clinical trial of recombinant human tumor necrosis factor given daily for five days.

A phase I trial of human recombinant tumor necrosis factor (rH-TNF) has been carried out in patients with advanced solid tumors. Sixty-six courses of the drug were given by 1 h IV infusion, daily for 5 days to 33 patients at doses of 5, 10, 20, 30, 45, 60, and 80 x 10(4) U/m2/day. All patients received isotonic saline (up to 21/day) and either indomethacin or ketoprofen. Acute toxicity resembled that seen with the phase I study of a single dose (5). Dose limiting toxicity was acute, rapidly reversible, hepatic dysfunction and hypotension. Hypertension during drug infusion and dyspnea were marked in some patients. There was one complete and one minor response, both in patients with renal cell carcinoma. The dose of 80 x 10(4) U/m2/day x 5 was poorly tolerated and the recommended starting dose for phase II studies is 60 x 10(4) U/m2/day x 5. Caution is recommended in treating patients with pre-existing hepatic function abnormalities, hypertension, hypotension or significant obstructive airway disease.

Phase I trial of a new nitrosourea, CGP 6809, given every 2 weeks.

A phase I study was carried out on a new water-soluble nitrosourea, 6-deoxy-3,5 di-O-methyl 6-(3 methyl-3-nitrosoureido)-alpha-D-glucofuranoside (EDMN, CGP 6809), given every 2 weeks. A total of 18 patients received doses of 1, 2, 3, and 3.75 g/m2 as a 2- to 5-h infusion. Toxicity principally involved nausea and vomiting, hepatotoxicity, and abdominal pain. There was no evidence of cumulative toxicity. The dose of 3.75 g/m2 was not exceeded because in a previous phase I study, 4.5 g/m2 every 6 weeks was not tolerated; the recommended dose for phase II studies is 3.75 g/m2 every 2 weeks.

Identification of cis-dichloro-bis-isopropylamine platinum(II) as a major metabolite of iproplatin in humans.

Iproplatin is a quadrivalent second-generation platinum complex undergoing clinical evaluation. In plasma and urine of patients receiving this drug, iproplatin- and platinum-containing metabolites of iproplatin were separated by reverse-phase gradient high performance liquid chromatography. One of the metabolites was identified by cochromatography and electron impact mass spectrometry as cis-dichloro-bisisopropylamineplatinum(II), a metabolite formed by reduction of iproplatin. Incubation of iproplatin with ascorbic acid and cysteine, in vitro, indicates that iproplatin can be easily reduced to cis-dichloro-bis-isopropylamineplatinum(II) by reducing agents. It is hypothesized that the reduction of the quadrivalent complex iproplatin to cis-dichloro-bisisopropylamineplatinum(II) occurs intracellularly.

Phase I clinical trial of ethyl 6-deoxy-3,5-di-O-methyl 6-(3 methyl-3-nitrosoureido)-alpha-D-glucofuranoside (CGP 6809).

A phase I study of single i.v. doses of a new sugar containing nitrosourea 6-deoxy-3,5 di-O-methyl 6-(3 methyl-3-nitrosoureido)-alpha-D-glucofuranoside (CGP 6809, EDMN) has been carried out in 47 patients with advanced solid tumors. Nine dose levels between 200 and 4500 mg/m2 were examined. Nausea and vomiting were seen in most patients but were controlled with antiemetics. Myelosuppression was minimal. The dose-limiting toxicity was hepatotoxicity, occurring early (peak at days 2-4) and resolving rapidly. No cumulative toxicity was seen with an every 6 weeks schedule. Other toxicities were abdominal pain, diarrhea, arm pain, restlessness, and headache. Pharmacokinetic studies in 20 patients using an HPLC assay and in 5 patients using [14C]EDMN showed a short half-life, rapid plasma clearance, rapid metabolism, and minimal excretion of unchanged drug. There was one partial response in a patient with colon carcinoma. The recommended dose for phase II studies in 3750 mg/m2 every 6 weeks.

Pharmacokinetics of cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum IV (CHIP) in patients with advanced cancer.

The pharmacokinetics of a second-generation platinum (Pt) analog cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum IV (CHIP) have been studied in 12 patients at doses from 20 to 350 mg/m2. Three Pt species have been measured: total Pt and non-protein-bound Pt by atomic absorption spectrophotometry, and unchanged CHIP by separation on high-performance liquid chromatography followed by atomic absorption spectrophotometry. Plasma decay of total Pt was biexponential at all doses with a beta-phase half-life of 32.1-124 h. Plasma decay of filterable Pt was monoexponential at low doses but biexponential at high doses, with a terminal-phase half-life of 17.8-54.6 h. Plasma decay of unchanged CHIP was monoexponential at all doses, with a half-life of 0.64-1.27 h. Excretion of Pt after CHIP was rapid up to 10 h after the end of infusion and then slow. The total recovery of Pt was 15%-61% of the dose at 24 h in 19 patients. The data indicated that essentially all plasma Pt after 12 h is in the form of metabolites, most of which are protein-bound. The most striking difference between CHIP and reported data for cisplatin is the biexponential decay of non-protein-bound Pt.

Studies on the pharmacokinetics and metabolism of cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum(IV) in the dog.

cis-Dichloro-trans-dihydroxy-bis-isopropylamine platinum(IV) (CHIP), a new antineoplastic platinum compound, was administered iv to dogs at a dose of 10 mg/kg. Thin-layer chromatography and high-pressure liquid chromatography (HPLC) were used to evaluate the pharmacokinetics of total Pt and of unchanged drug separated from the metabolites in urine. Both chromatographic procedures indicated a half-life of 0.3-0.5 hr for the unchanged CHIP (based on urinary excretion rates). Decay of total Pt after administration of CHIP was biphasic, with an alpha-half-life of 0.6 hr and a beta-half-life of 39.4 hrs. The long beta-half-life thus appears to be due to the retention of metabolites. Unchanged CHIP was separated from two groups of more polar Pt-containing metabolites by HPLC, as well as from another less polar Pt-containing complex that is found in urine of untreated dogs to which CHIP was added. AFter the administration of CHIP, with the simultaneous decline in its level, the proportion of the very polar Pt-containing metabolite(s) accumulated in the dog urine. Unlike cisplatin, CHIP did not bind to plasma proteins in vitro.

In vitro effects of 4-hydroperoxycyclophosphamide on human immunoregulatory T subset function. I. Selective effects on lymphocyte function in T-B cell collaboration.

The alkylating agent cyclophosphamide may suppress or enhance immune responses in vivo but is inactive in vitro unless metabolized by microsomal enzyme activation. 4-hydroperoxycyclophosphamide (4-HC) is a synthetic compound that is spontaneously converted in aqueous solution to the active metabolites. In this report, we examined the in vitro sensitivity of functional human T cell subsets to 4-HC in a polyclonal B cell differentiation assay and in the generation of mitogen-induced suppressor cells for effector B cell function. Con A-induced T suppression of B cell differentiation is completely abrogated by a 1-h pretreatment of T cells at very low concentrations of between 10(-2) and 20 nmol/ml, whereas inducer T cell function is sensitive only to concentrations in greater than 40 nmol/ml. The effects of 4-HC on suppressor T cells appear to occur at concentrations that do not result in DNA cross-linking or decreased blastogenesis. Con A-induced T suppressors are generated from within the OKT4+, OKT8- subset and are sensitive to low-dose 4-HC only before activation, whereas differentiated suppressor cells are resistant to concentrations in greater than 80 nmol/ml. Low-dose 4-HC pretreatment of the B cell population results in abrogation of immunoglobulin secretion when treated B cells are cocultured with unfractionated T cells, however, this effect is completely reversible if pretreated B cells are cocultured with T cells devoid of suppressor activity. These results demonstrate that human presuppressor cells for B-effector function differentiate in response to Con A from the OKT4+, OKT8- subset and are exquisitely sensitive to low concentrations of CYP whereas mature suppressor and inducer functions are resistant to all but very high concentrations in vitro. The differential sensitivity of functional T and B cell subsets to 4-HC in vitro can be a very useful probe in dissecting immunoregulatory interactions with man.

Chemistry of nitrosoureas. Decomposition of Deuterated 1,3-bis(2-chloroethyl)-1-nitrosourea.

BCNU-alpha-d4 [1,3-bis(2-chloro-1,1-dideuterioethyl)-1-nitrosourea] and BCNU-beta-d4 [1,3-bis(2-chloro-2,2-dideuterioethyl)-1-nitrosourea] were synthesized and decomposed in buffered (pH 7.4)water. The products were analyzed by GC-MS. The deuterium distribution in the products is inconsistent with vinylcarbonium ion or diazochloroethane intermediacy but is consistent with a 2-chloroethylcarbonium ion intermediate with some rearrangement to the 1-chloroethylcarbonium ion and the cyclic chloronium ion.