Characterization of glioma-cells derived from human polyomavirus-induced brain-tumors in hamsters

Intracerebral injection of human polyomavirus, JCV, into neonatal hamsters causes tumors of,glial origin. HJC is an established cell Line derived from a JCV-induced mixed hamster brain tumor with astrocytic and ependymal components. Flow cytometric and immunohistochemical analysis of HJC suggests that it is comprised of a mixed population of cells all of which contain the JCV early protein, T-antigen, in the nuclei. Five individual clonal lines, called HJC-15a to HJC-15e, were isolated by limiting dilution and were found to exhibit distinct morphological characteristics with 25-30% variation in their sizes. It was evident that each clone has unique growth rates, doubling times, and cell cycle parameters with different G(1), S, and G(2) phase times. All clonal cells showed the presence of the JCV early protein in the nucleus. Of interest was the observation from immunoprecipitation and Western analysis indicating qualitative and quantitative differences in the T-antigen isoforms produced in these cells. Similar to the parental clone, HJC-15b produced two distinct forms of JCV T-antigen isoforms, 88 kDa and 92 kDa proteins. In addition, HJC-15c was able to produce a 23-25 kDa protein which was recognized by anti-T-antigen antibody. The activity of cyclin-dependent kinases, in particular cdc2, was higher in HJC-15c than in the other cell lines. The data presented herein indicates that glioblastomas induced by viral T-antigen expression are composed of a multitude of distinct cells that possess a variety of different characteristics.

Identifying chemokine receptor signals required for thymic settling (36.26)

T cell generation requires the recruitment of bone marrow derived hematopoietic precursors to the thymus via the bloodstream. The chemokine receptor CCR9 and the selectin ligand PSGL-1 each independently support progenitor recruitment to the unirradiated thymus, but progenitors lacking each are not restricted from thymic entry. Hence, additional molecules are likely at work. We now show that the chemokine receptor CCR7 is also involved in this process, as CCR7-/- progenitors are impaired in thymic settling. Furthermore, mice lacking both CCR7 and CCR9 have severe reductions in the number of early intrathymic progenitors, and in competitive assays CCR7-/-CCR9-/- progenitors are almost completely restricted from thymic settling. The compensatory proliferation of rare intrathymic progenitors can allow CCR7-/-CCR9-/- thymi to achieve near-normal cellularity despite severely impaired settling by circulating progenitors. These studies, however, focused on the signals used in unirradiated mice. The mechanisms involved in reconstituting a lethally-irradiated thymus remain poorly defined. We found that during a brief period following irradiation, CCR7-/-CCR9-/- cells are now capable of thymic setttling. Together, these observations illustrate the critical role of chemokine receptor signaling in thymic settling and help to clarify the cellular identity of the physiologic thymic settling progenitors.

A phase II study of two dosing regimens of GSK 1363089 (GSK089), a dual MET/VEGFR2 inhibitor, in patients (pts) with papillary renal carcinoma (PRC)

5103

Background: GSK089 is a potent, orally available small molecule inhibitor of MET and VEGFR2. Activating mutations and/or amplifications in MET have been described in pts with PRC. Two of 4 PRC pts treated with intermittent dosing of GSK089 on a Phase I study sustained partial responses (PR) for 1 and > 3 years respectively. The aim of the current study is to evaluate the efficacy, safety and tolerability of 2 dosing regimens of GSK089 as a single agent in pts with advanced sporadic PRC (SPRC) or hereditary PRC (HPRC). Methods: Adults with advanced PRC are enrolled in 2 cohorts with different dosing schedules of GSK089: cohort 1) 240 mg/day on days 1–5 of every 14 days (5-on/9-off); cohort 2) 80 mg daily. Pts are stratified based on status of MET-pathway activation (activating MET mutation, MET [7q31] amplification, or trisomy 7). The primary endpoint is RECIST response rate, assessed every 8 weeks. Plasma markers reflecting potential effects of MET inhibition and anti-VEGF therapy are analyzed. Results: As of December 15, 2008, 37 pts were enrolled in the 5-on/9-off cohort (19 with MET activation including 5 HPRC, 18 SPRC without MET activation or unknown MET status), and 16 pts in the daily dosing cohort (2 with HPRC, 14 SPRC with unknown MET status). Enrollment is ongoing in cohort 2. In cohort 1, of the 35 evaluable pts, 4 pts (2 HPRC and 2 SPRC) had confirmed PRs and 27 had stable disease (SD) as best response with 6 ≥12mo, 3 ≥ 9mo and 3 ≥ 6mo. Four of 5 HPRC pts (1 not evaluated) had shrinkage (15–53%) in all measurable tumors. Twenty-three SPRC pts had shrinkage (2–58%) in the sum of measurable tumors. In cohort 2, of the 9 evaluable pts, 2 (both SPRC) had confirmed PRs, and 7 had SD. The most frequent adverse events (AEs) associated with GSK089 were fatigue, hypertension, nausea, vomiting, diarrhea, and increased ALT/AST, primarily grades 1 and 2. Preliminary results from cohort 1 indicated that plasma shed Met (sMET) and VEGF increased and sVEGFR2 decreased after 2 cycles with changes maintained after 4 cycles. Conclusions: GSK089 is well tolerated and demonstrates anti-tumor activity in pts with PRC with both 5-on/9-off and daily dosing. VEGF, sVEGFR2, and sMET are promising pharmacodynamic markers for biological activity of GSK089.

[Table: see text]

Phase II study of 2-methoxyestradiol NanoCrystal dispersion (2ME2) alone and in combination with sunitinib (SU) in patients with metastatic renal cell carcinoma (mRCC) progressing on SU

e16116

Background: Panzem NCD (2ME2) is a non-estrogenic derivative of estradiol with antiproliferative and antiangiogenic activity that downregulates HIF-1α. One mechanism of VEGFR TKI failure may be upregulation of HIF-1α. We hypothesized that 2ME2 may have single-agent activity in pts who previously progressed on SU and that addition of 2ME2 may restore response in pts progressing on SU. Methods: Pts with clear cell mRCC who had previously received or were currently receiving SU with disease progression were eligible. Pts who had previously received SU were treated with 2ME2 alone (arm A). Pts currently on SU continued on the 4:2 schedule, with the addition of 2ME2 (arm B). All pts received 2ME2 at 1,500 mg PO TID, repeated in 6 wk cycles. The primary endpoint was objective response (OR) rate by RECIST. An exploratory endpoint was metabolic response on FDG-PET. Simon optimal 2-stage design was used with plans to enroll 21 pts/arm, and if activity was seen to continue enrollment for a total of 41 pts/arm. Results: 17 pts were enrolled (A: 10; B: 7). Median number of cycles on study was 1 (range <1 to 5). A pt remains on study in cycle 8. Adverse events (AE) of grade 3 or greater occurred in 4 pts (29%). Most frequent AE were: fatigue (71%), diarrhea (50%), dysgeusia (29%), anemia or decreased hemoglobin (29%), and anorexia (21%). Reasons for treatment discontinuation include: disease progression (7), pt/doctor discretion (3), AE (3), and noncompliance (1). No ORs by RECIST were seen. Conclusions: 2ME2 appears to have some single-agent activity, with an MR in a pt removed from study due to AE and a metabolic PR (ΔSUVmax -84%) in a pt with SD by RECIST. With 6/17 pts discontinuing therapy before meeting any OR endpoint, 2ME2 was not tolerable in this population. The study was closed to accrual knowing that a more promising 2ME2 analog is currently under development for oncologic use. The rationale to target HIF-1α after (and during) SU therapy remains of interest. This study design provides a unique way to assess both single-agent and rational combination strategies in pts with mRCC and should be utilized with other agents to seek evidence for clinical activity.

[Table: see text]

Integrated report of the phase 2 experience with XL999 administered IV to patients (pts) with NSCLC, renal cell CA (RCC), metastatic colorectal CA (CRC), recurrent ovarian CA, acute myelogenous leaukemia (AML), and multiple myeloma (MM)

3591

Background: XL999 is a potent spectrum-selective inhibitor of tyrosine kinases including VEGFR2/KDR, FGFR1/3, PDGFR-β, FLT3, RET, KIT, & SRC. A Ph 1 study in pts w/advanced malignancies has shown anti-tumor activity (3 PRs &10 SD lasting 3–26+ months) DLTs were cardiac failure & transaminase elevation. Methods: XL999 is being investigated in 6 Ph 2 trials. Pts w/histologically confirmed NSCLC, RCC, CRC, recurrent ovarian CA, AML, & MM were enrolled. The primary objectives of these independent studies are to determine response rate and further evaluate safety and tolerability of XL999. The secondary objectives are to assess PFS, duration of response & OS. Pts receive a once wkly 4hr IV administration of XL999 (2.4 mg/kg). Tumor response is assessed every 8 wks. Results: A total of 79 pts were treated. A confirmed PR was reported in 1/ 9 pts w/NSCLC. An additional 2 pts have SD at 2 & 3 months w/1 showing tumor shrinkage (24%). Two of 11 pts w/RCC have SD at 2 & 4 months. Of 14 pts enrolled w/AML, 1 of 3 with an activating FLT3 mutation had a PR, and 8 of 10 w/circulating myeloblasts had >50% reduction in myeloblasts. AEs = Grade 2 in =10% of pts related to XL999 included N/V, constipation, diarrhea, dry mouth, oral hypoesthesia, fatigue, pyrexia, dizziness, dysguesia, & hypertension. Cardiovascular (CV) events considered SAEs were reported in 11 pts (14%), and all but 1 occurred with the 1st dose of XL999.These events were characterized by ST /T wave changes in ECG,LVEF decreases and /or troponin elevation. Most pts with CV SAEs recovered to baseline within 2–3 wks upon withdrawl of further XL999. Conclusions: XL999 administered IV at a dose of 2.4mg/kg wkly was associated w/CV AEs, the majority of which were associated w/the 1st dose and were generally reversible upon XL999 discontinuation. XL999 shows preliminary evidence of anti- tumor activity in pts w/NSCLC & AML.

[Table: see text]

A phase II study of the c-Met RTK inhibitor XL880 in patients (pts) with papillary renal-cell carcinoma (PRC)

15601

Background: XL880 is a novel inhibitor of receptor tyrosine kinases targeting MET and VEGFR2/KDR. (IC 50 for MET 0.4nM and KDR 0.8 nM). PRC is a rare (10–15%) subtype of kidney cancer which is notoriously resistant to systemic treatment. The familial form of PRC is associated with germline activating mutations of MET, while amplification and overexpression of MET is seen in the sporadic form. In an ongoing phase I dose escalation study of XL880 in forty patients with advanced solid tumors, five partial responses (PRs) were noted in 3 of 4 treated patients with PRC, and in two pts with thyroid cancer. The MTD in this study was 3.6 mg/kg of XL880 administered orally daily for 5 consecutive days every 2 weeks. Methods: In this phase 2 study, XL880 is administered orally as a single agent at a dose of 240 mg on days 1–5 of each 14 day cycle. Previously untreated pts with a histologic diagnosis of metastatic PRC are eligible and are stratified based on the presence or absence of MET germline mutations. Planned enrollment is 15 evaluable pts in each stratum. Inclusion criteria also include ECOG performance status < 3 and absence of brain metastases. Tumor response is assessed every 8 weeks by RECIST criteria. Archival primary tumor and lymph node metastasis were collected for pharmacodynamic assessments. Results: To date, 6 pts have been enrolled and received XL880. Five pts have tested negative for MET germline mutations; results for one pt are pending. Of 3 pts with at least one post baseline tumor assessment, 1 pt has demonstrated a PR and two pts have demonstrated stable disease > 3 months, one of whom has improvement in bone scan and bone pain. Hypertension has been reported in 2 pts who responded to anti- hypertensive treatment. Two SAEs have been reported as unrelated; pulmonary embolism and intratumoral hemorrhage. MET expression was detected in untreated primary and metastatic tumor. Reduction in Ki67, and an increase in TUNEL labeling were observed in the post treatment sample. Conclusions: XL880 is the 1st orally available small molecule inhibitor of MET to enter the clinic and appears to be generally well tolerated. Anti-tumor activity has been observed and XL880 may represent an active treatment option for pts with PRC. Enrollment continues and updated results will be presented.

No significant financial relationships to disclose.

Phase II trial of iboctadekin (rhIL-18) on a daily X 5 schedule in metastatic melanoma (MM)

10043

Background: Interleukin-18 (IL-18) is an immunostimulatory cytokine with potent antitumor activity in preclinical models. Two phase I studies of recombinant human (rh) IL-18 explored a wide dose range (0.03–1.0 mg/kg) without reaching a maximum tolerated dose (MTD) on the daily × 5 schedule. Pharmacodynamic data including inflammatory cytokine production and activation of lymphocyte subsets revealed optimal biologic activity at the lower end of the dose range (0.01–0.2 mg/kg) as did 2 unconfirmed partial responses (PRs) in a MM and a renal cancer patient (pt) at 0.1 mg/kg. Methods: An open-label, randomized, phase II trial in 60 adult pts with previously untreated MM was conducted to evaluate the efficacy and safety of rhIL-18 administered as a 2-hour IV infusion daily × 5 every 28 days for 6 cycles. Pts with PS ≤ 1, without known CNS involvement, and with adequate end organ function were randomized in stage 1 to 3 dose levels of IL-18 stratified according to AJCC M stage 1a/b vs. 1c. Two confirmed responses for a given dose level in Stage 1 were required to enroll 20 additional pts/level in Stage 2. The 1° objective was determination of overall response rate (ORR) for each dose level. Progression-free survival (PFS), tolerability, and immunogenicity were 2° endpoints. Results: 64 pts were treated at 3 dose levels. Nine pts remain on study. One pt experienced a confirmed PR. Based on preliminary data, the difference in PFS 6 months (mos) was significant (p=0.03) for 0.01 vs 0.1 mg/kg. Most common toxicities were mild to moderate fever, rigors, chills, n/v, and headache. Anti-IL18 antibody (Ab) development correlated with dose level. No clinically significant adverse events were associated with Ab development. Conclusion: Iboctadekin has an acceptable tolerability profile and has activity in MM but insufficient confirmed responses have been observed at this time to initiate Stage 2. Preliminary PFS 6 months indicates an advantage for pts treated at the lowest dose.

[Table: see text]

[Table: see text]

Kidney cancer: the Cytokine Working Group experience (1986-2001): part II. Management of IL-2 toxicity and studies with other cytokines

The Cytokine Working Group (CWG) was initially established in 1986 as the Extramural IL-2/LAK Working Group. With funding from the National Cancer Institute (NCI), the CWG was mandated to confirming data regarding the efficacy of the high-dose interleukin-2 (IL2)/lymphokine-activated killer cell (LAK cell) regimen piloted at the NCI in the treatment of renal cell cancer. Since those initial studies, the CWG has conducted a series of clinical trials, often with correlative immunologic investigations, to evaluate combination immunotherapy in attempts to enhance the efficacy of IL-2 or to reduce toxicity. Subsequently, the CWG conducted trials to demonstrate the activity of lower-dose outpatient combination cytokine regimens to help determine their role in the armamentarium of treatment for metastatic renal cell cancer. This has culminated in a phase III randomized trial comparing the activity of high-dose IL-2 with the activity of outpatient IL-2 plus interferon-alpha. The CWG also has honed the management of both high-dose IL-2 and outpatient IL-2 regimens to make these safer in the hands of experienced clinicians. In addition, the CWG has produced a series of carefully conducted clinical trials of new cytokines, again attempting to define their clinical efficacy as anticancer agents. These include studies of IL-4, IL-6, and IL-12. Currently, the CWG is conducting studies with new approaches to IL-2 therapy, as well as planning trials with new agents for treatment of renal cell cancer. This review describes these efforts conducted over the past 15 yr.

Kidney cancer: the Cytokine Working Group experience (1986-2001): part I. IL-2-based clinical trials

The Cytokine Working Group (CWG) was initially established in 1986 as the Extramural IL-2/LAK Working Group. With funding from the National Cancer Institute (NCI), the CWG was mandated to confirming data regarding the efficacy of the high-dose interleukin-2 (IL2)/lymphokine-activated killer cell (LAK cell) regimen piloted at the NCI in the treatment of renal cell cancer. Since those initial studies, the CWG has conducted a series of clinical trials, often with correlative immunologic investigations, to evaluate combination immunotherapy in attempts to enhance the efficacy of IL-2 or to reduce toxicity. Subsequently, the CWG conducted trials to demonstrate the activity of lower-dose outpatient combination cytokine regimens to help determine their role in the armamentarium of treatment for metastatic renal cell cancer. This has culminated in a phase III randomized trial comparing the activity of high-dose IL-2 with the activity of outpatient IL-2 plus interferon-alpha. The CWG also has honed the management of both high-dose IL-2 and outpatient IL-2 regimens to make these safer in the hands of experienced clinicians. In addition, the CWG has produced a series of carefully conducted clinical trials of new cytokines, again attempting to define their clinical efficacy as anticancer agents. These include studies of IL-4, IL-6, and IL-12. Currently, the CWG is conducting studies with new approaches to IL-2 therapy, as well as planning trials with new agents for treatment of renal cell cancer. This review describes these efforts conducted over the past 15 yr.

Phase II trial of interleukin 2, interferon alpha, and 5-fluorouracil in metastatic renal cell cancer: a cytokine working group study

The purpose of this study was to evaluate the potential efficacy of alternating two outpatient regimens for the treatment of metastatic renal cell cancer. These regimens consisted of 4 weeks of recombinant interleukin 2 (rIL-2) plus IFN-alpha2B followed by 4 weeks of 5-fluorouracil plus IFN-alpha2B. Fifty patients meeting eligibility criteria of previous Cytokine Working Group studies were treated on an outpatient basis. Patients received s.c. rIL-2 (Proleukin; Chiron, Emeryville, CA) during weeks 1-4 of the 8-week regimen. During weeks 1 and 4, the dosage for rIL-2 was 10 MIU/m2 twice daily on days 3-5, and the dosage for IFN-alpha2B (Intron; Schering Plough, Kenilworth, NJ) was 6 MIU/m2 on day 1. During weeks 2 and 3, the dosage for rIL-2 was 5 MIU/m2 on days 1, 3, and 5, and the dosage for IFN-alpha2B was 6 MIU/m2 on days 1, 3, 5. During weeks 5-8, 5-fluorouracil (750 mg/m2) was administered once weekly by i.v. infusion, and IFN-alpha2B (9 MIU/mZ) was administered as a s.c. injection three times weekly. Throughout the treatment, an assessment of quality of life was made and a symptom-distress scale was evaluated. There were two patients with complete responses (CRs) and seven with partial responses (PRs) for an objective response rate of 18% (95% confidence interval, 10-25). The median response duration was 8 months (range, 3-51+ months). The CRs lasted 5 months and 51+ months and the PRs ranged from 3+ to 18 months. After completing at least one course of treatment, eight patients (three with PR, one with minor response, four with stable disease) became CRs after surgery for remaining metastatic disease. Six remain alive at 43+ to 53+ months, and 5 remain disease-free since surgery. The median survival of the study group is 17.5 months, with a maximal follow-up of 53+ months. The range in survival is 1-53+ months. Toxicity was primarily constitutional. and treatment modifications were designed to maintain toxicity at grade 2/3. The most common toxicities during treatment with IL-2/IFN were fatigue, nausea/vomiting, anorexia, skin reaction, diarrhea, fever, and liver enzyme elevations. One-third had central nervous system toxicity (headache, depression, insomnia). During 5FU/IFN treatment, 49 of 50 patients experienced grade 2/3 myelosuppression during course 1. Eight patients experienced grade 4 toxicities. In conclusion, the activity of this alternating regimen is similar to that of IL-2/IFN alone, given in 4-week cycles. The addition of 5FU/IFN failed to increase the efficacy and added new toxicity (myelosuppression). This report does not confirm the results previously reported for either alternating or simultaneous administration of these three agents. Because 5FU does not appear to add to the antitumor activity of IL-2-based therapy for renal cancer, current efforts are directed toward a Phase III randomized comparison of high-dose i.v. bolus inpatient IL-2 treatment versus treatment with outpatient s.c. injection of IL-2 plus IFN.

Preventive practicum training in healthcare organizations. The Meharry model

BACKGROUND

Practicum training for preventive medicine residents often occurs in agencies whose community is geographically defined and whose governance is closely linked to public election. We were unsure about the financial ability of such departments to support training and are concerned that over-reliance on traditional health departments might not be best for either medically indigent populations or preventive medicine. We, therefore, sought to apply a public health model--based on a strategic partnership between nursing and preventive medicine--to a large health care organization. The result was formation of a mini-health department, suitable for fully accredited preventive medicine practicum training, within the Alvin C. York Veterans Affairs Medical Center, Murfreesboro, TN. This Center serves a defined population of 21,594 patients and about 1600 employees. The theoretical framework for the new department was based on demonstration of a close fit between the competencies expected of preventive medicine physicians by the American College of Preventive Medicine (ACPM) and activities required by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). Because of JCAHO requirements, many healthcare organizations already pay for preventive medicine services.

CONCLUSIONS

By placing preventive medicine training faculty into existing budget slots at our institution, systemwide personnel costs for prevention decreased by about $36,000 per year, even as personnel funding for preventive medicine physicians increased from about $24,000 to $376,000 per year. Moreover, there was dramatic, sustained improvement in 17 indicators of preventive care quality as determined by an external peer review organization. In addition to providing a new venue for training, this model may also improve the quality and reach of preventive services, decreased fixed costs for service delivery, and yield new employment opportunities for preventive medicine physicians.

Effects of sensor selection on exercise stroke volume in pacemaker dependent patients

The effects of sensor selection and sensor blending on the cardiovascular response to graded exercise was evaluated in 10 patients (age 74 +/- 2 yrs; 7 men and 3 women) implanted with a dual sensor rate adaptive VVIR pacemaker (Vitatron Topaz model 515). Patients underwent three graded exercise tests (GXT) with sensor programming randomly assigned. For a given graded exercise text the pacemaker was programmed into activity sensing (ACT), QT sensing, or dual sensing (ACT = QT). Data were recorded at rest and during each stage of the graded exercise text. Oxygen uptake (VO2) was measured continuously using a Q Plex I system. Heart rate (HR), stroke volume (SV), and cardiac output (Qc) were measured by impedance cardiography. Systolic time intervals were calculated from simultaneous recordings of the ECG, phonocardiogram, and the impedance cardiogram. In response to the GXT no differences in peak VO2 were observed across the three sensor settings. Regardless of the sensor setting Qc increased linearly with each increment in VO2. The HR response to ACT only pacing was significantly higher than in the other two pacing conditions. During ACT only pacing SV failed to rise in response to exercise. The increased exercise Qc during QT and ACT = QT pacing were mediated by significant increases in both HR and SV. The QT and dual pacing conditions were also associated with longer diastolic filling times. The data indicate that the mechanisms responsible for the increase Qc during exercise were different for ACT versus ACT = QT or QT sensor-driven pacing.

Stereotactic radiosurgery for brain metastasis from renal cell carcinoma

BACKGROUND

The authors evaluated results after stereotactic radiosurgery (SR) for brain metastases from renal cell carcinoma (RCC) and identified factors associated with improved survival and tumor control.

METHODS

The authors reviewed the management results from a total of 52 RCC brain metastases in 35 consecutive patients who underwent stereotactic radiosurgery (SR) during a 9-year interval. Twenty-eight patients also underwent whole brain radiation therapy (WBRT). The mean tumor volume was 2.4 mL (range, 0.1-14.1 mL). The mean dose delivered to the tumor margin was 17 gray (Gy) (range, 13-20 Gy). Univariate and multivariate testing was performed to determine significant prognostic factors.

RESULTS

The median survival was 11 months after SR and 14 months after brain tumor diagnosis. Only 2 patients (8%) died of progression of the irradiated tumor. Age < 55 years, lack of active systemic disease, and use of chemotherapy and/or immunotherapy after SR were significant favorable prognostic factors in multivariate testing. Post-SR imaging was evaluated in 26 patients (39 tumors). The local control rate from the 39 treated tumors imaged was 90% (tumor disappearance, 21%; tumor regression, 44%; and stable disease, 26%). Local recurrence developed in 3 patients (4 lesions) and remote brain disease in 12 patients. No patient developed a new focal neurologic deficit due to SR. Patients were classified into two groups: SR with and SR without WBRT. The addition of WBRT to SR did not improve survival. Distant failure occurred similarly in both groups (46% vs. 50%). WBRT combined with SR may contribute to local control, but did not prevent the development of new remote tumors.

CONCLUSIONS

SR for brain metastasis from RCC results in brain disease control in the majority of patients and was associated with few complications. Early detection of brain metastases and treatment with SR provides extended quality survival.

Interleukin-2-based therapy for metastatic renal cell cancer: the Cytokine Working Group experience, 1989-1997

PURPOSE

This article reviews long-term follow-up data from three phase II studies conducted by the Cytokine Working Group from 1989 to 1995 that evaluated various recombinant interleukin-2 (rIL-2) -based regimens in patients with metastatic renal cell cancer. Response rates, long-term response duration, and toxicity are compared.

PATIENTS AND METHODS

The Cytokine Working Group studies reviewed here investigated the safety and efficacy of two high-dose intravenous rIL-2-based regimens and two moderate-dose outpatient subcutaneous rIL-2-based regimens in patients with progressive metastatic renal cell cancer. A randomized phase II study, initiated in 1989, investigated the safety and efficacy of high-dose intravenous rIL-2 alone and high-dose intravenous rIL-2 plus recombinant interferon-alpha (rIFN-alpha). A second phase II study, initiated in 1992, tested the safety and efficacy of moderate-dose subcutaneous rIL-2 plus subcutaneous rIFN-alpha in the outpatient setting. The third trial, initiated in 1995, investigated a regimen consisting of the previous subcutaneous rIL-2 plus rIFN-alpha regimen alternating with intravenous bolus 5-fluorouracil (5-FU) plus subcutaneous rIFN-alpha. Median follow-up for these studies is 72 months, 48 months, and 24 months, respectively.

RESULTS

The overall response rates observed with each of these regimens were similar (17% with high-dose rIL-2 alone, 11% with high-dose rIL-2/rIFN-alpha, 17% with outpatient subcutaneous rIL-2/rIFN-alpha, and 16% with outpatient rIL-2/rIFN-alpha, plus 5-FU/rIFN-alpha). However, the high-dose rIL-2 regimen produced a 7% complete response rate, compared with 0%, 4%, and 4%, respectively, with each of the other regimens. Median response duration was also much longer with high-dose intravenous rIL-2 alone (53 months), compared with 7 months, 12 months, and 9 months, respectively, with each of the other regimens.

CONCLUSION

Complete response rate and response duration appear to favor the high-dose intravenous rIL-2 regimen. This will require verification in a randomized study comparing the best high-dose arm (rIL-2 alone) with the best outpatient regimen (rIL-2/IFN-alpha). The Cytokine Working Group is currently conducting such a study.

Analysis of the C-myc promoter-binding factor zf87/pur1 in transformed and nontransformed cell-lines

ZF87/Pur1 is a zinc finger protein that binds to the purine-rich element ME1a1 within the c-myc P2 promoter. To better understand the effect of ZF87/Pur1 on c-myc gene expression, the gene was stably expressed in nontransformed NIH3T3 fibroblasts or was transiently overexpressed in transformed COS cells. The protein was targeted almost exclusively to the nucleus. In nuclear extracts from both cell types, the ectopically expressed ZF87/Pur1 protein generated a novel band in the gel-shift assay, due possibly to a modification since it was found that the protein was phosphorylated on serine and threonine in vivo. When the NIH3T3 cell lines constitutively expressing ZF87/Pur1 were analyzed under a variety of growth conditions, it was found that c-myc expression was not affected. In addition; overexpression of ZF87/Pur1 in COS cells did not affect transcription from the c-myc promoter in a cotransfection assay, but did increase the level of transcription from a promoter containing multiple ME1a1 binding sites. The data indicate that overexpression of ZF87/Pur1 alone is not enough to affect transcription from the c-myc P2 promoter; transcriptional activation from P2 may require additional limiting factors such as E2F.

Physical characteristics of a factor related to the c-myc/insulin promoter binding protein ZF87/Pur-1

The ZF87/Pur-1 factor is a zinc finger containing protein that binds to sites within the c-myc and insulin promoters. The open reading frame of the mRNA predicts a 49 kd protein which migrates as a 58 kd protein by SDS-PAGE. Antiserum to ZF87/Pur-1 recognizes the 58 kd protein in western blots of Hela cell nuclear extracts. The antiserum also specifically recognizes an 87 kd protein (p87) that is distributed between cytosolic and nuclear extracts. p87 found in cytosolic extracts sediments faster in a glycerol gradient than that found in nuclear extracts. These data indicate that p87 may associate with specific factors or undergo a post-translational modification that changes its conformation.

1H, 13C and 15N backbone assignments of cyclophilin when bound to cyclosporin A (CsA) and preliminary structural characterization of the CsA binding site

The backbone 1H, 13C and 15N chemical shifts of cyclophilin (CyP) when bound to cyclosporin A (CsA) have been assigned from heteronuclear two- and three-dimensional NMR experiments involving selectively 15N- and uniformly 15N- and 15N,13C-labeled cyclophilin. From an analysis of the 1H and 15N chemical shifts of CyP that change upon binding to CsA and from CyP/CsA NOEs, we have determined the regions of cyclophilin involved in binding to CsA.

Randomized comparison of tamoxifen versus diethylstilbestrol in estrogen receptor-positive or -unknown metastatic breast cancer: a Southeastern Cancer Study Group trial

In a randomized study 115 postmenopausal women with advanced breast cancer who were estrogen receptor-unknown or -positive were treated initially with tamoxifen or diethylstilbestrol (DES). Their pretreatment characteristics showed no significant difference. The frequency of response was identical with tamoxifen and DES, showing a complete response rate of 2% versus 2% and a partial response rate of 4% versus 8%, respectively; stable disease was present in 78% versus 73% of the patients, respectively. The median time to disease progression (5 vs 6 months) and median survival depending on initial hormone therapy (34 vs 35 months) were identical for tamoxifen and DES, respectively. Gastrointestinal toxicity was more frequent and more severe with DES than tamoxifen. Responses were seen with withdrawal of each agent and on crossover to the alternative agent. Our conclusions are that: DES and tamoxifen are equally effective in treating metastatic breast cancer in the postmenopausal patient who is estrogen receptor-positive or -unknown; withdrawal and crossover responses are seen with both agents; side effects are minimal but more frequent with DES; and on the basis of cost-effectiveness DES is the preferable agent.