Reversion and non-reversion mechanisms of resistance to PARP inhibitor or platinum chemotherapy in BRCA1/2-mutant metastatic breast cancer

BACKGROUND

Little is known about mechanisms of resistance to poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and platinum chemotherapy in patients with metastatic breast cancer and BRCA1/2 mutations. Further investigation of resistance in clinical cohorts may point to strategies to prevent or overcome treatment failure.

PATIENTS AND METHODS

We obtained tumor biopsies from metastatic breast cancer patients with BRCA1/2 deficiency before and after acquired resistance to PARPi or platinum chemotherapy. Whole exome sequencing was carried out on each tumor, germline DNA, and circulating tumor DNA. Tumors underwent RNA sequencing, and immunohistochemical staining for RAD51 foci on tumor sections was carried out for functional assessment of intact homologous recombination (HR).

RESULTS

Pre- and post-resistance tumor samples were sequenced from eight patients (four with BRCA1 and four with BRCA2 mutation; four treated with PARPi and four with platinum). Following disease progression on DNA-damaging therapy, four patients (50%) acquired at least one somatic reversion alteration likely to result in functional BRCA1/2 protein detected by tumor or circulating tumor DNA sequencing. Two patients with germline BRCA1 deficiency acquired genomic alterations anticipated to restore HR through increased DNA end resection: loss of TP53BP1 in one patient and amplification of MRE11A in another. RAD51 foci were acquired post-resistance in all patients with genomic reversion, consistent with reconstitution of HR. All patients whose tumors demonstrated RAD51 foci post-resistance were intrinsically resistant to subsequent lines of DNA-damaging therapy.

CONCLUSIONS

Genomic reversion in BRCA1/2 was the most commonly observed mechanism of resistance, occurring in four of eight patients. Novel sequence alterations leading to increased DNA end resection were seen in two patients, and may be targetable for therapeutic benefit. The presence of RAD51 foci by immunohistochemistry was consistent with BRCA1/2 protein functional status from genomic data and predicted response to later DNA-damaging therapy, supporting RAD51 focus formation as a clinically useful biomarker.

A phase II trial of voreloxin in women with platinum-resistant ovarian cancer

5559

Background: Voreloxin is a naphthyridine analog that intercalates DNA and inhibits topoisomerase II, inducing apoptosis. Clinical activity has been observed in ovarian cancer and AML. Results are reported from a fully enrolled phase II study of 3 dose levels of single agent voreloxin in patients (pts) with 1° or 2° platinum-resistant or refractory ovarian cancer. Methods: Pts may have received ≤ 3 prior platinum regimens plus one additional non-platinum regimen. PS of 0–1 was required. Voreloxin regimens: Cohort A 48 mg/m2q3weeks (wk) (N = 65), Cohort B 60 mg/m2q4wk (N = 35), and Cohort C 75 mg/m2q4wk (N = 35) by short IV infusion. BRCA status is reported by pt consent. Results: Cohort A: 2CRs, 5PRs; ORR 11%; median PFS 82 days (52–98 days 95%CI); Cohort B: 1CR, 3PRs; ORR 11%, median PFS too early to evaluate (TETE); Cohort C - TETE. Cohort A: Febrile neutropenia (FN) incidence was low (8%). Other common G3 or G4 AEs reported (≥ 5%) were fatigue (14%) and nausea (5%). Dose delays or reductions (40%) occurred typically at Cycle 1, largely due to neutropenia. Cohort B: Dose was increased to 60 mg/m2 and dosing interval was lengthened to 4 wk, maintaining dose intensity (DI) and allowing adequate time for marrow recovery. ANC dosing criterion was changed from ANC ≥ 1,500 to ≥ 1,000. There was a marked decrease in dose delays and reductions (14%) with only 3% incidence of FN. Common G3 or 4 AEs reported (≥ 5%) were fatigue (11%) and nausea (5%). The safety profile supported further dose escalation to 75 mg/m2q4wk (Cohort C- DI increased by 25%). Data are TETE. Conclusions: Preliminary data suggest Cohorts A and B have similar safety and efficacy profiles as anticipated based on comparable DI. Fewer dose reductions and delays occurred in Cohort B, due to revised dosing criteria and increased cycle length to 4 wk. Accrual to Cohort C is complete. Efficacy and safety data for all cohorts will be reported.

[Table: see text]

Results from a phase II randomized, placebo-controlled, double-blind trial suggest improved PFS with the addition of pertuzumab to gemcitabine in patients with platinum-resistant ovarian, fallopian tube, or primary peritoneal cancer

5507

Background: Pertuzumab (P) is a humanized monoclonal antibody that blocks the ability of HER2 to heterodimerize with other HER/ErbB receptors. As a single agent, P has demonstrated clinical activity in relapsed/refractory epithelial ovarian cancer (EOC). Since platinum-resistant (CDDP-R) EOC remains a difficult disease to treat, this phase II study was conducted to determine if addition of P to gemcitabine (G) would improve results. Methods: Patients with CDDP-R EOC (including ovarian, fallopian tube, or primary peritoneal cancer) who had received up to one prior treatment for CDDP-R disease were randomized to Gem 800 mg/m2 on D1, 8 of a 21-day cycle ± P or placebo (pl). P was given as an 840 mg initial dose followed by 420mg IV every 3 weeks. Tumor response was assessed by RECIST every 6 weeks using GOG criteria. The primary endpoint was progression free survival (PFS). Results: One hundred thirty patients (n = 65 each treatment cohort) were treated. Clinical characteristics were balanced between the treatment groups. Pts received a median of 2 prior regimens (range 1–6) for EOC. Based on 83 events, the adjusted hazard ratio for PFS was 0.67 (95% CI: 0.43–1.02), p =0.06 in favor of P+Gem. The median PFS was 3.0 months (0–8.7 months) vs. 2.6 months (0–9+ months), and the PFS rate at 4 months was 49% vs. 34% in the P+Gem and Gem/pl arms, respectively. The most common AEs increased in the P-treated pts were fatigue, nausea, diarrhea, back pain, Gr 3–4 neutropenia, rash, headache, stomatitis, epistaxis, and rhinorrhea. Clinically significant CHF was reported in one patient in the pertuzumab cohort. There was no imbalance in the LVEF results between treatment arms. One patient who received pertuzumab + gemcitabine experienced an adverse event that resulted in death (hemolytic-uremic syndrome). Conclusions: These data suggest that pertuzumab may add activity to gemcitabine as reflected by improvements in PFS in patients with CDDP-R ovarian, primary peritoneal, or fallopian tube cancer. Survival data will be presented at ASCO.

No significant financial relationships to disclose.

Randomized trial of acupuncture versus sham control for prevention of myelosuppression in patients with gynecologic malignancies

19524

Background: CIM is a significant toxicity that is treated with cytokine growth factors, dose reductions and/or delays. Preliminary uncontrolled Chinese studies suggest that acupuncture lessens CIM. Methods: Patients (pts) with newly diagnosed or recurrent gyn cancers receiving chemotherapy were eligible. Trial design was a double blinded, randomized trial of active acupuncture or sham for 5 weeks (administered 3x per week). Primary endpoints were first nadir WBC and ANC levels at chemo cycle 2; other endpoints were recovering counts following the cycle 2 nadir, QOL, G-CSF levels, and feasibility. Results: >460 patients were screened. 21 pts were randomized to either active acupuncture (n=11) or sham control (n=10). Median age of the pts was 55 yrs (range: 28–81). 15 pts have completed the acupuncture treatment to provide the baseline and nadir WBC and ANC. Toxicities related to either sham or active acupuncture were minimal. The active pts group showed higher baseline WBC (median: 3,600 vs. 2,600, NS) and ANC (median: 2,269 vs. 1,922, NS) values. The nadir WBC was higher in the pts receiving acupuncture (median 3,600 vs. 2,300) but the difference was not statistically significant after adjusting for the baseline difference (p=0.16). Nadir ANC was higher among the pts receiving acupuncture (median: 2,424 vs. 1,274) but the difference was not statistically significant after adjusting for the baseline difference (p=0.1107). Recovering WBC in the pts receiving acupuncture was higher (median: 8,600 vs. 4,400) after adjusting for the baseline difference (p=0.045). The recovering ANC in the pts receiving acupuncture was higher (median: 6,530 vs. 4,038) but this difference was not statistically significant after adjusting for the baseline difference (p=0.0919). QOL and G-CSF data will be presented at ASCO. Conclusions: Although a larger randomized trial is necessary to determine the effects of acupuncture on CIM, there were consistent trends, and recovering WBC counts were significantly higher in patients receiving acupuncture. Formal evaluation of CAM is vital to confirm potentially clinically meaningful benefits.

No significant financial relationships to disclose.

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]

Chemotherapy and radiation therapy in UPSC

5535

Purpose: To analyze the impact of chemotherapy (Ch) and radiation therapy (RT) on relapse rates in patients with uterine papillary serous carcinoma (UPSC). Materials and Methods: The outcomes of 160 women with UPSC seen between 1980–2005 at the BW/DFCC were analyzed. Exclusion criteria included stage IVB disease, no hysterectomy, unknown stage, or unknown type of RT. Results: The median age was 67 years (range 31–90). FIGO Stage was IA (21), IB (28), IC (13), IIA (7), IIB (10), IIIA (42), IIIB (2), IIIC (21), and IVA (16). Treatment included none (40), Ch alone (20), Ch and whole abdominal radiation (WA) (11), Ch and pelvic radiation (P) (30), Ch and vaginal brachytherapy (VB) (2), WA alone (24), P alone (19), and VB alone (14). The median dose of RT was WA 30 Gy and P 45 Gy. Ch was given to 63 patients; the median number of cycles of Carboplatin, Adriamycin and Paclitaxel was 3. Overall survival (OS) and disease-free survival (DFS) for the entire group were 67% and 57% at 2 years, 62% and 51% at 3 years and 51% and 38% at 5 years. A total of 58 patients relapsed. Among those who received no RT or Ch, 48% (19/40) relapsed; among those treated with Ch only, 50% (10/20) relapsed; in the group treated with RT only, 26% (15/57) relapsed; and, in those treated with Ch and RT, 33% (14/43) relapsed. A significant difference in recurrence rate was seen in patients treated with RT compared to those who received no treatment (OR 0.40, p=0.03). This difference persisted after controlling for Stage, which did significantly affect the relationship between RT treatment and recurrence. Local recurrence (in an RT field) was a component of failure for 14% (14/100) treated with RT, versus 42% (25/59) that received no RT (OR 0.22, p=0.0001). Distant metastases were a component of first failure in 15% (9/61) that received Ch versus 11% (11/97) that did not; there was no significant difference in distant recurrence rate for patients treated with Ch (OR 1.35, p=0.53). Conclusion: This single-institution study represents the largest series of UPSC to date. The use of RT significantly decreases the overall recurrence rate of UPSC in this series and should be considered in patients with stages I-IVA UPSC. Future studies looking at the optimal type, dose and duration of chemotherapy, as well as the use of novel agents, are needed to improve outcomes in this population.

No significant financial relationships to disclose.

A phase II trial of EMD72000 (matuzumab), a humanized anti-EGFR monoclonal antibody, in patients with platinum-resistant ovarian and primary peritoneal malignancies

OBJECTIVE

The primary objective of this study was to determine the rate of response to matuzumab in patients with recurrent, EGFR-positive ovarian, or primary peritoneal cancer. Secondary end points included safety and tolerability, time to tumor progression, duration of response, and overall survival.

METHODS

A multi-institutional single arm phase II trial.

RESULTS

Of 75 women screened for the study, 37 were enrolled and treated. Median age of the treated patient population was 58 years, and most patients had more than four prior lines of chemotherapy. Therapy was well tolerated, the most common toxicities being a constellation of skin toxicities, including rash, acne, dry skin, and paronychia, as well as headache, fatigue, and diarrhea. Serious adverse events were very rare but included a single episode of pancreatitis that may have been drug related. All patients completed therapy, receiving 1 to 30 infusions of matuzumab. There were no formal responses (RR=0%, 95% CI: 0-9.5%), although 7 patients (21%) were on therapy for more than 3 months with stable disease.

CONCLUSIONS

Matuzumab at the dose and schedule selected is well tolerated. In this population of very heavily pretreated patients with epithelial ovarian and primary peritoneal malignancies, there was no evidence of significant clinical activity when matuzumab was administered as monotherapy.

Phase II trial of GM-CSF in women with asymptomatic müllerian cancer

5081

Background: GM-CSF is a recombinant human cytokine, which increases the proliferation of granulocytes and monocytes. Experience with this agent, including adjuvant studies in melanoma, vaccine-based studies using autologous tumor vaccines that secrete human GM-CSF, and studies in prostate cancer using GM-CSF have all suggested that GM-CSF might provide anti-tumor activity in a subset of cancer patients. Methods: Open label phase II study performed in asymptomatic patients with recurrent mullerian malignancy without an indication for immediate systemic chemotherapy. Patients could have measurable or evaluable disease (defined as CA-125 >35 U/ml or 2 successively rising values with the most recent 3x the nadir value.) GM-CSF 250 mcg/m2 was administered subcutaneously on days 1–14 of a 28-day cycle. Monthly follow-up included interim history, physical exam and CA-125, with radiologic evaluation q 3 months. Results: Enrollment to this cohort is complete. Thirty-five women with a median age of 60 were enrolled; data are available on 33:30 women with ovarian and 3 with primary peritoneal cancers. To date 31 women are evaluable for response. Best overall response of patients who have completed the study includes 6 patients with stable disease (18%). Median time to treatment termination (TTT) was 76 days. Four patients remain on study, 2 with SD >6 months. Toxicity was generally mild, including injection site reaction, fatigue, and bone pain, however 2 patients experienced excessive toxicity and withdrew consent. There were 3 bowel obstructions thought related to disease but contribution of drug could not be ruled out. After 14 days of GM-CSF, CA-125 dropped in 23 of 33 women (70%) from their baseline on study value (median change -23%, range −48 to +158%). The magnitude of CA-125 drop during the first two weeks of therapy was significantly and positively correlated with day 15 WBC (p = 0.04.) Conclusions: GM-CSF is well tolerated and frequently associated with a decline in CA-125 that is correlated with leukocytosis. Although median TTT for the entire group is modest, a subset of women have had prolonged stable disease. Strategies to maintain and titrate leukocytosis are now being explored in a separate cohort.

No significant financial relationships to disclose.

Evaluation of serial serum IL-6 levels in women with newly diagnosed ovarian cancer on a prospective clinical trial

5065

Background: Elevated levels of IL-6 in serum have been reported in patients (pts) with mullerian malignancies (MM) and have been associated with a poor prognosis. Little is know about the behavior of IL-6 during effective cytotoxic therapy and its correlation to various clinical parameters. Methods: Pts with surgically debulked FIGO Stage II, III, and IV MM were enrolled in the Modified Triple Doublets trial. 83 pts were assigned to a cohort in accordance with the extent of surgical debulking. Cohort I included women who had been optimally cytoreduced to <1cm of residual tumor. Cohort II consisted of pts who had either post-debulking residual disease >1cm or stage IV disease. Both cohorts were treated with 3 sequential chemotherapy doublets, gemcitabine/carboplatin, paclitaxel/carboplatin, and adriamycin/topotecan. Each doublet was delivered for 3 cycles. Serum was collected from pts prior to initiating each doublet at cycles 1, 4, 7 and at the end of study (post cycle 9). Serum IL-6 levels were measured in triplicate by sandwich ELISA. Results: Pts with MM had elevated levels of IL-6 following debulking surgery (mean = 12.7 pg/ml) as compared to normal controls (n = 11, mean IL-6 = 1.5 pg/ml, p =.01). While there was no significant correlation between IL-6 levels and stage of disease, the IL-6 serum concentrations did correlate with extent of surgical debulking (p = 0.0182). IL-6 concentrations dropped throughout all cycles of platinum based treatment with post platinum treatment mean concentration of 3.9pg/ml. IL-6 levels did not correlate with outcome of second look operation and there was no statistically significant correlation between IL-6 and CA-125 levels (p = 0.1612). Survival data is still immature with a median follow-up of 34 months, yet elevation of IL-6 levels following surgery demonstrates a trend towards inferior survival. Conclusions: IL-6 levels are elevated in ovarian cancer pts following surgical debulking and correlate with the volume of residual disease following surgical cytoreduction. Values decrease during cytoreductive platinum based chemotherapy although IL-6 was not as predictive of response as was CA-125. Data demonstrates a weak correlation betweenworse survival and elevated IL-6 levels. Supported by the Lana Vento Foundation.

No significant financial relationships to disclose.

Bevacizumab in patients with advanced platinum-resistant ovarian cancer

5006

Background: Bevacizumab (BV), a recombinant, humanized monoclonal antibody directed against vascular endothelial growth factor, has demonstrated clinical benefit in multiple tumor types. Activity in ovarian cancer (OC) has been reported in phase II studies in patients (pts) with recurrent disease. We now describe the activity/safety of BV in pts with platinum-resistant OC (PROC) that progressed after topotecan or liposomal doxorubicin (LD). Methods: Eligibility criteria for this multicenter, Phase II study included primary or secondary PROC that progressed within 3 months of topotecan or LD, 3 or fewer prior chemotherapy regimens, and a performance status (PS) 0 or 1. BV was dosed at 15 mg/kg q 3 weeks until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) as defined by RECIST. A two-stage design was utilized with H1 set at 15%. Secondary endpoints included progression-free survival (PFS), duration of response, overall survival (OS), and safety. Results: The study enrolled 44 of the intended 53 pts, closing early due to a higher than expected rate of gastrointestinal perforations (GIP). Baseline characteristics included median age 60 yrs (range 31–87); PS 0 in 26 pts, 1 in 18 pts; 2 prior chemotherapy regimens in 20 pts, 3 in 24 pts. Preliminary efficacy: ORR (CR+PR), 7/44 (16%). Median duration of response was 12 weeks, with 2 pts continuing on study >5 months. Serious adverse events (SAEs) were reported in 18/44 pts (41%). Selected SAEs included GIP 5 (11%; one occurred more than 30 days after coming off study while on paclitaxel and commercial Avastin®), bowel obstruction 5 (11%), arterial thromboembolic events 4 (9%), delayed wound healing 2 (5%), and one case each of pulmonary hypertension, hypertensive encephalopathy, and hypoxia. Conclusions: BV has single agent activity in women with PROC, but is associated with substantial toxicity in this population. Trials are ongoing in less heavily treated, newly diagnosed pts with OC to evaluate the efficacy and safety of BV in these disease settings. Identification of risk factors for BV-associated adverse events requires further study.

[Table: see text]

A randomized phase II trial with gemcitabine with or without pertuzumab (rhuMAb 2C4) in platinum-resistant ovarian cancer (OC): Preliminary safety data

13001

Background: Pertuzumab (P), a humanized HER2 antibody, represents a new class of targeted agents called HER dimerization inhibitors (HDIs). P inhibits dimerization of HER2 with EGFR, HER3 and HER4, and subsequently inhibits signaling through MAP and PI3 kinases. Single agent P has demonstrated clinical benefit in advanced OC (ASCO 2005 abstract #5051). Methods: 40 pts with platinum-resistant OC (progressed within 6 months of receiving a platinum-based chemotherapy) were enrolled in this 1:1 randomized, double blind, placebo controlled trial of gemcitabine with or without P. Gemcitabine was administered IV on day 1 and 8 at 800 mg/m2 of a 21 day cycle. Blinded placebo or 420 mg P was administered IV on day 1. Gemcitabine was dose reduced for neutropenia or thrombocytopenia. P was not dose reduced. Results: 40 pts have been enrolled and treated with at least 1 cycle of gemcitabine in combination with blinded study drug. The median age was 58.5 (range 18–82); 26 had PS ECOG 0, 13 ECOG 1, 1 ECOG 2. The most common grade 3/4 events were neutropenia in 7 pts (17.5%), thrombocytopenia in 6 pts (15%), small bowel obstruction in 4 pts (10%), constipation in 3 pts (7.5%) and elevated ALT in 3 pts (7.4%). There was one grade 3 diarrhea, but no grade 3 or 4 rash. There were 4 serious adverse events (SAEs) attributed to study drug. These were a pleural effusion, thrombocytopenia, febrile neutropenia, and a deep vein thrombosis. Nine pts required one or two dose reductions of gemcitabine for hematological toxicity. Of 29 pts with post-baseline echo or MUGA values obtained, no pt had LVEF drop to <50%. The adverse events evaluated after 40 pts did not meet the prespecified criteria to call for an independent safety monitoring board evaluation of unblinded data. Conclusions: Preliminary safety data indicate that pertuzumab or placebo combined with gemcitabine is well tolerated with no unexpected additive toxicity. The nature and frequency of the adverse events are similar to what has been observed with either single agent gemcitabine or P. Updated data will be presented at ASCO.

[Table: see text]

Phase II and pharmacokinetic study of ecteinascidin 743 in patients with progressive sarcomas of soft tissues refractory to chemotherapy

PURPOSE

To assess the efficacy of the marine-derived alkaloid ecteinascidin 743 (ET-743) in patients with soft tissue sarcomas that progressed despite prior conventional chemotherapy and to characterize the pharmacokinetic profiles of ET-743 in this patient population.

PATIENTS AND METHODS

Thirty-six previously treated soft tissue sarcoma patients from three institutions received ET-743 as a 24-hour continuous intravenous (IV) infusion at a dose of 1,500 microg/m(2) every 3 weeks. Pharmacokinetic studies were also performed. Patients were restaged every two cycles for response by objective criteria.

RESULTS

Objective responses were observed in three patients, with one complete response and two partial responses, for an overall response rate of 8% (95% CI, 2% to 23%). Responses were durable for up to 20 months. Two minor responses (43% and 47% tumor reduction) were observed, for an overall clinical benefit rate of 14%. The predominant toxicities were neutropenia and self-limited transaminitis of grade 3 to 4 severity in 34% and 26% of patients, respectively. The estimated 1-year time to progression and overall survival rates were 9% (95% CI, 3% to 27%) and 53% (95% CI, 39% to 73%), respectively. The maximum observed plasma concentration and total plasma clearance of ET-743 (mean +/- standard deviation), 1.04 +/- 0.48 ng/mL and 35.6 +/- 16.2 L/h/m(2), respectively, were consistent with previously reported values from phase I studies of the drug given as a 24-hour IV infusion.

CONCLUSION

ET-743 is a promising new option for the management of several histologic subtypes of sarcoma. Durable objective responses were obtained in a subset of sarcoma patients with disease progression despite prior chemotherapy. Additionally, the relatively high survival rate noted in this series of previously treated patients further justifies development of this agent.

A phase II trial of three sequential doublets for the treatment of advanced müllerian malignancies☆☆Funding provided by Eli Lilly Pharmaceutical Company and Amgen

OBJECTIVES

In an effort to improve the results of primary chemotherapy for müllerian malignancies a novel chemotherapy program was piloted that delivered three sequential chemotherapy doublets. The primary endpoints were surgically defined response rates and evaluation of toxicity.

METHODS

After primary cytoreductive surgery patients were treated with three sequential doublets including three initial cycles of carboplatin and paclitaxel (doublet 1) and then two cycles of cisplatin (day 1) and gemcitabine (days 1 and 8; doublet 2), and finally two cycles of doxorubicin (day 1) and topotecan (days 3,4, and 5; doublet 3). Cycles 4 through 7 were given with G-CSF (Neupogen) support at a dose of 5 mcg/kg/day. After therapy, all women were clinically staged and evaluated by second-look laparoscopy/laparotomy (SLO) if clinical staging was negative for residual disease.

RESULTS

A total of 49 eligible patients were enrolled with a median age of 52 (SD 9). Forty-four women had either ovarian cancer or primary peritoneal carcinoma with 3 women diagnosed with fallopian tube carcinoma and 2 with papillary serous carcinoma of the uterus. Eighty-four percent of patients had stage IIIc/IV tumors, with 29% having >1 cm residual disease after primary cytoreductive surgery. Thirty-nine of 49 (80%) patients completed therapy. A total of 283 cycles of chemotherapy were delivered with acceptable toxicities. There were no toxic deaths. Five women were withdrawn from trial (3 for Taxol hypersensitivity, 1 for gemcitabine pulmonary hypersensitivity, and 1 for serious line infection). Neutropenia, typically without fever, was relatively frequent in the first doublet. Nausea and thrombocytopenia were the predominant toxicities in doublet 2. Thirty-nine women completed all cycles of treatment. Thirty-six women had restaging results consistent with a clinical complete response (CR) and underwent SLO. The pathologic CR rate of the patients undergoing SLO was 38%.

CONCLUSIONS

Treatment with this sequential doublet regimen is feasible with a 38% pathologic CR rate.

Clinical Activity of Trastuzumab and Vinorelbine in Women With HER2-Overexpressing Metastatic Breast Cancer

PURPOSE: To determine the response rate and toxicity profile of trastuzumab administered concurrently with weekly vinorelbine in women with HER2-overexpressing advanced breast cancer.

PATIENTS AND METHODS: Forty women with HER2-positive (+3 by immunohistochemistry, n = 30; +2 or positive, n = 10) breast cancer were enrolled onto a study of trastuzumab (4 mg/kg × 1, 2 mg/kg weekly thereafter) and vinorelbine (25 mg/m2 weekly, with dose adjusted each week for neutrophil count). Eighty-two percent of women had received prior chemotherapy as part of adjuvant (30%), metastatic (25%), or both (28%) treatment, including substantial portions of patients who had previously received either anthracyclines (20%), taxanes (15%), or both types (38%) of chemotherapy.

RESULTS: Responses were observed in 30 of 40 patients (overall response rate, 75%, conditional corrected 95% confidence interval, 57% to 89%). The response rate was 84% in patients treated with trastuzumab and vinorelbine as first-line therapy for metastatic disease, and 80% among HER2 +3 positive patients. High response rates were also seen in women treated with second- or third-line therapy, and among patients previously treated with anthracyclines and/or taxanes. Combination therapy was feasible; patients received concurrent trastuzumab and vinorelbine in 93% of treatment weeks. Neutropenia was the only grade 4 toxicity. No patients had symptomatic heart failure. Grade 2 cardiac toxicity was observed in three patients. Prior cumulative doxorubicin dose in excess of 240 mg/m2 and borderline pre-existing cardiac function were associated with grade 2 cardiac toxicity.

CONCLUSION: Trastuzumab in combination with vinorelbine is highly active in women with HER2-overexpressing advanced breast cancer and is well tolerated.

Phase I trial of carboplatin, paclitaxel, etoposide, and cyclophosphamide with granulocyte colony stimulating factor as first-line therapy for patients with advanced epithelial ovarian cancer

OBJECTIVES

The goal of this study was to determine the maximally tolerated doses (MTDs) of carboplatin, paclitaxel (Taxol), etoposide, and cyclophosphamide (CTEC) with granulocyte-colony stimulating factor (G-CSF, Filgrastim) support as first-line chemotherapy in women with advanced epithelial ovarian cancer (EOC).

METHODS

Newly diagnosed patients with either stage IV EOC, or stage III EOC and any amount of gross residual tumor after surgical debulking were eligible to receive six cycles of CTEC over five different dose levels in this phase I trial (planned 21-day cycle length). Paclitaxel, carboplatin, and cyclophosphamide were administered intravenously on Day 1, and oral etoposide was administered on Days 1, 2, and 3. G-CSF was administered beginning Day 4.

RESULTS

Twenty patients received a total of 98 cycles of CTEC over the five dose levels evaluated. Bone marrow suppression was the major toxic effect, with grade 4 neutropenia and thrombocytopenia being observed in 25 and 23% of cycles, respectively. The overall incidence of febrile neutropenia was 10%, and no toxic deaths occurred. No grade IV thrombocytopenia or febrile neutropenia was observed once the carboplatin dose was reduced from AUC of 7 to 5. Nonhematologic toxicity was generally mild (grade 2 or less). Dose-limiting toxicity was not observed at the highest dose level evaluated in this study, preventing assignment of the MTD. The clinical complete response rate was 92%, although 15 of 16 evaluable patients have progressed with a median progression-free interval of 4 months (range, 2-11 months). One patient remains disease-free 9 months from the completion of CTEC.

CONCLUSIONS

The CTEC regimen is well tolerated and highly active. Although the MTD was not reached in this study, the short median progression-free interval suggests that this regimen is unlikely to be superior to standard treatment with paclitaxel and carboplatin. Strategies to optimize the development of future combination chemotherapy regimens in the treatment of newly diagnosed ovarian cancer are discussed.

B7-1 is superior to B7-2 costimulation in the induction and maintenance of T cell-mediated antileukemia immunity. Further evidence that B7-1 and B7-2 are functionally distinct

Although intact, viable tumor cells rarely induce a clinically significant immune response in vivo, immunogenicity can be elicited by irradiated tumor cells that protect against subsequent challenge with wild-type intact viable tumor cells. Genetic modification of murine tumor cells, by transfection of cDNAs encoding either cytokines, MHC molecules, or costimulatory molecules, has been capable of inducing antitumor immunity. We and others have previously demonstrated that expression of the B7-1 costimulatory molecule, in either immunogenic or nonimmunogenic tumors, can protect against subsequent challenge with wild-type tumor cells. In this work, using a murine model of acute myeloid leukemia, we demonstrate that the B7-1 costimulatory molecule is superior to the B7-2 molecule in its capacity to protect against wild-type tumor challenge and eradicate minimal residual disease. These results provide compelling evidence that the B7-1 and B7-2 costimulatory signals are functionally distinct, thus resulting in clinically significant differences in the induction of antitumor immunity in vivo.

B7-1 is superior to B7-2 costimulation in the induction and maintenance of T cell-mediated antileukemia immunity. Further evidence that B7-1 and B7-2 are functionally distinct

Although intact, viable tumor cells rarely induce a clinically significant immune response in vivo, immunogenicity can be elicited by irradiated tumor cells that protect against subsequent challenge with wild-type intact viable tumor cells. Genetic modification of murine tumor cells, by transfection of cDNAs encoding either cytokines, MHC molecules, or costimulatory molecules, has been capable of inducing antitumor immunity. We and others have previously demonstrated that expression of the B7-1 costimulatory molecule, in either immunogenic or nonimmunogenic tumors, can protect against subsequent challenge with wild-type tumor cells. In this work, using a murine model of acute myeloid leukemia, we demonstrate that the B7-1 costimulatory molecule is superior to the B7-2 molecule in its capacity to protect against wild-type tumor challenge and eradicate minimal residual disease. These results provide compelling evidence that the B7-1 and B7-2 costimulatory signals are functionally distinct, thus resulting in clinically significant differences in the induction of antitumor immunity in vivo.

Factor independence of human myeloid leukemia cell lines is associated with increased phosphorylation of the proto-oncogene Raf-1

The proliferation of normal hematopoietic cells is strictly factor dependent, while leukemic cell lines and primary leukemic cells are frequently factor independent. Although autocrine growth stimulation of human leukemias is occasionally observed in vitro, it is possible that mutations of signal-transduction or cell-cycle control genes may also be important in the development of factor independence. We have previously shown that the proto-oncogene Raf-1, a 70-kd serine/threonine protein kinase, is rapidly phosphorylated and activated by hematopoietic growth factors such as granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and Steel factor and is likely to be an important intermediate in mitogenic signal transduction pathways in hematopoietic cells. In an effort to better understand the possible role of abnormal signal transduction in the development of factor independence, we compared the state of phosphorylation and associated kinase activity of Raf-1 between a series of factor-dependent human and murine-myeloid normal cells or cell lines and a series of factor-independent myeloid cell lines. In factor-dependent myeloid cells (normal neutrophils; monocytes; and the cell lines MO7, 32Dc13, and FDC-P1), Raf-1 phosphorylation and associated kinase activity was strictly regulated by the supply of growth factor. In contrast, each of eight factor-independent leukemic cell lines examined, HL-60, KG-1, K562, U937, JOSK-S, JOSK-M, JOSK-K, and JOSK-I, expressed hyperphosphorylated Raf-1 with increased Raf-1 associated kinase activity in the absence of growth factor addition. To further explore the relationship of Raf-1 to factor-independent growth, factor-independent sublines were derived from two factor-dependent cell lines, MO7 and FDC-P1, by culture in CSF-deprived medium. Also, several factor-independent sublines were derived by transfection of a cDNA encoding p210BCR/ABL into three different cell lines: MO7, 32Dc13, and FDC-P1. In each case, the new sublines expressed constitutively hyperphosphorylated and activated Raf-1. The correlation of hyperphosphorylation of Raf-1 with factor independence was also observed with primary acute myeloblastic leukemia cells. The rate of "spontaneous" proliferation of primary acute myeloblastic leukemia (AML) cells in vitro correlated with the extent of Raf-1 phosphorylation. These results suggest that the evolution of myeloid leukemic cells to factor independence is associated with phosphorylation and activation of Raf-1, implicating Raf-1 and signal transduction pathways which activate RAf-1 in this process.

Prevention of Legionella infections in a bone marrow transplant unit: multifaceted approach to decontamination of a water system

OBJECTIVE

To evaluate measures intended to reduce Legionella infections in patients undergoing bone marrow transplantation (BMT).

DESIGN

Ongoing clinical and microbiological surveillance for Legionella colonization or infection was undertaken. All neutropenic patients with pulmonary infiltrates and fever unresponsive to broad-spectrum antibiotics were tested for Legionella organisms.

SETTING

A 505-bed medical-surgical hospital with a designated BMT unit.

PATIENTS

Two hundred twenty-five patients underwent BMT; 201 were treated on a new BMT unit. The incidence of Legionella infections was compared to that seen in an estimated 150 neutropenic patients treated on other units.

INTERVENTION

A combined approach to decontamination of a hospital water supply was assessed. This included heating, particulate filtration, ultraviolet sterilization, and monthly pulse hyperchlorination of water supplied to the BMT unit. The incidence of Legionella infections was assessed on the BMT unit and compared with the frequency elsewhere in the hospital.

RESULTS

There were only three cases of Legionella pneumonia among 201 patients undergoing transplantation on a new BMT unit. In contrast, 33 cases of Legionella infections were detected from approximately 150 patients treated on general medical floors.

CONCLUSION

A multifaceted approach to decontamination of a hospital water system led to a marked reduction in Legionella infections.