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.

Long-term safety in patients with recurrent ovarian cancer treated with niraparib versus placebo: Results from the phase III ENGOT-OV16/NOVA trial.

OBJECTIVE: Niraparib is a poly(ADP-ribose) polymerase (PARP) inhibitor approved for use in heavily pretreated patients and as maintenance treatment in patients with newly-diagnosed or recurrent ovarian cancer following a response to platinum-based chemotherapy. We present long-term safety data for niraparib from the ENGOT-OV16/NOVA trial. METHODS: This multicenter, double-blind, randomized, controlled phase III trial evaluated the efficacy and safety of niraparib for the treatment of recurrent ovarian cancer. Patients were randomly assigned 2:1 to receive either once-daily niraparib 300 mg or placebo. Two independent cohorts were enrolled based on germline BRCA mutation status. The primary endpoint was progression-free survival, reported previously. Long-term safety data were from the most recent data cutoff (September 2017). RESULTS: Overall, 367 patients received niraparib 300 mg once daily. Dose reductions due to TEAEs were highest in month 1 (34%) and declined every month thereafter. Incidence of any-grade and grade ≥ 3 hematologic and symptomatic TEAEs was also highest in month 1 and subsequently declined. Incidence of grade ≥ 3 thrombocytopenia decreased from 28% (month 1) to 9% and 5% (months 2 and 3, respectively), with protocol-directed dose interruptions and/or reductions. Acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) were reported in 2 and 6 niraparib-treated patients, respectively, and in 1 placebo patient each. Treatment discontinuations due to TEAEs were <5% in each month and time interval measured. CONCLUSION: These data demonstrate the importance of appropriate dose reduction according to toxicity criteria and support the safe long-term use of niraparib for maintenance treatment in patients with recurrent ovarian cancer. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01847274.

Overall survival and updated progression-free survival outcomes in a randomized phase II study of combination cediranib and olaparib versus olaparib in relapsed platinum-sensitive ovarian cancer.

BACKGROUND: Olaparib is a poly(ADP-ribose) polymerase inhibitor and cediranib is an oral anti-angiogenic. In the primary analysis of this phase II study, combination cediranib/olaparib improved progression-free survival (PFS) compared with olaparib alone in relapsed platinum-sensitive ovarian cancer. This updated analysis was conducted to characterize overall survival (OS) and update PFS outcomes. PATIENTS AND METHODS: Ninety patients were enrolled to this randomized, open-label, phase II study between October 2011 and June 2013 across nine United States-based academic centers. Data cut-off was 21 December 2016, with a median follow-up of 46 months. Participants had relapsed platinum-sensitive ovarian cancer of high-grade serous or endometrioid histology or had a deleterious germline BRCA1/2 mutation (gBRCAm). Participants were randomized to receive olaparib capsules 400 mg twice daily or cediranib 30 mg daily and olaparib capsules 200 mg twice daily until disease progression. RESULTS: In this updated analysis, median PFS remained significantly longer with cediranib/olaparib compared with olaparib alone (16.5 versus 8.2 months, hazard ratio 0.50; P = 0.007). Subset analyses within stratum defined by BRCA status demonstrated statistically significant improvement in PFS (23.7 versus 5.7 months, P = 0.002) and OS (37.8 versus 23.0 months, P = 0.047) in gBRCA wild-type/unknown patients, although OS was not statistically different in the overall study population (44.2 versus 33.3 months, hazard ratio 0.64; P = 0.11). PFS and OS appeared similar between the two arms in gBRCAm patients. The most common CTCAE grade 3/4 adverse events with cediranib/olaparib remained fatigue, diarrhea, and hypertension. CONCLUSIONS: Combination cediranib/olaparib significantly extends PFS compared with olaparib alone in relapsed platinum-sensitive ovarian cancer. Subset analyses suggest this margin of benefit is driven by PFS prolongation in patients without gBRCAm. OS was also significantly increased by the cediranib/olaparib combination in this subset of patients. Additional studies of this combination are ongoing and should incorporate analyses based upon BRCA status. TRIAL REGISTRATION: Clinicaltrials.gov Identifier NCT0111648.

Antitumor activity and safety of pembrolizumab in patients with advanced recurrent ovarian cancer: results from the phase II KEYNOTE-100 study.

BACKGROUND: Advanced recurrent ovarian cancer (ROC) is the leading cause of gynecologic cancer-related death in developed countries and new treatments are needed. Previous studies of immune checkpoint blockade showed low objective response rates (ORR) in ROC with no identified predictive biomarker. PATIENTS AND METHODS: This phase II study of pembrolizumab (NCT02674061) examined two patient cohorts with ROC: cohort A received one to three prior lines of treatment with a platinum-free interval (PFI) or treatment-free interval (TFI) between 3 and 12 months and cohort B received four to six prior lines with a PFI/TFI of ≥3 months. Pembrolizumab 200 mg was administered intravenously every 3 weeks until cancer progression, toxicity, or completion of 2 years. Primary end points were ORR by Response Evaluation Criteria in Solid Tumors version 1.1 per blinded independent central review by cohort and by PD-L1 expression measured as combined positive score (CPS). Secondary end points included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS: Cohort A enrolled 285 patients; the first 100 served as the training set for PD-L1 biomarker analysis. Cohort B enrolled 91 patients. ORR was 7.4% for cohort A and 9.9% for cohort B. Median DOR was 8.2 months for cohort A and not reached for cohort B. DCR was 37.2% and 37.4%, respectively, in cohorts A and B. Based on the training set analysis, CPS 1 and 10 were selected for evaluation in the confirmation set. In the confirmation set, ORR was 4.1% for CPS <1, 5.7% CPS ≥1, and 10.0% for CPS ≥10. PFS was 2.1 months for both cohorts. Median OS was not reached for cohort A and was 17.6 months for cohort B. Toxicities were consistent with other single-agent pembrolizumab trials. CONCLUSIONS: Single-agent pembrolizumab showed modest activity in patients with ROC. Higher PD-L1 expression was correlated with higher response. CLINICAL TRIAL NUMBER: Clinicaltrials.gov, NCT02674061.

Final report on serial phase II trials of all-intraperitoneal chemotherapy with or without bevacizumab for women with newly diagnosed, optimally cytoreduced carcinoma of Müllerian origin.

BACKGROUND: Intraperitoneal (IP) chemotherapy can improve outcomes for women with optimally cytoreduced epithelial ovarian cancer but toxicities are a concern. We conducted 2 phase 2 trials of an IV/IP regimen using carboplatin and paclitaxel without (Trial A) and with bevacizumab (Trial B). METHODS: Both trials consisted of carboplatin AUC 6 day 1, and paclitaxel 60 mg/m2 on days 1,8, 15 of a 21-day cycle; in Trial B, patients received IV bevacizumab 15 mg/kg every cycle starting cycle 2. Chemotherapy was administered IV for cycle 1 and then IP for all subsequent cycles. Primary objectives included safety and tolerability, pathologic CR rate (Trial A), and the rate of completion of IP cycles of therapy (Trial B). Progression-free (PFS), overall survival (OS), and pharmacokinetic analysis were secondary endpoints. RESULTS: 81 patients were treated on both trials (n = 40 and 41 in trials A and B, respectively). Median age for trials A and B was 59 (range, 36-76) and 55 (range, 19-69) years, respectively. 68% and 85% of patients, respectively for A and B, completed at least 4 cycles of treatment in both trials. Treatment with bevacizumab resulted in higher rates of grade 3 fatigue (37 versus 33%) and grade 3-4 diarrhea (22 versus 8%). Median PFS was 23.5 (95%CI 16.2-35.3) and 25 (95%CI 16.4-42.7) months, respectively; median OS was 68 (95%CI 49.5-NR) and 79.7 (95%CI 59.0-79.7) months, respectively for Trial A and B. CONCLUSIONS: Weekly administered IP carboplatin and IP paclitaxel is tolerable and safe with similar activity with and without concommittant bevacizumab in these 2 trials.

Safety and dose modification for patients receiving niraparib.

Background: Niraparib is a poly(ADP-ribose) polymerase inhibitor approved in the USA and Europe for maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to platinum-based chemotherapy. In the pivotal ENGOT-OV16/NOVA trial, the dose reduction rate due to treatment-emergent adverse event (TEAE) was 68.9%, and the discontinuation rate due to TEAE was 14.7%, including 3.3% due to thrombocytopenia. A retrospective analysis was carried out to identify clinical parameters that predict dose reductions. Patients and methods: All analyses were carried out on the safety population, comprising all patients who received at least one dose of study drug. Patients were analyzed according to the study drug consumed (i.e., as treated). A predictive modeling method (decision trees) was used to identify important variables for predicting the likelihood of developing grade ≥3 thrombocytopenia within 30 days after the first dose of niraparib and determine cut-off points for chosen variables. Results: Following dose modification, 200 mg was the most commonly administered dose in the ENGOT-OV16/NOVA trial. Baseline platelet count and baseline body weight were identified as risk factors for increased incidence of grade ≥3 thrombocytopenia. Patients with a baseline body weight <77 kg or a baseline platelet count <150 000/µl in effect received an average daily dose ∼200 mg (median = 207 mg) due to dose interruption and reduction. Progression-free survival in patients who were dose reduced to either 200 or 100 mg was consistent with that of patients who remained at the 300 mg starting dose. Conclusions: The analysis presented suggests that patients with baseline body weight of <77 kg or baseline platelets of <150 000/µl may benefit from a starting dose of 200 mg/day. ClinicalTrials.gov ID: NCT01847274.

Phase I dose escalation study of the PI3kinase pathway inhibitor BKM120 and the oral poly (ADP ribose) polymerase (PARP) inhibitor olaparib for the treatment of high-grade serous ovarian and breast cancer.

Background: Based upon preclinical synergy in murine models, we carried out a phase I trial to determine the maximum tolerated dose (MTD), toxicities, pharmacokinetics, and biomarkers of response for the combination of BKM120, a PI3K inhibitor, and olaparib, a PARP inhibitor. Patients and methods: Olaparib was administered twice daily (tablet formulation) and BKM120 daily on a 28-day cycle, both orally. A 3 + 3 dose-escalation design was employed with the primary objective of defining the combination MTD, and secondary objectives were to define toxicities, activity, and pharmacokinetic profiles. Eligibility included recurrent breast (BC) or ovarian cancer (OC); dose-expansion cohorts at the MTD were enrolled for each cancer. Results: In total, 69 of 70 patients enrolled received study treatment; one patient never received study treatment because of ineligibility. Twenty-four patients had BC; 46 patients had OC. Thirty-five patients had a germline BRCA mutation (gBRCAm). Two DLTs (grade 3 transaminitis and hyperglycemia) were observed at DL0 (BKM120 60 mg/olaparib and 100 mg b.i.d.). The MTD was determined to be BKM120 50 mg q.d. and olaparib 300 mg b.i.d. (DL8). Additional DLTs included grade 3 depression and transaminitis, occurring early in cycle 2 (DL7). Anticancer activity was observed in BC and OC and in gBRCAm and gBRCA wild-type (gBRCAwt) patients. Conclusions: BKM120 and olaparib can be co-administered, but the combination requires attenuation of the BKM120 dose. Clinical benefit was observed in both gBRCAm and gBRCAwt pts. Randomized phase II studies will be needed to further define the efficacy of PI3K/PARP-inhibitor combinations as compared with a PARP inhibitor alone.

Olaparib monotherapy in patients with advanced relapsed ovarian cancer and a germline BRCA1/2 mutation: a multistudy analysis of response rates and safety.

BACKGROUND: The PARP inhibitor olaparib (Lynparza™) demonstrates antitumor activity in women with relapsed ovarian cancer and a germline BRCA1/2 mutation (gBRCAm). Data from olaparib monotherapy trials were used to explore the treatment effect of olaparib in patients with gBRCAm ovarian cancer who had received multiple lines of prior chemotherapy. PATIENTS AND METHODS: This analysis evaluated pooled data from two phase I trials [NCT00516373 (study 2); NCT00777582 (study 24)] and four phase II trials [NCT00494442 (study 9); NCT00628251 (study 12); NCT00679783 (study 20); NCT01078662 (study 42)] that recruited women with relapsed ovarian, fallopian tube or peritoneal cancer. All patients had a documented gBRCAm and were receiving olaparib 400 mg monotherapy twice daily (capsule formulation) at the time of relapse. Objective response rate (ORR) and duration of response (DoR) were evaluated using original patient outcomes data for patients with measurable disease at baseline. RESULTS: Of the 300 patients in the pooled population, 273 had measurable disease at baseline, of whom 205 (75%) had received ≥3 lines of prior chemotherapy. In the pooled population, the ORR was 36% [95% confidence interval (CI) 30-42] and the median DoR was 7.4 months (95% CI 5.7-9.1). The ORR among patients who had received ≥3 lines of prior chemotherapy was 31% (95% CI 25-38), with a DoR of 7.8 months (95% CI 5.6-9.5). The safety profile of olaparib was similar in patients who had received ≥3 lines of prior chemotherapy compared with the pooled population; grade ≥3 adverse events were reported in 54% and 50% of patients, respectively. CONCLUSION: Durable responses to olaparib were observed in patients with relapsed gBRCAm ovarian cancer who had received ≥3 lines of prior chemotherapy. CLINICALTRIALSGOV: NCT00516373; NCT00494442; NCT00628251; NCT00679783; NCT00777582; NCT01078662.

Phase I study of safety and pharmacokinetics of the anti-MUC16 antibody-drug conjugate DMUC5754A in patients with platinum-resistant ovarian cancer or unresectable pancreatic cancer.

BACKGROUND: MUC16 is a tumor-specific antigen overexpressed in ovarian (OC) and pancreatic (PC) cancers. The antibody-drug conjugate (ADC), DMUC5754A, contains the humanized anti-MUC16 monoclonal antibody conjugated to the microtubule-disrupting agent, monomethyl auristatin E (MMAE). PATIENTS AND METHODS: This phase I study evaluated safety, pharmacokinetics (PK), and pharmacodynamics of DMUC5754A given every 3 weeks (Q3W, 0.3-3.2 mg/kg) or weekly (Q1W, 0.8-1.6 mg/kg) to patients with advanced recurrent platinum-resistant OC or unresectable PC. Biomarker studies were also undertaken. RESULTS: Patients (66 OC, 11 PC) were treated with DMUC5754A (54 Q3W, 23 Q1W). Common related adverse events (AEs) in >20% of patients (all grades) over all dose levels were fatigue, peripheral neuropathy, nausea, decreased appetite, vomiting, diarrhea, alopecia, and pyrexia in Q3W patents, and nausea, vomiting, anemia, fatigue, neutropenia, alopecia, decreased appetite, diarrhea, and hypomagnesemia in Q1W patients. Grade ≥3-related AE in ≥5% of patients included neutropenia (9%) and fatigue (7%) in Q3W patients, and neutropenia (17%), diarrhea (9%), and hyponatremia (9%) in Q1W patients. Plasma antibody-conjugated MMAE (acMMAE) and serum total antibody exhibited non-linear PK across tested doses. Minimal accumulation of acMMAE, total antibody, or unconjugated MMAE was observed. Confirmed responses (1 CR, 6 PRs) occurred in OC patients whose tumors were MUC16-positive by IHC (2+ or 3+). Two OC patients had unconfirmed PRs; six OC patients had stable disease lasting >6 months. For CA125, a cut-off of ≥70% reduction was more suitable for monitoring treatment response due to the binding and clearance of serum CA125 by MUC16 ADC. We identified circulating HE4 as a potential novel surrogate biomarker for monitoring treatment response of MUC16 ADC and other anti-MUC16 therapies in OC. CONCLUSIONS: DMUC5754A has an acceptable safety profile and evidence of anti-tumor activity in patients with MUC16-expressing tumors. Objective responses were only observed in MUC16-high patients, although prospective validation is required. CLINICAL TRIAL NUMBER: NCT01335958.

Society of Gynecologic Oncology Journal Club: Controversial conversations in Gynecologic cancer - The ABCs of ADCs (Antibody drug Conjugates).

The Society of Gynecologic Oncology (SGO) Journal Club is held quarterly to discuss topics related to gynecological malignancies. On November 8, 2022, the SGO Journal Club focused on antibody-drug conjugates (ADCs) in gynecologic malignancies, including the pharmacology, toxicities, and results of recent clinical trials leading to FDA approval of two new therapies for cervical and ovarian cancer. The invited discussants included Drs. Erin Hickey Zacholski, Roisin O'Cearbhaill, and Ursula Matulonis who discussed the pharmacology of ADCs, GOG-3023/ENGOT-cx6 (Coleman et al., 2021 May) and the SORAYA study (Ursula Matulonis, Domenica Lorusso, Ana Oaknin, Sandro Pignata, Hannelore Denys, Nicoletta Colombo, Toon Van Gorp, Jason Konner, Margarita Romeo Marin, Philipp Harter, Conleth Murphy, Jiuzhou Wang, Elizabeth Noble, Brooke Esteves, Michael Method, Robert Coleman, Efficacy and Safety of Mirvetuximab Soravtansine in Patients with Platinum-Resistant Ovarian Cancer with High Folate Receptor Alpha Expression: Results from the SORAYA Study (LBA 4), Gynecologic Oncology, Volume 166, Supplement 1, ,2022).

Phase II trial of erlotinib in women with squamous cell carcinoma of the vulva.

OBJECTIVE: To evaluate the efficacy and toxicity of erlotinib in the management of squamous cell carcinoma (SCC) of the vulva. METHODS: Patients with vulvar lesions amenable to surgery or chemoradiation (cohort 1) or those with metastatic measurable disease (cohort 2) received erlotinib 150 mg daily. Patients were monitored for toxicity. Responses were determined by digital photography or RECIST 1.1. Cohort 1 underwent pre and post treatment biopsies. EGFR immunohistochemistry (IHC), fluorescence in-situ hybridization (FISH), and mutational analysis were performed. RESULTS: 41 patients were enrolled: 17 in cohort 1 and 24 in cohort 2. Notable grade 3 or 4 toxicities included allergic reaction (1), diarrhea/electrolyte abnormalities (3), ischemic colitis (1), and renal failure (3) and electrolyte abnormalities (n=2). Mean number of cycles for cohort 2 was 3.3. Overall clinical benefit rate was 67.5% with 11 (27.5%) partial responses (PR), 16 (40.0%) stable disease (SD), and 7 (17.5%) progressive disease. Responses were of short duration. All pre and post treatment biopsies exhibited 2-3+ EGFR staining. 5 of 14 patients (35%) were found to have EGFR amplification (n=3) or high polysomy/trisomy (n=2). These five patients had either a PR (n=3) or SD (n=2). Gain of function mutations were not been identified. CONCLUSIONS: This is the first reported controlled trial evaluating erlotinib for the management of vulvar carcinoma. Toxicities were acceptable given the lack of treatment options for these patients. Given the observed clinical benefits erlotinib may represent one of the most active agents available to treat vulvar SCC.

Long-term adjustment of early-stage ovarian cancer survivors.

The objectives of this study were to describe the quality of life (QOL), consequences of treatment, complementary therapy use, and factors correlating with psychologic state in 58 survivors of early-stage ovarian cancer since little is known about the QOL of early-stage ovarian cancer survivors. Survivors were interviewed using standardized measures to assess physical, psychologic, social, and sexual functioning; impact of cancer on socioeconomic status; and complementary therapy use. Survivors reported good physical QOL scores and few unmet needs. However, menopausal symptoms and negative impact on sexuality were reported. Less than 10% of survivors reported either an interest in sex or were sexually active. Psychologic assessment yielded a subset of 26% of patients with scores suggestive of posttraumatic stress disorder (PTSD) and 40% of survivors scored below the norm on the Mental Health Inventory-17 Survey. One third of patients required treatment for family/personal problems and took antianxiety medications. About 56% of survivors reported fear of cancer recurrence and 59% reported anxiety when their CA125 is tested. Better mental health was significantly related to less fatigue (Functional Assessment of Cancer Therapy [FACT]-fatigue, r = 0.61, P < 0.0001), less pain (European Organisation for Research and Treatment of Cancer [EORTC], r =-0.54, P < 0.0001), fewer stressful life events (Life Event Scale, r =-0.44, P > 0.001), and greater social support (MOS Social Support Survey, r = 0.41, P < 0.01). Early-stage ovarian cancer survivors had few physical complaints and unmet needs, but psychologic distress was evident in a subset of survivors; the majority of survivors reported sexual dysfunction. These results indicate the need for intervention and improved distress screening in the early-stage ovarian cancer population.

Docetaxel administered on a weekly basis for metastatic breast cancer.

PURPOSE: To evaluate the safety and efficacy of weekly docetaxel in women with metastatic breast cancer. PATIENTS AND METHODS: Twenty-nine women were enrolled onto a study of weekly docetaxel given at 40 mg/m(2)/wk. Each cycle consisted of 6 weeks of therapy followed by a 2-week treatment break, repeated until disease progression or removal from study for toxicity or patient preference. Fifty-two percent of patients had been previously treated with adjuvant chemotherapy; 21% had received prior chemotherapy for metastatic breast cancer, and 31% had previously received anthracyclines. All patients were assessable for toxicity; two patients were not assessable for response but are included in an intent-to-treat analysis. RESULTS: Patients received a median of 18 infusions, with a median cumulative docetaxel dose of 720 mg/m(2). There were no complete responses. Twelve patients had partial responses (overall response rate, 41%; 95% confidence interval, 24% to 61%), all occurring within the first two cycles. Similar response rates were observed among subgroups of patients previously treated either with any prior chemotherapy or with anthracyclines. An additional 17% of patients had stable disease for at least 6 months. The regimen was generally well tolerated. There was no grade 4 toxicity. Only 28% of patients had any grade 3 toxicity, most commonly neutropenia and fatigue. Acute toxicity, including myelosuppression, was mild. Fatigue, fluid retention, and eye tearing/conjunctivitis became more common with repetitive dosing, although these side effects rarely exceeded grade 2. Dose reductions were made for eight of 29 patients, most often because of fatigue (n = 5). CONCLUSION: Weekly docetaxel is active in treating patients with metastatic breast cancer, with a side effect profile that differs from every-3-weeks therapy.

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.

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 x 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.

Interleukin-3 and p210 BCR/ABL activate both unique and overlapping pathways of signal transduction in a factor-dependent myeloid cell line.

Chronic myelogenous leukemia (CML) is characterized by a specific chromosomal translocation occurring between the long arms of chromosomes 9 and 22 resulting in a fusion product, p210 BCR/ABL, which has elevated tyrosine kinase activity. Expression of p210 BCR/ABL in murine interleukin-3 (IL-3)--dependent cell lines typically converts these cell lines to factor-independence by a non-autocrine mechanism. The IL-3 receptor is believed to function in part by activating a receptor-associated tyrosine kinase, leading to the hypothesis that p210 BCR/ABL may induce factor-independence of myeloid cells by constitutively phosphorylating some common signal-transducing proteins that normally would be phosphorylated on tyrosine residues in response to IL-3. p210 BCR/ABL subclones were constructed from an IL-3-dependent murine myeloid cell line, 32Dcl3, by transfection of a plasmid containing a full-length p210 BCR/ABL cDNA. Following transfection, the cells became completely factor-independent within 3 weeks. We examined the effects of p210 BCR/ABL and IL-3 on the pattern of tyrosine phosphorylation of cellular proteins in 32Dcl3 cells using one- and two-dimensional antiphosphotyrosine immunoblotting. WEHI-3B conditioned media (WEHI-CM) was used as a source of IL-3. The introduction of p210 BCR/ABL results in constitutively increased levels of tyrosine phosphorylation of more than 20 new proteins, while WEHI-CM induced transient tyrosine phosphorylation of 6 to 10 new proteins. Using two-dimensional immunoblots to examine phosphoproteins, four categories could be identified: (1) proteins that are inducibly tyrosine phosphorylated in response to WEHI-CM in 32Dcl3 cells only, (2) proteins inducibly tyrosine phosphorylated by WEHI-CM only in p210 BCR/ABL+ cells, (3) proteins that are inducibly tyrosine phosphorylated in response to WEHI-CM in both 32Dcl3 cells and p210 BCR/ABL+ cells, and (4) proteins inducibly tyrosine phosphorylated in response to WEHI-CM and constitutively phosphorylated in the presence of p210 BCR/ABL. We have identified one of the proteins in category 4 as p42 mitogen-activated protein (MAP) kinase (ERK2). Overall, however, we found that the signal transduction pathways of IL-3 and BCR/ABL are strikingly different, suggesting that most of the immediate substrates of the IL-3 receptor-activated tyrosine kinase and p210 BCR/ABL kinase are different. Convergence of signaling pathways at p42 MAP kinase is of interest since activation of this kinase has been linked to mitogenesis in many systems. Identification of the overlapping proteins of both IL-3 signal transduction in 32Dcl3 cells and p210 BCR/ABL+ cells may help explain the growth-promoting effects of this oncogene.

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.