Gemcitabine in patients with non-small-cell lung cancer previously treated with platinum-based chemotherapy: a phase II California cancer consortium trial

A phase II trial was designed to evaluate the efficacy and toxicity of gemcitabine in patients with non-small-cell lung cancer (NSCLC) previously treated with platinum-containing regimens and prospectively categorized for platinum response status. Treatment consisted of gemcitabine 1000 mg/m2 given intravenously on days 1 and 8 of a 21-day cycle. The status of p53 in pretreatment tumor tissue was assessed by immunohistochemistry (IHC). Sixty-one patients who progressed or recurred following platinum-based therapy were enrolled, 26 platinum-sensitive and 35 platinum-refractory. A median of 4 treatment courses (range, 2-7 courses) was delivered. Of the 55 patients assessable for response, there was 1 confirmed complete response and 3 with a confirmed partial response for an overall response proportion of 7%. Twenty-one patients had stable disease while 28 progressed and 2 patients had an unconfirmed partial response. Three of the responders (2 confirmed, 1 unconfirmed) were platinum-refractory. Median progression-free survival (PFS) and overall survival for all patients were 4.1 months and 8.6 months, respectively. Median PFS and overall survival for the platinum-sensitive and platinum-refractory cohorts were 5.4 months versus 3.1 months, and 11.9 months versus 7.1 months, respectively. Toxicity was principally hematologic with grade 3/4 neutropenia in 21% and grade 4 platelets in 8%. There were no treatment-related deaths. Twenty-four of 33 patients (73%) had p53-positive tumors. Although no significant association between platinum sensitivity and p53 status was seen, patients with platinum-sensitive disease and negative p53 by IHC had a trend toward longer survival compared to those with platinum-refractory disease and/or p53 positivity (P = 0.06). We concluded that salvage gemcitabine in this dose and schedule is safe and tolerable in previously platinum-treated patients with NSCLC.     

Trastuzumab plus docetaxel in HER2/neu-positive non-small-cell lung cancer: a California Cancer Consortium screening and phase II trial

HER2 is reported to be overexpressed in 20% of cases of non-small-cell lung cancer (NSCLC), principally adenocarcinoma. Trastuzumab is a monoclonal antibody against HER2 that, when combined with a taxane, improves survival compared with chemotherapy alone in advanced breast cancer. In view of these observations, we conducted a phase II HER2 screening and efficacy trial of trastuzumab plus weekly docetaxel in cases of advanced NSCLC in which primary platinum-based therapy had failed. Patients with advanced or metastatic NSCLC were screened for HER2 overexpression by immunohistochemistry. Patients with HER2-positive tumors (2+ or 3+) were initially randomized to either single-agent trastuzumab or docetaxel. After completing 2 treatment cycles, all patients went on to receive the trastuzumab/docetaxel combination regardless of response to the single agents. Treatment consisted of docetaxel 30 mg/m2 weekly for 6 weeks followed by a 2-week break and trastuzumab 4 mg/kg intravenously on week 1 followed by 2 mg/kg per week thereafter. Cycle length was 8 weeks. Sixty-nine patients with NSCLC (33 men, 36 women) were screened between August 1999 and March 2001. Only 13 patients (19%) had HER2-positive disease; all 13 enrolled in the efficacy trial. Of 9 patients receiving docetaxel alone, 1 partial response (PR) was seen. None responded to trastuzumab alone. The overall outcomes to the sequence of single-agent therapy followed by combination therapy included a PR rate in 8% of cases, stable disease in 23%, progression in 46%, and nonassessable disease in 23%. Estimated event-free and overall survival times were 4.3 and 5.7 months, respectively. Treatment was well tolerated. The screening component of this trial demonstrated that the target population for trastuzumab therapy in NSCLC is relatively small. Because of the limited clinical activity of trastuzumab-based therapy in this cohort and the similar disappointing reports from other studies of trastuzumab in NSCLC, this trial was closed to further accrual. In view of the limited target population for HER2 inhibition, future efforts and resources should be directed toward molecular targets other than HER2 in NSCLC.     

Intermittent dosing of the farnesyl transferase inhibitor tipifarnib (R115777) in advanced malignant solid tumors: a phase I California Cancer Consortium Trial

Tipifarnib (R115777) inhibits farnesylation of key proteins that modulate signaling pathways implicated in cell growth and proliferation, including members of the Ras and Rho families. It has broad-spectrum antiproliferative activity in vitro and in vivo. Clinical trials employing a continuous administration schedule have demonstrated dose-limiting neurotoxicity and myelosuppression. Preclinical studies have shown that intermittent oral administration can suppress tumor growth comparable to continuous administration. We conducted a National Cancer Institute-sponsored phase I trial to determine the feasibility of an intermittent dosing schedule of R115777 given orally twice daily on weeks 1 and 3 of a 28-day cycle in patients with malignant solid tumors. Starting dose was 300 mg twice daily (b.i.d.) with escalation by 300 mg b.i.d. increments over six dose levels to a maximum of 1800 mg b.i.d. Dose-limiting toxicity (DLT) was defined as any grade 3 or 4 non-hematologic toxicity, grade 4 thrombocytopenia, grade 4 neutropenia (ANC) with fever (38.3 degrees C or above) or a documented infection. Twenty-one patients with advanced solid tumors, all of whom had prior systemic therapy, were accrued. Grade 3 fatigue was dose limiting for two of three patients at the 900 mg b.i.d. dose level. Although no responses were seen, four of six patients with stable disease remained on study for at least a year (16, 17, 13 and 12 months) before developing progressive disease. Three of these prolonged stable disease patients had non-small cell lung cancer. We conclude that intermittent dosing of R115777 is feasible and tolerable. The recommended phase II dose is 600 mg orally b.i.d. on alternate weeks.     

Fcgamma receptor IIa and IIIa polymorphisms in childhood immune thrombocytopenic purpura

Fcgamma receptor-mediated destruction of autoantibody-sensitized platelets is central to the immune pathophysiology of childhood immune thrombocytopenic purpura (ITP). Allelic variants exist among the random population for some Fcgamma receptors. The variants represent single nucleotide polymorphisms, leading to functional differences in the ability to bind immunoglobulin (Ig)G or IgG subclasses. The genotypic frequencies for two Fcgamma receptor single nucleotide polymorphisms, FcgammaRIIa-131 arginine (R) versus histidine (H) and FcgammaRIIIa-158 valine (V) versus phenylalanine (F) were examined in 98 children diagnosed with childhood ITP. The genotype frequencies were compared with those of 130 healthy control subjects. Chi-square analysis was used to determine whether the allelic frequencies of the high-affinity receptor variants were associated with childhood ITP. Both the FcgammaRIIa-131H and the FcgammaRIIIa-158V were significantly over-represented in children with ITP versus the control subjects (P-values 0.03). The same statistical difference was noted with the combined FcgammaRIIa-131H and FcgammaRIIIa-158V allelic gene frequencies. There was no statistical difference between children who later developed chronic ITP compared with children with acute ITP, suggesting that additional factors are responsible for the development of the chronic form of the disease. These observations underscore the importance of Fcgamma receptor-mediated cell clearance in childhood ITP.     

Diminution and enhancement of visuo-spatial neglect with sequential trials

We report three cases of visuo-spatial neglect after unilateral right hemisphere damage. Each patient undertook 100 sequential trials of line bisection. All patients were grossly impaired, placing their transections of the longer lines significantly to the right of true centre. When the trials were analysed in two consecutive halves, one patient showed only minimal differences in accuracy between the two blocks. One patient improved greatly on the second block, and one patient became significantly worse. The results are discussed in terms of differential learning and fatigue effects, and their clinical significance is outlined.     

Plasmodium falciparum erythrocyte membrane protein 1 is anchored to the actin-spectrin junction and knob-associated histidine-rich protein in the erythrocyte skeleton

A distinctive pathological feature of Plasmodium falciparum malaria is the endothelial attachment of erythrocytes infected with mature asexual-stage parasites in microvessels of the major organs. Electron-dense protrusions described as knobs are displayed on the surface of parasitized erythrocytes and act as attachment points in cytoadherence. Parasite-encoded knob-associated histidine-rich protein (KAHRP) is a major component of knobs found on the cytoplasmic side of the host cell membrane. P. falciparum erythrocyte membrane protein 1 (PfEMP1) is a family of parasite-encoded cytoadherence receptors localized to knobs on the surface of parasitized erythrocytes. Despite its high antigenic diversity, PfEMP1 has a remarkably conserved cytoplasmic domain. We demonstrate in this study that the cytoplasmic domain of PfEMP1 (VAR(CD)) binds to host spectrin and actin and to full-length KAHRP in vitro. Apparent dissociation constants determined for VAR(CD)/F-actin and VAR(CD)/KAHRP interactions are 44.9+/-6.4 and 10. 7+/-2.2 nM, respectively. Further, we provide evidence that KAHRP polypeptides self-associate in solution to form structures similar to knobs and show binding of self-associated KAHRP clusters to spectrin-actin-protein 4.1 complexes. Findings in this study suggest that PfEMP1 is localized to the knob in P. falciparum-infected erythrocytes by binding to the host spectrin-actin junction and to self-associated KAHRP through its conserved cytoplasmic domain.