Chimeric anti-CD20 (IDEC-C2B8) monoclonal antibody sensitizes a B cell lymphoma cell line to cell killing by cytotoxic drugs

More than 50% of patients with aggressive B lymphomas and the majority of patients with low grade lymphomas are not cured by current therapeutic strategies. The lymphomas express the B cell antigen CD20 on the cell surface and this antigen serves as target for antibody-directed therapies. Clinical studies with encouraging results have been underway with the use of a chimeric anti-CD20 antibody (IDEC-C2B8), consisting of human IgG1-6 constant regions and variable regions from the murine monoclonal anti-CD20 antibody IDEC-2B8. This study investigated the potential anti-tumor therapeutic value of combination treatment with anti-C2B8 and cytotoxic drugs. The in vitro study examined the sensitizing effect of C2B8 antibody on the DHL-4 B lymphoma line to various cytotoxic agents. Cytotoxicity was determined by the MTT assay. Surface and cytoplasmic proteins were determined by flow cytometry. Pretreatment of DHL-4 with C2B8 resulted in inhibition of cell proliferation and cell death and a fraction of the cells underwent apoptosis. While the DHL-4 tumor cells were relatively resistant to several cytotoxic drugs, pretreatment with C2B8 rendered the cells sensitive to TNF-alpha, ricin, diphtheria toxin (DTX), adriamycin and cisplatin but not to VP-16. Chemosensitization of DHL-4 tumor cells was not due to downmodulation of either the MDR-1 or bcl-2 gene products. However, treatment of DHL-4 with C2B8 inhibited TNF-alpha secretion. These findings demonstrate that C2B8 antibody potentiates the sensitivity of DHL-4 tumor cells to several cytotoxic agents. Further, the findings suggest that combination treatments with C2B8 antibody and drugs may be of clinical benefit in the treatment of patients with resistant aggressive B lymphomas.

Role of natural killer cells in the destruction of circulating tumor emboli

A close correlation was demonstrated between levels of host natural cytotoxic (NC) and/or natural killer (NK) cell activity and capacity to eliminate blood-borne tumor cells. The outcome of experimental metastasis of several tumors with defined biologic behavior was studied in syngeneic mice exhibiting low NK cell activity [3-wk-old normal mice and cyclophosphamide (Cy)-treated adult mice] and high NK cell activity (normal adult mice). An iv injection of metastatic tumor cells into 3-week-old or Cy-treated mice markedly enhanced experimental pulmonary metastasis. The increased incidence of metastasis in mice exhibiting low activity of NK cells was not due to enhanced tumor cell arrest in the lung but rather to increased tumor cell survival. Boosting the NK activity of 3-week-old, but not Cy-treated, mice with interferon inducers inhibited metastasis formation. The adoptive transfer of spleen cells from syngeneic mice or allogeneic nude mice that have high NK activity shortly before (but not after) iv tumor challenge abrogated the Cy-induced enhancement of metastasis. The reactive lymphoid cells were non-T, nonadherent to nylon wool, sensitive to Cy treatment, and endowed with a natural ability to kill tumor cells during a short (12-24 hr) period. The conclusions were that NC-NK cells are important in host defense against circulating tumor cells and therefore can prevent the development of tumor cells into metastases.

Gestational age-dependent expression of IL-10 and its receptor in human placental tissues and isolated cytotrophoblasts

Control of antifetal immune responses is thought to be regulated locally by the placenta. Because the physiologic programming of the placenta across gestation is likely to influence the local immunity, we hypothesize that a potent anti-inflammatory cytokine such as IL-10 may be produced in a gestational age-dependent manner. In the present study, we examined the expression of IL-10 and its receptor in placental explants or freshly isolated cytotrophoblasts from different gestational ages and compared it with the expression profiles of other cytokines. First and second trimester placental tissues from normal pregnancies predominantly expressed IL-10, whereas the levels of IL-2, IL-4, and IFN-gamma were mostly below detection throughout pregnancy. The expression of IL-10, but not its receptor, diminished significantly in term placental tissues collected "before" the onset of labor and did not change appreciably "after" labor. On the other hand, TNF-alpha and IL-1beta were significantly up-regulated in response to labor-associated conditions. IL-10 expression was transcriptionally attenuated at term as observed in cytotrophoblasts. In contrast to the placental cytokine milieu, autologous PBMCs, when activated with PHA, secreted significant amounts of IL-2, IL-4, IL-10, and IFN-gamma, albeit with a statistically significantly enhanced IL-10 production in first trimester compared with age-matched nonpregnant women. These data suggest that IL-10 is expressed in the placenta in a gestational age-dependent manner and that its down-regulation at term may be an important mechanism underlying the subtle changes associated with parturition.

Consensus guidelines from The American Society of Peritoneal Surface Malignancies on standardizing the delivery of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer patients in the United States

BACKGROUND

The American Society of Peritoneal Surface Malignancies (ASPSM) is a consortium of cancer centers performing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). This is a position paper from the ASPSM on the standardization of the delivery of HIPEC.

METHODS

A survey was conducted of all cancer centers performing HIPEC in the United States. We attempted to obtain consensus by the modified method of Delphi on seven key HIPEC parameters: (1) method, (2) inflow temperature, (3) perfusate volume, (4) drug, (5) dosage, (6) timing of drug delivery, and (7) total perfusion time. Statistical analysis was performed using nonparametric tests.

RESULTS

Response rates for ASPSM members (n = 45) and non-ASPSM members (n = 24) were 89 and 33 %, respectively. Of the responders from ASPSM members, 95 % agreed with implementing the proposal. Majority of the surgical oncologists favored the closed method of delivery with a standardized dual dose of mitomycin for a 90-min chemoperfusion for patients undergoing cytoreductive surgery for peritoneal carcinomatosis of colorectal origin.

CONCLUSIONS

This recommendation on a standardized delivery of HIPEC in patients with colorectal cancer represents an important first step in enhancing research in this field. Studies directed at maximizing the efficacy of each of the seven key elements will need to follow.

Long-term toxicity of cisplatin in germ-cell tumor survivors

CONTEXT

Testicular germ-cell tumors (GCT) are highly curable. A multidisciplinary approach, including cisplatin-based chemotherapy has resulted in cure in the majority of patients with GCT. Thus, the life expectancy of survivors will extend to many decades post-diagnosis. Late treatment toxicities associated with cisplatin-based chemotherapy may impact their future health.

OBJECTIVE

To systematically evaluate evidence regarding the long-term toxicity of cisplatin in GCT survivors.

EVIDENCE ACQUISITION

We carried out a critical review of PubMed/Medline in February 2017 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. Identified reports were reviewed according to the Consolidated Standards of Reporting Trials (CONSORT) criteria. Eighty-three publications were selected for inclusion in this analysis.

EVIDENCE SYNTHESIS

Included reports evaluated long-term toxicities of cisplatin-based chemotherapy in GCT survivors. Studies reporting neuro- and ototoxicity, secondary malignancies, cardiovascular, renal and pulmonary toxicities, hypogonadism and infertility were found. Seven studies (8%) reported genetic underpinnings of long-term toxicities and 3 (4%) and 14 (19%) studies correlated long-term toxicities with circulating platinum levels and cumulative dose of cisplatin, respectively. Significant risks for long-term toxicities associated with cisplatin and platinum-based regimens were reported. The cumulative dose of cisplatin and circulating platinum were reported as risk factors. Several single-nucleotide polymorphisms identified patients susceptible to cisplatin compared with wild-type individuals.

CONCLUSIONS

GCT survivors cured with cisplatin-based chemotherapy are at risk for long-term side-effects. Detection of single-nucleotide polymorphisms could be a valuable tool for predicting long-term toxicities.

PATIENT SUMMARY

Herein, this article summarizes the available evidence of long-term toxicity of cisplatin-based chemotherapy in GCT survivors and provide insights from Indiana University.

Prognostic significance of postchemoradiation stage following preoperative chemotherapy and radiation for advanced/recurrent rectal cancers

PURPOSE

To evaluate the prognostic significance of postchemoradiation pathologic stage and implications for further therapy following preoperative chemoradiation and surgery for advanced/recurrent rectal cancer.

METHODS AND MATERIALS

Seventy-seven patients with advanced (fixed or tethered T4) or recurrent rectal cancer were treated with preoperative chemoradation followed by surgical resection of disease. Chemotherapy consisted of either of bolus 5-FU 500 mg/m(2) per day or continuous venous infusion 225 mg/m(2) per day for the duration of radiation. Radiation therapy was planned to be delivered to the whole pelvis to a dose of 45 Gy followed by a boost to the area of the tumor of 5-15 Gy. Total radiation doses ranged from 40 to 63 Gy with a median of 55.8 Gy. Surgical resection was then carried out 6-10 weeks following the completion of treatment (median, 7 weeks). Twenty-eight patients underwent abdominoperineal resection and and 49 patients had sphincter-sparing surgical procedures. None of the patients received postoperative chemotherapy. Follow-up in these patients ranges from 1 year to 8 years with a median of 3 years.

RESULTS

Significant downstaging of disease was observed with 12/77 (16%) having no residual disease(pT0) and 13% (10/77) found to have pT1-2, N0 disease, 31% (24/77) with pT3-4, N0 and 40% (31/77) for pT0-4, N1-2 cancers. Survival by pathologic stage was 100% for pT0-2, N0 cancers, 80% for pT3-4, N0 and 73% for pTx, N1-2. Local recurrence of disease was observed in 0% of patients with pT0-2, N0 as compared with 13% (3/24) in pT3-4, N0 and 16% (5/31) in pT0-4, N1-2 patients.

CONCLUSION

Downstaging following preoperative chemoradiation is a significant prognostic factor. Patients with pT0, T1, or T2 disease have an excellent prognosis and are unlikely to fail locally or with systemic disease. However, patient with T3/T4 or N+ disease may benefit from further adjuvant chemotherapy.

Expression of metastatic potential of tumor cells in young nude mice is correlated with low levels of natural killer cell-mediated cytotoxicity

Of 6- and 3-week-old nude mice given intravenous injections of murine tumor cells with well-defined metastatic properties, only the 3-week-old mice developed lung tumor colonies in significant numbers. The quantitative differences in metastatic potential among tumor cell lines injected into syngeneic recipients were also maintained following intravenous injection into young nude mice. Successful metastasis in 3-week-old nude mice is correlated with the low levels of natural killer cell activity detected in these young recipients. Boosting of the natural killer cell activity of 3-week-old nude mice by the administration of bacterial adjuvants and interferon inducers significantly inhibited metastasis formation. The differences in metastasis development could not be attributed to differences in the initial arrest of tumor cells in the pulmonary vascular bed, but rather to a better survival of the arrested cells in the lungs of 3-weeks-old nude mice as compared with 6-week-old counterparts. We concluded that low levels of NK cell activity are associated with increased incidence of experimental metastasis.

Structural analysis of the human immunodeficiency virus-binding domain of CD4. Epitope mapping with site-directed mutants and anti-idiotypes

The CD4 molecule, a differentiation marker expressed primarily by T lymphocytes, plays an important role in lymphocyte activation. CD4 is also the receptor for HIV. A number of recent studies have localized the high affinity binding site of the HIV envelope glycoprotein, gp120, to the NH2-terminal (V1) domain of CD4, a region with sequence and predicted structural homology with Ig kappa chain V domains (V kappa). In this report, we show that V1 bears structural similarities with V kappa regions through detailed epitope mapping of 26 CD4 mAbs. The binding sites of these mAbs were initially defined relative to one another by crossblocking analysis and were then localized to specific domains of CD4 in blocking studies with truncated, soluble CD4 proteins. The epitopes within the V1 domain were mapped in detail with a panel of 17 substitution mutants, and the specificities of several mAbs that appear to recognize very similar epitopes were examined in crossblocking studies with anti-idiotype antibodies. The location of the epitopes is consistent with a V kappa-like structure of V1. Most of the epitopes lie within regions of predicted exposed loops. A number of these epitopes span discontinuous residues in the linear sequence that lies in close proximity in an Ig fold. Alignment of CD4 V1 with the Ig V kappa chains places these epitopes within stretches corresponding to the complimentarity-determining regions. This epitope analysis is relevant for a vaccine strategy for HIV based on anti-idiotype antibodies to CD4 mAbs and for studies with CD4 antibodies on the role of CD4 in T lymphocyte activation.

Role of natural killer cells in control of cancer metastasis

There is a close association between levels of natural killer (NK) cell activity and the ability of the host to eliminate circulating tumor cell emboli. Mice that exhibit low levels of NK-cell-mediated cytotoxicity (3-week-old syngeneic mice, 3-week-old allogeneic nude mice, cyclophosphamide- or beta-estradiol-treated mice, and beige mice) also exhibit enhanced survival of tumor cells in the vascular bed of the lung and increased incidence of pulmonary tumor metastasis. Conversely, hosts with high NK cell activity (adult nude mice and syngeneic mice treated with NK-cell-stimulating biological response modifiers (BRM) ) are very resistant to metastasis. Lymphoid adoptive transfer studies have shown that the effector cell responsible for the antimetastatic activity is the NK cell. In these studies, NK cells were highly effective in destroying circulating tumor cells before their extravasation into the organ parenchyma, whereas they exerted only a minimal inhibiting effect on already established micrometastases. The ability to activate NK cells selectively (without subsequently inducing suppressor macrophages) provides a valuable tool for the evaluation of the role of activated NK cells in therapy of tumor metastasis. The validity of this approach is supported by the finding that NK cells activated by BRM are effective in killing, both in vivo and in vitro, solid tumor cells that developed NK-cell-resistance as a result of adaptive growth in vivo or selection during the metastatic process. An understanding of the mechanisms that regulate NK cell activation or suppression as well as elucidation of the circulatory patterns and anatomical compartmentalization of activated NK cells will help achieve a sustained systemic and/or in situ activation of NK cells which may prove effective in the control of cancer metastasis.

Elimination of Fc receptor-dependent effector functions of a modified IgG4 monoclonal antibody to human CD4

Several CD4 mAbs have entered the clinic for the treatment of autoimmune diseases or transplant rejection. Most of these mAbs caused CD4 cell depletion, and some were murine mAbs which were further hampered by human anti-mouse Ab responses. To obviate these concerns, a primatized CD4 mAb, clenoliximab, was generated by fusing the V domains of a cynomolgus macaque mAb to human constant regions. The heavy chain constant region is a modified IgG4 containing two single residue substitutions designed to ablate residual Fc receptor binding activity and to stabilize heavy chain dimer formation. This study compares and contrasts the in vitro properties of clenoliximab with its matched IgG1 derivative, keliximab, which shares the same variable regions. Both mAbs show potent inhibition of in vitro T cell responses, lack of binding to complement component C1q, and inability to mediate complement-dependent cytotoxicity. However, clenoliximab shows markedly reduced binding to Fc receptors and therefore does not mediate Ab-dependent cell-mediated cytotoxicity or modulation/loss of CD4 from the surface of T cells, except in the presence of rheumatoid factor or activated monocytes. Thus, clenoliximab retains the key immunomodulatory attributes of keliximab without the liability of strong Fcgamma receptor binding. In initial clinical trials, these properties have translated to a reduced incidence of CD4+ T cell depletion.

An emulsion formulation of amphotericin B improves the therapeutic index when treating systemic murine candidiasis

Incorporating amphotericin B into liposomes was reported to decrease amphotericin B toxicity without a concomitant loss of antifungal efficacy. We formulated an alternative emulsion-based delivery system for amphotericin B and compared it with Fungizone. The maximal tolerated dose (MTD) in mice was 1 mg of Fungizone/kg; however, the MTD was greater than 9 mg of the Intralipid emulsion formulation/kg. The emulsion formulation and Fungizone were equipotent for treating systemic candidiasis in mice. Amphotericin B nephrotoxicity, as manifested by polyuria that was resistant to antidiuretic hormone, was markedly diminished when amphotericin B was administered as an emulsion to rats. Loss of potassium from human red blood cells was also reduced by formulating this agent within emulsions. The emulsion formulation extended the survival time of mice that had established Candida albicans infections, when compared with the Fungizone treatment. The efficacy and reduced toxicity of the amphotericin B emulsion are findings suggesting that the emulsion formulation is preferable to Fungizone.

Two-dimensional and 3-dimensional optical coherence tomographic imaging of the airway, lung, and pleura

BACKGROUND

Methods for obtaining real-time in vivo histologic resolution by means of noninvasive endoscopic optical imaging would be a major advance for thoracic surgical diagnostics and treatment. Optical coherence tomography is a rapidly evolving technology based on near-infrared interferometry that might provide these capabilities. The purpose of this study is to investigate the feasibility of real-time 2- and 3-dimensional optical coherence tomographic imaging of airway, pleural, and subpleural lung tissues in normal, inflammatory, and malignant animal models and patients with known or suspected airway malignancy.

METHODS

Freshly excised lungs and pleural tissue obtained from rabbits with inhalation lung injury and induced empyema, metastatic sarcomas, and pleural sarcomas and from patients with airway disease were imaged by using 2- and 3-dimensional optical coherence tomography with a prototype superluminescent diode optical coherence tomographic system constructed in our laboratory. Lungs and pleural tissue were subsequently processed for standard hematoxylin and eosin histology for comparison with optical coherence tomography.

RESULTS

Optical coherence tomographic imaging achieved an ex vivo resolution of 10 microm and an in vivo resolution of about 30 microm with a depth penetration of 1 to 2 mm with 2- and 3- dimensional reconstruction capabilities. Tumors as small as 500 microm were detectable with optical coherence tomography. The acquired images closely matched histologic images, demonstrating details at the level of mucosal layers, glands, alveoli, and respiratory bronchioles.

CONCLUSIONS

Optical coherence tomography with near-infrared interferometric methods enables near real-time in vivo near-histologic resolution optical imaging. With further advances, optical coherence tomography has the potential for real-time accurate and early pleural and subpleural diagnostics by using small-diameter flexible fiberoptic endoscopic probes for a wide range of thoracic surgical applications.

Effect of storage on breast milk antioxidant activity

BACKGROUND

Human milk, which contains compounds beneficial to infants, is often expressed and stored before use. Changes in its antioxidant activity with storage have not been studied.

OBJECTIVES

To measure antioxidant activity of fresh, refrigerated (4 degrees C), and frozen human milk (-20 degrees C), stored for two to seven days; to compare the antioxidant activity of milk from mothers delivering prematurely and at term; to compare the antioxidant activity of infant formulas and human milk.

METHODS

Sixteen breast milk samples (term and preterm) were collected from mothers within 24 hours of delivery and divided into aliquots. Fresh samples were immediately tested for antioxidant activity, and the rest of the aliquots were stored at -20 degrees C or 4 degrees C to be analysed at 48 hours and seven days respectively. The assay used measures the ability of milk samples to inhibit the oxidation of 2,2'-azino-di-3-(ethylbenzthiazolinesulphonate) to its radical cation compared with Trolox.

RESULTS

Antioxidant activity at both refrigeration and freezing temperatures was significantly decreased. Freezing resulted in a greater decrease than refrigeration, and storage for seven days resulted in lower antioxidant activity than storage for 48 hours. There was no difference in milk from mothers who delivered prematurely or at term. Significantly lower antioxidant activity was noted in formula milk than in fresh human milk.

CONCLUSIONS

To preserve the antioxidant activity of human milk, storage time should be limited to 48 hours. Refrigeration is better than freezing and thawing.

Updated survival and outcomes for older adults with inoperable stage III non-small-cell lung cancer treated with cisplatin, etoposide, and concurrent chest radiation with or without consolidation docetaxel: analysis of a phase III trial from the Hoosier Oncology Group (HOG) and US Oncology

BACKGROUND

Concurrent chemoradiation with etoposide and cisplatin (EP/XRT) is standard treatment for inoperable stage III locally advanced non-small-cell lung cancer (LA-NSCLC). Consolidation docetaxel (D; Taxotere) after EP/XRT resulted in increased toxicity but no improvement in survival compared with observation (O). We report updated survival for the entire study population and include an analysis of efficacy and tolerability of EP/XRT with or without D in patients aged ≥ 70 years.

PATIENTS AND METHODS

Hoosier Oncology Group LUN 01-24 enrolled 243 patients with LA-NSCLC and randomized 166 after EP/XRT to three cycles of D versus O. the trial was terminated after an analysis of the first 203 patients demonstrated futility of D.

RESULTS

Median survival time (MST) for the overall study population was 21.5 months, and 3-, 4-, and 5-year survival rates were 30.7%, 18.0%, and 13.9%, respectively. No differences in MST or 3-year survival were noted between D and O arms. Older patients had similar MST (17.1 versus 22.8 months for younger patients, P = 0.15) but higher rates of grade 3/4 toxicity and hospitalization during induction.

CONCLUSIONS

Consolidation docetaxel after EP/XRT does not improve survival in LA-NSCLC. Fit older adults with LA-NSCLC benefit from concurrent chemoradiation similarly as younger patients but experience higher rates of hospitalization and toxicity.

“Primatization” of Recombinant Antibodies for Immunotherapy of Human Diseases: A Macaque/Human Chimeric Antibody Against Human CD4

Immunoglobulin variable region genes from non-human primates, cynomolgus macaques, were shown to have 85%-98% homology with human immunoglobulin sequences and yet macaques are phylogenetically distant enough to respond against conserved human antigens. Immunoglobulin genes were isolated from monkeys immunized with human CD4 antigen and a human/monkey chimeric anti-CD4 antibody with 91-92% homology to human immunoglobulin framework regions was cloned and expressed. The antibody has an apparent affinity of 3.2 x 10(-11) M and exhibits potent immunosuppressive properties in vitro.

SK&F 86002: a structurally novel anti-inflammatory agent that inhibits lipoxygenase- and cyclooxygenase-mediated metabolism of arachidonic acid

The effects of SK&F 86002 [5-(4-pyridyl)-6 (4-fluorophenyl)-2,3-dihydroimidazo (2,1-b) thiazole] on the generation of eicosanoids in vitro and on inflammatory responses in vivo are described and compared to other non-steroidal anti-inflammatory drugs. SK&F 86002 inhibited prostaglandin H2 (PGH2) synthase activity (IC50 120 microM) as well as prostanoid production by rat basophilic leukemia (RBL-1) cells (IC50 70 microM) and its sonicate (IC50 100 microM) and human monocytes (IC50 1 microM). In addition, SK&F 86002 inhibited the generation of dihydroxyeicosatetraenoic acid (diHETE) and 5-hydroxyeicosatetraenoic acid (5-HETE) by a high speed supernatant fraction of RBL-1 cells (IC50 10 microM). Cellular production of 5-lipoxygenase products was inhibited by SK&F 86002 as measured by leukotriene B4 (LTB4) generation from human neutrophils (IC50 20 microM), leukotriene C4 (LTC4) generation by human monocytes (IC50 20 microM), and 5-HETE production by RBL-1 cells (IC50 40 microM). The in vivo profile of anti-inflammatory activity of SK&F 86002 supports the dual inhibition of arachidonate metabolism as indicated by its activity in inflammation models that are insensitive to selective cyclooxygenase inhibitors. The responses of arachidonic-acid-induced edema in the mouse ear and rat paw, as well as the cell infiltration induced by carrageenan in the mouse peritoneum and by arachidonic acid in the rat air pouch, were inhibited by SK&F 86002 and phenidone but not by the selective cyclooxygenase inhibitors naproxen and indomethacin.

Inhibition of monocyte IL-1 production by the anti-inflammatory compound, SK&F 86002

The effects of several anti-inflammatory/anti-arthritic drugs on the in vitro production of interleukin-1 (IL-1) by human monocytes were examined. SK&F 86002, a novel dihydroimidazo thiazoline which inhibits both 5-lipoxygenase- and cyclooxygenase-mediated arachidonate metabolism was shown to be a potent inhibitor of IL-1 production by LPS-stimulated human monocytes. The inhibition was dose-dependent (IC50 = 1.30 +/- 1 microM), reversible and was independent of the concentration or type of stimulus used. The compound also inhibited cell-associated IL-1 activity. The compound did not exert general inhibitory effects on such parameters as adherence, cytotoxic function and protein synthesis of the monocytes. Other cyclooxygenase and/or 5-lipoxygenase inhibitors of arachidonic acid metabolism tested, with the exception of nordihydroguaiaretic acid, were inactive in inhibiting monocyte IL-1 production suggesting that the inhibition of IL-1 production by 86002 may be dissociated from its inhibition of the fatty acid oxygenases. The inhibition of IL-1 production by SK&F 86002 adds another facet of drug action contributing to its spectrum of anti-inflammatory activities.

The impact of induction chemotherapy on the outcome of second-line therapy with pemetrexed or docetaxel in patients with advanced non-small-cell lung cancer

BACKGROUND

Using data from a large phase III study of previously treated advanced non-small-cell lung cancer (NSCLC) that showed similar efficacy for pemetrexed and docetaxel, this retrospective analysis evaluates the impact of first-line chemotherapy on the outcome of second-line chemotherapy.

PATIENTS AND METHODS

In all, 571 patients with advanced NSCLC were randomly assigned to receive pemetrexed 500 mg/m(2) or docetaxel 75 mg/m(2) on day 1 of a 21-day cycle. Comparisons were made based on type of first-line therapy [gemcitabine + platinum (GP), taxane + platinum (TP), or other therapies (OT)], response to initial therapy, time since initial therapy, and clinical characteristics. The two second-line treatment groups were pooled for this analysis due to similar efficacy and were assumed to have no interaction with the first-line therapies.

RESULTS

Baseline characteristics were generally balanced. By multivariate analysis, gender, stage at diagnosis, performance status (PS), and best response to first-line therapy significantly influenced overall survival (OS). Additional factors by univariate analysis, histology, and time elapsed from first- to second-line therapy significantly influenced OS.

CONCLUSIONS

Future trials in the second-line setting should stratify patients by gender, stage at diagnosis, PS, and best response to first-line therapy.

The pharmacology of arachidonic acid-induced rat paw edema

Arachidonic acid (AA) injected into hindpaws of Lewis rats produces a severe edematous response. Treatment with corticosteroids (dexamethasone, prednisolone), dual inhibitors of arachidonate metabolism (phenidone, SK & F 86002), anti-histamine/serotonin agents (chlorpheniramine, cyproheptadine) and a gold compound (auranofin) inhibited AA-induced edema. In contrast, administration of high doses of cyclooxygenase inhibitors (indomethacin, piroxicam, naproxen, ibuprofen, meclofenamic acid and tiflamizole) did not affect AA-induced hind paw edema. The involvement of lipoxygenase products and mast cell mediators in the edematous response to arachidonic acid render this model potentially useful for studying antiinflammatory agents with a mechanism of action different from that of cyclooxygenase inhibitors.

Induction of antigen-specific class I-restricted cytotoxic T cells by soluble proteins in vivo

Cytotoxic T lymphocytes (CTL) are induced specifically against viral and tumor antigens presented by major histocompatibility complex class I molecules on the surface of infected or transformed cells. Intracellular synthesized antigens are processed and associated with class I antigens within cells before presentation on the cell surface. Because of this special requirement for CTL induction, exogenous soluble antigens do not, in general, induce specific CTL responses. To overcome this problem, various laboratories have resorted to the use of vaccinia virus and other replicating expression vectors for intracellular antigen delivery leading to the stimulation of humoral and cell-mediated immunity to specific proteins. However, for human use it is safer to use purified and defined antigens for inducing immune responses. Using soluble ovalbumin and human immunodeficiency virus glycoprotein gp120, we have explored the possibility of using an antigen formulation consisting of squalane and Tween 80 to elicit antigen-specific CTL responses in mice. We have demonstrated that this antigen formulation is a potent inducer of CD8+, class I-restricted, antigen-specific CTLs. The CTL priming induced by soluble antigen in squalane/Tween 80 resembles the reported response to the vaccinia recombinant containing human immunodeficiency virus envelope protein and by splenocytes cytoplasmically loaded with soluble ovalbumin. The ramifications of these findings for vaccine development are discussed.