Thomas K. Hoffmann

Icatibant, a New Bradykinin-Receptor Antagonist, in Hereditary Angioedema

BACKGROUNDnHereditary angioedema is characterized by recurrent attacks of angioedema of the skin, larynx, and gastrointestinal tract. Bradykinin is the key mediator of symptoms. Icatibant is a selective bradykinin B2 receptor antagonist.nnnMETHODSnIn two double-blind, randomized, multicenter trials, we evaluated the effect of icatibant in patients with hereditary angioedema presenting with cutaneous or abdominal attacks. In the For Angioedema Subcutaneous Treatment (FAST) 1 trial, patients received either icatibant or placebo; in FAST-2, patients received either icatibant or oral tranexamic acid, at a dose of 3 g daily for 2 days. Icatibant was given once, subcutaneously, at a dose of 30 mg. The primary end point was the median time to clinically significant relief of symptoms.nnnRESULTSnA total of 56 and 74 patients underwent randomization in the FAST-1 and FAST-2 trials, respectively. The primary end point was reached in 2.5 hours with icatibant versus 4.6 hours with placebo in the FAST-1 trial (P=0.14) and in 2.0 hours with icatibant versus 12.0 hours with tranexamic acid in the FAST-2 trial (P<0.001). In the FAST-1 study, 3 recipients of icatibant and 13 recipients of placebo needed treatment with rescue medication. The median time to first improvement of symptoms, as assessed by patients and by investigators, was significantly shorter with icatibant in both trials. No icatibant-related serious adverse events were reported.nnnCONCLUSIONSnIn patients with hereditary angioedema having acute attacks, we found a significant benefit of icatibant as compared with tranexamic acid in one trial and a nonsignificant benefit of icatibant as compared with placebo in the other trial with regard to the primary end point. The early use of rescue medication may have obscured the benefit of icatibant in the placebo trial. (Funded by Jerini; ClinicalTrials.gov numbers, NCT00097695 and NCT00500656.)

Combined analysis of HPV-DNA, p16 and EGFR expression to predict prognosis in oropharyngeal cancer

Molecular prognostic indicators for oropharyngeal squamous cell carcinoma (OSCC), including HPV‐DNA detection, epidermal growth factor receptor (EGFR) and p16 expression, have been suggested in the literature, but none of these are currently used in clinical practice. To compare these predictors, 106 newly diagnosed OSCC for the presence of HPV‐DNA and expression of p16 and EGFR were analyzed. The 5‐year disease‐free survival (DFS) and overall survival (OS) were calculated in relation to these markers and a multivariate Cox analysis was performed. Twenty‐eight percent of the cases contained oncogenic HPV‐DNA and 30% were positive for p16. The p16 expression was highly correlated with the presence of HPV‐DNA (p < 0.001). Univariate analysis of the 5‐year DFS revealed a significantly better outcome for patients with p16‐positive tumors (84% vs. 49%, p = 0.009). EGFR‐negative tumors showed a tendency toward a better prognosis in DFS (74% vs. 47%, p = 0.084) and OS (70% vs. 45%, p = 0.100). Remarkable and highly significant was the combination of p16 and EGFR expression status, leading to 5‐year DFS of 93% for p16+/EGFR− tumors vs. 39% for p16−/EGFR+ tumors (p = 0.003) and to a 5‐year OS of 79% vs. 38%, respectively (p = 0.010). In multivariate analysis p16 remained a highly significant prognostic marker for DFS (p = 0.030) showing a 7.5‐fold increased risk for relapse in patients with p16‐negative tumors. Our data indicate that p16 expression is the most reliable prognostic marker for OSCC and further might be a surrogate marker for HPV‐positive OSCC. HPV+/p16+ tumors tended to have decreased EGFR expression, but using both immunohistological markers has significant prognostic implications.

Diagnostic strategies in cervical carcinoma of an unknown primary (CUP)

Abstract. In patients with cervical cancer of an unknown primary (CUP), no established concept exists for the necessary diagnostic procedures. In order to find the primary tumor, extensive diagnostic steps are generally recommended; however, they are often not performed consistently. In the current study, we consistently used a diagnostic algorithm and analyzed its consequences on patients prognoses. We retrospectively studied 57 patients who were found to have a cervical metastasis of the upper- or midneck and an unknown primary tumor after routine examination of the head and neck region. Patients were analyzed for the value of applied diagnostic measures, tumor classification, survival rates and frequencies of subsequent lymph node or distant metastases after the initial treatment. Our results showed that a diagnostic algorithm (lymph node biopsy, rigid panendoscopy with systematic biopsies of suspect regions as well as blind biopsies of endoscopically inconspicuous regions, including the tongue base and nasopharynx and bilateral tonsillectomy) led to the detection of 14 occult oropharyngeal and 5 nasopharyngeal primary tumors in the patients. These tumors were primarily diagnosed as CUP. Oropharyngeal tumors either grew submucosally or were so small that only microscopic evaluation of the entire tonsil uncovered the tumor. Imaging procedures (X-ray, ultrasound, CT, MRT and FDG-PET) as well as gynecological, urological and gastroenterological consultations did not reveal the primary tumors in any of the cases. The 3-year survival rate for the patients with occult oropharyngeal primary tumors was 100% after treatment, while the patients in which our diagnostic schedule did not reveal a primary tumor showed a survival rate of 58%. The prognosis of all of the patients with cervical carcinoma metastasis was dependent on the initial nodal stage. Metachronous metastasis after completion of the initial treatment was prognostically infaust, while secondary detection of the primary tumor was worthwhile during follow-up as long as further treatment options were offered. The prognosis of patients with cervical carcinoma metastases of the upper- and midneck is much more favorable than that of patients with a CUP syndrome of other localizations. Identification of an occult pharyngeal tumor is prognostically relevant, since it opens up the possibility of specific locoregional treatment. In patients with cervical CUP, blind but systematic pharyngeal biopsies, including bilateral tonsillectomy, should be performed.

Tumor immune escape by the loss of homeostatic chemokine expression

The novel keratinocyte-specific chemokine CCL27 plays a critical role in the organization of skin-associated immune responses by regulating T cell homing under homeostatic and inflammatory conditions. Here we demonstrate that human keratinocyte-derived skin tumors may evade T cell-mediated antitumor immune responses by down-regulating the expression of CCL27 through the activation of epidermal growth factor receptor (EGFR)–Ras–MAPK-signaling pathways. Compared with healthy skin, CCL27 mRNA and protein expression was progressively lost in transformed keratinocytes of actinic keratoses and basal and squamous cell carcinomas. In vivo, precancerous skin lesions as well as cutaneous carcinomas showed significantly elevated levels of phosphorylated ERK compared with normal skin, suggesting the activation of EGFR–Ras signaling pathways in keratinocyte-derived malignancies. In vitro, exogenous stimulation of the EGFR–Ras signaling pathway through EGF or transfection of the dominant-active form of the Ras oncogene (H-RasV12) suppressed whereas an EGFR tyrosine kinase inhibitor increased CCL27 mRNA and protein production in keratinocytes. In mice, neutralization of CCL27 led to decreased leukocyte recruitment to cutaneous tumor sites and significantly enhanced primary tumor growth. Collectively, our data identify a mechanism of skin tumors to evade host antitumor immune responses.

Clinical trial with escalating doses of the antiepidermal growth factor receptor humanized monoclonal antibody EMD 72 000 in patients with advanced squamous cell carcinoma of the larynx and hypopharynx.

Abstract. In this open uncontrolled phase I study, nine patients with stage III and IV squamous cell carcinoma of the head and neck (SCCHN) were treated with five administrations of the humanized antiepidermal growth factor receptor monoclonal antibody EMD 72xa0000 in three consecutive ascending dose groups. Loading doses of 100xa0mg (group I), 200xa0mg (group II), and 400xa0mg (group III) were followed by four weekly maintenance doses of half the loading doses, i.e. 50, 100, and 200xa0mg, respectively. Two EMD 72xa0000 administrations were scheduled before and three after surgery. The objectives of this trial were (a) to investigate the safety and toxicity of multiple EMD 72xa0000 doses, (b) to determine the cumulative maximum tolerated dose of EMD 72xa0000xa0at dosages between 300xa0mg and 1200xa0mg, and (c) to determine the serum pharmacokinetics of EMD 72xa0000. In total, 102 adverse events (AEs) were reported: five of toxicity grade 3, 18 of toxicity grade 2, 66 of toxicity grade 1, and 38 of toxicity grade 0. All AEs of toxicity grade 3 were considered to be not or remotely related to EMD 72xa0000. The most frequent study drug-related AEs were fever and a transient elevation of liver enzymes. In all patients, the time to reach peak serum concentrations (tmax) was within 1–3xa0h of the start of each EMD 72xa0000 infusion. Average peak serum concentrations (Cmax) after correction for dosage appeared to be dose-independent, whereas the half-life (t1/2) showed dose dependency. In conclusion, EMD 72xa0000 was very well tolerated in patients with advanced stage SCCHN. The pharmacokinetic data from this trial suggest the feasibility of conducting future studies with weekly doses of 200xa0mg EMD 72xa0000.

Chemokine receptors in head and neck cancer: association with metastatic spread and regulation during chemotherapy.

Head and neck carcinomas are histologically and clinically heterogeneous. While squamous cell carcinomas (SCC) are characterized by lymphogenous spread, adenoid cystic carcinomas (ACC) disseminate preferentially hematogenously. To study cellular and molecular mechanisms of organ‐specific metastasis, we used SCC and ACC cell lines and tumor tissues, obtained from patients with primary or metastatic disease. Comprehensive analysis at the mRNA and protein level of human chemokine receptors showed that SCC and ACC cells exhibited distinct and nonrandom expression profiles for these receptors. SCC predominantly expressed receptors for chemokines homeostatically expressed in lymph nodes, including CC chemokine receptor (CCR) 7 and CXC chemokine receptor (CXCR)5. No difference in expression of chemokine receptors was seen in primary SCC and corresponding lymph node metastases. In contrast to SCC, ACC cells primarily expressed CXCR4. In chemotaxis assays, ACC cells were responsive to CXCL12, the ligand for CXCR4. Exposure of ACC cells to cisplatin resulted in upregulation of CXCR4 on the cell surface, which was repressed by the transcriptional inhibitor, α‐amanitin. Treatment of ACC cells with CXCL12 resulted in the activation of Akt and ERK1/2 pathways. Furthermore, CXCL12 suppressed the rate of apoptosis induced by cisplatin in ACC cells, suggesting that signaling via CXCR4 may be part of a tumor cell survival program. Discrimination of the chemokine receptor profile in SCC and ACC in vitro and in tissues provided insights into their distinct biologic and clinical characteristics as well as indications that chemokine receptors might serve as future therapeutic targets in these malignancies.

T cells specific for HPV16 E7 epitopes in patients with squamous cell carcinoma of the oropharynx

Squamous cell carcinomas of the oropharynx (SCCO) are often infected with oncogenic human papilloma virus (HPV) subtype 16. To determine the frequency of T cells specific for human leukocyte antigen (HLA)‐A2.1 restricted HPV16 E7 protein‐derived epitopes, tetramer analysis was performed using peripheral blood lymphocytes of 20 HLA‐A2.1+ patients and 20 HLA‐A2.1+ healthy individuals. Tetramers specific for 3 HPV16 peptides (E711–20, E782–90 and E786–93), an influenza matrix peptide (a model recall antigen) or an HIV reverse transcriptase peptide (a model novel antigen) were used in multicolor flow analysis. The HPV‐specific T‐cell frequencies were correlated with the HPV16 E7 and p16 status in tumor sections. In vitro stimulation (IVS) with autologous dendritic cells (DC) pulsed with HPV16 E7 epitopes was performed to demonstrate proliferation and antitumor activity of the HPV‐responsive T cells. Frequencies of CD8+ T cells specific for HPV16 E7 peptides were not significantly different in patients with SCCO relative to normal donors. However, patients with tumors expressing HPV16 E7 (60%) and p16 (50%) had an increased frequency (p < 0.05) of T cells specific for the E711–20 epitope compared to those with tumors negative for both markers. HPV16 E711–20 and HPV16 E786–93 specific T cells were expandable upon IVS with cognate peptide‐pulsed DC and were reactive against peptide‐pulsed targets or, in case of the E711–20 epitope‐specific T cells, against HPV16 E7 expressing CaSki cell line. Thus, in patients with HPV16+ SCCO, precursor T cells specific for E711–20 epitope are present (1/3,947) in the circulation, are responsive to stimulation with the cognate viral peptide and recognize in vitro HPV16 E7+ tumor cells. Further studies have to elucidate why those T cells are unable to eliminate the tumor in vivo and this might also allow for finding potential strategies that will increase the chances of developing a future HPV‐based vaccine in patients with SCCO.

Development and Management of Severe Cutaneous Side Effects in Head-and-Neck Cancer Patients during Concurrent Radiotherapy and Cetuximab

Background:The concurrent administration of cetuximab to radiotherapy has recently been shown to improve the clinical outcome of head-and-neck cancer (HNC) patients. An aggravation of the radiation-induced skin toxicity was not described. Here, however, two cases with severe skin toxicity during the combined treatment are reported.Clinical Observations:In a small group of five patients with locally advanced HNC treated with irradiation and concurrent cetuximab, two cases of unusually severe radiation dermatitis were observed. Both patients developed confluent moist desquamations confined to the irradiation field at a dose of 40 Gy (CTC [Common Toxicity Criteria] grade 3), which progressed into an ulcerative dermatitis (grade 4) at 58 Gy and 46 Gy, respectively. Histopathology showed a vacuolic degeneration of basal keratinocytes, subepidermal blister formation, and mixed perivascular and interstitial inflammatory infiltrates leading to a complete loss of the epidermis. These cutaneous side effects led to the discontinuation of radiotherapy. Topical corticosteroids and systemic antibiotic treatment resulted in wound healing, which allowed the continuation of radiotherapy.Conclusion:These findings indicate that cetuximab may have the potential to enhance the severity of radiation dermatitis in HNC patients. A systematic monitoring of cutaneous side effects during radiotherapy plus cetuximab is advised in order to reliably estimate the frequency of severe (grade 3/4) radiation dermatitis.Hintergrund:Die simultane Applikation von Cetuximab zur Strahlentherapie verbessert nach einer kürzlich publizierten Studie die Prognose von Patienten mit Kopf-Hals-Tumoren (HNC). Hinweise auf eine Verstärkung der strahlenbedingten Hautreaktion ergaben sich nicht. Im Folgenden wird allerdings über zwei Fälle mit schwersten Hautreaktionen während der kombinierten Behandlung berichtet.Beobachtungen:In einer kleinen Gruppe von fünf Patienten mit HNC, die mit Bestrahlung und simultanem Cetuximab behandelt wurden, war bei zwei Patienten eine ungewöhnlich starke Radiodermatitis zu beobachten. Beide Patienten entwickelten während der Behandlung bei einer Dosis von 40 Gy zunächst konfluierende feuchte Epitheliolysen in den Bestrahlungsfeldern (CTC [Common Toxicity Criteria] Grad 3), welche bei einer Dosis von 58 Gy bzw. 46 Gy in ulzerative Dermatitiden übergingen (CTC Grad 4). Histopathologisch zeigten sich vakuolische Degenerationen der basalen Keratinozyten, subepidermale Blasenbildungen sowie perivaskuläre und interstitielle inflammatorische Infiltrate mit komplettem Verlust der Epidermis. Diese Nebenwirkungen führten in beiden Fällen zu einer Unterbrechung der Radiotherapie. Durch eine intensive Therapie mit topischen Glukokortikosteroiden sowie eine systemische antibiotische Behandlung kam es zur kompletten Abheilung, was die Fortsetzung der Bestrahlung ermöglichte.Schlussfolgerung:Diese Beobachtungen zeigen, dass Cetuximab das Potential haben könnte, den Grad der Radiodermatitis bei Patienten mit HNC wesentlich zu verstärken. Ein systematisches Monitoring der Hautnebenwirkungen während der Radiotherapie in Kombination mit Cetuximab ist erforderlich, um die Häufigkeit der schweren Radiodermatitis (Grad 3/4) verlässlich einschätzen zu können.

[22] Synthetic singlet oxygen quenchers

Publisher Summary The quenching of singlet oxygen 1 O 2 ( 1 Δ g ) by synthetic compounds is described in this chapter. The following classes of π- or n-electron containing substrates are considered: olefins, aromatic and heteroaromatic compounds, amines, sulfur compounds, phenols, metal chelates, nonaromatic heterocycles, and indigoids. Singlet oxygen is quenched by or reacts with many organic and bioorganic molecules, which possess, in most cases, reactive π electrons, or n lone pairs of sufficiently low ionization energy. The quenching process can be physical (the quencher enters a vibrational or an electronic excited state) or chemical (the quencher combines with oxygen or is oxidized by oxygen) in nature. Physical quenching may occur via triplet energy transfer or by simple catalysis of the singlet oxygen ( 1 O 2 ) ground state oxygen ( 3 O 2 ) transition via spin-orbit coupling. Charge transfer interactions are important during the quenching process. In many reactions, intermediates are involved—for example, exciplexes, diradicals, or zwitterions.

Alterations in the p53 pathway and their association with radio- and chemosensitivity in head and neck squamous cell carcinoma

Chemotherapy and/or radiotherapy are established measures in treatment protocols of head and neck squamous cell carcinoma (HNSCC). However, we still lack reliable predictive markers for the response to radio- and chemotherapy. The p53 pathway is involved in stress response and thus might influence chemo-/radiosensitivity. Using 29 HNSCC cell lines previously characterized for p53 mutations, we simultaneously analyzed several key players in the p53 pathway by RT-PCR, transcript sequencing and immunohistochemistry, and investigated their association with chemosensitivity and radiosensitivity. Cell lines with p53 mutations were slightly more sensitive to cisplatin than those with wild-type p53. The type of mutation did not influence radio- or chemosensitivity. p14(ARF), an activator of p53, was lost or mutated in all cell lines. Three cell lines showed overexpression of HDM-2, a major negative regulator of p53; however, HDM-2 levels did not correlate with radio- or chemosensitivity. HPV-16 oncoproteins were detected in one highly chemoresistant cell line. Our findings suggest that molecular events resulting in the inactivation of the p53 pathway occur in all HNSCC cell lines. However, single alterations in the p53 pathway are not reliable predictors for the response to radio- or chemotherapy in HNSCC.