Long-term (6 and 12 months) follow-up of two prospective, randomized, controlled phase III trials of photodynamic therapy with BF-200 ALA and methyl aminolaevulinate for the treatment of actinic keratosis

Background

Two phase III trials of photodynamic therapy (PDT) with BF-200 ALA, a recently approved nanoemulsion formulation of 5-aminolaevulinic acid (ALA) demonstrated high clearance rates in mild-to-moderate actinic keratosis (AK). The comparison to a registered methyl aminolaevulinate (MAL) cream demonstrated significantly superior total patient clearance rates.

Objectives

To evaluate long-term efficacy and safety of PDT for AK 6 and 12 months after the last PDT with BF-200 ALA, MAL or placebo.

Methods

The follow-up phase (FUP) was performed with patients of two phase III studies. Both studies compared BF-200 ALA with placebo, one of the studies additionally with MAL. Overall recurrence rates and various subgroups (light source, lesion severity, lesion location, complete responders after first PDT) were assessed 6 and 12 months after the last PDT.

Results

Recurrence rates were similar for BF-200 ALA and MAL, with a tendency to lower recurrence rates for BF-200 ALA. The proportion of patients who were fully cleared during PDT and remained completely clear for at least 12 months after PDT were 47% for BF-200 ALA (both studies) and 36% for MAL treatment. The subgroup that was illuminated with narrow wavelength LED lamps reached 69% and 53% for BF-200 ALA (both studies, respectively) and 41% for MAL. No safety concerns were reported.

Conclusions

The FUP data confirmed the high efficacy and safety of PDT with BF-200 ALA. The slightly lower recurrence rates after BF-200 ALA treatment compared with MAL treatment enhanced the better treatment outcome due to the significantly superior efficacy.

Photodynamic therapy with BF-200 ALA for the treatment of actinic keratosis: results of a multicentre, randomized, observer-blind phase III study in comparison with a registered methyl-5-aminolaevulinate cream and placebo

BACKGROUND

Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) or its methylester [methyl-5-aminolaevulinate (MAL) or 5-amino-4-oxopentanoate] was recently ranked as first-line therapy for the treatment of actinic keratosis (AK) and is an accepted therapeutic option for the treatment of neoplastic skin diseases. BF-200 ALA (Biofrontera Bioscience GmbH, Leverkusen, Germany) is a gel formulation of ALA with nanoemulsion for the treatment of AK which overcomes previous problems of ALA instability and improves skin penetration.

OBJECTIVES

To evaluate the efficacy and safety of PDT of AKs with BF-200 ALA in comparison with a registered MAL cream and with placebo.

METHODS

The study was performed as a randomized, multicentre, observer-blind, placebo-controlled, interindividual trial with BF-200 ALA, a registered MAL cream and placebo in a ratio of 3:3:1. Six hundred patients, each with four to eight mild to moderate AK lesions on the face and/or the bald scalp, were enrolled in 26 study centres in Germany, Austria and Switzerland. Patients received one PDT. If residual lesions remained at 3months after treatment, PDT was repeated.

RESULTS

PDT with BF-200 ALA was superior to placebo PDT with respect to patient complete clearance rate (78·2% vs. 17·1%; P<0·0001) and lesion complete clearance rate (90·4% vs. 37·1%) at 3months after the last PDT. Moreover, superiority was demonstrated over the MAL cream regarding the primary endpoint patient complete clearance (78·2% vs. 64·2%; P<0·05). Significant differences in the patient and lesion complete clearance rates and severity of treatment-related adverse events were observed for the narrow- and broad-spectrum light sources.

CONCLUSIONS

BF-200 ALA is a very effective, well-tolerated new formulation for AK treatment with PDT and is superior to a registered MAL medication. Efficacies and adverse events vary greatly with the different light sources used.

Photodynamic therapy with BF-200 ALA for the treatment of actinic keratosis: results of a prospective, randomized, double-blind, placebo-controlled phase III study

BACKGROUND

Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) provides a therapeutic option for the treatment of actinic keratosis (AK). Different strategies are applied to overcome the chemical instability of ALA in solution and to improve skin penetration. A new stable nanoemulsion-based ALA formulation, BF-200 ALA, is currently in clinical development for PDT of AK.

OBJECTIVES

To evaluate the efficacy and safety of PDT of AK with BF-200 ALA.

METHODS

The study was performed as a randomized, multicentre, double-blind, placebo-controlled, interindividual, two-armed trial with BF-200 ALA and placebo. A total of 122 patients with four to eight mild to moderate AK lesions on the face and/or the bald scalp were included in eight German study centres. The efficacy of BF-200 ALA after one and two PDT treatments was evaluated. BF-200 ALA was used in combination with two different light sources under illumination conditions defined by European competent authorities.

RESULTS

PDT with BF-200 ALA was superior to placebo PDT with respect to patient complete clearance rate (per-protocol group: 64% vs. 11%; P < 0.0001) and lesion complete clearance rate (per-protocol group: 81% vs. 22%) after the last PDT treatment. Statistically significant differences in the patient and lesion complete clearance rates and adverse effect profiles were observed for the two light sources, Aktilite CL128 and PhotoDyn 750, at both time points of assessment. The patient and lesion complete clearance rates after illumination with the Aktilite CL128 were 96% and 99%, respectively.

CONCLUSIONS

BF-200 ALA is a very effective new formulation for the treatment of AK with PDT. Marked differences between the efficacies and adverse effects were observed for the different light sources used. Thus, PDT efficacy is dependent both on the drug and on the characteristics of the light source and the illumination conditions used.

A genome survey indicates a possible susceptibility locus for bipolar disorder on chromosome 22

Bipolar disorder or manic depressive illness is a major psychiatric disorder that is characterized by fluctuation between two abnormal mood states. Mania is accompanied by symptoms of euphoria, irritability, or excitation, whereas depression is associated with low mood and decreased motivation and energy. The etiology is currently unknown; however, numerous family, twin, and adoption studies have argued for a substantial genetic contribution. We have conducted a genome survey of bipolar disorder using 443 microsatellite markers in a set of 20 families from the general North American population to identify possible susceptibility loci. A maximum logarithm of odds score of 3.8 was obtained at D22S278 on 22q. Positive scores were found spanning a region of nearly 32 centimorgans (cM) on 22q, with a possible secondary peak at D22S419. Six other chromosomal regions yielded suggestive evidence for linkage: 3p21, 3q27, 5p15, 10q, 13q31-q34, and 21q22. The regions on 22q, 13q, and 10q have been implicated in studies of schizophrenia, suggesting the possible presence of susceptibility genes common to both disorders.

The recycling of ERGIC-53 in the early secretory pathway. ERGIC-53 carries a cytosolic endoplasmic reticulum-exit determinant interacting with COPII

Further investigation of the targeting of the intracellular membrane lectin endoplasmic reticulum (ER)-Golgi intermediate compartment-53 (ERGIC-53) by site-directed mutagenesis revealed that its lumenal and transmembrane domains together confer ER retention. In addition we show that the cytoplasmic domain is required for exit from the ER indicating that ERGIC-53 carries an ER-exit determinant. Two phenylalanines at the C terminus are essential for ER-exit. Thus, ERGIC-53 contains determinants for ER retention as well as anterograde transport which, in conjunction with a dilysine ER retrieval signal, control the continuous recycling of ERGIC-53 in the early secretory pathway. In vitro binding studies revealed a specific phenylalanine-dependent interaction between an ERGIC-53 cytosolic tail peptide and the COPII coat component Sec23p. These results suggest that the ER-exit of ERGIC-53 is mediated by direct interaction of its cytosolic tail with the Sec23p.Sec24p complex of COPII and that protein sorting at the level of the ER occurs by a mechanism similar to receptor-mediated endocytosis or Golgi to ER retrograde transport.

A C-terminally-anchored Golgi protein is inserted into the endoplasmic reticulum and then transported to the Golgi apparatus

Unlike conventional membrane proteins of the secretory pathway, proteins anchored to the cytoplasmic surface of membranes by hydrophobic sequences near their C termini follow a posttranslational, signal recognition particle-independent insertion pathway. Many such C-terminally-anchored proteins have restricted intracellular locations, but it is not known whether these proteins are targeted directly to the membranes in which they will ultimately reside. Here we have analyzed the intracellular sorting of the Golgi protein giantin, which consists of a rod-shaped 376-kDa cytoplasmic domain followed by a hydrophobic C-terminal anchor sequence. Unexpectedly, we find that giantin behaves like a conventional secretory protein in that it inserts into the endoplasmic reticulum (ER) and then is transported to the Golgi. A deletion mutant lacking a portion of the cytoplasmic domain adjacent to the membrane anchor still inserts into the ER but fails to reach the Golgi, even though this mutant has a stable folded structure. These findings suggest that the localization of a C-terminally-anchored Golgi protein involves at least three steps: insertion into the ER membrane, controlled incorporation into transport vesicles, and retention within the Golgi.

Ca2+ oscillations and Ca2+ influx in Xenopus oocytes expressing a novel 5-hydroxytryptamine receptor

1. We expressed a novel 5-hydroxytryptamine receptor (SRL) in Xenopus oocytes and monitored cytosolic Ca2+ through the endogenous Ca(2+)-dependent Cl- channel activity using the double electrode voltage-clamp technique. 2. 5-Hydroxytryptamine (5-HT; 200 nM) led to an initial rapid oscillatory current followed by a pronounced secondary one, which lasted long after 5-HT wash-out (20-40 min) and was not affected by the receptor antagonist yohimbine. 3. Both phases of the current were abolished by heparin demonstrating a key role for IP3-induced Ca2+ release. 4. Caffeine (10 mM) alone did not evoke a current but reduced both phases of the current evoked by 5-HT. Ryanodine had no effect. No evidence for Ca(2+)-induced Ca2+ release was found. 5. The secondary current activated by 5-HT was sensitive to changes in extracellular Ca2+, suggesting it was evoked by Ca2+ influx. Reducing external Na+ did not affect this current, demonstrating that it was rather specific for Ca2+. 6. The Ca2+ influx pathway was much more sensitive to Cd2+ than other divalent ions (Co2+, Mn2+, Sr2+, Ba2+). It was insensitive to verapamil. 7. Injection of D-myo-inositol 1,4,5-trisphosphate, 3-deoxy-3-fluoro (IP3-F; an analogue not metabolized to D-myo-inositol 1,3,4,5-tetrakisphosphate (IP4)), evoked either an oscillatory current or a rapid current followed by a sustained secondary one. The latter was sensitive to external Ca2+ and was blocked by Cd2+. Heparin dramatically reduced the IP3-F-evoked current. 8. Perfusion in Ca(2+)-free solution, once a secondary current had been generated, significantly decreased the amount of intracellular Ca2+ mobilized by 5-HT, indicating that the Ca2+ influx pathway plays an important role in pool refilling. 9. Block of Ca2+ influx by Cd2+ in cells that were oscillating transiently increased the amplitude and then either abolished the oscillations or made them irregular. This effect was also elicited by increasing external Ca2+. 10. These results demonstrate that 5-HT, acting via IP3, both releases Ca2+ from internal stores and evokes a pronounced Ca2+ influx. This last step is activated by pool depletion and is important for both refilling of the agonist-sensitive stores and modifying the oscillatory pattern.

Long-term regulation of serotonergic activity in the rat brain via activation of protein kinase A

Serotonergic neurons located at the base of the mammalian brain innervate practically every region of the brain and the spinal cord. These neurons exhibit spontaneous electrical discharges in a rhythmical way. Their firing frequency is modulated by serotonin autoreceptors which also regulate intracellular cAMP levels. We have investigated how elevated levels of cAMP alter the development and the functional properties of serotonergic neurons in culture. To study the influence of cAMP on the expression of genes underlying serotonergic activity, a quantitative RT-PCR approach using internal standards was developed. Cultures of embryonic rat brain serotonergic neurons were continuously treated with cAMP analogues. Increased cAMP levels had three effects. First, the neuronal morphology was changed towards that typical for mature serotonergic neurons. Second, the expression of tryptophan hydroxylase, the rate-limiting enzyme in serotonin production, was increased in dibutyryl-cAMP treated cultures. Third, the expression of the inhibitory autoreceptor (5-HT1A) was down-regulated. These results suggest the existence of a mechanism by which the neurons react to synaptic input regulating intracellular cAMP levels. Increased cAMP concentrations affect the development and cause a prolonged activation of serotonergic transmission. Since 5-HT1A receptors inhibit cAMP formation, their down-regulation argues against a negative feedback control in this system, consistent with observations in vivo.

Cloning and functional characterization of the rat stomach fundus serotonin receptor

A DNA segment homologous to the third exons of the serotonin 1C and 2 receptor genes was isolated from a mouse genomic library. The positions of the introns flanking these exons were conserved in the three genes. To examine whether the new fragment was part of an active gene, we used a quantitative PCR protocol to analyse rat RNAs from different tissues and ages. The gene was expressed in stomach fundus at an abundance of 1 x 10(5) mRNA molecules. This tissue contracts in response to serotonin via a receptor that has previously resisted classification. We constructed a cDNA library from rat stomach fundus and isolated clones containing 2020 bp inserts with open reading frames of 465 amino acids comprising seven putative membrane-spanning regions. The protein was transiently expressed in COS cells and binding of serotonergic ligands to the membranes was analysed. The pharmacological profile resembled that described for the serotonin-stimulated contraction of the stomach fundus. After expression of this receptor in Xenopus oocytes, the application of serotonin triggered the typical chloride current which presumably results from the activation of phospholipase C. The coupling to this response system was less efficient than that of the 5-HT1C or 5-HT2 receptors.

APP RNA splicing is not affected by differentiation of neurons and glia in culture

Amyloid precursor protein (APP) gene expression was investigated in primary cultures of neurons, astrocytes, microglial cells and oligodendrocytes. Neurons from various rat brain regions, as well as oligodendrocytes, contained RNA encoding APP695, while astrocytes and microglial cells expressed high levels of RNAs for APP770 and APP751. It was studied whether the cell type-specific regulation of APP gene expression could be modified by induction of cellular differentiation in vitro. While neuronal differentiation of PC12 cells has been shown to correspond with an altered pattern of APP splicing, in the primary cultures neither the time in culture nor a treatment of the cells with appropriate differentiation factors affected this pattern.

Structure of the mouse 5-HT1C, 5-HT2 and stomach fundus serotonin receptor genes

By analysis of the mouse 5-HT1C receptor gene we found that its coding region contains three introns. We next isolated cDNA and genomic clones for the closely related 5-HT2 receptor using a probe derived from the 5-HT1C receptor sequence. This probe also hybridized to an additional gene, called SRL (Serotonin Receptor Like). We have evidence demonstrating that it encodes the stomach fundus 5-HT receptor. Two introns are present within the coding regions of the mouse 5-HT2 receptor gene and the SRL gene at positions which correspond to those of introns in the 5-HT1C receptor gene. This intron distribution is unique and distinguishes these receptors from other members of the family of receptors coupled to G-proteins.

Functional expression cloning and characterization of the hepatocyte Na+/bile acid cotransport system

Liver parenchymal cells continuously extract high amounts of bile acids from portal blood plasma. This uptake process is mediated by a Na+/bile acid cotransport system. A cDNA encoding the rat liver bile acid uptake system has been isolated by expression cloning in Xenopus laevis oocytes. The cloned transporter is strictly sodium-dependent and can be inhibited by various non-bile-acid organic compounds. Sequence analysis of the cDNA revealed an open reading frame of 1086 nucleotides coding for a protein of 362 amino acids (calculated molecular mass 39 kDa) with five possible N-linked glycosylation sites and seven putative transmembrane domains. Translation experiments in vitro and in oocytes indicate that the transporter is indeed glycosylated and that its polypeptide backbone has an apparent molecular mass of 33-35 kDa. Northern blot analysis with the cloned probe revealed crossreactivity with mRNA species from rat kidney and intestine as well as from liver tissues of mouse, guinea pig, rabbit, and man.