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These data suggest that the addition of alpha-interferon to octreotide has antiproliferative efficacy in a subgroup of patients with advanced metastatic disease unresponsive to octreotide monotherapy. Prolonged survival was seen in the responder group.

The place of the long-acting somatostatin analogue octreotide in the management of symptoms in patients with functional gastroenteropancreatic (GEP) tumors and of growth in patients with metastatic disease is reviewed in this report. Numerous studies indicate that octreotide is, currently, the therapeutic principle of first choice in the symptomatic treatment of patients with carcinoid syndrome, Verner-Morrison syndrome and glucagonoma syndrome but not of insulinoma and gastrinoma patients. A beneficial effect on tumor growth has been demonstrated in 40% of patients with metastatic GEP tumors with stabilization of the disease as the most favorable response. However, further studies have to identify subgroups of patients in whom octreotide alone or in combination with alpha-interferon inhibits tumor growth.

Acute intermittent porphyria (AIP) is an autosomal dominant disorder caused by a partial defect of the heme biosynthesis enzyme, porphobilinogen deaminase (PBGD). PBGD is encoded by two distinct mRNA species expressed in a tissue-specific manner from a single gene. One transcript is expressed in erythroid tissues, while the housekeeping transcript is expressed in all tissues. In classical AIP (95% of cases) the housekeeping and the erythroid-specific enzymes both have half-normal activity in erythroid and non-erythroid tissues, whereas in the variant non-erythroid form of the disease the enzymatic defect is present only in non-erythroid cells. A large allelic heterogeneity of mutations (n>135) has been demonstrated in classical AIP, but to date only three different mutations have been characterized in the non-erythroid variant form of AIP. We describe the molecular abnormalities responsible for the non-erythroid variant form of AIP in two French and two German unrelated AIP patients with normal PBGD activity in the erythrocytes. Three different splicing defects located in the intron 1 donor splice site were identified: a 33+1 g-->a mutation, previously described in a Dutch family, was found in two patients; two novel mutations (33+2 t-->a, 33+5 c-->g) affected the two remaining patients. All the mutations resulted in the activation of a cryptic splice site 67 bp downstream in intron 1, leading to a frameshift and a premature stop codon in exon 4. Mutations in the exon 1 donor splice site are involved in eight of the nine non-erythroid variant AIP families reported in the literature. These data show that most mutations causing the non-erythroid variant AIP are exon 1 splice defects, in contrast with classical AIP, where missense mutations are chiefly involved. Moreover, the allelic heterogeneity of PBGD gene defects causing the non-erythroid variant AIP is demonstrated, with five different mutations identified. These mutations could be easily detected by a single denaturing gradient gel electrophoresis which also allows the presymptomatic detection of gene carriers in the affected families.

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Porphyria cutanea tarda (PCX) is characterized by cutaneous symptoms in association with hepatic accumulation and urinary excretion of mainly uro- and heptacarboxyporphyrins. 24 PCX patients excreting urinary porphyrins between 1.9 and 5.8 µmol/24 h (normal < 0.2) were treated with chloroquine at a dose of 125 mg twice a week. During the first phase of therapy urinary porphyrin excretion transiently increased 1.1- to 2.9-fold indicating a phase of mobilization. A slight initial elevation was also found regarding the activities of serum amino-transferases reflecting the hepatotoxic effect of chloroquine. Xhe clinical symptoms disappeared after a period ranging from 2 to 6 months, and after an average of 12 months the porphyrin excretion in all patients had returned to nearly normal values.