Phase I study of humanized monoclonal antibody AVE1642 directed against the type 1 insulin-like growth factor receptor (IGF-1R), administered in combination with anticancer therapies to patients with advanced solid tumors.

BACKGROUND: Type 1 insulin-like growth factor receptor (IGF-1R) mediates resistance to chemotherapy and targeted agents. This study assessed the safety, pharmacokinetics (PK), and tolerability of humanized IGF-1R antibody AVE1642 with other cancer treatments. PATIENTS: Patients with advanced solid tumors received three weekly AVE1642 dosed at 6 mg/kg, chosen following previous study, with 75 (cohort A) or 100 mg/m(2) (B) docetaxel, 1250 mg/m(2) gemcitabine/100 mg erlotinib (C1), or 60 mg/m(2) doxorubicin (D1). Blood samples were assayed for PK, IGFs, and IGF-BP3. RESULTS: Fifty-eight patients received 317 AVE1642 infusions. The commonest adverse events were diarrhea (37/58 patients), asthenia (34/58), nausea (30/58), and stomatitis (21/58). Dose-limiting toxic effects in cohorts C1 (diarrhea) and D1 (neutropenia) prompted addition of cohorts C2 (1000 mg/m(2) gemcitabine/75 mg erlotinib) and D2 (50 mg/m(2) doxorubicin). Grade 3-4 hyperglycemia (three cases) accompanied steroid premedication for docetaxel administration. No PK interactions were detected. There were three partial responses in cohorts B (melanoma) and C (leiomyosarcoma, two cases) and 22 stabilizations ≥12 weeks, giving a control rate of 25/57 (44%). On treatment IGF-II rose by 68 ± 25 ng/ml in patients discontinuing treatment <12 weeks, and fell by 55.5 ± 21 ng/ml with disease control (P < 0.001). CONCLUSION: AVE1642 was tolerable with 75-100 mg/m(2) docetaxel and 1000 mg/m(2) gemcitabine/75 mg erlotinib, achieving durable disease control in 44%, with an association between IGF-II and response.

Fatal case of sorafenib-associated idiosyncratic hepatotoxicity in the adjuvant treatment of a patient with renal cell carcinoma.

BACKGROUND: Sorafenib is an orally available kinase inhibitor with activity at Raf, PDGFß and VEGF receptors that is licensed for the treatment of advanced renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC). Current evidence-based post-nephrectomy management of individuals with localized RCC consists of surveillance-based follow up. The SORCE trial is designed to investigate whether treatment with adjuvant sorafenib can reduce recurrence rates in this cohort. CASE PRESENTATION: Here we report an idiosyncratic reaction to sorafenib resulting in fatal hepatotoxicity and associated renal failure in a 62 year-old man treated with sorafenib within the SORCE trial. CONCLUSION: This is the first reported case of sorafenib exposure associated fatal toxicity in the adjuvant setting and highlights the unpredictable adverse effects of novel adjuvant therapies.

Importance of mitochondrial haplotypes and maternal lineage in sprint performance among individuals of West African ancestry.

Mitochondrial DNA (mtDNA) is inherited solely along the matriline, giving insight into both ancestry and prehistory. Individuals of sub-Saharan ancestry are overrepresented in sprint athletics, suggesting a genetic advantage. The purpose of this study was to compare the mtDNA haplogroup data of elite groups of Jamaican and African-American sprinters against respective controls to assess any differences in maternal lineage. The first hypervariable region of mtDNA was haplogrouped in elite Jamaican athletes (N=107) and Jamaican controls (N=293), and elite African-American athletes (N=119) and African-American controls (N=1148). Exact tests of total population differentiation were performed on total haplogroup frequencies. The frequency of non-sub-Saharan haplogroups in Jamaican athletes and Jamaican controls was similar (1.87% and 1.71%, respectively) and lower than that of African-American athletes and African-American controls (21.01% and 8.19%, respectively). There was no significant difference in total haplogroup frequencies between Jamaican athletes and Jamaican controls (P=0.551 ± 0.005); however, there was a highly significant difference between African-American athletes and African-American controls (P<0.001). The finding of statistically similar mtDNA haplogroup distributions in Jamaican athletes and Jamaican controls suggests that elite Jamaican sprinters are derived from the same source population and there is neither population stratification nor isolation for sprint performance. The significant difference between African-American sprinters and African-American controls suggests that the maternal admixture may play a role in sprint performance.

Information for genetic management of mtDNA disease: sampling pathogenic mtDNA mutants in the human germline and in placenta.

BACKGROUND: Families with a child who died of severe, maternally inherited mitochondrial DNA (mtDNA) disease need information on recurrence risk. Estimating this risk is difficult because of (a) heteroplasmy-the coexistence of mutant and normal mtDNA in the same person-and (b) the so-called mitochondrial bottleneck, whereby the small number of mtDNAs that become the founders for the offspring cause variation in dose of mutant mtDNA. The timing of the bottleneck and of segregation of mtDNA during foetal life determines the management options. Therefore, mtDNA heteroplasmy was studied in oocytes and placenta of women in affected families. RESULTS: One mother of a child dying from Leigh syndrome due to the 9176T-->C mtDNA mutation transmitted various loads of mutant mtDNA to < or =3 of 20 oocytes. This was used to estimate recurrence as < or =5%. She subsequently conceived a healthy son naturally. Analysis of the placenta showed that some segregation also occurred during placental development, with the mutant mtDNA load varying by >10% in a placenta carrying 65% 3243A-->G mutant mtDNA. DISCUSSION: This is the first report of (a) an oocyte analysis for preconception counselling, specifically, refining recurrence risks of rare mutations and (b) a widely different load of a pathogenic mtDNA mutation in multiple oocytes, apparently confined to the germline, in an asymptomatic carrier of an mtDNA disease. This suggests that a major component of the bottleneck occurs during oogenesis, probably early in the foetal life of the mother. The variable mutant load in placenta implies that estimates based on a single sample in prenatal diagnosis of mtDNA disorders have limited accuracy.

The VHL tumor suppressor inhibits expression of the IGF1R and its loss induces IGF1R upregulation in human clear cell renal carcinoma.

Clear cell renal cell cancer (CC-RCC) is a highly chemoresistant tumor characterized by frequent inactivation of the von Hippel-Lindau (VHL) gene. The prognosis is reportedly worse in patients whose tumors express immunoreactive type I insulin-like growth factor receptor (IGF1R), a key mediator of tumor cell survival. We aimed to investigate how IGF1R expression is regulated, and found that IGF1R protein levels were unaffected by hypoxia, but were higher in CC-RCC cells harboring mutant inactive VHL than in isogenic cells expressing wild-type (WT) VHL. IGF1R mRNA and promoter activities were significantly lower in CC-RCC cells expressing WT VHL, consistent with a transcriptional effect. In Sp1-null Drosophila Schneider cells, IGF1R promoter activity was dependent on exogenous Sp1, and was suppressed by full-length VHL protein (pVHL) but only partially by truncated VHL lacking the Sp1-binding motif. pVHL also reduced the stability of IGF1R mRNA via sequestration of HuR protein. Finally, IGF1R mRNA levels were significantly higher in CC-RCC biopsies than benign kidney, confirming the clinical relevance of these findings. Thus, we have identified a new hypoxia-independent role for VHL in suppressing IGF1R transcription and mRNA stability. VHL inactivation leads to IGF1R upregulation, contributing to renal tumorigenesis and potentially also to chemoresistance.

Human melanoma cells expressing V600E B-RAF are susceptible to IGF1R targeting by small interfering RNAs.

The type 1 insulin-like growth factor receptor (IGF1R) is overexpressed by malignant melanomas compared with benign naevi, and mediates proliferation, motility and protection from apoptosis. However, the utility of IGF1R targeting as anti-cancer therapy may be limited by activating mutations in downstream signaling intermediates. We previously showed that IGF1R knockdown blocked survival of prostate cancer cells in which Akt activation was deregulated by PTEN loss. The current study investigated effects of IGF1R targeting in cells harboring activating RAS-RAF mutations, found in 70-80% of human melanomas. We assembled a panel of eight human melanoma cell lines: two expressing wild-type (WT) B-RAF and N-RAS, two with activating N-RAS mutations and four harboring V600E B-RAF. We also generated isogenic cell populations overexpressing WT or V600E B-RAF. Cells expressing V600E B-RAF were relatively resistant to apoptosis. However, IGF1R gene silencing was capable of inducing significant inhibition of survival, enhancement of apoptosis, and approximately two-fold sensitization to cisplatin and temozolomide. These effects were independent of mutation status and were associated with reduced activation of Akt and also, unexpectedly, of ERKs. These results support development of IGF1R targeting as therapy for melanoma, regardless of the presence of activating mutations in the RAS-RAF pathway.

IGF1R signalling and its inhibition.

The type 1 IGF receptor (IGF1R) is a transmembrane tyrosine kinase that is frequently overexpressed by tumours, and mediates proliferation and apoptosis protection. IGF signalling also influences hypoxia signalling, protease secretion, tumour cell motility and adhesion, and thus can affect the propensity for invasion and metastasis. Therefore, the IGF1R is now an attractive anti-cancer treatment target. This review outlines the effects of IGF1R activation in tumour cells, and will describe the strategies that are available to block IGF signalling, both as investigational tools and as novel anti-cancer therapeutics. Design of specific IGF1R inhibitors has been problematic due to close homology with the insulin receptor, but recently it has proved possible to design selective IGF1R inhibitors. These compounds and IGF1R antibodies are showing promise in preclinical models of human cancer, and several agents are now in early phase clinical trials. Both classes of agents affect insulin receptor signalling, either by direct kinase inhibition or antibody-induced insulin receptor downregulation. This effect may lead to clinical toxicity, but could be therapeutically beneficial in blocking signalling via variant insulin receptors capable of a mitogenic response to IGF-II. Specificity for IGF1R targeting can be achieved by antisense and siRNA-mediated IGF1R downregulation; these approaches have undoubted utility as research tools, and may in future generate nucleic-acid-based therapeutics. It will be important to use data from preclinical and early clinical trials to establish the molecular correlates of sensitivity to IGF1R blockade, and the optimum means of combining this new approach with standard treatment modalities.

Autocrine function for insulin-like growth factor I in human small cell lung cancer cell lines and fresh tumor cells.

We showed previously that insulin-like growth factor I (IGF-I) is detectable in small cell lung cancer (SCLC) tumor biopsies and cell lines and that recombinant human IGF-I stimulates DNA synthesis in SCLC cells. Here we report further studies on the role of IGF-I in 2 SCLC cell lines: HC12, classic; and ICR-SC17, variant. Immunoreactive IGF-I was detected in medium conditioned by HC12 but not ICR-SC17. Both HC12 and ICR-SC17 bound IGF-I with 100-fold greater affinity than insulin. Scatchard analysis revealed two classes of IGF-I binding site of high (Kd 0.1 nM, n = 2,300) and lower (Kd 3 nM, n = 28,000) affinity. In both cell lines [3H]thymidine incorporation was enhanced by recombinant human IGF-I, 100-1000 ng/ml. ICR-SC17 also showed growth enhancement as measured by increase in cell numbers. There was no response in HC12, probably due to endogenous IGF-I production. 125I-IGF-I binding and basal and IGF-I-stimulated mitogenesis were inhibited by monoclonal antibodies to IGF-I (SM1.20B, SM1.25) or the type I IGF receptor alpha IR3 but not an isotypic control monoclonal antibody. Antiproliferative effects were manifest in [3H]thymidine incorporation assays in serum-free conditions and growth of serum-supplemented liquid cultures. We also tested fresh or newly cultured tumor cells obtained by fine needle aspiration of metastases in three previously untreated and four relapsed patients with SCLC. IGF-I binding sites were demonstrable on fresh SCLC cells, and specific binding was inhibited by SM1.20B. All seven samples showed stimulation of [3H]thymidine incorporation in the presence of recombinant human IGF-I, 100-500 ng/ml. As in cultured cells, basal and IGF-I-stimulated DNA synthesis was inhibited by monoclonal antibodies SM1.20B, SM1.25, and alpha IR3 but not the isotypic control. These results confirm the findings of previous studies and suggest that IGF-I can function as an autocrine growth factor in SCLC in vitro and possibly also in vivo.

Downregulation of the type 1 insulin-like growth factor receptor in mouse melanoma cells is associated with enhanced radiosensitivity and impaired activation of Atm kinase.

The type 1 insulin-like growth factor receptor (IGF1R) is required for growth, tumorigenicity and protection from apoptosis. IGF1R overexpression is associated with radioresistance in breast cancer. We used antisense (AS) RNA to downregulate IGF1R expression in mouse melanoma cells. Cells expressing AS-IGF1R transcripts were more radiosensitive in vitro and in vivo than controls. Also they showed reduced radiation-induced p53 accumulation and p53 serine 18 phosphorylation, and radioresistant DNA synthesis. These changes were reminiscent of the cellular phenotype of the human genetic disorder ataxia-telangiectasia (A-T), caused by mutations in the ATM gene. Cellular Atm protein levels were lower in AS-IGF1R-transfected cells than in control cells, although there was no difference in Atm expression at the transcriptional level. AS-IGF1R cells had detectable basal Atm kinase activity, but failed to induce kinase activity after irradiation. This suggests that IGF1R signalling can modulate the function of Atm, and supports the concept of targeted IGF1R downregulation as a potential treatment for malignant melanoma and other radioresistant tumours.

Phase I study of intrapleural batimastat (BB-94), a matrix metalloproteinase inhibitor, in the treatment of malignant pleural effusions.

Tumor cells and associated stromal cells secrete matrix metalloproteinases (MMPs), contributing to invasion, angiogenesis, and metastasis. Batimastat (BB-94) is a broad-spectrum MMP inhibitor that causes resolution of ascites and/or tumor growth delay in animal models of breast, ovarian, and colorectal cancer. We recruited 18 patients with cytologically positive malignant pleural effusions into a Phase I study of intrapleural BB-94. Three patients received single doses of BB-94 at each dose level: 15, 30, 60, 105, 135, and 300 mg/m2. Two patients were retreated with a second course at 60 and 105 mg/m2. BB-94 was detectable in plasma 1 h after intrapleural administration, and peak levels of 20-200 ng/ml occurred after 4 h to 1 week. BB-94 persisted in the plasma for up to 12 weeks, at levels exceeding the IC50s for target MMPs. Peak values were higher, and persistence in the plasma was longer after higher doses of BB-94. The treatment was well tolerated. Toxic effects included low-grade fever for 24-48 h (6 of 18 patients, 33%) and reversible asymptomatic elevation of liver enzymes (8 patients, 44%). Toxicity seemed unrelated to BB-94 dose or plasma levels. Sixteen patients evaluable for response required significantly fewer pleural aspirations in the 3 months after BB-94 compared with the 3 months before. Seven patients (44%) required no further pleural aspiration until death/last follow-up. After 1 month, patients treated with 60-300 mg/m2 BB-94 had significantly better dyspnea scores, indicating improved exercise tolerance, compared with baseline scores the day after BB-94. The maximum tolerated intrapleural dose remains to be defined, but it is clear that intrapleural BB-94 is well tolerated, with evidence of local activity.

Inhibition of aromatase expression by a psoralen-linked triplex-forming oligonucleotide targeted to a coding sequence.

The cytochrome P450 enzyme aromatase (P450arom) is an important target in breast cancer treatment. We have designed a 20-base pyrimidine oligodeoxynucleotide (ODN) which forms a sequence-specific triple helix (triplex) with a purine-rich tract in the P450arom coding sequence. The psoralen-linked ODN (Pso20T) formed photo-induced cross-linked products with target double-stranded DNA. Cross-linked adducts formed in vitro between ODNs and P450arom expression constructs were used to transfect COS and human MCF-7 breast cancer cells. Levels of aromatase transcripts and enzyme activity were significantly lower in cultures transfected with Pso20T-treated cDNA relative to controls. Pso20T had a lesser inhibitory effect on aromatase expression from a mutant P450arom construct, consistent with predicted effects of the mutations on triplex formation. These results are compatible with triplex-mediated interruption of transcription within intact cells.

[D-Arg1, D-Phe5, D-Trp7,9, Leu11] substance P inhibits the growth of human small cell lung cancer xenografts in vivo.

We report the effect of substance P analogue, [D-Arg1, D-Phe5, D-Trp7,9, Leu11] substance P (D-Phe5SP), on the growth of human small cell lung cancer (SCLC) xenografts HC12 and ICR-SC112. Daily intraperitoneal (ip) administration (500 micrograms/day for 3 weeks) had no effect on HC12 growth rate. When administered by continuous 14-day subcutaneous (sc) infusion by osmotic minipump implanted adjacent to the tumour, D-Phe5SP 2.1 micrograms/day, caused significant inhibition (P < 0.05) of the growth of HC12 and ICR-SC112 on day 7 and day 14 compared with phosphate buffered saline (PBS)-treated controls. HC12 and ICR-SC112 tumour volume remained at 53-67% of control for 14-21 days postinfusion. D-Phe5SP 1 mg/day did not inhibit tumour growth, but dense fibrous capsules developed at the minipump outlet. Animals treated by sc infusion (but not ip) of PBS or D-Phe5SP failed to gain weight, and some groups lost weight. D-Phe5SP-treated animals had lower white blood counts than controls (not significant). These data suggest a potential clinical role for D-Phe5SP in the treatment of SCLC.

Mitochondrial DNA recombination-no need to panic.

Recombination has recently been invoked as an explanation for the large amount of homoplasy observed in a collection of complete or nearly complete human mitochondrial sequences. Here we show that some of the data on which this conclusion was based are likely to be unreliable and that if these data are excluded, the results are no longer significant.

Ancient DNA suggests a recent expansion of European cattle from a diverse wild progenitor species.

A total of 11 Bos primigenius and Bos taurus bones from archaeological sites between 500 and 12000 years old were examined for the presence of DNA. It was possible to amplify and sequence mitochondrial control region DNA extracted from seven of the 11 samples, including two Pleistocene B. primigenius samples. We compared the results with published data by constructing phylogenetic networks. The two B. primigenius samples clustered with the extant B. taurus samples in the networks. The similarity between B. primigenius and modern taurine cattle confirms that these should be considered members of a single species. The sequences obtained from the B. taurus specimens were either identical to the reference sequence for modern European cattle or closely related to it. They included two sequences not previously documented. The network analysis of the ancient data highlights the intermediary nature of the B. primigenius sequences between modern European and African B. taurus and the proximity of the ancient DNA B. taurus sequences to modern European B. taurus. Further analysis of the extant data in the light of the ancient DNA results suggests that a degree of Pleistocene diversity survives in the extant European Bos population that is mainly derived from a more recent population expansion.

Human Y-chromosome variation in the western Mediterranean area: implications for the peopling of the region.

Y-chromosome variation was analyzed in a sample of 1127 males from the Western Mediterranean area by surveying 16 biallelic and 4 multiallelic sites. Some populations from Northeastern Europe and the Middle East were also studied for comparison. All Y-chromosome haplotypes were included in a parsimonious genealogic tree consisting of 17 haplogroups, several of which displayed distinct geographic specificities. One of the haplogroups, HG9.2, has some features that are compatible with a spread into Europe from the Near East during the Neolithic period. However, the current distribution of this haplogroup would suggest that the Neolithic gene pool had a major impact in the eastern and central part of the Mediterranean basin, but very limited consequences in Iberia and Northwestern Europe. Two other haplogroups, HG25.2 and HG2.2, were found to have much more restricted geographic distributions. The first most likely originated in the Berbers within the last few thousand years, and allows the detection of gene flow to Iberia and Southern Europe. The latter haplogroup is common only in Sardinia, which confirms the genetic peculiarity and isolation of the Sardinians. Overall, this study demonstrates that the dissection of Y-chromosome variation into haplogroups with a more restricted geographic distribution can reveal important differences even between populations that live at short distances, and provides new clues to their past interactions.

Proteolytic modification of insulin-like growth factor-binding proteins: comparison of conditioned media from human cell lines, circulating proteases and characterized enzymes.

Proteolytic modification of circulating insulin-like growth factor binding protein-3 (IGFBP-3) has been described in a number of conditions. Using Western ligand blotting and SDS-PAGE analysis of fragmentation patterns of 125I-labelled IGFBP-3 and 125-labelled IGFBP-1, we have examined conditioned media from cultured human cell lines for the presence of proteolytic activity and compared this with the action of circulating proteases and with characterized enzymes including cathepsin D, kallikrein, plasmin and tissue plasminogen activator. 125I-Labelled IGFBP-3 was incubated with serum from pregnant women, patients following heart surgery and patients with cancer of the breast, lung or head/neck. Following separation of the preincubated samples by SDS-PAGE, a distinct pattern of degradation fragments was observed which was similar in all cases. This proteolytic activity was inhibited in the presence of EDTA, phenanthroline and 4(-2-aminoethyl)-benzenesulphonylfluoride, HCl. These proteases had no detectable effect on IGFBP-1. Serum-free conditioned medium from a human dermal fibroblast cell line, a rabdomyosarcoma, a cervical, a bladder, a chorio- and two-tongue squamous cell carcinoma cell lines all contained proteolytic activity which fragmented IGFBP-3. The pattern of fragments was similar in all cell lines but different from that produced by the circulating proteases. Six out of nine cell lines produced protease(s) which degraded IGFBP-1 in addition to IGFBP-3. Whilst all the characterized enzymes tested also fragmented IGFBP-3 and plasmin cleaved IGFBP-1, none of these acted in the same way as either circulating or cell line-derived proteolytic activity. The activity associated with the characterized enzymes and cell lines was inhibited in the presence of serum from normal healthy subjects. These results demonstrate that the serum of pregnant women, post-operative patients and patients with cancer contain circulating proteases which cause fragmentation of IGFBP-3 but have little effect on IGFBP-1. Cell-derived proteases were shown to act on IGFBP-3 and IGFBP-1 in a number of instances but are not active in the presence of circulating inhibitors. These proteases may play an important role in regulating the availability of IGFs to normal and neoplastic tissues.

The control and biological importance of intratumoural aromatase in breast cancer.

The existence of aromatase activity in human breast carcinomas has been established for about 20 years but the clinical and biological importance of this remains unclear. A number of studies in clinical material suggest that aromatase activity may be a prerequisite of response to aromatase inhibitors and that aromatase activity may be enhanced in those tumours relapsing during treatment with one such inhibitor, aminoglutethimide. These results would carry more significance, however, if it was demonstrable that the growth of breast carcinomas is affected by the conversion of androgens to oestrogens by intratumoural aromatase. We have tried to address this by establishing model systems with aromatase-transfected MCF7 breast cancer cells. We have demonstrated that these cells can be stimulated mitogenically with androgen and that this proliferation is suppressible with aromatase inhibitors. Similarly the growth of aromatase transfected cells but not wild type cells as xenografts is supported by androstenedione and inhibitable by both the steroidal aromatase inhibitor, 4-hydroxyandrostenedione and non-steroidal inhibitor, CGS 20267. Work with the former of these, which is a suicide inhibitor allowed us to demonstrate that growth can proceed with aromatase activity approximating to the highest level seen in breast carcinomas indicating that at least at this extreme level the intratumoural conversion of androgens to oestrogens may indeed be able to support tumour growth. Further work with this mode system should allow us to define the minimal amount of intratumoural activity which can support tumour growth.

Control of aromatase in breast cancer cells and its importance for tumor growth.

Three approaches have been taken to elucidate further the biological importance of intratumoural aromatase activity. (i) MCF7 and T47D hormone-dependent breast cancer cell lines both showed detectable aromatase activity in vitro. The up-regulation of this by TGF alpha indicates the possible existence of an autocrine growth stimulatory loop involving aromatase. (ii) Both tamoxifen and cytotoxic chemotherapy caused the suppression of aromatase activity in breast carcinomas in vivo. Aromatase activity prior to treatment did not predict for clinical response to tamoxifen. (iii) Transfection of aromatase into MCF7 cells led to their growth being stimulated by low doses of androgens and this was inhibited by the aromatase inhibitor CGS 16949A.

Prophylaxis against hypomagnesaemia induced by cis-platinum combination chemotherapy.

Hypomagnesaemia is recognised as a feature of the renal tubular defect produced by cis-platinum therapy for cancer. It may be sufficiently severe to cause tetany and grand mal fits. Attempts to correct established hypomagnesaemia whilst continuing cis-platinum therapy have not proved satisfactory. We have therefore investigated the prophylactic addition of 3 g magnesium sulphate to the high-dose platinum regimen with which metastatic malignant teratoma is treated in this unit. Serum magnesium levels have been measured in eight patients treated in this way and compared with those recorded for eight matched patients previously treated without routine magnesium supplements. Magnesium levels fell into the range frequently associated with clinical manifestation in five of the eight unsupplemented patients and only one of those given magnesium prophylactically. Mean serum magnesium levels were significantly higher in the supplemented group when compared using the paired t-test (P less than 0.01). Routine supplementation with intravenous magnesium sulphate is a simple and effective way of preventing symptomatic hypomagnesaemia associated with cis-platinum therapy.