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David Gibbs

Publications and source records attributed to David Gibbs.

6 recordsLinked to original sources

Adjuvant chemotherapy for non-small cell lung cancer: a New Zealand perspective.

This article reviews recent developments with the use of adjuvant chemotherapy for resected early-stage non-small cell lung cancer (NSCLC) and the implications of these developments for healthcare in New Zealand (NZ). Non-small cell lung cancer is a major cause of mortality and morbidity in NZ, and is greatly over-represented among Maori and socioeconomically deprived populations. Early-stage NSCLC is potentially curable by surgery, but long-term outcome after surgical resection is limited by disease recurrence locally or at sites distant from the primary disease. Three recent large randomised controlled phase III trials using modern platinum-based combination chemotherapy protocols have shown significant survival benefits for the use of postoperative adjuvant chemotherapy after resection of early-stage NSCLC. Cisplatin plus vinorelbine was used as the adjuvant chemotherapy regimen in two of these trials resulting in improvements in 5-year survival of 51.2% versus 42.6% (p=0.013) and 69% versus 54% (p=0.03), respectively. In NZ, adjuvant chemotherapy for NSCLC is expected to prevent up to 15 lung cancer deaths each year for relatively low drug expenditure and has the potential to benefit Maori and the economically-deprived disproportionately more than other populations. In conclusion, it is the opinion of this group of NZ lung cancer specialists that adjuvant chemotherapy with cisplatin plus vinorelbine should now be adopted as a standard of care for patients with resected stage II and III NSCLC. For this to occur, current PHARMAC policies preventing its use for these eligible patients will need to be revised.

Antineoplastic Agents, Phytogenic↗

Pemetrexed disodium.

In February 2004, pemetrexed disodium (Alimta; Eli Lilly), an anticancer drug that targets folate-dependent reactions that are essential for cell proliferation, became the first drug to be approved by the US FDA for the treatment of the rare cancer malignant pleural mesothelioma. Its accelerated approval for the second-line treatment of non-small-cell lung cancer followed in August 2004.

Antineoplastic Agents↗

Selective delivery of CB300638, a cyclopenta[g]quinazoline-based thymidylate synthase inhibitor into human tumor cell lines overexpressing the alpha-isoform of the folate receptor.

The alpha-isoform of the glycosylphosphatidylinositol cell membrane tethered folate receptor (alpha-FR) is overexpressed in some carcinomas (notably ovarian carcinomas) relative to normal tissues. The nonpolyglutamatable folate-based thymidylate synthase (TS) inhibitor, CB300638 (TS K(i) = 0.24 nM) displayed an IC(50) of 0.0028 microM for the inhibition of the growth of human A431-FBP cells transfected with the alpha-FR. In contrast, the IC(50) for the neotransfected A431 cells was 0.81 microM (300-fold higher). Similarly, this compound inhibited the growth of human KB cells that constitutively overexpress the alpha-FR with an IC(50) of 0.0036 microM. These data were derived from cells grown in a physiological concentration of folate (20 nM R,S-leucovorin). Incubation of KB cells with a 1 microM excess of folic acid (FA), to selectively block uptake via the alpha-FR, increased the CB300638 IC(50) to 0.39 microM. The relatively low potency of CB300638 under these conditions, or in cell lines not expressing the alpha-FR, is ascribed to its low affinity for the ubiquitously expressed folate transporter, the reduced-folate carrier (K(i) for inhibition of [(3)H]methotrexate transport >100 microM). The high potency of CB300638 in alpha-FR-overexpressing cell lines is attributable to high affinity of the alpha-FR (53% of FA) and efficient endosomal trafficking mediated by the alpha-FR. Sixteen-h exposure to CB300638 inhibited the rate of (3)H(2)O release from 5-[(3)H]dUrd (in situ TS assay) in A431, A431-FBP, and KB cells with IC(50) values of 0.1 microM, 0.005 microM, and 0.002 microM, respectively. The coaddition of 1 micro M FA increased the IC(50)s for A431-FBP and KB cells to approximately 0.1 microM consistent with alpha-FR-mediated transport of CB300638. In conclusion, alpha-FR-mediated uptake of CB300638 leads to TS and growth inhibition that is highly selective for alpha-FR overexpressing tumor cell lines. The low expression of the alpha-FR in normal tissues, particularly those sensitive to TS inhibitors, together with the low affinity of CB300638 for the reduced-folate carrier, suggests that the compound may have potential as an antitumor agent with a high therapeutic index.

Antineoplastic Agents↗

Mesenteric lymphatic malformation associated with small-bowel volvulus - two cases and a review of the literature.

Cystic mesenteric lymphatic malformations are uncommon abdominal masses, which can cause abdominal signs and symptoms for a wide variety of reasons. Symptoms owing to volvulus are uncommon and have not been illustrated previously in the radiology literature. We present two cases to illustrate volvulus as a complication of mesenteric lymphatic malformations and how imaging can aid in the diagnosis of this complication. While uncommon, volvulus should be considered in any child with sonographic findings of an abdominal lymphatic malformation and acute abdominal pain.

Abnormalities, Multiple↗