A scalable low-cost cGMP process for clinical grade production of the HIV inhibitor 5P12-RANTES in Pichia pastoris.

In the continued absence of an effective anti-HIV vaccine, approximately 2 million new HIV infections occur every year, with over 95% of these in developing countries. Calls have been made for the development of anti-HIV drugs that can be formulated for topical use to prevent HIV transmission during sexual intercourse. Because these drugs are principally destined for use in low-resource regions, achieving production costs that are as low as possible is an absolute requirement. 5P12-RANTES, an analog of the human chemokine protein RANTES/CCL5, is a highly potent HIV entry inhibitor which acts by achieving potent blockade of the principal HIV coreceptor, CCR5. Here we describe the development and optimization of a scalable low-cost production process for 5P12-RANTES based on expression in Pichia pastoris. At pilot (150 L) scale, this cGMP compliant process yielded 30 g of clinical grade 5P12-RANTES. As well as providing sufficient material for the first stage of clinical development, this process represents an important step towards achieving production of 5P12-RANTES at a cost and scale appropriate to meet needs for topical HIV prevention worldwide.

Highly potent, fully recombinant anti-HIV chemokines: reengineering a low-cost microbicide.

New prevention strategies for use in developing countries are urgently needed to curb the worldwide HIV/AIDS epidemic. The N-terminally modified chemokine PSC-RANTES is a highly potent entry inhibitor against R5-tropic HIV-1 strains, with an inhibitory mechanism involving long-term intracellular sequestration of the HIV coreceptor, CCR5. PSC-RANTES is fully protective when applied topically in a macaque model of vaginal HIV transmission, but it has 2 potential disadvantages related to further development: the requirement for chemical synthesis adds to production costs, and its strong CCR5 agonist activity might induce local inflammation. It would thus be preferable to find a recombinant analogue that retained the high potency of PSC-RANTES but lacked its agonist activity. Using a strategy based on phage display, we set out to discover PSC-RANTES analogs that contain only natural amino acids. We sought molecules that retain the potency and inhibitory mechanism of PSC-RANTES, while trying to reduce CCR5 signaling to as low a level as possible. We identified 3 analogues, all of which exhibit in vitro potency against HIV-1 comparable to that of PSC-RANTES. The first, 6P4-RANTES, resembles PSC-RANTES in that it is a strong agonist that induces prolonged intracellular sequestration of CCR5. The second, 5P12-RANTES, has no detectable G protein-linked signaling activity and does not bring about receptor sequestration. The third, 5P14-RANTES, induces significant levels of CCR5 internalization without detectable G protein-linked signaling activity. These 3 molecules represent promising candidates for further development as topical HIV prevention strategies.

Economic evaluation of enoxaparin for the prevention of venous thromboembolism in acutely ill medical patients.

OBJECTIVE: To conduct an economic evaluation of the prevention of venous thromboembolism in acutely ill medical patients. METHOD: We used a previously described economic model created in the context of the UK National Health Service and applied it to St. Thomas' Hospital, London. A clinical review to determine the number of medical admissions that would require thromboprophylaxis at St. Thomas' Hospital, based on the inclusion criteria of a medical thromboprophylaxis trial (MEDENOX), was conducted. Costs and effectiveness were determined, based on the provision of thromboprophylaxis to 2000 medical patients. RESULTS: Comparing treatment with low-molecular-weight heparin (enoxaparin, 40 mg once daily), unfractionated heparin (5000 IU twice daily), or no prophylaxis, the highest cost of thromboprophylaxis was associated with unfractionated heparin (199,000 pounds sterling = 4306,000 Euros), compared with enoxaparin (198,000 pounds sterling = 305,000 Euros) or no prophylaxis (176,000 pounds sterling = 271,000 Euros). The model suggested that enoxaparin thromboprophylaxis would result in fewer thromboembolic-related events. Using sensitivity analysis, incorporating certain St. Thomas'-specific costs showed enoxaparin compared with unfractionated heparin or no thromboprophylaxis was cost saving. The cost savings of 65,000 pounds sterling ( = 100,000 Euros) and 31,000 pounds sterling ( = 48,000 Euros) respectively are based on maximum uptake of thromboprophylaxis. CONCLUSIONS: The graded implementation of enoxaparin thromboprophylaxis over a four-year period would require funding redistribution. The funding Health Authority would save overall but St. Thomas' would require an increase in drug expenditure across the clinical directorates of 35,000 pounds sterling ( = 54,000 Euros) after 4 years.