Biotech Strategy Blog

Commentary on Science, Innovation & New Products with a focus on Oncology, Hematology & Cancer Immunotherapy

Posts tagged ‘Chemokine’

How does sunburn cause pain?

Everybody who has sat too long in the sun knows how painful sunburn can be, and how ineffective current treatments such as topical creams can be.

Research by John Dawes and colleagues at King’s College London & University College London has shed new light on how sunburn causes pain.

They investigated the inflammatory response associated with ultraviolet B radiation of the skin and found that the chemokine CXCL5 (also known as epithelial-derived neutrophil-activating peptide-78) mediates UVB irradiation-induced pain in the skin of rats.

The results, published in Science Translational Medicine (STM), suggest that CXCL5 mediates UVB irradiation-induced pain and may be a target for the development of new analgesics or pain killers.

The elegant series of experiments done by Dawes and colleagues attempted to overcome one of the main challenges of pain research – the results from animal models don’t always predict pain relief in humans.

They designed custom-made Taqman array cards to determine the expression of inflammatory mediators in UVB treated rat and human skin, and found chemokine CXCL5 expression to be up-regulated in both rat and humans 40 hours after UVB treatment.

They then tested the hypothesis that CXCL5 was the cause of the pain, and that neutralization of this reduced mechanical hypersensitivity in rats and decreased the number of infiltrating cells. The STM paper is well worth reading for the series of experiments they performed.

Inflammation and inflammatory mediators are poorly understood in many diseases such as osteoarthritis (OA), so generating a better understanding of the underlying biology and mediators of inflammation is key to drug development.

It is too early to tell whether CXCL5 will turn out to be a druggable target, but the work by Dawes and colleagues is a good example of translational medical research worth exploring further.

ResearchBlogging.orgDawes, J., Calvo, M., Perkins, J., Paterson, K., Kiesewetter, H., Hobbs, C., Kaan, T., Orengo, C., Bennett, D., & McMahon, S. (2011). CXCL5 Mediates UVB Irradiation-Induced Pain Science Translational Medicine, 3 (90), 90-90 DOI: 10.1126/scitranslmed.3002193

Merck’s cathepsin-K inhibitor odanacatib in osteoporosis

Following on from my recent blog post on emerging treatments in osteoporosis, one of new approaches in development is the inhibition of cathepsin-K.

Cathepsin-K inhibition is a novel approach to osteoporosis treatment and Merck’s odanacatib is leading the way in this new class of drugs. It is currently in phase III development, with 16,716 subjects enrolled (NCT00529373).

Cathepsins are lysosomal proteases. Cathepsin K (Cat-K) is a cysteine protease that plays an important role in the function of osteoclasts (the cells responsible for bone destruction). Cat-K acts to degrade bone collagen. By inhibiting it, the removal of bone matrix proteins by osteoclasts is reduced.

However, Cat-K inhibitors such as odanacatib do not kill off the osteoclast, but allow it to still produce chemokines and growth factors such as WNT that are responsible for the effective function of osteoblasts (the cells responsible for bone formation).

The net result is that Cat-K inhibitors reduce bone resorption.

Phase II clinical trial results for odanacatib presented at the American Society of Bone and Mineral Research (ASBMR) annual meeting last year (abstract #1247),  showed an increase in spine and hip bone mineral density (BMD) after four years of follow-up, suggesting that odanacatib use leads to increased bone strength. As reported by Merck in their press release:

In postmenopausal women who received odanacatib 50 mg weekly for four years (N=13), an increase in BMD of 2.8 percent at the lumbar, and 2.7 percent at the hip were demonstrated between years three and four of treatment. Over four years of treatment, these women had increases in lumbar spine (10.7 percent) and hip (8.3 percent) BMD from baseline.

If you are looking for further information on the science, the February 2011 issue of “The Journal of Bone and Mineral Research” has several papers on odanacatib, osteocytes and cathepsin K inhibitors.

Merck has 16,716 subjects enrolled in their phase III trial for odanacatib, and July 2012 is indicated as the date when data will be available for the primary end-point of reduction in fracture risk over the three year treatment period.  We can expect the phase III results shortly after that, and if positive, an FDA approval could be expected in 2013.

The development of odanacatib by Merck is clearly a strategy to combat generic alendronate, which has eroded Merck’s market share and profits for Fosamax.  Both odanacatib and generic alendronate, are once weekly doses. The timeline for a product launch for odanacatib appears to be in the late 2013/2014 period, and I am sure further clarity on this will appear from Merck nearer the time.

The challenge for odanacatib is that by 2015, analysts estimate that Amgen’s RANKL inhibitor denosumab will be a blockbuster (more than $1 billion in sales) and sales of parathyroid hormone analogues will have tripled to $1.4 billion.

Although the market opportunity in osteoporosis is likely to grow given the aging population around the world, it remains to be seen how the cost/benefit of odanacatib will stack up against the competition, and whether Merck can capitalize on this.