Biotech Strategy Blog

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

Posts tagged ‘FDA approval’

One of the themes of this blog is innovation in biopharmaceutical new product development. Innovation can take many forms ranging from nanotechnology based drug delivery to a novel scientific mechanism of action.  The March 17, 2011 edition of Nature, highlights how innovative preclinical animal models are having an impact on drug development.

In their article on translational medicine, “Cancer lessons from mice to humans”, David Tuveson and Douglas Hanahan, describe how preclinical mouse models helped predict the recent phase III clinical trial results for sunitinib and everolimus in pancreatic neuorendocrine tumor (PNET).

The data was a major breakthrough for this disease. As Sally Church noted on Pharma Strategy Blog, sunitinib doubled the progression free survival (PFS) time and improved OS.

Tuveson and Hanahan in Nature note that “a vast number of potential anticancer drugs are currently in the pipelines of biopharmaceutical companies.” The challenge is not one of a shortage of candidates nor of potential targets, but in deciding which have most promise and where to spend valuable clinical development resources.

The authors conclude that there’s now optimism that genetically engineered mouse models may be able to mimic the progression of human cancer at the cellular and tissue levels. The mouse model of PNET (RIP-Tag2) successfully predicted that sunitinib and everolimus would be effective in treating humans.

Of course, not all human cancers can be modeled and adaptive resistance can subsequently occur in clinical trials, suggesting that preclinical models do have their limitations.

I hope we will see further innovation in mouse models of human cancer as translational medicine develops.

ResearchBlogging.orgTuveson, D., & Hanahan, D. (2011). Translational medicine: Cancer lessons from mice to humans Nature, 471 (7338), 316-317 DOI: 10.1038/471316a

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.

Last week on January 20, 2011, the FDA’s Peripheral and Central Nervous System Drugs Advisory Committee decided not to recommend approval of Lilly’s Amyvid™ (florbetapir) in a 13:3 vote.  Florbetapir is an imaging agent used with Positron Emission Tomography (PET) to show accumulation of beta-amyloid plaque in the brain. I previously wrote about Lilly’s acquisition of Avid Radiopharmaceuticals for florbetapir on this blog.

This imaging approach aids in the early detection of Alzheimer’s disease, as a negative scan, not showing any beta-amyloid plaque, would rule out Alzheimer’s disease.  Given that it is currently, hard to distinguish age related memory less and different types of dementia, diagnostic imaging tools have an important role to play.

The FDA advisory committee’s decision would probably have come as a surprise to Lilly, since the clinical trial data showed clear efficacy and no safety concerns.  While the committee rejected immediate approval, they did recommend approval (16:0), conditional on a training program to show that radiologists and readers of the scans could be accurate and consistent in their image interpretation. The FDA is not bound by the Committee’s recommendations but is required to take them into consideration when deciding whether to grant approval.

Imaging is becoming increasingly important in clinical trial design. In therapeutic areas such as osteoporosis, rheumatoid arthritis and oncology, imaging end points are often surrogates for drug efficacy.

The challenge that emerging biotechnology companies face in linking imaging to drug use, is the variability of readers outside a controlled clinical trial environment where images may be read centrally.  Standardization of image acquisition and reading needs to take place, so that a radiologist in different hospitals can come up with the same findings.  Those involved with imaging clinical trials know how hard this can be, even within the controlled clinical trial setting.

The recommendation of the FDA advisory committee that Lilly needs to put in place a training program to show accuracy and consistency of readers is a valid concern and one that all biotechnology companies and pharmaceutical companies should take note of when developing imaging agents.

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