Osteoporosis sufferers are set to benefit from an influx of new drug treatments which are expected to dominate the market and give patients an unprecedented choice of treatment options, according to new market research which suggetss the size of the market could double by 2010, writes Wai Lang Chu.
A report released yesterday by market analysts Datamonitor reveals how research and development trends in the osteoporosis market will provide a boost to available treatments. Market sales are forecasted to reach $10.4 billion by 2011, from approximately $5.0 billion in 2003.
Antiresorptive agents, which slow down or halt the loss of bone, dominate current treatment and are expected to maintain this position in the future. Roche's Boniva/Bonviva (ibandronate), Novartis's Zometa (zoledronic acid), Pfizer's lasofoxifene, Wyeth's bazedoxifene, NPS's Preos (recombinant parathyroid hormone) and Servier's Protos (strontium ranelate) are products expected to launch between 2004-08.
Within the class of antiresorptive agents are the bisphosphonates, including the market leader Fosamax (alendronate), sold by Merck & Co, and second-in-class Actonel (risedronate) from Procter & Gamble and Aventis). New bisphosphonates benefit from longer dosing intervals which could be monthly, quarterly or even yearly. Patients would not need to take as many tablets, improving compliance rates, Datamonitor suggests.
The introduction of new drugs in each category could oust established brands, the report claims. New bisphosphonates with less frequent dosing - including Boniva and Zometa - could in time overtake older drugs such as Fosamax and Actonel, even though their therapeutic efficacy may remain identical.
Datamonitor predicts that a once-yearly formulation of Zometa, currently in Phase III trials, could garner blockbuster sales in excess of $1 billion (€841m) a year by 2011, while positive trial results for monthly or quarterly Boniva could drive sales of up to $800 million over the same period.
Other types of drugs include the selective oestrogen receptor modulators (SERM). Pfizer's lasofoxifene is in trials investigating osteoporosis and also breast cancer and heart disease. Wyeth's approach to its SERM product bazedoxifene targets the range of menopause symptoms, one of which is osteoporosis.
Lilly's parathyroid hormone (PTH) drug, Forteo (teriparatide), launched in December 2002 is currently the only drug on the market capable of building new bone.
PTH is a protein hormone secreted by the parathyroid gland which is the most important regulator of body calcium and phosphorus - two minerals important for building bone density.
NPS Pharmaceutical's Preos, a full length recombinant version of the PTH hormone from which Forteo is also derived, and Servier's Protos, a salt reported to have both an antiresorptive and anabolic effect on bone, are expected to file for approval in late 2004 after encouraging results from their Phase III trials. A launch date is set for 2005.
Preos in particular could achieve sales of over $430 million by 2011, and is expected to drive class sales growth by over 40 per cent. The drug will be Forteo's first direct competitor, notes the report.
Currently the cost of PTH therapy is approximately $20 per day - the most expensive of osteoporosis treatments. While Protos may compete successfully in this area its most likely to be positioned against the bisphosphonates and SERMs. Its low manufacturing costs can position it as an inexpensive, effective and easy-to-use agent to prevent fractures.
Victoria Williams, women's health analyst at Datamonitor, said: "Crucial to the success of these drugs will be clinical equivalence or improvements in vertebral and non-vertebral fracture reduction compared to established products, as well as clear benefits in side effects, delivery, dosing and cost-effectiveness.
"However, the patent expiry of market-leader Fosamax in 2008, and entry of generic equivalents, could limit the sales potential of some of the newer anti-resorptives."
Looking to the future
Meanwhile, Datamonitor notes that the early stage pipeline (Phase II or lower) is 'bursting' with potential candidates for osteoporosis drugs, with five entirely new therapeutic classes in development. Three of these classes hold significant potential in osteoporosis, accoridng to the report: the cathepsin K inhibitors, osteoprotegerin and calcilytics.
Cathepsin K inhibitors are receiving the most R&D attention, with compounds investigated by Novartis (Phase II), GSK (Phase I) and Merck (preclinical). Like Protos, these drugs could have both anti-resorptive and anabolic properties. Osteoprotegerin (OPG), under development by Amgen, is one of the first genomic derived drug candidates in osteoporosis. However, while OPG represents a scientifically innovative approach to slowing bone loss, as an antiresorptive it will still face strong competition from the bisphosphonates.
Calcilytics, currently being developed in a joint program by NPS and GSK, represent some of the few truly anabolic agents in the pipeline. As such, calcilytics have huge potential in the osteoporosis market, where further advantages of the compounds include oral delivery and relatively low costs compared to PTH products.