Osteoporosis market forecast to reach $10.4bn

A report from independent market analyst Datamonitor (DTML), reveals how key r&d trends in the osteoporosis market are focusing on novel dosing regimens and expanding indications, and forecasts strong growth driven by new market entrants.

The late-stage osteoporosis pipeline will soon provide a boost to the number of available treatments, with a flurry of launch activity expected between 2004-8. Six key products should reach the market in this time, including; Roche's Boniva, Novartis's Zometa, Pfizer's lasofoxifene, Wyeth's bazedoxifene, NPS's Preos and Servier's Protos. It is clear that antiresorptives will continue to dominate therapy. Market sales are forecast to reach $10.4bn by 2011, from approximately $5.0bn in 2003 (excluding HRT sales).

new antiresorptives

Antiresorptive agents, drugs that slow down or halt the rapid loss of bone characteristic in osteoporosis, dominate current treatment. Key marketed products with this kind of activity include the bisphosphonates, such as the market-leader Fosamax (alendronate, Merck) and second-in-class Actonel (risedronate, P&G/Aventis), as well as another top selling drug, Lilly's Evista (raloxifene), a selective estrogen receptor modulator (SERM).

The pipeline holds two new drugs in each of these classes with the potential to oust established brands from their market position. New bisphosphonates Boniva (ibandronate) and Zometa (zoledronate) could offer benefits over older drugs such as Fosamax and Actonel, although therapeutic efficacy is not expected to differ greatly between these products. The primary benefits of the new bisphosphonates are their longer dosing intervals; whereby monthly, quarterly and yearly doses are in development, versus the weekly regimens currently available. These novel regimens could offer patients greater convenience by lowering the number of tablets or doses they have to take, and help improve poor compliance rates by reducing the likelihood of missed or inaccurately administered doses. Datamonitor believes Zometa's yearly dose, currently in Phase III trials, could garner blockbuster sales by 2011, while positive trial results for monthly or quarterly Boniva could drive sales of up to $800m over the same period.

Novel SERMs are taking a different tack in the r&d stakes. In this class, Pfizer's lasofoxifene is in trials investigating potential beneficial effects on breast cancer prevention and heart disease, as well as osteoporosis. Positive results in these areas would make the drug very attractive to patients at-risk for those conditions and postmenopausal bone loss, vastly extending the drug's patient potential. Wyeth's approach to their SERM bazedoxifene targets the range of menopause symptoms. The drug is in trials with Premarin as a potential new hormone therapy product. However, with the aftermath of the WHI still negatively affecting HRT sales, the clinical data on this combination product will likely undergo close scrutiny and commercialisation could be difficult.

New anabolics

Osteoporosis is a progressive bone deterioration disease and novel bone-forming drugs are one of the most promising approaches to improving bone density and preventing fractures. Lilly's PTH drug, Forteo (teriparatide), launched in December 2002, is currently the only drug on the market capable of building new bone. However, new anabolic agents are set to hit the market by 2005, opening it up to direct competition and widening the treatment choices.

Key anabolic agents in the pipeline are NPS Pharmaceutical's Preos, a full length recombinant version of the PTH hormone from which Forteo is also derived, and Servier's Protos (strontium ranelate), a salt reported to have both an anti-resorptive and anabolic effect on bone. Both these drugs have recently reported results from their pivotal Phase III trials detailing fracture reduction efficacy, and are expected to file for approval later in 2004. Preos in particular could achieve sales of over $430m by 2011, and is expected to drive class sales growth by over 40%. The drug will be Forteo's first direct competitor, but will be at a disadvantage both in terms of NPS's marketing power, currently without a commercial partner for the drug, and Lilly's three years detailing experience with their product by the time Preos is launched.

Price will be an important factor in positioning Preos, particularly as the cost of PTH therapy is currently the most expensive of osteoporosis treatments at around $20 per day. This is an area where Protos could find its niche. More likely to compete against the bisphosphonates and SERMs, as a salt, Protos' comparatively low manufacturing costs could be reflected in its price. Canny positioning as an inexpensive, effective and easy to use agent to prevent fractures is likely to appeal across the board in the face of escalating pressure on healthcare budgets.

pipeline offers?

The early stage pipeline (Phase II or lower) is bursting with potential candidates for osteoporosis drugs. The focus on innovation is clear among these drugs, an approach distinct from products in the later stage pipeline where the candidates are second-third to market, or me-too drugs. Successful development of the early pipeline could see the introduction of five entirely new therapeutic classes to the market. Three of these classes hold significant potential in osteoporosis: 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. 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 comparied to PTH products.

Victoria Williams, Women's Health analyst at Datamonitor comments: 'The impending launch of six new osteoporosis drugs over the next four years will shake up the market and offer patients and physicians an unprecedented choice of treatment options. Crucial to the success of pipeline 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.'