Fluoroquinolone use set to increase, despite resistance warnings

New research from Datamonitor suggests that increasing reports of bacterial resistance to older drugs will drive uptake of fluoroquinolones, a class of broad-spectrum antibiotics, despite warnings of decreasing sensitivities and adverse events. The extensive pathogen activity exhibited by these compounds, alongside their wide range of available formulations, creates significant challenges for companies looking to introduce novel products

In the report 'Stakeholder Opinions: Fluoroquinolone Market Assessment', Datamonitor examines quinolones, the fastest growing antibacterial class which are being used increasingly in both hospital and community sectors to treat a broad range of infections. Global and regional (US and EU) sales for leading quinolones in 2001 and 2002 are presented along with projections for future performance up to 2008.

An effective alternative

Fluoroquinolones offer a relatively cheap broad-spectrum treatment option that, to date, have a low reported resistance in key bacteria. With reduced bacterial sensitivity to a wide range of older antibiotics, most notably penicillin and erythromycin, physicians are now looking for alternatives with guaranteed efficacy and convenient dosing schedules. In community settings outside hospitals, broad-spectrum products have particular advantages, especially in cases where determining the bacteria is prevented by limited diagnostic services.

Increasing resistance however, presents a major threat to continued uptake of fluoroquinolones. The FDA recently upheld its proposal to ban the use of ciprofloxacin-like antibiotics in poultry production, amid concerns it reduces the effectiveness of Cipro in treating Campylobacter, a common cause of food poisoning.

The Centers for Disease Control and Prevention in the US, have released data suggesting resistance to Cipro in Campylobacter has increased to 19%, from less than 1% prior to the approval of such compounds for agricultural use in 1995. Reducing the non-medical use of such compounds should help preserve the efficacy of these drugs in human therapy. However, agricultural antibiotic suppliers are not the only targets of campaigns to prevent fluoroquinolone resistance.

Increasing resistance in humans

There have been a number of reports associating increased fluoroquinolone use in the hospital and community with the growth of resistant pathogens, notably S. pneumoniae. In addition, recent reports from Canada and Spain, among other countries, highlight some of the important risks of which clinicians are becoming increasingly aware.

For example, a CDC monitoring program reported ciprofloxacin resistance in the Shigella species for the first time in October 2003. While antibiotic therapy is not essential in all such cases, it can be critical to reducing mortality risks in more serious circumstances. Of 1,170 isolates submitted between 1999 and 2001, the CDC reported that 93% were resistant to at least one antimicrobial agent and one isolate demonstrated resistance to ciprofloxacin.

Medical practices under scrutiny

The use of fluoroquinolone ear-drops and repetitive empiric fluoroquinolone use in uncomplicated urinary tract infections have been identified as causes of rising resistance to such products. In addition, Davidson et al. (2002) report four cases in which oral levofloxacin treatment failed as a result of resistant strains of bacteria and concluded that these cases should encourage the medical community to treat recent therapy with a fluoroquinolone as a contraindication to the use of a different fluoroquinolone for the empiric treatment of CAP.

Consequently, increasing awareness of studies, such as that reported by Davidson et al., could lead to increased restrictions on fluoroquinolone use. Already, some experts do not advocate the use of fluoroquinolones for first-line treatment of community-acquired infection because of concerns regarding the emergence of resistance in pneumococci.

Instead these authors suggest that fluoroquinolones should be used in patients whose previous therapy has failed, who are allergic to alternatives or who have documented infection with highly drug-resistant pneumococci. However, while resistance issues in competitor classes, most notably the penicillins, remain problematic, Datamonitor believes that use of quinolones will continue to increase.

RTIs to drive uptake

Despite the warnings of increased use leading to resistance problems, research suggests that by 2008 more patients with common infections will be treated with fluoroquinolone products. For example, UK physicians questioned regarding their use of fluoroquinolones in community respiratory tract infections (RTI) suggested that, by 2008, 25% of their RTI patients would be treated using fluoroquinolones, compared to 20% in 2002.

The reduced sensitivity of pathogens to older antibacterials, along with the increasing number of moderate to severely ill patients cared for in the community setting and growing numbers of elderly and immunocompromised, will help to justify the wider use of fluoroquinolones in both the US and EU. This will be facilitated in the EU and, by 2005, the US by the patent expiry of Bayer's Cipro, which will result in a continued influx of cheaper generic equivalents.

Related research:

• Commercial Perspectives: Fluoroquinolones - Established Products Drive Market Growth - $3200.00 Jan 2004

• Stakeholder Opinions: Community Acquired Respiratory Tract Infections - Room for Ketek? - $3400.00 March 2004

• Pipeline Insight: Antibacterials - Select Classes, Select Uses - $9600.00 December 2003

To order these reports contact peter.barfoot@bioportfolio.com or telephone +44 1300 321501 or +1 415 680 2472 and a representative will get back to you.

You can also order on line at: http://www.bioportfolio.com/cgi-bin/acatalog/search.html