Postmarketing surveillance study of a non-chlorofluorocarbon inhaler according to the safety assessment of marketed medicines guidelines

Challenges of post-authorization safety studies: Lessons learned and results of a French study of fentanyl buccal tablet

PURPOSE

Recruiting and retaining participants in real-world studies that collect primary data are challenging. This article illustrates these challenges using a post-authorization safety study (PASS) to assess adverse events (AEs) experienced with fentanyl buccal tablet (FBT) over 3 months of treatment.

METHODS

This was an observational, prospective, multicenter study in France conducted over 1 year. The study employed primary data collection in FBT-treated patients and their treating physicians via a site qualification questionnaire and patient log completed by physicians and a questionnaire and pain diary completed by patients. Strategies to increase participation included reminders, newsletters, frequent follow-up telephone calls, and reducing the extent of data collected.

RESULTS

Of the 1118 physicians contacted who returned the participation form or responded to a telephone call, only 128 expressed willingness to participate. Key reasons for non-participation were lack of interest (69.7%) and FBT not being used in practice by the contacted physician (25.1%). Overall, 224 patients were screened by 31 physicians, and 97 were enrolled. Key reasons for patient non-inclusion were unwillingness or inability to complete the patient AE diary or questionnaire (40.9% [52/127]) and patients' decision (33.9% [43/127]).

CONCLUSIONS

Despite efforts to increase participation, enrollment in this study was low. Recruitment and retention methods are limited in their capacity to optimally execute a primary data collection in a PASS. For a PASS to provide reliable and valid information on medication use, involvement from health care agencies, regulators, and pharmaceutical companies is needed to establish their importance, drive study participation, and reduce patient withdrawal.

Albuterol HFA for the management of obstructive airway disease

Albuterol (salbutamol outside the USA) is used to acutely relieve symptoms related to airway obstruction and prevent exercise-induced bronchospasm. Albuterol is most commonly administered by metered-dose inhaler (MDI). MDIs had used chlorofluorocarbon (CFC) propellants, but CFCs accumulate in the stratosphere and contribute to ozone catabolism. Loss of the 'ozone layer', which filters UVB rays, has public health concerns. Albuterol has been reformulated in MDIs using hydrofluoroalkane (HFA) propellants, which do not affect the ozone layer. Albuterol HFA MDIs deliver the same amount of drug per puff with similar particle size distributions as albuterol CFC MDIs, resulting in comparable bronchodilator efficacy of the two products. The highly favorable safety profile of albuterol has not been altered with reformulation. The propellant HFA-134a appears to be devoid of safety concerns.

How best to deliver aerosol medications to mechanically ventilated patients

Pressurized metered-dose inhalers (pMDIs) and nebulizers are employed routinely for aerosol delivery to ventilator-supported patients, but the ventilator circuit and artificial airway previously were thought to be major barriers to effective delivery of aerosols to patients receiving mechanical ventilation. In the past two decades, several investigators have shown that careful attention to many factors, such as the position of the patient, the type of aerosol generator and its configuration in the ventilator circuit, aerosol particle size, artificial airway, conditions in the ventilator circuit, and ventilatory parameters, is necessary to optimize aerosol delivery during mechanical ventilation. The best techniques for aerosol delivery during noninvasive positive-pressure ventilation are not well established as yet, and the efficiency of aerosol delivery in this setting is lower than that during invasive mechanical ventilation. The most efficient methods of using the newer hydrofluoroalkane-pMDIs and vibrating mesh nebulizers in ventilator-supported patients also require further evaluation. When optimal techniques of administration are employed, the efficiency of aerosolized drug delivery in mechanically ventilated patients is comparable to that achieved in ambulatory patients.

Recommendations for postmarketing surveillance studies in haemophilia and other bleeding disorders

Prospective surveillance studies to monitor drug safety in the postapproval period are rarely employed systematically, although they are of greatest value for caregivers, drug users and regulatory authorities. Safety issues have affected not only conventional pharmaceuticals, but also especially coagulation factors in haemophilia treatment. The reputation of postmarketing surveillance (PMS) studies has been questionable, mainly due to their misuse to solicit prescriptions. Other weaknesses include inappropriate design, lack of standardized observation, limited follow-up periods, absence of rigour in identifying potential adverse drug effects, and infrequent publication. Although well-designed clinical trials represent the gold standard for generating sound clinical evidence, a number of aspects would make PMS studies valuable, if properly conducted. One of their main advantages is broader inclusion, and absence of an 'experimental' design. Lack of proper guidelines, and standardization may constitute a reason for the generally low quality of PMS studies. This paper proposes guidelines for haemophilia-specific PMS studies, in order to improve the acceptance of a basically valuable tool. In the absence of consistent regulatory guidance it will be especially important that the design and supervision of PMS studies involves physicians from the beginning. This will not only make such studies more scientifically relevant, but also help to implement them into daily clinical practice. Specifically in haemophilia, PMS studies may provide valuable data on clinical outcomes, or Quality of Life, which is of great importance when considering adequate standards of care in haemophilia patients.

The contribution of cohort studies to prescribing research

This paper highlights the main issues in the design, analysis and interpretation of cohort studies used in prescribing research.

Use of hydrofluoroalkane propellant delivery system for inhaled albuterol in patients receiving asthma medications

OBJECTIVE

This study was undertaken to assess drug-use patterns associated with albuterol delivery via a new propellant device compared with conventional chlorofluorocarbon (CFC) metered-dose inhalers (MDIs) in patients taking asthma medications in a population with pharmacy benefits.

BACKGROUND

In addition to their ozone-depleting properties, conventional CFC inhalers often deliver inconsistent doses because of loss of prime and temperature instability. A new propellant, hydrofluoroalkane (HFA), incorporates a re-engineered delivery system associated with dosing reproducibility throughout the life of the canister.

METHODS

Drug markers associated with management of asthma were used to identify a study cohort of new users of inhaled albuterol from a geographically diverse pharmacyclaims database from July 1, 1997, through December 31, 1997. A population of 282,879 members was identified over the 20-month follow-up period. In addition, a subset of chronic albuterol inhaler users (> or = 12 months; n = 96,879) was also identified to support a longitudinal analysis. Disease severity was controlled for by use of inhaled corticosteroids (ICS). To control for canisters received via physician office samples, HFA patient use was corrected by a physician-based canister adjustment based on HFA sample data.

RESULTS

A total of 53.1% of participants were women and 46.1% were men; most of the population (72.5%) was <65 years of age. Canister use for HFA patients was consistently lower (2.7+/-3.2 vs 5.4+/-6.7) than for CFC MDIs for the entire cohort over the 20-month assessment period. This difference was consistently observed for albuterol canister use in patients with and without concomitant ICS use (3.3+/-3.8 HFA vs 7.2+/-7.5 CFC for ICS users and 2.1+/-2.1 HFA vs 4.1+/-5.7 CFC for non-ICS users). Time to next prescription also was longer for HFA patients than for CFC patients (61.6+/-50.9 days HFA vs 47.3+/-40.8 days CFC). When duration of therapy and physician samples associated with product launch were controlled for, similar differences were consistently observed. CFC patients used, on average, 1.3 more canisters per year than did HFA patients (P < 0.001), averaging 10.7 canisters (95% CI, 10.6 to 10.7), compared with 9.4 canisters used by HFA patients (95% CI, 8.9 to 9.9). Further analyses indicated that this finding was consistent when ICS use was controlled for (CFC plus ICS mean, 11.9 canisters vs HFA plus ICS mean, 10.4 canisters; P < 0.001).

CONCLUSION

This study provides useful information about the effect of use of a new albuterol delivery system on asthma inhaler management. These data suggest that CFC patients use an average of 1.3 more canisters per year compared with HFA patients independent of asthma severity as measured by ICS use. This improvement in dosing characteristics has the potential to translate into enhanced economic outcomes.

Challenges in changing to non-chlorofluorocarbon inhalers in the treatment of asthma

The chlorofluorocarbon (CFC)-based metered dose inhaler, which has been the mainstay of the management of obstructive lung diseases, will soon be phased out world wide and replaced by CFC-free devices. Patients will have to be changed to the devices in a co-ordinated manner to avoid any risk to their health and safety. The different shapes and aerosol delivery characteristics of the new inhalers, as well as their distinctive taste, could add to the levels of poor drug use already experienced in asthma. From previous change scenarios in disease management, the potential for unstable asthma control is a real possibility with all the attendant costs. By using the time available before CFC-based inhalers are withdrawn, there is an opportunity to enhance asthma management during this period of change.