US infectious disease specialists’ prescribing choices for GNIs

A majority of US surveyed infectious disease (ID) specialists are willing to prescribe novel antibiotics, developed under the Infectious Diseases Society of America’s proposed Limited Population Antibacterial Drug (LPAD) approval pathway and costing $15,000 or more for a course of therapy, if they demonstrate superiority in improving clinical cure rates or reducing mortality rates in patients with multi-drug-resistant gram-negative infections (GNIs).

However, according to a new report from health care advisory firm Decision Resources, given that cost-related factors - namely direct acquisition costs and cost per patient, including treatment and secondary costs - are important considerations in formulary decision making, surveyed hospital pharmacy directors (PDs) are less receptive to formulary inclusion of an LPAD-approved agent costing $15,000 or more irrespective of the level of demonstrated superiority.

Current premium-priced branded antibiotics subject to Rxing restrictions

The US Physician and Payer Forum report, titled Novel Antibiotics Targeting Gram-Negative Infections: US Payer and Prescriber Perspectives on Opportunities for Growth and Barriers to Success, also finds that, with regard to the formulary status of currently marketed antibiotics, premium-priced branded antibiotics - such as Merck’s Invanz (ertapenem), Johnson & Johnson’s Doribax (doripenem), Bayer’s Avelox (moxifloxacin), Pfizer’s Tygacil (tigecycline) and Forest’s Teflaro (ceftaroline fosamil) - continue to be subject to prescribing restrictions, likely in efforts to limit inappropriate use, prevent emergence of drug resistance and reduce treatment costs.

The report finds that carbapenems with generically available formulations are increasingly included on hospital formularies without restrictions and around half of surveyed physicians and nearly two-thirds of hospital PDs indicate that meropenem and imipenem/cilastatin are unrestricted on their hospital’s formulary, likely a reflection of the increasing incidence of difficult-to-treat GNIs and the limited number of available treatment options.

Emerging therapies need to be differentiated

“Despite a pressing need for novel treatment options targeting multi-drug-resistant gram-negative pathogens (GNPs), hospital PDs are sensitive to premium prices of branded agents, given the widespread availability of lower-cost generic antibiotics,” said Decision Resources analyst Hannah Cummings, adding: “Emerging therapies will need to differentiate themselves from marketed antibiotics in terms of impact on overall hospitalization cost, activity spectrum, or activity against multi-drug resistant GNPs to secure formulary inclusion and uptake in the hospital antibiotic market.”

When asked of their willingness to include emerging therapies on hospital formularies, such as AstraZeneca/Forest’s ceftazidime/avibactam, Cubist’s ceftolozane/tazobactam, Tetraphase’s eravacycline and Achaogen’s plazomicin, surveyed hospital PDs indicated that inclusion of these therapies will be largely influenced by pricing relative to marketed competitors. Among surveyed hospital PDs who anticipate including these emerging therapies on their hospital formularies, a majority expect these therapies to be included with prescribing restrictions, such as requiring prior ID consult or limiting use to microbiologically confirmed infections due to susceptible pathogens.