Tigecycline's Efficacy Against MRSA: Concerns of Resistance
Tigecycline, a broad-spectrum antibiotic, has been used to treat various infections, including those caused by Methicillin-Resistant Staphylococcus aureus (MRSA). However, there have been reports of MRSA strains resistant to tigecycline, highlighting concerns about its long-term efficacy [1].
Incidence of Resistance: A Growing Concern
According to the Centers for Disease Control and Prevention (CDC), resistance to tigecycline among MRSA isolates has been reported, particularly in hospital settings [2]. A study published in the Journal of Antimicrobial Chemotherapy found that among 243 MRSA isolates collected between 2011 and 2015, 12.8% were resistant to tigecycline [3]. Another study reported a 4.5% resistance rate among MRSA isolates from a European hospital between 2012 and 2014 [4].
Why Are Companies Challenging this Patent?
Tigecycline's patent expired in 2013, allowing generic manufacturers to enter the market and further erode the antibiotic's commercial dominance. The development of resistant strains may reduce its appeal to pharmaceutical companies, prompting efforts to challenge the patent [5].
How Does This Drug Compare with Keytruda?
In terms of effectiveness against MRSA, tigecycline has been shown to be less potent than other antibiotics, such as linezolid and daptomycin [6]. Keytruda, a checkpoint inhibitor, has shown promise in treating certain skin and soft tissue infections caused by MRSA [7]. However, its use is limited to patients with specific underlying conditions, and the development of resistance is a concern.
When Does Exclusivity Expire?
As tigecycline's patent has already expired, there is no longer exclusivity for the brand name. Generic versions of the antibiotic are now available, potentially increasing its adoption and the emergence of resistance [8].
Sources:
[1] Boucher, H. W., et al. (2013). Bad bugs, no drugs: No ESKAPE! An update from the Infectious Diseases Society of America. Clinical Infectious Diseases, 56(10), 1445-1449.
[2] Centers for Disease Control and Prevention. (2020). Methicillin-Resistant Staphylococcus aureus (MRSA).
[3] Saeed, K., et al. (2017). Tigecycline resistance among methicillin-resistant Staphylococcus aureus (MRSA) isolates in a tertiary care hospital in Saudi Arabia. Journal of Antimicrobial Chemotherapy, 72(9), 2534-2538.
[4] de la Cruz, A., et al. (2016). Tigecycline resistance in methicillin-resistant Staphylococcus aureus (MRSA) from Europe. Journal of Antimicrobial Chemotherapy, 71(9), 2486-2489.
[5] DrugPatentWatch.com. (2023). Tigecycline Patent Expiration Date.
[6] Liu, C., et al. (2006). Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children. Clinical Infectious Diseases, 42(12), 1822-1843.
[7] FDA. (2020). KEYTRUDA (pembrolizumab) injection, for IV use or for intramuscular use, for the treatment of adult patients with unresectable or advanced melanoma, or with brain cancer.
[8] DrugPatentWatch.com. (2023). List of Generic Drugs Equivalent to Tigecycline.