Cubist Pharmaceuticals will launch its new antibiotic Sivextro in the next few days after getting approval of the drug for treating acute bacterial skin and skin structure infections (ABSSSI) in the US.
The launch of a new antibiotic has become a rare event in recent years given the pharma industry’s lack of R&D in this area, so it is encouraging that Sivextro (tedizolid phosphate) is the second new antibacterial to be approved by the FDA to treat ABSSSI in the past month after Durata Therapeutics’ Dalvance (dalbavancin).
Sivextro is in the oxazolidinone class of antibiotics has been approved to treat ABSSSIs caused by certain Gram-positive bacteria, including ‘superbug’ methicillin-resistant Staphylococcus aureus (MRSA), and is available in both oral and intravenous formulations.
ABSSSIs is a catch-all term for a range of infections including cellulitis, cutaneous abscesses and would infections, which can be life-threatening and may require surgery and hospitalisation. Increasingly, ABSSSIs are associated with drug-resistant pathogens.
Sivextro is the first antibiotic to be approved under the FDA’s qualified infectious disease product (QIDP) framework, which was set up to try to encourage research into new antibacterials. In addition to an expedited review by the US regulator, QIDP status also gives an extra five years of market exclusivity.
Cubist was also given QIDP status for its ceftolozane/tazobactam antibiotic – developed for complicated urinary tract infections and intra-abdominal infections – which was given priority review status by the FDA last week.
Speaking to PMLiVE last month, Cubist’s chief scientific officer Dr Steven Gilman explained that the QIDP status is “important because it gives companies access to longer exclusivity and some regulatory facilitation in terms of the speed of regulatory review”.
“We have to have some encouragement in investment in this area,” he added.
In clinical trials, Sivextro given at a dose of 200mg once a day for six days was shown to be at least as effective as Pfizer’s oxazolidinone Zyvox (linezolid) 600mg administered twice a day for 10 days. It has also shown some activity against infections that show some resistance to Zyvox, which has become a $1bn-plus product despite being reserved for use as a last-line therapy.
Until the approval of Dalvance (which is only available as an injectable formulation), Zyvox was the only antibiotic approved for use against complicated skin infections caused by MRSA.
FDA approval of tedizolid makes it the first new oral drug to be approved under an Infectious Diseases Society of America (IDSA) initiative to bring 10 new antibiotics to market by 2020.
Other drugs in development to treat ABSSSIs include Furiex Pharmaceuticals’ avarofloxacin (phase III), Melinta Therapeutics’ delafloxacin (phase III) and The Medicines Company’s oritavancin (filed for approval in the US).
Cubist’s Dr Gilman explained that the company’s approach to research was based entirely on unmet medical need and that Cubist, which has recently joined the Innovative Medicines Initiative via its membership of EFPIA, was open to collaboration to make that happen.
“We are completely agnostic to what science we need to fill that that medical need whether that’s science in our laboratories or science in someone else’s laboratory, or whether it’s a small molecule approach or a biological approach. We are open to all of those.”
“We’re one of the few companies that has stayed in that game because we do believe it’s important for patients and for public health across the globe. We think we are the largest company that invests the most in R&D in new antibacterials – in 2014 we will spend just over $400m on R&D in this area.”
Dr Gilman is also aware that treatment of infections should not make the same mistakes as the past.
“We want responsible use of antibiotics,” he said. “We’re not the kind of company that goes out and puts these drugs in people’s hands and says use them. They should only be used in patients with the highest medical need and used at right dose and duration.”