FDA Approves New Drug for MRSA Infections

The U.S. Food and Drug Administration (FDA) has just approved a new intravenous antibiotic to treat dangerous skin infections. Oritavancin (Orbactiv) is designed for people with skin and skin structure infections caused by drug-resistant bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), other Streptococcus species, and Enterococcus faecalis. The U.S. Centers for Disease Control and Prevention estimates that more than 2 million Americans are infected with bacteria that are resistant to antibiotics every year.

The FDA also approved dalbavancin (Dalvance) and tedizolid phosphate (Sivextro) earlier this year to treat these types of stubborn infections. Orbactiv is the third new drug categorized as a Qualified Infectious Disease Product (QIDP) under the Generating Antibiotic Incentives Now act.

Orbactiv received the QIDP designation because it treats serious or life-threatening infections. The special designation means the company that makes the drug, The Medicines Company, gets five additional years of marketing exclusivity before a generic drugmaker can come out with a similar product.

“The approval of several new antibacterial drugs this year demonstrates that we are making progress in increasing the availability of treatment options for patients and physicians,” Dr. Edward Cox, director of the antimicrobial products division at the FDA’s Center for Drug Evaluation and Research, said in a press statement. “However, more work is needed in this area, and the FDA remains a committed partner to help promote the development of antibacterial drugs.”

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Orbactiv has some common side effects reported during clinical trials, such as headache, nausea, vomiting, skin and soft tissue abscesses on the arms and legs, and diarrhea. The drug's label warns patients that the medication could interfere with blood coagulation tests and the blood-thinning drug warfarin.

Single Injection Cuts Down Hospital Stays

“I can see this antibiotic decreasing length of stay in hospitals and even avoiding hospitalization altogether since it could be administered in a doctors' office,” said Dr. Dalilah Restrepo, a physician at Mount Sinai Roosevelt hospital in New York City.

Restrepo said Orbactiv is similar to vancomycin, which is the “drug of choice” for infections caused by MRSA and other resistant pathogens. Patients must often be hospitalized to bring drug-resistant infections under control.

“This drug is a single infusion,” Restrepo added. “This drug in one dose was comparable to seven to 10 days of the standard antibiotic.”

The main issue is the drug's cost, Restrepo said.

“When you think of the savings of avoiding a hospitalization, it really is worthwhile 10 times over, but it will be a challenge to prove that to insurance companies and hospital administrators,” she said.

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The Promise of Biologic Drugs, Sans Side Effects

Despite new advances in drug development, drug-resistant infections are a growing concern nationwide. Researchers are trying everything in their arsenal to slow the epidemic.

Synthetic Biologics has developed SYN-004, a drug that prevents Clostridium difficile (C. diff), an infection resistant to many drugs. It is the leading hospital-acquired infection in the U.S., and it is known for eating into and perforating patients' intestinal walls.

John Monahan, Ph.D., executive vice president of research and development at Synthetic Biologics, said that SYN-004, an enzyme, is taken along with an antibiotic to prevent C. diff. He said that SYN-004 should be available for patient use in just a few years.

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“What we have is a way of breaking down any excess of antibiotics into the gut, but in the same time not affecting the antibiotic in the bloodstream,” he said. “Should any of the excess antibiotic go into intestines, it’s immediately broken down.”

In prescribing antibiotics, doctors need to know that drug resistance is not the only issue, Monahan said. 

“Physicians first and foremost have to be cautious of this,” Monahan said, emphasizing the dangers of C. diff infections, which can be triggered by large doses of antibiotics. “They have to weigh the amount of antibiotic in the blood against the potential of so much of the excess leaching into the intestine.”

Photo courtesy of NIAID.