Nabriva goes 2 for 2 in Phase III antibiotic program, scoring on a key catalyst — but shares plunge on safety worries

Nabriva Therapeutics $NBRV has scored a second, pivotal Phase III win for its antibiotic lefamulin in community acquired bacterial pneumonia — setting up a pitch to the FDA later this year and quite likely clearing a path to its first commercial launch.

Their antibiotic achieved non-inferiority compared to moxifloxacin for early clinical response (ECR) — 72 to 120 hours following initiation of therapy in the intent to treat patient population. In this trial, ECR rates were 90.8% for lefamulin and 90.8% for moxifloxacin. The trial also achieved European goals outlined for an approval.

Nabriva’s shares rocketed up 24% on the news, and then reversed course as investors wrestled over the safety data, falling 17% by the end of trading. Diarrhea proved a more expansive concern than the efficacy data, with the antibiotic arm doing worse than moxi. Toxicity issues grabbed investors by the throat, with plenty of fretting about potential limits to its use.

A crucial catalyst for this biotech, lefamulin came out of the second late-stage study looking identical to moxi, fitting a profile regulators require for a marketing approval. If everything goes according to plan, and gets around the safety worries, that will set up a launch in 2019 as the biotech seeks to carve out a large segment of a big market, and not just due to drug resistance.

Colin Broom

“I do not see this as an antibiotic to keep in reserve,” CEO Colin Broom tells me in a preview of the news. “It’s a short course of therapy (5 days for lefamulin compared to 7 days for moxi), highly effective, with complete coverage of the pathogens we worry about….It’s really the only antibiotic out there that has the opportunity to be used out of the gate.”

Making that argument stick with payers will require some moderation on the pricing, he adds, without spelling out the numbers. Analysts will likely stay mindful that payers will keep focused on price, always requiring cheap generics whenever possible.

The biotech also reported that one patient in their study also developed C diff during an extended hospital stay.

Gary Sender

Neither Broom nor CFO Gary Sender are offering their own peak sales estimates, but the CFO notes that analysts covering the company have pencilled in estimates ranging from $500 million to $700 million a year — and they expect those analysts to do some recalculations in their favor with the latest batch of pivotal data.

Even now Nabriva has a sales force of 20 working the pre-commercialization market. That will likely expand to the 30-to-60 range, says the CEO, and eventually up to around 100. Broom expects to line up partners for the ex-US market.

In doing so, Nabriva may soon find itself going up against Paratek’s antibiotic, which also succeeded for CABP and was filed for an approval in February. Broom shrugs that off, though, discounting the rival as a broad spectrum alternative that will likely be held in reserve, allowing lefamulin to push ahead into a broader market.

It won’t hurt Nabriva that the FDA heightened its warnings against the use of fluoroquinolones like maxi a couple of years ago, after identifying new safety issues that includes disabling side effects involving tendons, muscles, joints and nerves. And he adds that the commonly used z packs have become little better than a placebo for about half of all cases of bacterial pneumonia.

Still, for years now the development of new antibiotics has been left to small biotechs like Nabriva, after Big Pharma’s largely bowed out of a field they identified with narrow margins — despite the growing number of alarms from multitude of global health agencies over a steadily rising tide of drug resistance. It’s not an easy field, as a slate of recent clinical mishaps underscore. And cheap generics are typically thrown at cases as they arise.

Broom, though, like other CEOs in the field, believes the economics of antibiotics will gradually improve as more cases of resistance rise up. And he plans to be there with one of the new breed when it does.

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VP Oncology Biology
Skyhawk Therapeutics Waltham, MA
Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT

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