Loxo takes center stage at ASCO with its groundbreaking shot at a biomarker-based cancer drug approval

CHICAGO — Loxo Oncology made it into the ASCO showcase over the weekend, boasting of a small but growing number of cases where children and adults with TRK fusion cancer responded to their lead drug, larotrectinib (LOXO-101). And they’re packaging it into a new drug application they expect to hustle to regulators either later this year or early 2018, while showing off a next-gen drug coming up the pipeline that they’re already claiming has established proof-of-concept evidence of efficacy in two cases.

This Stamford, CT-based biotech $LOXO is all about hustle.

For a small company with just 35 staffers, Loxo has enormous ambitions that include shooting at some groundbreaking advances in drug development. At ASCO, the biotech boasted a 76% tumor response rate among patients with multitude of different tumor types. Unlike a typical cancer drug focused on the anatomy, Loxo is going after a biomarker — tropomyosin receptor kinase (TRK) fusions — and at ASCO it cobbled together response data from three early-stage trials.

Specifically there were 50 patients — 43 adults and 12 children — with 12% complete and 64% partial responders. That’s a high rate of success and it fits with their earlier statements on progress in the clinic. Small groups of patients like this are also not unusual for a cancer type shared by only a few thousand US patients.

The investor crowd ate it up. Loxo’s shares spiked 51% midday Monday.

Just days ago Merck won the first pioneering approval for the genetically defined use of a cancer drug, another boost for its global star Keytruda. Larotrectinib is being pushed down the same pathway, but it is experimental. And Loxo is the polar opposite of a giant like Merck, which has been pouring cash into its well-established Keytruda program in simultaneous pursuit of dozens of targets.

Josh Bilenker, Loxo Oncology

Going after an FDA approval for both children and adults like this “has never been done before,” Loxo CEO Josh Bilenker tells me. But he is absolutely convinced that the data he has is enough to form the basis of a winning application.

It’s not unusual these days to see biopharma companies use early-stage data to go after an accelerated approval at the FDA. What was once the exception is now the rule. But Loxo — which partnered with Array on the program — is pressing the envelope, using small groups of patients across Phase I and II trials to provide the evidence they need that larotrectinib works. That strategy is necessary to achieve their goal, they say, and they have the agency’s breakthrough therapy designation to provide an open door, which Bilenker says led to a meeting with the FDA 18 months ago that set them on this path.

As a public company, Loxo also has touted — and benefited — from just about every scrap of data execs can lay its hands on, with new instances of partial responses used to rev up its stock price.

In Chicago Saturday, that strategy was on full view as they noted the first glimmer of evidence that its next-gen drug LOXO-195 triggered two partial responses after it was used in emergency cases involving resistance to a TRK fusion inhibitor.

Courtesy Loxo Oncology.

If in fact they can prove that it can work against cases of TRK fusion drug resistance, their drug could become a regular part of the treatment landscape for patients with their biomarker. And they will tout any evidence of efficacy they gather on their next trip to regulators.

Loxo’s market cap is up to $1.3 billion as some market analysts cheer them at every stage.

Loxo, though, also has competition in the field. Ignyta $RXDX has a Phase II underway for entrectinib for TRK-fusion positive adult and pediatric patients. Just a couple of weeks ago Ignyta won their own breakthrough stays for their drug, giving them the same easy access that Loxo enjoys. And not all analysts are ignoring the potential for a matchup as these two small outfits compete for the limelight in cancer R&D.

“The company guided for NDAs for Trk+ and ROS1+ pts in 2018 and a U.S. launch in 2019 (MAA submission in 2019),” noted Jefferies recently. “The breakthrough designation for entrectinib helps level the playing field some with LOXO-101, which received BTD in July 2016 (NDA submission expected in late-2017 or early-2018).”

If they do make it to the market, Bilenker says Loxo plans to set up a commercial group and launch this itself. “We own worldwide rights to the drug and that’s our plan,” he says, shrugging off the suggestion of a company sale.

It’s a big goal.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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