As Roche rival draws near, TG Therapeutics' stock crashes on disappointing MS drug sales

The convenience of shorter infusion time is a big selling point for TG Therapeutics’ newly FDA-approved multiple sclerosis drug Briumvi. But an under-the-skin version of Roche’s well-established Ocrevus could pose a threat to TG’s lone offering.

Adding onto the anxiety over the potential competition, Briumvi’s sales disappointed in its first full quarter on the market. The drug generated $16 million in the three months ended in June.

The second-quarter haul came only $3 million below Wall Street analysts’ consensus estimates, according to Evercore ISI. But TG’s stock price crashed by nearly 50% in Tuesday’s trading.

The big stock sell-off was largely caused by a $25 million-plus “whisper number” that was floating among the buyside community, Evercore analyst Michael DiFiore said in a Tuesday note. Buyside investors seek to identify promising investment opportunities.

The estimates were likely based on Briumvi’s prescription trends in the past few weeks. TG recorded more than 800 Briumvi scripts through the company’s service hub in the second quarter, bringing the total to over 1,200, chief commercial officer Adam Waldman said during a conference call Tuesday. The drug has achieved payer coverage for 80% of commercial and Medicare patients, a goal that TG was originally aiming to reach by the end of the year, Waldman noted.

But as DiFiore pointed out, not all scripts can automatically be counted as infusions because of a lag in administration. During the early days of launch, it takes longer to go from a doctor’s prescription to an actual infusion, TG’s CEO Mike Weiss said on the call.

Besides lower-than-expected sales, an ex-U.S. commercialization deal with Neuraxpharm that TG unveiled Tuesday also drove down its share price. The European company will pay TG $140 million up front for certain ex-U.S. rights to Briumvi.

Investors were concerned that the price is too low, Evercore’s DiFiore noted. Besides, the deal makes a potential acquisition of TG less likely.

But the “big elephant in the room,” as DiFiore said, is competition from rival subcutaneous CD20 antibodies for multiple sclerosis, namely, Novartis’ Kesimpta and Roche’s upcoming subcutaneous Ocrevus, which just reported positive phase 3 data.

Ocrevus is the CD20 leader, posting CHF 3.2 billion ($3.6 billion) in sales in the first half of the year. But the Roche stalwart requires about three hours of infusion, whereas an infusion of TG’s Briumvi takes about one hour.

For the under-the-skin version, Roche is proposing a 10-minute injection, although it will still be administered by a healthcare professional. The Swiss pharma is also evaluating a self-administered option to be delivered via an on-body injector patch, Roche’s pharma chief Teresa Graham told investors on the company’s second-quarter call last week.

Last month, Roche said that the subcutaneous Ocrevus was noninferior to the IV version on measurements of pharmacokinetics, impact on brain lesions and safety. TG’s Weiss said he’ll be interested to see subcutaneous Ocrevus’ data on the potential side effect of injection-related pain. Besides, the Roche version’s requirement for a healthcare professional’s attention might also deter some treatment centers from getting too excited about its convenience, he added.

It’s still early to gauge how much of the IV market will be consumed by a subQ offering, analysts at J.P. Morgan argued in a Monday note. Roche currently has 12 weeks of data, and longer follow-up data out to a year are likely needed to substantiate the subcutaneous drug’s equivalence to the IV version, they said. Besides, the lack of efficacy data on relapse rate may prevent some physicians from embracing the new formulation, at least in the early days.