Just six months after its debut on the Nasdaq, resTORbio is trotting out late-stage data this morning for its lead drug candidate — a TORC1 inhibitor they’re hoping will prevent respiratory infections in elderly folks. While it flopped in a combo trial, the company’s drug met its primary endpoint when tested by itself.
Investors are thrilled with the news, with resTORbio’s share price $TORC flying up 161% as of press time. Yesterday’s close was at $9.01 per share, and today its so far climbed to $23.50. If it holds, that’s a decent jump from its IPO price of $14 to $16 per share.
The drug — spun out of Novartis into its own startup just last year — is now called RTB101, although it once went under the code name BEZ235. In a Phase IIb trial, the 10 mg dose of the drug showed a statistically significant reduction in respiratory infections when taken by patients once a day. That cohort saw a 30.6% decrease in the percentage of patients who developed a respiratory infection when compared to the placebo cohort: p=0.026.
Interestingly, the drug flopped big time when tested in combination with an already-approved immunosuppressant called everolimus, an mTOR inhibitor often used to prevent the rejection of organ transplants. When resTORbio tested RTB101 combination with everolimus, they found no decrease in the percentage of patients with respiratory infections. The drug also saw lousy results when the 10 mg dose was taken twice daily instead of once.
“We’re finding that less TORC1 inhibition works better than more TORC1 inhibition,” the company’s co-founder and CMO Joan Mannick tells me. They saw a similar response in their Phase IIa trial, she said.
The company’s CEO Chen Schor said he wasn’t too concerned that the combo and double doses didn’t perform well. In fact, the drug working as a monotherapy is beneficial.
“We prefer to move forward with the monotherapy, because it’s easier to manufacture,” he said. “That was our hope.”
The company also homed in on a few specific patient groups in which they saw more promising results. For example, in asthma patients, they saw a 68% reduction in respiratory infections (p=0.0002), and in patients 85 years or older they saw 67% (p=0.007). The trial involved some 650 patients, according to clinicaltrials.gov, but when resTORbio whittles down the patient group to these select populations, we’re talking much fewer people. I asked Mannick just how many we’re talking here. In asthma, it was only 47 patients, she said, and a mere 27 people were 85 years old and older.
But Mannick defended the data’s significance regardless of the smaller patient group. “When you have fewer patients, it’s much harder to reach statistical significance,” she said. “You have to have a big effect.”
The company is meeting with the FDA at the end of this year to discuss how it should move forward with a Phase III trial. Mannick and Schor said the company will be shooting for a similar trial design, in which they test cohorts of narrow patient groups within the same trial.