Regeneron, Sanofi make their case for another PD-1 drug — and they’re not settling for sixth place

CHICAGO — The two top immuno-oncology investigators for Regeneron $REGN and Sanofi, Israel ‘Izzy’ Lowy and Jo Lager, came to Chicago to offer a very promising snapshot of the early data they’ve reaped from a study of their PD-1 drug REGN2810 for cutaneous squamous cell carcinoma — the second deadliest form of skin cancer behind melanoma.
Like Novartis or Incyte or some of the other companies working on PD-(L)1 therapies in the large second wave forming in the pipeline following the first 5 that have been approved, these two major league players see this as a key building block for the combos they want to develop. But it would be a mistake, they say, to simply write this one off as the latest checkpoint of this stripe looking to line up for the market.

“I don’t think we’re the sixth,” Lowy told me in a conversation over the weekend. “We’re the third.”
Regeneron has some of the best antibody specialists in the business, which they’ve proved with a string of new drug approvals. Lowy says he’s learned a lot about PD-(L)1 while they’ve been working on REGN2810. And some of their insights have major implications for everyone working in the field.
One of the biggest lessons is that PD-1 is a significantly better pathway to follow than PD-L1, says Lowy.
The team created a PD-L1 as a complementary program in case their work on PD-1, but they feel now that PD-1 therapies offer a much more effective way to unleash an immune attack, something that’s been underscored by the dominance of Keytruda and Opdivo as well as Roche’s recent stunning setback with the PD-L1 drug Tecentriq.
And that’s why Regeneron and Sanofi feel they can leapfrog ahead of some of the early entries.
Regeneron and Sanofi also didn’t set out to create a better PD-1 than Keytruda or Opdivo.
“One of the things was a major requirement for it to be at least as good as anyone else’s,” says Lowy, “not assuming that we could make an antibody that was better. That being said, we’re very happy with it. We screened many antibodies to pick the one that was our better candidate.”
Not only is the first cut of the data very good, this checkpoint is already in a potentially pivotal Phase II trial.
Here’s what they found:
REGN2810 delivered an impressive overall response rate of 46.2% — 12 of 26 patients — which includes 2 complete responses, 9 partial responses and 1 unconfirmed partial response. The disease control rate hit 69.2%, covering 18 of 26 patients with 12 ORR and 6 with stable disease. The median progression-free survival and overall survival rate were not reached at the data cutoff date with a median follow-up of 6.9 months. Ten patients remain in response as of the data cutoff date, with a range of 8 to 40 weeks duration of response.

Leerink’s Geoffrey Porges called the results “compelling,” noting that the Regeneron/Sanofi team could have a $300 million peak sales opportunity in the US alone. “(T)he company will almost certainly file an application with the two trials, and then take the risk of a possible advisory committee review (new drug/new indication for PD-1) about the clinical significance of the result and the importance of the indication.”
“We recognized long ago that blockade of the PD-1 pathway is an essential component of any immuno-oncology program,” Lowy tells me. “Although a fabulous advance, it’s really just the first chapter, or a preface.”
“We want to have our own to facilitate the ability to develop novel combinations without having to rely on anyone else’s agent,” he adds.
Regeneron and Sanofi are well on their way. The rest of the industry might want to pay more attention.