Relay Impresses With Early Study Data For Targeted Cancer Drug

Updated data released ahead of a medical conference suggest Relay’s medicine could be more effective than others like it in treating a type of bile duct cancer.

Clinical trial results released Wednesday offer the most convincing evidence to date that Relay Therapeutics, a Cambridge, Massachusetts-based biotechnology company, can develop better drugs by studying how proteins move.

Data from an early study, published online ahead of the European Society for Medical Oncology’s annual conference, suggest an experimental medicine developed by Relay could be more effective than currently available treatments for a type of bile duct cancer called cholangiocarcinoma.

Treatment shrank tumors in 63% of 38 cholangiocarcinoma patients who received Relay’s drug in the study. Among the 17 study participants who received the dose Relay selected for further testing, 88% responded to therapy — a rate more than twice the 23% to 42% previously reported for other drugs in similar groups of patients.

Notably, Relay’s drug did not cause significant rates of high phosphorus levels, a worrisome side effect reported with those other medicines. Treatment was associated with “low-grade” mouth sores and a skin condition associated with some cancer treatments called hand-foot syndrome.

To analysts, the data were validation of Relay’s drug and, more broadly, its approach to developing medicines. Bradley Canino, an analyst at Stifel, wrote in a note to clients that the biotech “delivered on high efficacy expectations,” providing “further data that Relay’s drug discovery machine can produce best-in-class medicines.”

“Credit where credit is due,” wrote Akash Tewari, an analyst at Jefferies who has argued Relay shares are overvalued, in a Wednesday note. “We think the updated efficacy looks solid at the go-forward dose.”

Relay’s results are from a small number of patients and the data made available Wednesday come from a study abstract rather than a full presentation, which is scheduled for Sunday. The abstract did not provide information on whether any patients needed to discontinue treatment or drop to a lower dose due to side effects.

“We’ll also note that there are a [significant amount of patients] that are not yet evaluable for efficacy, so we’ll need to keep an eye out for potential regression over time,” wrote Tewari.

Additionally, comparing across trials can disguise differences in the patients enrolled and treated, as well in prior treatments.

Relay is currently enrolling a cohort of 100 patients that, along with supporting data from other groups, may eventually support a filing for an accelerated approval of its medicine, dubbed RLY-4008.

The drug is Relay’s most advanced candidate and was designed using models of how the protein it targets moves. Researchers at the biotech found that two related proteins, called FGFR1 and FGFR2, shape-shift in slightly different ways, opening an opportunity to design a drug aimed only at FGFR2 rather than hitting both proteins.

The distinction is important, as blocking FGFR1 is associated with the high phosphorus levels seen with the three FGFR inhibitors that are currently approved — Incyte’s Pemazyre and QED Therapeutics’ Truseltiq in cholangiocarcinoma and Johnson & Johnson’s Balversa in bladder cancer. (Genetic alterations in FGFR2 are associated with multiple tumor types, including cholangiocarcinoma and bladder cancer.)

Relay’s premise is that by finding these types of nuances it can develop more selective therapies that are both safer and more potent. It’s been an effective pitch, helping Relay raise more than $1 billion in private funding and stock offerings. RLY-4008’s advancement through testing is a major test for the company, and will help set expectations for a pipeline of other drugs for breast cancer and other solid tumors.

Shares in Relay rose by nearly 20% in Thursday morning trading.

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