A skirmish is brewing over the apparently botched isomeric structure described in the patent for Oncoceutics Pharmaceuticals Inc.'s cancer drug ONC201. It's too early to tell whether the dispute could hamstring the early stage candidate or for how long, but the bigger question involves what the fight may mean for the patients who need effective new drugs – in this case and others like it that could arise.

"What we have here is a situation where there were some errors regarding the chemistry" as detailed in the ONC201 patent, said Theresa Kavanaugh, partner at law firm Goodwin Procter LLC's Boston-based life sciences team. "Another industry-savvy research group, once they realized that, also happened to realize that there could be some value in obtaining the patent around that [compound] in an aggressive move."

The two factors coming together again in such a way is pretty unlikely, she said. But that doesn't solve Hummelstown, Pa.-based Oncoceutics' problem, which blogger Derek Lowe called "every medicinal chemist's nightmare."

Patent US8673923, filed in April 2012 and published in March 2014, involves a compound called TIC10 found in the free National Cancer Institute's (NCI) database by Penn State University's Wafik S. El-Deiry, whose research led to the founding of Oncoceutics. (See BioWorld Today, July 30, 2009.)

Scripps Research Institute also pursued TIC10 in oncology, but figured out that the structure given in the patent, when synthesized, didn't work – though a sample of TIC10 from the NCI did prove functional. It turned out that the biologically active version of the drug candidate is a different structure than the patented one. So Scripps applied for a patent on the operative structure, and has licensed it exclusively to Sorrento Therapeutics Inc., of San Diego.

"It wasn't quite a clerical mistake," Kavanaugh said of the Penn patent. "It was a chemistry, where-the-carbons-go type mistake. 'Goof' might be too strong a word, since we don't know a lot of those chemical facts" and the chemical structure may have been especially tough to characterize. "Interestingly, it looks like the Penn folks and their licensee either didn't confirm [the structure as given by the NCI] or came to the same conclusion when they did their chemistry work," she said.

In March, Oncoceutics won clearance of its investigational new drug application and made known its plan to commence a phase I/II study. Neither Oncoceutics nor Sorrento replied to emails.

"As to whether [Oncoceutics] should continue their clinical trials or not, at the end of the day, these things are financially driven," Kavanaugh said. "What I suspect is that if they did need additional funding or partnering, it may be that those type of things might not be forthcoming until and unless they do get additional patent protection."

Duncan Greenhalgh, also a partner in the life sciences group at Goodwin Procter, echoed Kavanaugh and added another piece to the picture. "If somebody were to look to invest in the company to run the clinical trial, you'd want some clarity around the situation," he said, but "it's not clear to me what is patentable to Scripps, given the facts that we're aware of. The compound is what it is, and the properties of that compound are what they are. It just so happens that somebody somewhere drew the structure wrong. Penn has at least the opportunity to try and fix or remediate the situation," Greenhalgh added.

"It does appear that their patent attorneys have filed a continuation" that would make this possible, noted Kavanaugh. "They could potentially still get meaningful patent protection on their method of use. It just wasn't drawn correctly. If the patent office was agreeable, they could potentially get a claim that calls out the compound using, for example, the NCI number." The Penn method-of-use patent "can be very valuable, but they weren't able to get claims to the compound itself. In this case, it was because the compound was known, it was already in the prior art, sitting in the NCI database when they picked it up," she said.

What's next? Probably not much will happen until Oncoceutics and the rest of the world know what exactly Scripps has filed. "It doesn't appear to be publicly available yet," Kavanaugh said. Meanwhile, the situation is "not a tempest in a teapot," but neither is it going to be become an industrywide legal hurricane that will sweep away – or painfully delay – good drugs from needy patients, she said.