Skip to main content
Premium Trial:

Request an Annual Quote

Mirrx Scores Win Over Santaris in microRNA Drug Technology Lawsuit


Mirrx Therapeutics this month scored a major victory in its efforts to secure European patent protection on its microRNA inhibition technology when a Danish court dismissed a lawsuit filed against the company by Santaris Pharma alleging misappropriation of trade secrets.

Having been cleared of wrongdoing, Mirrx and its founder Thorleif Moller have asked the European Patent Office to resume its review of a patent application covering the firm’s core technology, which had been put on hold for more than three years pending a final court ruling.

It is unclear whether the EPO will do so, however, as Santaris intends to appeal the court decision, according to Moller. Officials from Santaris were not available for comment.

Mirrx was created in 2010 as a spinout of Stealth Biotech, also founded by Moller, to develop miRNA antagonists called Blockmirs as human therapeutics. According to the company, they are steric antisense oligos that bind to specific miRNA target sites, preventing regulation of a particular messenger RNA.

Blockmirs "do not recruit any cellular enzymes which mediate degradation of target mRNAs … [so if they do] bind to a non-intended RNA, it will only cause an effect if it prevents binding of a [miRNA] or another cellular factor," an unlikely event, reducing the possibility of off-target effects, the company states.

Mirrx’s efforts to establish itself as a drug developer hit a roadblock in 2009 when Santaris sued the company, alleging that Blockmirs were developed using its proprietary information obtained through Moller’s employment with a patent firm that represented Santaris and his personal relationship with a former Santaris staffer (GSN 5/6/2010).

Specifically, Moller worked as a consultant for the Danish patent firm Plougmann & Vingtoft, which was an intellectual property agent for Santaris. During a six-month period in 2006, the agency filed six patent applications for Santaris related to the use of the drug shop's locked nucleic acid technology for creating oligonucleotides capable of binding to miRNAs, Santaris charged in its suit. "Moller participated in the handling of at least one of these patent applications."

Shortly thereafter, Moller filed patent applications in his own name related to the oligonucleotides that bind to mRNA, "including LNA oligonucleotides [that] are structurally identical to the microRNA-binding oligonucleotides disclosed in" Santaris' patent applications, the lawsuit charged. "The connection and overlap between Santaris Pharma's technology and … Moller's applications is so close that there is a presumption against them having been prepared … without knowledge of Santaris … confidential patent applications and the current research developments at Santaris.”

Additionally, Santaris alleged that one of its employees, who was listed as Moller’s “cohabitating partner,” provided him with confidential information from a company meeting in 2007.

Moller denied all Santaris’ claims, arguing to the court that his inventions are not based on Santaris technology.

In fact, the Mirrx technology relates to "antisense oligonucleotides that bind to microRNA-binding sites in target RNA," which are typically messenger RNA, but never miRNAs, he told the court. Additionally, Blockmirs only prevent a miRNA from regulating one specific target mRNA, while Santaris’ technology, which is based on locked nucleic acids, prevents a miRNA from regulating all of its target RNAs.

According to Moller, Santaris initiated the litigation as a way to overcome its own intellectual property worries related to its miR-122-targeting drug miravirsen, which is in phase II testing as a treatment for hepatitis C.

Moller said that in 2009 he met with Santaris officials, who expressed concern over the firm’s freedom to operate in two areas — RNase H-activating antisense oligos that bind to miRNA binding sites on target RNA; and so-called Micromirs, which are short antisense oligos that bind to the seed sequence of an miRNA — and that he offered to grant a non-exclusive license to his IP.

Santaris rejected the offer, he stated, because such a deal would not have alleviated the company’s true problem: that rival Regulus Therapeutics holds IP around the use of miR-122 inhibitors to treat HCV.

"Only a license to the use of Blockmirs or a complete transfer of … Moller's rights can relieve that problem," he told the court, claiming that this IP issue led to GlaxoSmithKline backing out of a deal to license miravirsen and partner up with Regulus on its own miR-122 HCV program.

Though it did not comment on his claims regarding GlaxoSmithKline and Regulus, the Danish court ruled that there was no wrongdoing by either Moller or Plougmann & Vingtoft.

According to documents on file with the EPO, the court determined that knowledge of Santaris’ patent applications would not have enabled someone with expertise in the field to more quickly develop Moller’s inventions, nor were they necessary to those inventions.

“The basic principles concerning microRNA and mRNA were widely known in the literature” when Moller filed its patent application, and information contained in Santaris’ applications would not have contributed to them.

In view of the evidence provided, the court said it “does not find that Santaris has lifted the burden” that Moller’s IP has been “unlawful in relation to Santaris.”

The court did take Moller and Plougmann & Vingtoft to task for failing to properly address the potential for a conflict of interest between Moller and Santaris.

“The court [finds] it very difficult to understand how … Moller could have imagined that continuing his inventions within the antisense [field] and filing … patent applications could be compatible with a consultant position” at the firm.

Even if Moller’s claim that he conceived of the Blockmir technology prior to his employment at Plougmann & Vingtoft, it “might have been obvious to him that the … technology … was within Santaris’ technology area. He should have realized that there was a conflict of interest and informed” Plougmann & Vingtoft, the court said.

Further, Plougmann & Vingtoft failed to adequately uncover potential conflicts of interest, which “contributed to the escalation of the matter,” it added.

In the end, though, Santaris’ allegations are based solely on the argument that Moller was obligated to transfer his Blockmir invention to the company due to his association with Plougmann & Vingtoft — a line of reasoning the court said it does not agree with.

“Santaris, by its failure to have a closer review of … Moller’s inventions and what interest it might have in them, shares a responsibility for the matter having escalated so far,” despite his efforts to “enter into a dialogue” with the company, the court noted.

“On this basis, Santaris’ claims against … Moller … and Mirrx are dismissed,” it concluded.

Buoyed by the legal victory, Mirrx this month filed a petition with the EPO to resume proceedings on its Blockmir patent application, which was put on hold in 2011 at Santaris request (GSN 7/21/2011).

Santaris’ confidential patent applications “are considered by the court to be no more relevant [to Mirrx’s application] than other prior art documents,” the company told the EPO. “Moreover, no confidential information from [Santaris] has been included in the subject matter of the [patent] application or has been used to arrive” at it.

“For these reasons, the [EPO’s] legal division is respectfully requested to allow the resumption of the grant proceedings,” Mirrx said in its petition.