By Doug Macron
Tekmira Pharmaceuticals' top official this week provided some new details on the company's drug-development pipeline, stating that the firm would focus its efforts on its investigational cancer and Ebola therapies, while keeping a beleaguered cholesterol candidate on the back burner.
Tekmira President and CEO Mark Murray also said that the firm remains committed to continuing litigation with partner Alnylam Pharmaceuticals and laid claim to a lipid nanoparticle delivery technology at issue in the dispute.
The company this week also released its 2011 financial results, posting narrower losses despite lower revenues.
Tekmira's most advanced drug candidate, TKM-PLK1, is an siRNA designed to silence polo-like kinase 1 to treat cancer. In late 2010, the drug entered phase I testing in a dose-escalating trial set to enroll up to 52 patients with advanced solid tumors. In mid-2011, the company began another trial in collaboration with the National Cancer Institute to test TKM-PLK1 in patients with primary liver cancer or liver metastases.
According to Tekmira, the first study has thus far enrolled 20 patients, who have received 82 doses of the drug. The study continues, with data and a maximum tolerated dose expected to be announced in the “next few months.”
The trial with the NCI, however, has been discontinued, Murray said this week.
“We initiated [the] joint clinical trial to achieve the objective of obtaining human proof-of-concept data” for the company's lipid nanoparticle delivery vehicles, he explained.
But since then, Alnylam has released positive interim phase I data from its first-generation transthyretin-mediated amyloidosis treatment ALN-TTR01 and its hypercholesterolemia treatment ALN-PCS, both of which Murray said incorporate Tekmira's nanoparticle technology (GSN 12/1/2011 & 1/5/2012).
Since these study results have provided the proof-of-concept data Tekmira hoped to generate through its trial with the NCI, “we've decided to focus our clinical resources … on the main PLK1 clinical trial and our Ebola program,” Murray said during a conference call held to discuss Tekmira's fourth-quarter financials.
The Ebola drug, dubbed TKM-Ebola, comprises siRNAs targeting the Zaire Ebola virus L polymerase, viral protein 24, and viral protein 35. Being developed with the support of a $140 million contract from the US government, the drug entered a 55-patient phase I study earlier this year (GSN 2/9/2012). Thus far, 12 patients have been dosed in the trial.
Despite the end of the NCI-affiliated study, Tekmira will “continue to support research at the NCI as this has been, and continues to be, a very valuable collaboration focused on identifying novel oncology targets,” Murray noted.
Tekmira's cholesterol drug TKM-ApoB, however, remains on hold for the foreseeable future.
TKM-ApoB is designed to inhibit apolipoprotein B and was the first drug Tekmira moved into the clinic with a 2009 phase I trial. However, early the next year, the company said that it had halted that study after a patient receiving the highest dose under investigation experienced flu-like symptoms consistent with stimulation of the immune system caused by the ApoB siRNA payload (GSN 1/14/2010).
Tekmira said at the time that it planned to tweak the drug with a new siRNA and delivery formulation, and that it expected the program to resume in the second half of 2010.
It did not meet this goal, and this week Murray said that the firm does not expect to restart clinical testing of TKM-ApoB anytime soon.
“We have been waiting for the development of a next-generation formulation,” he said. “We believe that we have that now, but at least for this year, with PLK1 and the Ebola program, we have enough on our plate. We're not likely to initiate another clinical trial with ApoB this year, unless something materially changes in our business.”
Meantime, as its own pipeline programs advance, Tekmira is keeping a close eye on the efforts of Alnylam, which incorporates Tekmira's lipid nanoparticles in certain of its drug candidates. But while Alnylam acknowledges that it uses Tekmira technology in ALN-TTR01 and its phase I liver cancer drug ALN-VSP, the two firms disagree elsewhere.
Earlier this month, Alnylam moved a second-generation version of the TTR amyloidosis treatment called ALN-TTR02 into a phase I study, deciding that even though ALN-TTR01 performed well in phase I, it wanted to take advantage of an improved delivery technology called MC3 (GSN 3/22/2012).
The MC3 technology, which Alnylam says is proprietary, is also being used with its hypercholesterolemia treatment ALN-PCS.
Tekmira has long maintained that it is the rightful owner of the MC3 technology, and sued Alnylam last year for misappropriating trade secrets (GSN 3/17/2011). Tekmira later expanded its legal assault to include claims against Alnylam collaborator AlCana Technologies in a Canadian court.
Both Tekmira and AlCana are based in Canada.
“Alnylam is highly dependent on our LNP technology, and they use our technology to enable the majority of their product candidates,” Murray said during this week's conference call, noting that Tekmira views both of Alnylam's TTR amyloidosis drugs as using his company's technologies.
In its suit against Alnylam, “a trial date has now been set for October 30 of this year, which removes any uncertainty about the timeline,” he said. “Our goal today is the same as when we launched the litigation: to retain control of our technology and to preserve its value for Tekmira shareholders.
“We firmly believe this is the right and only course of action for us to pursue, as it respects the work we have done in developing this important technology,” he added.
Earlier this year, a Canadian court ordered AlCana officials to return documents allegedly stolen from Tekmira. Murray said that a review of these documents “supports our allegation that Tekmira's confidential information was used to make the lipid MC3.
“I think it's abundantly clear that Alnylam and its product candidates are being advanced on the back of our leading LNP delivery technology,” he said, declining to comment further on the pending litigation.
For the year ended Dec. 31, Tekmira's net loss fell to $9.9 million, or $0.88 per share, from a year-ago loss of $12.4 million, or $1.20 a share.
Revenues in 2011 dipped to $16.6 million from $21.4 million the year before.
Research and development spending dipped to $19.9 million from $22.1 million, while general and administrative costs climbed to $6.3 million from $4.8 million, reflecting the expenses associated with the Alnylam and AlCana litigation.
At the end of 2011, Tekmira had cash and cash equivalents totaling $9.2 million.
Looking ahead, Tekmira said that revenues in 2012 are expected to be flat with 2011, and the company said its current financial position, along with expected income from collaborators and access to a loan facility, will be sufficient to fund its product-development operations until the second half of 2013.
Murray said that Tekmira could also receive an additional financial boost should a now-divested drug candidate receive US Food and Drug Administration approval.
Tekmira out-licensed certain non-RNAi assets, including the leukemia treatment Marqibo, to Talon Therapeutics. This month, an FDA advisory panel recommended the drug's approval, and the agency is set to make a final determination by mid-May.
Should the FDA approve Marqibo, Tekmira would be paid a $1 million milestone payment from Talon, and stand to receive royalties on product sales, Murray noted.
“Although this isn't the core focus of our business, it can provide some nice upside for Tekmira,” he said.
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