Tekmira Pharmaceuticals this week unveiled new preclinical data from its Ebola and Marburg virus programs, showing that its siRNA-based therapies were effective in non-human primates even when treatment was delayed by as much as 48 hours after infection.
Tekmira also reported its third-quarter financial results, posting a higher net loss amid increased operating expenses, and disclosed that it is poised to receive a milestone payment from Alnylam Pharmaceuticals related to a drug delivery technology licensing arrangement between the firms.
Tekmira has been developing its Ebola treatment, dubbed TKM-Ebola, since at least 2006, when the company — then known as Protiva Biotherapeutics — published data in collaboration with the United States Army Medical Research Institute of Infectious Diseases showing that its lipid nanoparticles could be used to protect guinea pigs from the virus.
Since then, the company has continued to refine its candidate, and in early 2012 began phase I testing of TKM-Ebola with the support of a contract from the US Department of Defense potentially worth up to $140 million.
Tekmira later halted that trial in order to reformulate TKM-Ebola with a next-generation version of its lipid nanoparticle technology, and in May received clearance from the DoD to swap out the older drug for the newer iteration (GSN 5/9/2013).
As it waits for US Food and Drug Administration approval to begin a phase I study with the improved TKM-Ebola, Tekmira has released new data indicating that the drug does not need to be administered immediately after infection to work.
In 2010, Tekmira and USAMRIID published data showing that Ebola-targeted siRNAs delivered using the company's nanoparticles could provide 100 percent protection to non-human primates previously infected with an ordinarily lethal dose of Zaire Ebola virus (GSN 6/03/2010).
This week, the company released additional data showing non-human primate survival even after infection with a lethal dose of the most deadly strain of Zaire Ebola virus.
Animals were exposed to the virus, and then treated with seven daily 0.5 mg/kg doses of the drug TKM-Ebola at 24, 48, 72, or 96 hours after infection.
Treatment resulted in 83 percent survival when given 24 or 48 hours after infection, and 67 percent survival when given 72 hours after infection. No animals survived when they were treated at 96 hours or were given placebo.
Meanwhile, Tekmira obtained similarly positive results with its earlier-stage Marburg virus candidate TKM-Marburg, achieving 100 percent survival in non-human primates with seven daily 0.5 mg/kg doses of the drug beginning 48 hours after infection with the most lethal strain of the virus.
Tekmira previously released data showing that TKM-Marburg could offer complete protection in non-human primates when dosed beginning one hour after infection (GSN 9/26/2013).
"These delay-to-treat studies in animals infected with lethal doses of rapidly replicating viruses such as Ebola and Marburg are rigorous tests of antiviral efficacy in established infections," Tekmira President and CEO Mark Murray said during a conference call held to discuss the quarterly results. "We are excited about [these] positive data for the sake of these programs, but also because [they] provide validation for our approach and our technology in other antiviral programs."
Tekmira said that it anticipates starting the new phase I trial of TKM-Ebola in the first quarter of 2014, with data available in the second half of the year. Murray noted that once this study in healthy volunteers is completed, the company is planning to begin a phase II trial in animals.
Pursuant to the FDA's so-called "animal rule," a drug may be tested in animals if it is unethical or infeasible to conduct human efficacy trials and if those animal studies show that the compound is reasonably likely to produce a clinical benefit in humans.
The company has not provided guidance on the timing of its Marburg program.
For the three-month period ended Sept. 30, Tekmira's net loss climbed to $6.1 million, or $0.42 a share, from $3.4 million, or $0.25 a share, in the year-ago period.
Revenues in the quarter were flat with the previous year at $3 million, of which about $2.9 million came from the company's Ebola contract with the DoD.
Costs associated with research, development, collaborations, and contracts rose to $5.7 million from $3.1 million, in part due to expenses associated with moving TKM-Ebola and other compounds to the clinic.
General and administrative costs, meantime, fell to $1 million from $1.5 million partly as a result of the settlement of Tekmira's litigation with Alnylam in late 2012 (GSN 11/15/2012).
At the end of the third quarter, Tekmira had cash and cash equivalents totaling $36.9 million.
Since then, the company closed a public stock offering that netted $32.1 million. Murray said it is also due a $5 million milestone payment from Alnylam based on the recent initiation of a phase III trial of TTR-mediated amyloidosis drug patisiran, which uses Tekmira's lipid nanoparticle delivery vehicles.
Tekmira said that it expects its funds on hand and expected income to be sufficient to support its operations into early 2016.