PROTIVA - EXHIBIT 2014
`Moderna Therapeutics, Inc. v. Protiva Biotherapeautics, Inc. - IPR2018-00739
`
`

`

`Combating the incurable: researchers are testing
`the idea that the RNAi pathway, which shuts
`downthe genesof invading viruses, can block
`the replication of hepatitis C virus (far lefi, RNA
`shown in yellow) and HIV (left and middleleft).
`
`news feature
`
`sequence that binds tightly to the mRNA.
`This, the theory goes, should prevent
`the
`mRNA from being translated into protein.
`Scientists tried a variety of waysto get theanti-
`sense RNAsinto cells — for example, they
`packed the RNAinside fatty globules, called
`liposomes, which can cross cell membranes.
`But antisense has not performed well in clini-
`caltrials, partly because these delivery systems
`were not particularly effective. Khvorova
`believes that the medical benefits of RNAiwill
`be hugeif the delivery issues can be resolved.
`“But we've lookedata lotofthe delivery meth-
`ods that have been used for antisense, and so
`far [haven't been impressed,” shesays.
`
`
`
`
`
`company merged with
`this
`June,
`In
`Ribopharma of Kulmbachin Germany.
`Both Avocel and Alnylam are planning to
`beginclinicaltrials as early as 2005. And hot
`on theirheels is Sirna Therapeutics of Boul-
`der, Colorado, which has already raised
`US$43 million frominvestors. Sirna aims to
`develop therapies for hepatitis C and aneye
`condition called macular degeneration. For
`now, these companies are maintaining ami-
`Harmless HIV
`cable relations. But the situation could get
`messier as RNAi moves towards the clinic,
`Another optionis to use a harmless virus as a
`vector to ferry RNAi-triggering genes into
`because patentoffices aroundthe world have
`their target cells. Molecular biologist John
`not yet decided who ownstherights to some
`Rossi of the Beckman Research Institute of
`key RNAi-based technologies.
`the City of Hope Medical Center in Duarte,
`Before worrying about the ownership of
`California, is experimenting with one such
`key intellectual property, however,scientists
`vector, based on a version of HIV from
`must figure out how to make RNAi therapies
`work, Theyare facing some formidable tech-
`which the disease-causing genes have been
`stripped, Together with colleagues led by
`nical barriers, chief among which is
`the
`problem of getting siRNAs into the right
`Ramesh Akkina of Colorado State University
`cells. This is nota trivial issue, because RNA
`in Fort Collins, Rossi engineered this vector
`to contain sequences encoding siRNAstar-
`is rapidly broken downin the bloodstream,
`(ref. 4). Meanwhile, other researchers have
`geted against HIV genes. The researchers
`and our cells don’t readily absorb it through
`used their vector to infect the human stem
`shown that, in cultures of humancells, RNAi
`their membranes. And even when RNAgets
`cells that develop into irmmunecells, Next,
`intoits target cell, scavenger proteins quickly
`can similarly combat viruses as diverse as
`respiratory syncitial virus®, and those that
`they either grew the cells into mature cells in
`chew it up. “The major hurdle right now is
`causeinfluenza’ andpolio’.
`delivery, delivery, delivery,” says Sharp.
`the lab, or injected thern into mice from a
`RNAi may work like a charm in petri
`
`Researchers are exploringavariety of ways special strain that accepts human trans-
`dishes — but what about in live animals?
`to combat the problem. Some involve tech-
`plants. In both cases, the mature immune
`
`MarkKay,ageneticist at Stanford University cells fought off HIV whenresearchers tried
`niques developedto facilitate an older tech-
`in California, addressed this question by
`to infect them with disease-causing HIV in
`nology knownas‘antisense. The idea behind
`culture dishes",
`fusing a genetic sequence fromthe hepatitis
`antisense is to muffle a cell's single-stranded
`C virus to a gene for the enzymeluciferase,
`mRNA — the’sense’strand — usinga pieceof
`Rossi hopes that a similar technique could
`antisense RNA with a ‘complementary’
`which stimulates a reactionthat emits light.
`When Kay injected the fused gene into
`mouse livers, he could track its location by
`detecting the glow. And whenthe mice were
`treated with siRNAs targeted against
`the
`hepatitis C gene, this glow dimmed dramati-
`cally*. Hepatitis C doesn't make mice sick,
`but Kayand his colleagues have since gone on
`to show that RNAi can drastically reduce
`signs of infection by hepatitis B (ref. 9),
`which can damage the animalslivers.
`
`REFS
`
`work in human patients with HIV. Doctors
`
`Firm plans
`Results such as these are attracting intense
`commercial
`interest.
`In August, Kay
`announced that he has licensed his work
`on hepatitis C to a company called Avocel
`in Sunnyvale, California, which aims to
`develop RNAi therapies against the disease.
`Other RNA pioneers are lining up with
`their own start-up biotech firms. For
`instance, Phillip Sharp of the Massachusetts
`Institute of Technology in Cambridge, who
`shared the Nobel Prize in Physiology or
`
`

`

`newsfeature
`
`would extract stem cells froma patient's bone
`marrow,infect them with the RNAi-trigger-
`ing vector, and then put themback into the
`patient. Rossi is now working to perfect this
`technique in mice, and is also beginningtests
`in rhesus monkeys to ensure that the treat-
`ment has no unwanted side effects. He hopes
`to convince the US Food and Drug Adminis-
`tration to authorizea clinical trial in the next
`twoorthreeyears. “] think when we getall this
`data compiledwe'll havea fairly free road into
`astem-cell trial,” Rossi predicts.
`This may be so, but there are nagging
`safety concerns about vectors made from
`viruses in the same farnily as HIV, whichare
`called retroviruses. This is dueto the fact that
`retroviruses work by forcing their way into a
`cell's own DNA.If the vector lands in the
`wrongplace it can damage important genes
`and even cause cancer. These concerns were
`borne out by last year’s revelation that a
`retroviral vector had triggered leukaemia in
`some children in a gene-therapy trial!!,
`Becauseof these concerns, Rossi says that he
`will not usestemcells in his first clinicaltrial.
`Instead, he will
`initially
`treat mature
`immune cells, because these cells are less
`likely to grow out of control.
`
`Safe delivery
`Kay, meanwhile, is pinning his hopes for an
`RNAi vector on a virus known as adeno-
`associated virus, or AAV. He has already used
`AAV-based vectors in clinical trials of gene
`therapy against haemophilia’, AAV does not
`cause disease in people, and so far there has
`been no cause for any serious safety concern
`— even though AAV can also integrate into
`a cell's own DNA.
`Another important question mark hang-
`ing over RNAiis its specificity. Before regula-
`tors give the go-ahead for a clinicaltrial,
`scientists need to prove that that RNAiwill
`not shut down vital human genes as well as
`the targetviral sequences.
`Somestudies on specificity have yielded
`encouraging results. In May this year, for
`instance, researchers led by Patrick Brown of
`Stanford University reported on experi-
`ments in which they engineered humankid-
`ney cells to produce a fluorescent protein.
`They shut downthe gene for this glowing
`protein by using RNAi, and then used DNA
`microarrays to monitor some 20,000 other
`genes — noneof which seemedto be affected
`by the treatment",
`Butjust a couple of weekslater, researchers
`with Rosetta Inpharmatics in Kirkland, Wash-
`ington, cast a shadow over this rosy picture.
`The Rosetta team, led by Aimee Jackson and
`Steven Bartz, used a rangeofdifferent siRNAs
`to target two genes in cultured humancells.
`Disturbingly, the treatment caused changes in
`the expression of dozens of other genes.
`
`
`
`Little helpers: Mark Kay hopes to use harmless
`viruses to deliver RNAi therapyto patients.
`
`Jackson and Bartz are not sure why their
`results were so different from those obtained
`by Brown's team, but one possible explana-
`tion is that they used larger doses of siRNA.
`The Rosetta researchersalsotested for off-tar-
`get effects soonerafter beginning their experi-
`ment than other groups have in their studies.
`But whatever the explanation, the findings
`have shaken up the RNAi camp. “We've had
`somereally lively discussions,”says Bartz.
`New data from a group at Case Western
`Reserve University in Cleveland, Ohio, seem
`to support the Rosetta findings’. Last week,
`Bryan Williams and his colleagues reported
`that whenthey introduced siRNAsintocells,
`certain genes that are part of the interferon
`
`
`
`system were activated, a mechanism by which
`cells shut themselves down in response to
`invading germs. The siRNAsactivated genes
`that act early in the interferon pathway, and
`Williams’ group did not measure whether the
`activated genes stopped working. But the
`tearnsays thatits findings provide a warning
`that off-target effects are perhaps more com-
`mon than scientists have realized.
`Researchers argue that these hints of off-
`target RNAieffects highlight the need for a
`deeper understanding of how,exactly, the sys-
`tem works. For instance, westill don't know
`for sure how many proteins work together to
`shut down a target mRNA.It's also unclear
`why some siRNAs are incredibly effective,
`whereas others, targeted at a different region
`of the same gene, don’t work as well. Given
`these unknowns, some researchers urge cau-
`tion before rushinginto clinicaltrials, “Before
`you know what you could perturb, you have
`to know what's there,” says Tom Tuschl, a
`biochemist and RNAi pioneerat Rockefeller
`University in New York.
`Even someofthe scientists workingin the
`commercial sector, where excitement about
`the clinical prospects of RNAi
`is most
`intense, agree that a great deal of pround-
`work remains to be done. “For real clinical
`development, this has to be doneright," says
`Khvorova. “Investing a little more time on
`the basic steps will pay back in years of time
`savedlater on."
`But despite all of these caveats, most
`researchers workingin this fast-movingfield
`have high hopes that RNAiwill deliver on its
`therapeutic promise. “This is the honey-
`moonperiod; things are looking great,” says
`Kay.“Wewill encounter technological issues
`along the way, but our goalis to solve these
`problemsandget it to work.”
`a
`Erika Check is Nature's Washington biomedical
`correspondent.
`. Fire, A. e¢ al, Nature 391, 806-811 (1998)
`. Hannon, G, J. Nature 418, 244-251 (2002),
`. Elbashir, 8. M. et al, Nature 411, 494-498 (2001)
`Coburn, GA, & Cullen, B. R, J. Viral. 76, 9225-9231 (2002)
`. Bitko, V. & Barik, $8. BMC Microbial. 1, 34 (2001).
`. Ge, Q. et al. Proc. Natl Acad. Set. USA 100, 2718-2723 (2003)
`. Gitlin, L., Karelsky, §. & Andino, R. Nature 418, 430-434 (2002).
`McCaffrey, A. P et al, Nature 418, 38-39 (2002)
`. MeCaffrey, A. P et al. Nature Biotechnol. 21, 639-644 (2003)
`10, Banerjea, A. et al. Mol, Ther. 8, 62-71 (2003)
`11.Check. E. Nature 420, 116-118 (2002).
`12.Manno, C.§. et af, Blood 101, 2963-2972 (2003).
`13.Chi, |-T. et.al. Proc. Nal Acad. Sei. USA 100, 6343-6346 (2003)
`14. Jackson, A. L. et al. Nature Biotechnol. 21, 635-637 (2003)
`15. Sledz, C. A., Holko, M., de Veer, M.J., Silverman, R. H. &
`Williams, B. R. G. Narure Cell Biol. dol:10.1038/ncb1038 (2003)
`
`aeecr)
`
`Dharmacon
`> www.dharmacon.com
`Avocel
`+ www.avocel.com
`
`Alnylam Pharmaceuticals
`+ www.alnylam.com
`Sima Therapeutics
`
`