Download Submitted by Heather Thompson on Thu, 2014-04

Crossing the Blood-Brain Barrier: 3 Promising Drug
Delivery Technologies
Submitted by Heather Thompson on Thu, 2014-04-24 02:01
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Stratos is pleased to bring you exclusive, on-going content by Heather Thompson, former editor in chief of MD+DI
magazine. With 10 years of experience covering medical technologies and FDA regulations, Heather specializes in
delivering the latest trends and news in the medical device industry.
by Heather Thompson, freelance writer
The latest technologies in drug delivery to areas of the
brain aim to treat cancer, pain, and even mental illness.
The challenge is delivering the pharmaceutical across the
blood-brain barrier. A few look to the nasal cavity to deliver
drugs directly into the brain, and some simply ignore the
barrier altogether to deliver treatment to brain cells through
the blood stream.
1. Delivering Pain Drugs Through the Nose
Drug delivery by inhalation isn’t new. Metered dose inhalers have been around for
almost 60 years—and the first pressurized nebulizer was invented in 1858. (If you are
interested, here is a fascinating paper on the history of inhalation technology.) But
companies are making leaps in how and where the inhaled drugs are delivered. And of
course, those first inhalers were designed to reach the lungs—not the brain.
New inhalation systems actually try to avoid the lungs and throat. The designers of
these devices instead focus on nasal delivery in order to reach the sinus cavity so that
therapeutics can be absorbed into the brain.
Nasal sprays have also been around for several years, but designers have struggled
with getting any therapies beyond the nasal cavity. Two key problems have been getting
drugs past the narrow entrance and keeping the agents in the cavity to be absorbed by
the brain, rather than just dripping out of the nose.
Scientists working for Avanir Pharmaceuticals recently finished a pilot study for the
nasal delivery of sumatriptan powder in the treatment of migraines. The company
partnered with OptiNose to improve the method of delivery.
Because the nasal cavity is complex with the entrance to the cavity being very narrow,
most drugs tend to drip out or be wiped away. OptiNose’s technology works by having
the patient blow into the mouthpiece of the device to send the drug to the nosepiece. A
natural inhalation then propels the naturally warmed drug, released from a standard
drug capsule, into the nasal cavity. Because the soft palate is closed during this action,
the drug is kept out of the lungs and throat, and instead moves past the narrow opening
in the nasal cavity to the larger passage where it can enter the brain.
OptiNose’s President and COO, Ramy Mahmoud M.D. MPH, says his team worked to
ensure the design could fit a variety of users. Mahmoud says “the size of the nares (the
opening of the nostril) varies and matters... for gender age, ethnicity, and other factors.”
According to Mahmoud, one key challenge the design team had to tackle was “making
the device easier and more intuitive to use and towards reducing or eliminating
coordination or other “learning curve” type requirements to use the device.” To do so,
the team developed a sealing nasal piece that inserts past the narrow entrance, and
then rotates the mouthpiece. Check out the video on how it works.
Results of the pilot study found that 68% of users found migraine relief in as little as 15
minutes. Based on these results, FDA accepted Avenir’s New Drug Application.
Mahmoud also notes that Optinose’s device has a liquid delivery design, and is
currently being tested in Phase III program for the treatment of nasal polyps— a type of
chronic rhinosinusitis.
2. Biologicals Jet Past Nasal Barriers
Impel NeuroPharma has developed a pressurized nasal sprayer designed to deliver
antidepressants for major depressive disorder (MDD). The Canada-based Centre for
Addiction and Mental Health (CAMH) recently published a study on the nasal spray’s
effects in Nature.com. It delivers interfering peptides, which disrupt dopamine
receptors—a process that is being explored as a promising treatment option for MDD.
However, up until about 3 years ago, scientists struggled with delivery methods. Most
research for interfering peptides used direct injection to the brain, at considerable risk to
the subject. But then researchers partnered with Impel, a firm spun out of the University
of Washington that collaborates with pharmaceutical and biotech firms for clinical
research.
Impel’s nasal spray device is fairly simple in design. But John Hoekman, cofounder and
chief science officer of Impel says its precision olfactory delivery (POD) technology is
different from other nasal sprays. He explains that typical nasal sprays deliver a cloud
that can’t get deep into the nose—it’s a passive system that typically only delivers 5% of
any drug. By contrast, POD is a narrow “jet, as opposed to a plume,” he says. Hoekman
says the system is a cross between an inhaler and a nasal pump. The drug is contained
within the tip of the nasal and hydrofluoroalkane (HFA) is in the canister. The
technology has been shown to achieve more than 50% deposition, thereby improving
uptake to the central nervous system.
Results from the MDD study detected the presence of the peptides in the brain two
hours after delivery via the olfactory device. Hoekman says Impel is also working on a
project to deliver pain medication to the central nervous system for cancer patients.
3. Ignoring Blood Brain with a Drug Bomb
It could be that some devices don’t need to blast the brain if they instead design a drug
that is drawn to the tumor site through the blood. Treatment for glioblastoma, an
aggressive brain cancer, may be evolving with GenSpera’s molecular “grenade.” The
biomedical is G-202 and it is now entering Phase II trials with 34 patients.
Here is how GenSpera describes the technology on its Website:
“Our cell-killing agent called “12ADT” has an attached targeting/masking peptide –
similar to a grenade with an intact pin – that is inactive and soluble in the blood stream
until it finds the target site of cancer cells and hits the enzyme associated with the
cancer. The enzyme “pulls the pin on the grenade” and cleaves the peptide, releasing
the 12ADT into the cancer cell. The cell-killing agent is no longer soluble and
precipitates directly into nearby cancer cells, killing them.”
G-202 is designed to target the blood supply to the tumor. Prostate-specific membrane
antigens (PSMA) are enzymes found only in blood vessels supporting the tumor. PSMA
removes the protective cover of prodrug. The active drug, 12ADT, then attacks the
blood cells, thereby starving the cancerous cells. Essentially, the delivery method
bypasses the brain barrier because it only works on the blood, according to an article
published on FierceDrugDelivery.