Stroke Drug Tenecteplase Dissolves Clots as Well as Standard TPA—but in a Single Dose
Tissue plasminogen activator (TPA) was one of the biggest revelations in stroke treatment of the past 30 years, and for three decades has been the only approved medication for acute ischemic strokes.
Now, a drug derived from TPA called tenecteplase (TNKase or TNK), which has been used to treat acute heart attacks, has been proven to perform equally as well as standard TPA at dissolving blood clots that cause strokes.
Similar to TPA, TNK activates plasminogen in the blood to dissolve clots that block the flow of oxygenated blood to the brain, resulting in an ischemic stroke. But TNK is modified with a higher attraction to clots, which could result in less unintended bleeding in other areas of the brain compared with TPA.
A study out of Canada published in The Lancet showed that in approximately 1,600 patients at multiple care sites, both drugs performed equally well when comparing bleeding rate and dissolving the clot. In the study, half of patients received TPA and half received TNK. Outcomes were similar:
- About 34%-36% of patients in both groups had excellent outcomes
- About 55%-57% had good outcomes
- About 3.5% in both patient groups experienced bleeding complications
What’s more, TNK can be delivered in a single dose, whereas TPA requires two separate doses and takes an hour to administer.
Approximately 700,000 people have ischemic strokes each year in the U.S., and only approximately 15%-32% get clot-dissolving drugs. TPA or TNK must be administered within 4.5 to 6 hours of stroke symptom onset. That timeframe is a significant barrier for patients who live far from a hospital or those whose care is delayed when stroke symptoms such as facial drooping or speech difficulty aren’t recognized quickly.
However, because TNK is easier to administer and works as well as TPA, our stroke specialists and telestroke team could help thousands more patients achieve better stroke outcomes.
Telestroke & TNK Increase Chances of Good Outcomes
UNM Hospital is a Comprehensive Stroke Center, which means we offer the highest level of stroke care. Using video calling, we have expanded our UNM ACCESS telestroke consultation service to 22 hospitals within the state of NM. This service allows us to assess patients remotely and counsel providers on the use of TNK or TPA to dissolve the clot and prepare the patient for transfer to UNM Hospital.
TPA is given in two doses: 10% is given as an injection, followed by the remaining 90% given over 60 minutes as an IV drip. TNK is given as just one injection with no IV required. While both drugs can be administered as the patient is being transferred by ambulance to a stroke center, giving TNK:
- Requires fewer hands
- Is faster
- Avoids issues such as incorrect IV placement or pulling it out accidentally
Related reading: Young Adults Can Have Strokes, Too: BE FAST to Spot the Signs
TNK Might Work Better on Large Clots
Approximately 24%-46% of patients who have an acute ischemic stroke have a large vessel occlusion (LVO). These large clots traditionally are removed by a procedure called endovascular mechanical thrombectomy rather than medication alone.
Endovascular mechanical thrombectomy became a standard of care for acute ischemic stroke with LVOs in 2015. At a stroke center, a specialist guides a catheter through the blood vessel to the clot, and we move a small tool through the catheter to collect and remove the clot.
For LVOs, thrombectomy generally provides better outcomes than clot-dissolving medication alone. But when thrombectomy must be delayed—for example, at hospitals that are far from a stroke center—TNK might help initiate the dissolving process better than TPA.
Research out of Australia published in Stroke by the American Heart Association (AHA)showed that TNK was twice as effective as TPA at dissolving clots, a difference of 22% and 10% respectively. These data were among the basis for AHA to recommend TNK for patients with large clots—a practice the UNM Department of Neurology adopted over a year ago.
Related reading: A Day in the Life of a Neuro ICU Resident
Continued Research in TNK
As an academic medical center, we are on the leading edge of the latest scientific literature, even before impactful research makes it into official national guidelines. We update our internal processes in accordance with the most up-to-date literature to give our patients the best chance at optimal outcomes.
One ongoing clinical study that has our attention is the TIMELESS trial (Tenecteplase in Stroke Patients Between 4.5 and 24 Hours), which is examining whether it is safe to extend the timebox of when TNK can be used after stroke symptom onset.
Another, the TWIST trial (Tenecteplase in Wake-up Ischaemic Stroke Trial), is studying whether patients who have a stroke in their sleep could benefit from TNK—right now, these patients are not eligible for clot-dissolving drugs due to the timeboxing constraints.
As ongoing trials bring in new data, our clinicians will begin implementing the findings that can benefit our patients. The more patients who can receive fast, effective stroke care, the better chances they will have for positive outcomes.