DOACs are accepted as the new standard of care for the management of cancer-associated thrombosis (CAT) because of their clear superiority in efficacy and an equivalence in bleeding rates, a conference has heard.
Speaking in a sponsored session at COSA 2021, haematologist Dr Scott Dunkley said the change was driven by results from a series of pivotal trials, in particular the Caravaggio study.
The trial of apixaban versus dalteparin found recurrent VTE was less frequent with the DOAC than with the LMWH (5.6% v 7.9%; HR 0.63; p<0.001 for noninferiority) without an increased risk of major bleeding.
Dr Dunkley said this year’s ASH guidelines have also recommended DOACs as the new standard of care in CAT.
However he said there had been some early indication from the Garfield-VTE study that the uptake of DOACs for the specific indication of CAT had not kept pace with the uptake of DOACs overall.
Professor Harshal Nandukar, from Alfred Health, said real world data of apixaban versus LMWH has also confirmed the DOACs equivalence or benefit across high-risk subgroups including cancer patients with metastases, those on active treatment including chemotherapy and patients with GI cancers.
He said results from the ongoing EVE and API-CAT studies will answer the next question about the use of extended treatment beyond an initial 6 months for patients with active cancer.
Management is more than DOACs; includes education
Professor Simon Noble, a palliative care physician at Cardiff University, Wales who runs a dedicated cancer-associated thrombosis service, told the meeting that clinicians would be seeing more CAT.
“People are living longer with metastatic disease and we are using more and more systemic anti-cancer therapies all of which increase the risk of thrombosis,” he said.
Professor Noble said patients were most at risk of CAT during hospitalisations, chemotherapy treatment, metastatic disease and disease progression.
However many patients do not appreciate their risk of CAT – up to 1 in 5 cancer patients will develop VTE – or that their risk of death from CAT was the same as that from infection.
While well informed about either potential complications such as febrile neutropenia during chemotherapy, they did not have a similar understanding about their risk of clots.
“What we know from qualitative data is that patients with CAT see themselves as cancer patients first. The clot they see as a complication of the cancer.”
They therefore prioritised a treatment for CAT which didn’t interfere with their cancer treatment well above anticoagulant efficacy and the risk of major bleeding.
“And if those three things were met, yes they would prefer a tablet to an injection.”
Professor Noble said adequate patient education around the risk of thrombosis in cancer could reduce the mean time to presentation of symptoms from about 9 days to 3 days.
“And we know that the sooner you get a patient on treatment of their CAT, you are going to reduce clot progression, decrease the likelihood of propagation and large clot burden complications.”
“This could be the difference between serious morbidity or even life and death.”
“I think we need to try and make sure we have the same robust pathways [for CAT] that we are putting in for FN,” he said.
The session was sponsored by Bristol Myers Squibb and Pfizer.