Australian multiple myeloma patients are failing to advance to subsequent lines of therapy and are therefore missing out on newer therapies, a registry study finds.

Presenting the findings at Blood 2019, Dr Jessie Zhao from Dorevitch Pathology, in Heidelberg, Melbourne, said recent advances meant there were increased treatment options for multiple myeloma patients but there was no uniform standard of care treatment strategy.

“With these increased treatment options there have been improved patient outcomes but there is still a gap between clinical trial efficacy and real-world outcomes… and indeed 40% of patients don’t meet clinical trial eligibility criteria,” she told delegates.

“With the limited data available regarding local and contemporary treatment practices we aimed to evaluate the real-world treatment patterns in relapse/refractory myeloma in Australia”.

The research team identified 887 MM patients from the Myeloma and Related Diseases Registry who had initiated a first-line therapy between 2011 and 2017.

They found that only 35% of patients (n=310) advanced to second line treatment (2L), 14% (n=121) to third-line treatment (3L), 5% (n=46) to fourth-line (4L) treatment and 2% (n=20) to fifth-line treatment.

Overall response rates (≥PR) decreased in later lines of therapy (83% in 1L, 55% in 2L, and 37% in 3L). Median overall survival was 59.3m from 1L initiation, 29.4m from 2L, and 17.4m from 3L.

First-line therapy was dominated by bortezomib-based therapy (85%), most frequently VCD (76%) whereas 2L therapy was most commonly thalidomide-based (39%) and lenalidomide-based (30%), with lenalidomide-based regimens becoming predominant from 2018.

The authors noted that 5 out of 45 (11%) of 2L therapies incorporated carfilzomib despite its listing on the PBS in January 2018.

The most common 3L therapy was lenalidomide based (44%)followed by bortezomib-based (17%) and thalidomide based (10%) therapies.

Only  8/106 (8%) of 3L incorporated pomalidomide following its listing in August 2015, the data revealed.

Whereas 4L therapies most commonly incorporated carfilzomib (24%)and pomalidomide (24%) and forty percent of 5L therapies incorporated carfilzomib.

“Within the limitations of registry data, few multiple myeloma patients are advancing to subsequent therapies and are therefore failing to access new agents,” Dr Zhao said.

Given later lines of therapy yield diminishing gains, earlier utilisation of optimal regimens incorporating novel agents for MM is urgently warranted,” she added.