Ixazomib/lenalidomide maintenance promising after ASCT in MM

Eight of the 16 patients who progressed had high-risk disease. Among the 16, the median PFS was 17 months (range, 3 – 43).

Seven patients died with an overall survival of 4 months (n=1), 16 months (n=2), 20 months (n=2), or 48 months (n=2).

Dose reductions

Sixteen patients started ixazomib at a dose of 4 mg, and 48 started at 3 mg.

Fifteen patients had their ixazomib dose reduced to 2.4 mg due to peripheral neuropathy (n=8), neutropenia (n=3), hearing loss (n=2), rash (n=1), or thrombocytopenia (n=1).

Five patients had a second dose reduction to 1.5 mg due to neuropathy (n=3), neutropenia (n=1), or thrombocytopenia (n=1).

Four patients who required a third dose reduction for neuropathy (n=2), neutropenia (n=1), and thrombocytopenia (n=1) went off study.

All patients started lenalidomide at 10 mg for 28 days.

Twenty-four patients required a lenalidomide dose reduction. Fifteen patients stayed at 10 mg but for 21 of 28 days, and 9 patients reduced to 5 mg for 28 days.

Reasons for these reductions were neutropenia (n=12), rash (n=4), thrombocytopenia (n=3), fatigue (n=2), memory impairment (n=1), infection (n=1), and pruritis (n=1).

Five patients required a second dose reduction to 5 mg for 21 of 28 days. Reasons for these reductions were neutropenia (n=2), neuropathy (n=1), thrombocytopenia (n=1), and fatigue (n=1).

“There are about 10 patients who did not have any ixazomib reductions that needed lenalidomide reductions, mostly for the pancytopenia,” Dr Patel noted.

Efficacy

Fifty-six percent of patients achieved a very good partial response, 26% a complete response (CR), 8% a stringent CR, and 10% a partial response.

Twenty-nine patients (45%) experienced an improvement in their best overall response from post-transplant baseline.

The median time to response was 10.1 months. The median duration of response has not yet been reached. Investigators estimated the 4-year duration of response to be 62%.

At a median follow-up of 38.2 months, the median PFS had not yet been reached. Investigators estimated the 2-year PFS to be 81%.

The median PFS for patients with high-risk disease is 21.85 months.

Based on these results, the investigators believe ixazomib-lenalidomide maintenance is safe, feasible, and well-tolerated and should be further explored in phase 3 studies.

Dr Patel has received research funding from and served on an advisory committee for Pfizer. She has consulted for Juno and Celgene.

The study was supported by Takeda Oncology.

* Data in the presentation differ slightly from the abstract.