Safety
Dr. Lonial said, in general, lenalidomide was “very well tolerated.” However, 80% of patients in phase 2 and 51% in phase 3 discontinued lenalidomide due to toxicity.
The rates of treatment-related adverse events (AEs) in the phase 2 portion were 34.1% for grade 3 AEs, 11.4% for grade 4, and 4.5% for grade 5. In the phase 3 portion, 35.2% of patients had grade 3 treatment-related AEs, and 5.7% had grade 4 treatment-related AEs.
Common AEs in phase 3 were grade 4 neutrophil count decrease (4.5%) and grade 3 infections (20.5%), hypertension (9.1%), fatigue (6.8%), skin AEs (5.7%), dyspnea (5.7%), and hypokalemia (3.4%).
Efficacy
“It is worth noting that about 50% of patients had an objective response to lenalidomide in both the phase 2 and the phase 3 trial,” Dr. Lonial said. “I think it’s also important to realize that, in the phase 2 portion of this study, of the 44 patients enrolled, 78% of them did not progress to myeloma with a median follow-up of over 5 years.”
In phase 2, PFS was 98% at 1 year, 87% at 3 years, and 78% at 5 years.
In phase 3, PFS was 98% in the lenalidomide arm and 89% in the observation arm at 1 year. At 2 years, PFS was 93% in the lenalidomide arm and 76% in the observation arm. At 3 years, PFS was 91% in the lenalidomide arm and 66% in the observation arm.
“What’s really quite interesting is that each [risk] group appeared to benefit almost equally from the early intervention of lenalidomide as a single agent,” Dr. Lonial said. “[W]hile the high-risk group may be the target now, this may be a fertile area for investigation in the intermediate-risk group as well.”
Dr. Lonial has relationships with AbbVie, Amgen, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen Oncology, Juno Therapeutics, Merck, Novartis, and Takeda. The trial was funded by the National Institutes of Health.
SOURCE: Lonial S et al. ASCO 2019. Abstract 8001.