Apollo study details
Apollo was an open-label, phase 3 study that randomly assigned patients with RRMM to receive SC daratumumab in combination with pomalidomide and low-dose dexamethasone (D-Pd; n = 151) or the two-drug combination of Pd (n = 153).
Approximately 80% of the patients were refractory to lenalidomide and half were refractory to a proteasome inhibitor.
Median duration of SC daratumumab administration was 5 minutes. Median duration of study treatment was longer for patients on D-Pd (11.5 months vs. 6.6 months for Pd).
For the primary endpoint, at a median follow up of 16.9 months, median PFS was 12.4 months for patients receiving D-Pd and 6.9 months for those receiving Pd. One-year PFS was 52% for patients receiving the triplet combination and 35% for those receiving Pd. Treatment effect was generally consistent across subgroups examined, Dr. Dimopoulos reported.
Depth of response was significantly higher for patients on D-Pd. Stringent complete remission or CR was seen in 25% of patients on D-Pd versus 4% on Pd. Overall response rate was 69% for patients on D-Pd and 45% for patients on Pd alone (P < .0001). Minimal residual disease negativity was more than four times higher with D-Pd (9% vs. 2% for Pd; P = .0102).
The safety profile of D-Pd was consistent with the known safety profile of SC daratumumab and Pd. Infusion-site reactions were grade 1-2 and occurred in 5% of patients; in addition, only grade 1 injection-site reactions were seen and occurred in 2% of patients. The most serious treatment-emergent adverse events in patients on D-Pd were pneumonia (15% vs. 8% for Pd) and lower respiratory tract infection (12% vs. 9% for Pd). Incidence of secondary primary malignancy was 2% for each group.
Apollo results were ‘no surprise’
“These results are of no surprise and further support the current practice of using a three-drug combination in the relapsed setting,” Henry Fung, MD, chair of the department of bone marrow transplant and cellular therapies at Fox Chase Cancer Center, Philadelphia, said in an interview.
Although Dr. Fung agreed that the triplet of a proteasome inhibitor, an immunomodulating drug such as lenalidomide, and the steroid dexamethasone is becoming the standard of care for newly diagnosed MM, D-Pd should be considered an excellent option for patients who have limited choices in the relapsed/refractory setting.
However, he said that the median PFS of 12.4 months for patients receiving D-Pd after a median of two prior regimens is not satisfactory.
“The impact on the natural history of the disease will be limited and the duration of responses decline with each treatment regimen, and the true impact on the disease will be an effective frontline strategy.” Dr. Fung said. “This will not be a practice-changing trial. We need to find out which three-drug regimen works best and what biomarkers can predict the response to individual regimen.”
Dr. Dimopoulos reported receiving honoraria from Beigene, Bristol-Myers Squibb, Amgen, Takeda, Celgene, and Janssen. Dr. Mikhael reported receiving honoraria from Amgen, GlaxoSmithKline, Janssen, Karyopharm, Sanofi, Takeda; consulting with Celgene; and receiving research funding from Celgene and Sanofi. Dr. Fung is on the speakers’ bureau of Apollo and receives honoraria from Jansen Oncology and Celgene/Bristol-Myers Squibb. Dr. Raje is a consultant for Bristol-Myers Squibb and Janssen.
A version of this article originally appeared on Medscape.com.