Optimizing the Outcome of Anti-Myeloma Treatment with Daratumumab

A search of the scientific literature for Daratumumab and myeloma gives more than 600 results (January 2021), which reflects the interest and activity around this antibody, an interest that was also reflected by the assignment of breakthrough designation for Daratumumab as a treatment for multiple myeloma by FDA in 2013. The high expectations have been supported and met due to a very active clinical development program, and our insight into Daratumumab’s modes of action have been expanded by a concomitant, systematic activity of translational research. The scope of this article is to point to some areas where the outcome of treatment with Daratumumab for multiple myeloma may be improved with a focus on areas such as when to initiate treatment with Daratumumab, the use of supportive treatment, duration of therapy and some general thoughts about anti-myeloma treatment as a two-step process involving initial de-bulking followed by reprogramming of the host’s immune system and immune-mediated control of myeloma.

Niraparib in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) and biallelic DNA-repair gene defects (DRD): Correlative measures of tumor response in phase II GALAHAD study.

118 Background: Niraparib, a highly potent and selective poly (ADP-ribose) polymerase inhibitor (PARPi) received breakthrough designation by US FDA for treatment of pts with BRCA1,2 mutant mCRPC who progressed on taxane and androgen receptor-targeted therapy. Circulating tumor cells (CTC) detection associates with poor outcomes, with declining counts consistent with improved survival [1,2]. Methods: GALAHAD study assessed niraparib (300 mg daily) in pts with mCRPC+DRD (NCT02854436). Patients with non-measurable soft tissue disease by RECIST 1.1 were required to have a baseline CTC count ≥1 cell/7.5 mL blood. CTC response was defined as CTC conversion to <5 for pts with baseline CTC≥5 and CTC drop to 0 post-baseline for pts with ≥1 baseline CTC. Alkaline phosphatase (ALP) was collected at each monthly cycle. Results: For primary efficacy population of pts with BRCA1/2 mutations, the objective response rate (ORR) by RECIST 1.1 criteria was 41.4%. CTC response rates for this population were as high as ORR regardless of measurability (Table). Time to CTC response for each CTC responder will be shown. Radiographic progression-free survival (rPFS) durations were similar for patients with a measurable disease response and patients with CTC conversion. Median duration of treatment for responders of any type was 6.7mo (range: 2–27). DRD status, both BRCA and non- BRCA, for each responder will also be discussed. Trends in disease burden and markers of bone metabolism will also be quantitatively explored including 24% pts who were on treatment for at least one cycle who had ≥25% decreased unfractionated ALP from baseline. Conclusions: Niraparib showed clinical activity with CTC response and decline in ALP levels in mCRPC pts having biallelic BRCA mutations, which further supports its recent breakthrough designation. Clinical trial information: NCT02854436. [Table: see text]