Fig. 3: Treatment-related adverse events, and basophil activation test (BAT) as a predictor of anaphylaxis. | Nature Communications

Fig. 3: Treatment-related adverse events, and basophil activation test (BAT) as a predictor of anaphylaxis.

From: Safety and anti-tumour activity of the IgE antibody MOv18 in patients with advanced solid tumours expressing folate receptor-alpha: a phase I trial

Fig. 3

a Adverse events (AEs) experienced by ≥10% of patients (as well as anaphylaxis in 1/26 (4%)) are grouped according to severity and by dose cohort (1–7(ii) from left to right for each AE). No related AEs occurred at the lowest dose (cohort 1), and there was no grade 4 or 5 toxicity at any dose. Acute hypotension responding promptly to intramuscular adrenaline was seen in 1 patient treated at 500 μg (cohort 3). b Serum tryptase was elevated in this patient at 2 and 6 h following the infusion, supporting a diagnosis of drug-related anaphylaxis to explain this adverse event (dotted line represents upper limit of normal for serum tryptase [14 ng/ml]). c Fold change (Log2) in median circulating cytokine levels post-dose (2, 6, 24 h and 7 days) relative to normalised baseline values for each patient (n = 26). d Marked upregulation of the basophil activation marker CD63 in response to ex vivo stimulation of patient blood using positive controls (1 = anti-FcεRI, 2 = fMLP, 3 = anti-IgE), but not to MOv18 or control IgEs. This BAT result (n = 26) remained negative when performed following the 1st (n = 24) and 3rd (n = 20) MOv18 IgE doses (mean ± SEM) for all trial subjects excluding the single patient who experienced anaphylaxis. Negative control IgE was not included in all assays. e By contrast, the baseline BAT was positive for the patient experiencing anaphylaxis at the time of their subsequent MOv18 IgE infusion (n = 1). Unlike all other patients, MOv18 IgE antibody produced a 17-fold increase in basophil activation in this individual’s blood at baseline (left panel, blue bars). The BAT for this patient became negative after the episode of anaphylaxis (right panel), likely as a result of basophil depletion. f Peripheral basophil counts fell immediately following MOv18 IgE infusion and anaphylaxis in this patient, but not in other trial subjects after their MOv18 IgE dosing (Supplementary Fig. 1), recovering by day 7 (n = 1). Source data are provided as a Source Data file.

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