Genmab has reported encouraging preliminary safety and efficacy data from the first Phase I/II clinical study of daratumumab (HuMax-CD38) in multiple myeloma.

Reductions of 49%, 55%,and 61% in the serum M-component were observed in the three patients treated at the highest dose examined so far.

The serum M-component is an abnormal protein produced by the cancerous plasma cells and is a direct marker for tumour activity.

The reduction in the serum M-component is a key factor for response evaluations in multiple myeloma, the company said.

The observed level of reduction therefore indicates that daratumumab was clinically active.

The data presented, which was from 23 patients who received daratumumab in doses up to 4mg/kg, also showed that the drug has an acceptable safety profile.

Genmab CEO Jan van de Winkel said that they have not yet reached the maximum tolerated dose and therefore the study will continue.

"We look forward to announcing detailed safety and response data at a later date," Winkel said.

The most common adverse events seen in the study were pyrexia, coughing, free haemoglobin, anaemia, dizziness, hemolysis, flu-like illness, nausea, lymphopenia and monocytopenia.

The ongoing Phase I/II dose escalation study will include a maximum of 122 patients with multiple myeloma that is relapsed or refractory to at least two different prior treatments.

The primary objective of the study is to establish the safety profile of daratumumab, and secondary objectives are to establish maximum tolerated dose and efficacy.

An independent data monitoring committee evaluates the safety data for each cohort before dose-escalation.