The U. S. Food and Drug Administration approved elotuzumab in combination with lenalidomide and dexamethasone for the treatment of patients with multiple myeloma who have received one to three prior therapies.

Elotuzumab is a monoclonal antibody directed against Signalling Lymphocyte Activation Molecule Family 7 (SLAMF7).

SLAMF7 is present on myeloma cells and is also present on natural killer cells.

The approval was based on a multicenter, randomised, open-label, controlled trial evaluating progression-free survival (PFS) and overall response rate (ORR) in patients with relapsed or refractory multiple myeloma who had received 1 to 3 prior lines of therapy. 

A total of 646 patients were randomised (1:1) to receive elotuzumab in combination with lenalidomide and dexamethasone (n=321) or lenalidomide plus dexamethasone alone (n=325). 

Patients continued treatment until disease progression or the development of unacceptable toxicity.

The trial demonstrated a statistically significant improvement in both PFS and ORR, the trial’s co-primary endpoints. 

The median PFS in the elotuzumab-containing arm was 19.4 months and 14.9 months in the lenalidomide plus dexamethasone alone arm (hazard ratio 0.70, 95% CI: 0.57, 0.85; p = 0.0004). 

The ORR in the elotuzumab-containing arm was 78.5% (95% CI: 73.6, 82.9) compared to 65.5% (95% CI: 60.1, 70.7) in the lenalidomide plus dexamethasone alone arm (p=0.0002).

The safety data reflect exposure in 318 patients to elotuzumab in combination with lenalidomide and dexamethasone and 317 patients to lenalidomide plus dexamethasone.

The most common adverse reactions (greater than or equal to 20%), with an increased rate in the elotuzumab arm compared to the control arm, were fatigue, diarrhoea, pyrexia, constipation, cough, peripheral neuropathy, nasopharyngitis, upper respiratory tract infection, decreased appetite, and pneumonia.

Other important adverse reactions include infusion reactions, infections, second primary malignancies, hepatotoxicity, and interference with determination of complete response. 

As elotuzumab is an IgG kappa monoclonal antibody, it can be detected in the serum protein electrophoresis and immunofixation assays used to assess response.

Serious adverse events occurred in 65.4% of patients in the elotuzumab-containing arm compared to 56.5% in the lenalidomide plus dexamethasone alone arm.

The most common serious adverse reactions were pneumonia, pyrexia, respiratory tract infection, anaemia, pulmonary embolism, and acute renal failure.

The recommended dose and schedule for elotuzumab is 10 mg/kg intravenously every week for the first two cycles and every 2 weeks, thereafter, until disease progression or unacceptable toxicity with lenalidomide 25 mg daily orally on days 1 through 21. 

Dexamethasone is administered as follows: In weeks with elotuzumab infusion, dexamethasone is to be administered in divided doses, 8 mg intravenously prior to infusion and 28 mg orally; in weeks without elotuzumab infusion, dexamethasone is to be administered 40 mg orally. 

Pre-medication with an H1 blocker, H2 blocker, and acetaminophen should be administered prior to elotuzumab infusion.

Source: FDA