Lumos' oral growth hormone drug falls short of Novo's injectable incumbent at interim analysis

Lumos Pharma’s oral treatment for moderate pediatric growth hormone deficiency has failed to match up to Novo Nordisk’s injected drug Norditropin at the interim analysis of a phase 2 trial. But with growth in the Norditropin arm exceeding expectations, Lumos has pinned the blame on baseline imbalances. 

Texas-based Lumos is developing the drug candidate LUM-201, a small molecule that Merck previously studied in patients with growth hormone deficiency, in the belief it promotes secretion of the hormone from the pituitary gland. If Lumos is right, the candidate can provide an oral alternative to the injectable treatments for the pediatric condition that are already on the market. 

The release of interim data from a pair of phase 2 trials gave Lumos a chance to provide early evidence in support of the program. In the larger of the two studies, investigators randomized patients to take one of three doses of LUM-201 or the injectable recombinant human growth hormone Norditropin.

At the interim analysis, Lumos had data on 41 patients, around half its enrollment target. After six months, annualized growth in the three LUM-201 arms ranged from 7.26 cm to 8.57 cm, with the fastest growth seen at the middle dose of 1.6 mg/kg. Lumos said the results matched its expectations, which were based on the 8.3 cm annualized growth seen in a phase 4 study run by Eli Lilly. 

However, while growth in the 1.6-mg/kg arm, Lumos’ phase 3 dose, beat the historical control, it fell short of the result seen in the active control cohort of the clinical trial. Annualized height velocity in the 10 patients who received Norditropin averaged 11.05 cm.

According to Lumos, the Norditropin cohort grew at a much faster rate than expected or previously reported in similar patient populations. The company attributed the growth in the Norditropin arm, and the difference with the LUM-201 cohorts, to imbalances in baseline characteristics, notably the presence of two of the youngest subjects in the control group. The two subjects grew 15.6 cm and 12.7 cm.