Growth hormone could be filed without further trials, says OPKO

OPKO Health’s weekly growth hormone injection could be approvable in adults without need for further clinical trials, the company has told pharmaphorum.

The biotech has worked with Pfizer to co-develop its weekly growth hormone, but suffered a setback in its phase 3 of  hGH-CTP, in adult growth hormone deficiency.

The trial failed to show statistical superiority over the placebo arm, but the company says ‘outlier’ results in the placebo arm may have skewed the results.

Speaking to pharmaphorum, executive vice president, Steven Rubin said the drug may still be approvable in the US if an analysis of the outlier results proves favourable.

OPKO will be presenting at this week’s JP Morgan Healthcare Conference, to reassure investors that the drug could still be filed with regulators despite the setback.

Rubin told pharmaphorum that around 97% of patients treated with the drug saw an increase in IGF levels, compared with only 6% in the placebo arm.

There was just one case in a 6o-patient placebo arm from the 26-week trial involving 180 patients in total, where a patient experienced a large increase in trunk fat, the primary indicator of efficacy.

This has prompted the company to run a post-hoc analysis that accounts for all outliers, to see if any other anomalous data could have influenced findings.

The drug could be ready to file in four to six weeks’ time, and an important paediatric trial will go ahead as planned, said Rubin.

“If that analysis shows what we have suspected, we will be able to send applications to European and US authorities for approval,” said Rubin.

“Assuming that is positive we will submit the data to the FDA, which has rules to deal with outliers, as does the EMA. It is a matter of doing the work correctly.”

A secondary endpoint showed that a greater percentage of patients on hGH-CTP normalised serum concentrations of insulin-like growth factor-1 (IGF) compared with placebo.

Rubin added that safety data seemed promising, with no evidence that the patients produced antibodies against the drug, and concentrations remained within acceptable safety limits.

OPKO has produced the drug as all patients requiring growth hormone treatment have to endure daily jabs.

It is one of four pharma companies developing longer-lasting alternatives – Novo Nordisk, Versartis and Ascendis are OPKO’s rivals.

The growth hormone market is worth around $3 billion, with adults making up around 20% of the market.

Just how much of that market OPKO will be able to gain rests on results of a phase 3 trial, to test if the drug is effective in the much larger paediatric population, and whether the competitor drugs run into trouble.

Pfizer is ready to market the drug if OPKO succeeds – and will pay the biotech up to $275 million if it makes it to market.

In the meantime, Rubin is optimistic about the prospects for hGH-CTP in adults. “We remain confident that we will not need to do another trial – a modified statistical analysis will potentially show our drug is effective,” he said.

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