Allos blood cancer data hastens drug filing


News that Allos Therapeutics’ one and only late stage product had passed its final pivotal phase II trial with flying colours, yesterday caused shares in the group to initially gain 15% in early morning trading before settling back down to a more modest 4% rise.

Pralatrexate, which is being developed for patients with relapsed or refractory peripheral T-cell lymphoma (PTCL), reported impressive duration of response of 9.2 months. The time span compares favourably with the four to five months that many analysts had been expecting following a peek at some of the data at last year’s Asco.

The duration of response data appears to have gone someway to making up for the harsh looking treatment the group received back in December, when it released a second tranche of data for pralatrexate, also known as PDX, that showed a lower response rate than an earlier study (Allos data disappoints but not the end of the road, December 9, 2008).

Falling numbers

But the results also showed a dip in patients with a complete response to the drug from 10 to 7, in the 27% of patients who responded to treatment, a factor that may have caused the damping of the share price reaction.

However, it is worth bearing in mind that Allos shares have risen by over 30% since the beginning of the year, mainly on the expectation of the phase II data, and some analysts believe that some investors may have seen this as an opportunity to take profits. 

Filing soon

Although the data is only phase II the group believes it is strong enough to now file an NDA for PDX, something that it plans to do in the second half of this year. Given that the drug has both fast track designation and orphan drug status, it could theoretically be approved by the end of the year.

At present there are no approved products either in the US or Europe for PTCL and the patients that were on the trial on average had undergone four different types of chemotherapy treatment before being given PDX. With so few options available to patients it is likely that the FDA will give the drug the green light.

The regulator has also recently demonstrated that it is prepared to grant approval for hard-to-treat lymphoid cancers with relatively small trials, including Tasigna and Clolar, which should give investors quiet hope of a first time pass.

Golden future?

Yesterday’s positive data could also be the trigger for the group to start partnering talks for the drug in Europe, which with the expected filing could cause the shares to rise even further this year. PDX is forecast to have sales of $352m by 2014, according to consensus forecasts from EvaluatePharma.

Importantly, if it is forthcoming, approval of the product will be an event that will greatly de-risk Allos, which alongside PDX, only has phase I product RH1 in development. 

What remains to be seen is whether the company will be around to strike a licensing deal in Europe and see PDX through to approval. Although the shares are near historic highs, making it look less of a bargain, investors might want to look at the number of deals over the last few years that have seen companies such as Pharmion and Millennium Pharmaceuticals, which specialised in lymphomas, being bought out by larger players.

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