FDA approval of lung cancer drug Tagrisso welcome news for AZ

AstraZeneca has secured a valuable accelerated FDA approval for Tagrisso, its new targeted lung cancer drug.

Tagrisso has been approved three months ahead of schedule, the rapid decision reflecting its status as a promising new treatment option for a subset of non-small cell lung cancer (NSCLC) patients who have progressed on existing treatment.

The drug is targeted to patients with metastatic epidermal growth factor receptor (EGFR) T790M mutation-positive NSCLC, who have progressed on or after EGFR tyrosine kinase inhibitor therapy, such as AstraZeneca's existing Iressa or Roche's Tarceva.

The approval is hugely important for AstraZeneca, whose chief executive Pascal Soriot has set a target of raising revenues to $45 billion by 2023, an ambitious growth target set when it was fighting off a Pfizer takeover bid last year.

Hitting the target will be a tough call, not least because blockbuster Nexium went off patent this year, to be followed by Crestor, another multi-billion dollar earner, in 2016.

But Tagrisso's approval is a major filip for AstraZeneca, allowing it to steal a march on Clovis and its rival treatment, rociletinib (CO-1686). Pascal Soriot predicts AZ's drug could earn as much as $3 billion in peak sales, despite the number of patients with the gene mutation being relatively small.

Between 10 and 15 per cent of patients with NSCLC are EGFR mutation-positive. Around two-thirds of patients treated with EGFR TKI therapy will eventually develop resistance related to the T790M mutation.

The success of the drug will hinge on these patients being identified, and AZ is collaborating with Roche to develop the cobas EGFR Mutation Test v2 as the companion diagnostic, which will identify a range of EGFR mutations, including T790M.

The FDA approval was based purely on the overall response rate (59 per cent) the drug showed in its two AURA trials, but the drug will have to show clearer benefits to patients to be a success.

It recently recorded a median progression free survival of 8.6 months, however Clovis achieved a similar performance with its drug, so Tagrisso's dominance in the market is far from confirmed.

Also not yet confirmed is the price of the drug, a contentious issue which is now part and parcel of the launch of new cancer drugs.

Tagrisso's approval follows the December 2014 approval of another AZ drug, ovarian cancer treatment Lynparza, (olaparib) helping the company fulfil its goal to make oncology one of six 'growth platforms'. The most important oncology drug in its pipeline is durvalumab, a PD-L1 checkpoint inhibitor being developed for numerous tumours, with NSCLC as its lead indication. AstraZeneca believes it can compete with BMS's Opdivo and Merck's Keytruda, the trailblazers in the new immune-oncology market, However Soriot recently warned that durvalumab would not get the fast track treatment given to Tagrisso, given that Keytruda and Opdivo are already serving these patients – adding pressure for AZ's drug to outperform the first-to-market drugs.