Pfizer's leukaemia drug gets opposing regulatory decisions on either side of the Atlantic

Pfizer has received a bittersweet bout of news as it emerges that its drug Besponsa (inotuzumab ozogamicin) has received approval in the US, but has been rejected in the UK.

The firm announced that the FDA has awarded US approval to the therapy for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukaemia, making it the first and only CD22-directed antibody-drug conjugate authorised for this indication.

The decision was made based on results of the drug’s recent Phase 3 trial, in which it 81% of the 326 participants achieved complete remission rate compared to just 29% for placebo, and these responding patients also demonstrated a higher rate of minimal residual disease negativity at 78% than the 28% with chemotherapy. Median overall survival hit 7.7 months for Pfizer’s drug, compared to 6.2 months, but it did not demonstrate statistically significant improvement in overall survival.

The drug was previously reviewed and approved under the FDA’s Breakthrough Therapy Designation and Priority Review programmes.

"The approval of Besponsa is an important step forward for adult patients with relapsed or refractory B-cell acute lymphoblastic leukaemia, a rare disease that can be fatal within a matter of months if left untreated," said Liz Barrett, Global President of Pfizer Oncology. "Besponsa will help address a significant need for new treatment options in B-cell acute lymphoblastic leukaemia, and may help more patients reach stem cell transplant, which provides the best chance for long term remission. We’re proud to build on our continued commitment to patients with hematologic malignancies, and will continue our work to find new treatments in acute lymphoblastic leukaemia and other blood cancers."

Despite this good news, NICE chose to reject the drug for use in England and Wales in its final appraisal decision for the treatment of relapsed or refractory B-cell CD22-positive B-cell precursor acute lymphoblastic leukaemia in patients with Philadelphia chromosome positive (Ph+) as well as Philadelphia chromosome negative (Ph-).

"Today’s frustrating decision for inotuzumab ozogamicin is another example of how NICE is not appropriately assessing the value of modern cancer medicines, leaving patients without access to new treatments that could transform their lives. We strongly believe this is an important and effective medicine which should be routinely available to patients and we will be appealing this decision," commented David Montgomery, Oncology Medical Director at Pfizer UK. "For this difficult-to-treat type of blood cancer, patients need to achieve complete remission in order to be eligible for a potentially curative bone marrow transplant. At the moment, treatment options that can achieve complete remission are few, and without new medicines like inotuzumab ozogamicin, patients have a very poor prognosis. We will continue to work with NICE in the hope that this decision can be overturned."

Pfizer has said it plans to appeal against the decision.