- Updated clinical data showed Blueprint Medicine's targeted cancer drug for RET-mutated lung and thyroid cancers caused tumors to shrink in roughly three-fifths of patients, supporting the biotech's plans to file for regulatory approval in the U.S. early next year.
- Between 1% and 2% of lung cancer cases and as many as 5% of thyroid cancers, harbor alterations in the RET gene, according to data from diagnostic company Foundation Medicine. Yet unlike more common EGFR or ALK mutations, there are currently no treatments specifically aimed at treating RET-driven tumors.
- Blueprint is not alone working to change that. Eli Lilly is advancing LOXO-292, a RET-targeted drug it acquired in its $8 billion buy of Loxo Oncology, and could submit the therapy in the second half of this year.
Blueprint is making its clinical case amid a surge in targeted cancer drug development that promises to add new treatment options for tumors spurred by aberrant genes.
"We've seen how targeted therapies have transformed care for EGFR and ALK [positive] patients and that's the result of a lot of research," said Alice Shaw, director of thoracic oncology at Massachusetts General Hospital in Boston, in an interview.
"It's exciting now to see this coming into other subsets of patients, in particular ROS1 and RET." Shaw consults with Blueprint Medicines, as well as Roche's Ignyta and Loxo Oncology, among others.
On Monday, updated results for Blueprint's drug, called BLU-667, in advanced lung cancer were presented at the American Society of Clinical Oncology's annual meeting. Data for the therapy in advanced thyroid cancer were included in a poster presented Saturday at the conference.
Among the 48 patients with non-small cell lung cancer who were evaluable for efficacy, 28 responded to treatment, including one who experienced a complete response.
That 58% response rate was similar to the 60% recorded in the 35 patients previously treated with platinum chemotherapy, a group for which Blueprint hopes to win approval for BLU-667 first.
Seven percent of all 120 lung cancer patients who were treated, though, discontinued therapy due to treatment-related toxicity — on par or slightly higher than some Wall Street analysts had expected.
A previous statement from Blueprint disclosed one patient death that was possibly related to treatment with BLU-667, but didn't specific which cancer type.
Acquired resistance is always a concern with targeted therapy, as tumors morph in response to treatment. Blueprint's data offered some reassurance on that front, with responses still ongoing in more than half of those whose tumors had shrunk.
Results from fewer thyroid cancer patients were available. BLU-667 led to partial responses in 10 of the 16 study participants previously treated with chemo.
Blueprint is studying BLU-667 in two types of thyroid cancer, papillary and medullary, in which the rates of RET mutations are much higher than the general prevalence in thyroid cancer overall.
Notably, two of four patients who had received prior treatment with LOXO-292 responded to treatment with BLU-667
"This finding is important because it expands the overall opportunity for both drugs, and also lessens the urgency that BLU-667 needs to be superior to LOXO-292 to have a meaningful market presence," wrote Leerink analyst Andrew Berens in a June 3 note to clients.
Investors will likely be quick to compare Blueprint's data with that of Lilly's for LOXO-292, which has also shown response rates in the 60% range.
Mass General's Shaw, though, cautioned against drawing conclusions yet.
"I don't think anyone can really say if one drug is clearly better than the other, it's just nice that we have two promising options," she said, noting efficacy for both was "impressive."
Blueprint plans to submit BLU 667 for approval in previously treated lung cancer patient by the first quarter of 2020.
Results to date, however, have spurred the company to expand its study to include patients who are treatment naive, aiming to support "expedited development" for first-line RET-mutated lung cancer.