- Puma Biotechnology doesn't expect to be able to report data from a key study of its cancer drug Nerlynx until the fourth quarter of this year at the earliest, a delay that sparked a sell-off in the company's shares Thursday.
- The company disclosed on a first quarter earnings call held Wednesday evening that a slower-than-anticipated event rate in the study, which is testing Nerlynx in third-line HER2-positive metastatic breast cancer, would likely push back the readout date.
- Puma cautioned that the event rate, or confirmed data on patients' progression-free survival, could slow further, potentially delaying data release into 2019. Puma shares closed Thursday trading down 21%, reaching the lowest level in almost a year.
Puma based its assumptions for the event rate in the NALA study of Nerlynx (neratinib) on historical controls, according to Alan Auerbach, CEO of Puma
"The endpoint on [the] blinded trial is centrally-confirmed progression-free survival. So, whereas we were expecting in some cases to be seeing a monthly event rate in double-digits, we're seeing one that's in the single-digits," Auerbach said on the May 9 earnings call.
The company had previously expected to read out results in late June.
Nerlynx was approved in the U.S. last year to prevent recurrence of HER2-positive breast cancer following adjuvant treatment with trastuzumab and is Puma's only commercialized product. Net product revenue from sales totaled $36 million in the first quarter of this year, up 79% from the fourth quarter of 2017. The company projects net revenues of between $175 million and $200 million for 2018.
For global sales, Puma has licensed Nerlynx to Pint Pharma in Latin America, CANbridge in China, Medison Pharma in Israel, and Specialised Therapeutics Asia in South East Asia.
Nerlynx is also being tested in a Phase 2 basket trial in a variety of tumors with HER2 and HER3 mutations. This study, known as SUMMIT, aims to look at the influence of both mutation and cancer type on response.
The NALA delay isn't the first for Nerlynx. In February, the EU's Committee for Medicinal Products for Human Use (CHMP) gave Nerlynx a negative opinion as an extended adjuvant treatment of early-stage HER2-positive breast cancer. The CHMP based their decision on concerns the benefit seen in trials would not translate to everyday practice, and that the side effects could be difficult to manage.
In March, Puma requested a re-examination of the CHMP's opinion; once it has received grounds from the company, the CHMP will reassess and issue a final opinion, which Puma anticipates in late June or early July this year, according to Auerbach.
Puma also plans to submit Nerlynx for approval for the extended adjuvant indication in a number of countries during the second half of 2018.