Juno Therapeutics (juno) shares plunged 30% last week when the Food and Drug Administration (FDA) put a hold on its clinical trials for a pioneering cancer therapy following three patient deaths. But just five days later, regulators released the hold on Tuesday, sending the biotech’s shares rallying nearly 10% on Wednesday.
Juno’s experimental product is part of a next-generation wave of cancer immunotherapy treatments. Generally, these drugs use patients’ own immune systems to identify and attack cancerous cells. But Juno’s experimental medication, JCAR015, is a specialized kind of immunotherapy called chimeric antigen receptor T-cell (CAR-T) technology that involves extracting a patient’s immune cells, re-engineering them to fight cancers, and then releasing them back into the body to hunt down the diseased cells.
It’s a complex process which has proven most effective in blood cancers like leukemias and lymphomas so far. And it’s combined with traditional chemotherapy agents like cyclophosphamide to make it more effective. But three patients enrolled in mid-stage trials for JCAR015 died after another chemotherapy agent called fludarabine was added to trial, according to Juno, leading to the clinical trial hold.
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The regulatory decision also dogged other companies involved in CAR-T such as Kite Pharma (kite) and Novartis (nvs), among others, and raised questions about Juno’s hopes of filing for FDA approval in early 2017.
Regulators now seem to have been appeased by Juno’s response to the hold and are allowing the study, dubbed the ROCKET trial, to go on without the chemotherapy agent that may have caused the deaths.
“Under the revised protocol, the ROCKET trial will continue enrollment using JCAR015 with cyclophosphamide pre-conditioning only,” said the company in a statement.
Juno presented promising trial data for JCAR015 during the American Society of Clinical Oncology (ASCO) annual conference in June. The biotech revealed that the drug erased all visible signs of cancer in 75% of hard-to-treat acute lymphoblastic leukemia patients (and had even stronger results for patients whose cancers were at an earlier stage).
“There’s absolutely no reason that every patient with a B-cell malignancy shouldn’t be cured with this technology,” Juno CFO Steve Harr told Fortune in an interview during the conference.