When it comes to getting a drug into a cell, size matters. Small molecules can easily pass through the cellular membrane in a way that larger therapeutic proteins can’t, which makes it difficult to develop a biological drug that can reach its target, says Dipal Doshi, CEO of biotech startup Entrada Therapeutics.

AstraZeneca has tapped Guardant Health to develop blood-based companion diagnostics for its cancer treatments Tagrisso and Imfinzi. Under the multiyear agreement, Guardant will pursue an FDA approval for a Guardant360 CDx liquid biopsy test to help identify non-small cell lung cancer patients for treatment with Tagrisso, an EGFR inhibitor.

Five-year old Hal was showing dangerous signs of respiratory distress. His lips were turning blue, his eyelids were drooping and the bedside monitor showed oxygen levels in his blood dropping fast.