Rain Therapeutics scores $18 million Series A round for lung cancer drug

The company plans a Phase II study next year in a subset of non-small cell lung cancer patients who usually don’t respond to existing therapies.

A company developing a drug for a hard-to-treat form of lung cancer has secured a funding round worth more than $18 million.

Fremont, California-based Rain Therapeutics said Monday that it had closed an $18.4 million Series A round led by the venture capital firm Biotechnology Value Fund, along with Perceptive Advisors, New Zealand-based Auckland UniServices Limited’s Investors Fund and others. The company has a global development and commercialization license for the drug, tarloxotinib, from the University of Auckland.

Rain plans to use its funding to start a Phase II clinical trial of tarloxotinib in the first half of 2019. The trial will include patients with non-small cell lung cancer whose disease exhibits EGFR and ErbB Exon 20 mutations. Despite expressing EGFR, EGFR Exon 20’s resemblance to wild-type EGFR means that most conventional drugs targeting the gene will result in toxicity, said company co-founder Robert Doebele, an associate professor of medicine at the University of Colorado, in a company statement Monday.

Drugs for NSCLC that target EGFR include Iressa, made by AstraZeneca, and Roche’s Tarceva, both tyrosine kinase inhibitors with the respective generic names gefitinib and erlotinib. However, according to the National Comprehensive Cancer Network Guidelines – a compendium that oncologists use to guide drug therapy for cancers – Exon 20 lung cancers usually will not respond to tyrosine kinase inhibitor therapy. Doebele said in the statement that tarloxotinib’s mechanism gives it potential to address the unmet clinical need of Exon 20 patients.

However, Rain is not the only company targeting Exon 20 patients. Spectrum Pharmaceuticals, a publicly traded drugmaker based in Henderson, Nevada, is developing poziotinib, which targets EGFR and HER2 Exon 20 insertion mutations. Spectrum is running a Phase II clinical trial that is expected to include 174 Exon 20 patients, divided between EGFR and HER2 mutations, according to the registry. The company announced last month an online publication in Nature Medicine summarizing preclinical and clinical data on poziotinib for EGFR and HER2 Exon 20 mutations. Spectrum has six marketed products already, primarily for blood cancers.

Meanwhile, researchers at Seoul National University in Korea launched a 28-patient Phase II study in January investigating AstraZeneca’s Tagrisso – generic name osimertinib – in Exon 20 patients, based on the premise that it has a wide therapeutic window in cells with EGFR Exon 20 insertion mutations. AstraZeneca is collaborating on the trial.

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