Aileron Therapeutics, Inc. today announced that it secured the second tranche in its Series D financing, bringing the total round to $42 million. Current investors Apple Tree Partners, Excel Venture Management, Lilly Ventures, Novartis Venture Funds, Roche Venture Fund and SR One participated in the round.

The payment of the second tranche was based on the successful progression through preclinical studies of Aileron's lead Stapled Peptide drug, ALRN-5281. Proceeds from this tranche will be directed to the clinical development of ALRN-5281 in patients with orphan endocrine disorders early this year. Initiation of the ALRN-5281 clinical trial will mark the first-ever Stapled Peptide human clinical trial.

"These proceeds will allow us to advance ALRN-5281 through Phase 1 development and continue to develop our pipeline of Stapled Peptide drugs," said Joseph A. Yanchik III, president and chief executive officer of Aileron Therapeutics. "This is a critical next step for our company, our collaborators and the emerging Stapled Peptide field. We appreciate the continued support of our investors and look forward to sharing more details around our orphan endocrine disorders program when we initiate the Phase 1 study in the coming months."

Stapled Peptides are a new class of drugs with a unique set of properties that fully capitalize on 25 years of genetic research to attack the key drivers of complex diseases, including cancer, endocrine/metabolic disorders and inflammation. ALRN-5281 is a proprietary, long-acting growth-hormone-releasing hormone (GHRH) agonist for treating orphan endocrine disorders, including adult growth hormone (GH) deficiency and HIV lipodystrophy, as well as broader patient populations involving a wide variety of metabolic/endocrine disorders. Aileron is also advancing Stapled Peptide drug candidates in collaboration with Roche, including a highly potent and specific dual inhibitor of MDM2 and MDMX for p53-dependent cancers. Preclinical data from this second program were recently presented at the 2012 EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics.

About ALRN-5281

ALRN-5281 is a proprietary, long-acting growth-hormone-releasing hormone (GHRH) agonist for treating orphan endocrine disorders, including adult growth hormone (GH) deficiency and HIV lipodystrophy, as well as broader patient populations involving a wide variety of metabolic/endocrine disorders. Relative to traditional GH injections, GHRH therapy produces a more physiological, pulsatile GH release, thereby minimizing safety and tolerability issues associated with chronic, excess GH replacement. ALRN-5281 was discovered and developed through Aileron's Stapled Peptide technology platform, an approach that locks peptides into their biologically active shape that provides first-in-class pharmacokinetic profiles allowing effective delivery of the peptide and pharmacological profiles that resemble the natural proteins. In preclinical studies, ALRN-5281 has demonstrated properties of a stable, long-acting hormone that may overcome the pharmacokinetic and dosing challenges that have limited the use and safety of traditional peptide hormones. Clinical evaluation of ALRN-5281 is expected to begin in early 2013 and will mark the first-ever Stapled Peptide human clinical trial.

About Aileron Therapeutics

Aileron Therapeutics is creating one of the first new classes of drugs in 20 years. Our proprietary Stapled Peptide drugs uniquely capitalize on 25 years of genetic research to attack the key drivers of complex diseases such as cancer, metabolic and endocrine conditions and inflammation. By harnessing one of the most common, but elusive, structures in nature - the alpha helical peptide, we believe that we can dramatically improve the treatment of these diseases and positively impact the lives of millions of patients. For more information, please visit www.aileronrx.com.