Ambrx Inc., of San Diego, said its IND is active for ARX788, the firm's lead internally developed site-specific antibody-drug conjugate aimed at treating a broader population compared to currently available HER2-targeting therapies. Ambrx plans to open U.S. sites for the first-in-human study, which already is recruiting in Australia and New Zealand. The primary endpoint is safety and tolerability. The pharmacokinetics and antitumor activity of ARX788 will also be evaluated.

Audentes Therapeutics Inc., of San Francisco, said the first patient was enrolled in INCEPTUS, a prospective study designed to characterize the disease presentation in children with X-linked myotubular myopathy (XLMTM). It is evaluating subjects prior to potential enrollment in ASPIRO, the planned phase I/II study intended to test safety and preliminary efficacy of gene therapy-based candidate AT123. INCEPTUS will enroll boys with XLMTM, ages 3 or younger, and will focus on respiratory measurements and assessment of muscle strength and function. Patients enrolled in INCEPTUS will be evaluated over a three- to 12-month period prior to participation in ASPIRO. INCEPTUS is designed to serve as a longitudinal baseline and within-patient control for subjects who enroll in the ASPIRO study, expected to start in 2017, with preliminary data anticipated in the fourth quarter of next year.

Cytokinetics Inc., of South San Francisco, said it completed enrollment in VITALITY-ALS (Ventilatory Investigation of Tirasemtiv and Assessment of Longitudinal Indices after Treatment for a Year in ALS), a phase III trial of tirasemtiv, a skeletal muscle activator, in patients with amyotrophic lateral sclerosis (ALS). The study, which is designed to assess the effects of tirasemtiv vs. placebo on slow vital capacity and other measures of skeletal muscle strength, enrolled more than 700 patients in 11 countries. Results are expected in the second half of 2017. The company also said enrollment in the open-label extension to VITALITY-ALS is expected to begin in the fourth quarter of this year. Last month, Astellas Pharma Inc., of Tokyo, expanded an existing collaboration with Cytokinetics to pick up an option to tirasemtiv in ALS. (See BioWorld Today, July 28, 2016.)

Inspyr Therapeutics Inc., of San Antonio, said the first patient was treated in a phase II investigator-sponsored trial of mipsagargin, an agent targeting prostate-specific membrane antigen, in patients newly diagnosed with prostate cancer. The open-label, single-arm study will enroll treatment-naïve patients prior to surgical removal of the tumor to receive mipsagargin via intravenous infusion on the first three consecutive days of a 28-day cycle, over a total of three cycles. The study will evaluate the drug's effect on the perfusion and volume of the prostate. Top-line data are expected in mid-2017.

Trillium Therapeutics Inc., of Toronto, said the FDA cleared the firm to start a phase I trial of TTI-621 (SIRPaFc) in solid tumors and mycosis fungoides. Patient enrollment is set to start by the end of the year. The open-label trial will evaluate safety, pharmacokinetics, pharmacodynamics and preliminary evidence of antitumor activity. In addition, detailed evaluation of serial, on-treatment tumor biopsies of both injected and non-injected cancer lesions will help characterize tumor microenvironment changes anticipated with CD47 blockade. TTI-621 is in development as a checkpoint inhibitor of the innate immune system and is also in phase I testing for relapsed or refractory hematologic malignancies.