Sorrento Therapeutics, Inc. announced that the phase 1b study of its non-opioid, afferent nerve ablating drug candidate for the treatment of pain from osteoarthritis in the knee (intra-articular route of administration) interim data analysis of over 30 patients had positive activity, prompting Sorrento to start planning pivotal studies to start in 2019. Rapid onset of pain relief (day following injection) and sustained clinical benefits (84 days) at the lowest dose tested. Pain at walking (10 points WOMAC scale) reduced by 4.7 points versus control at day 84. No dose limiting toxicities, nor adverse events of interest noted for any dose group. The “Phase 1b double-blind study to assess the safety and preliminary efficacy of intra-articular administration of resiniferatoxin versus placebo for the treatment of pain due to moderate to severe osteoarthritis of the knee” was expected to recruit about 40 patients in 5 dose level cohorts or until a maximum tolerated dose (MTD) was reached. In each cohort six patients received intra-articular RTX and two received a saline control (placebo arm). No dose limiting toxicities have been observed to date at any dose group and a majority of the patients treated with the active drug are reporting positive clinical benefits in pain reduction. The lowest dose cohort treated with a single injection into the knee joint (with 5 mcg RTX) was unblinded after twelve weeks of observation as authorized per protocol. The RTX treated patients had a mean pain score 4.7 points lower than controls (on the 10 point WOMAC pain scale) at Day 84. Onset of pain reduction was as early as the day following drug administration and sustained over time. Patients in higher dose groups are also displaying rapid and sustainable improvements (data still blinded). As specified in the current protocol, patients will be monitored for 12 months after injection. A clinically effective dose will be determined by the end of the current study.