A landmark study hoping to find new treatments for ALS has notched two more failures, as experimental medicines from Denali Therapeutics and Calico Life Sciences proved no better than a placebo at slowing the nerve-destroying disease or keeping patients alive longer.Denali disclosed high-level results from the study Monday. After about six months, treatment with the companys drug didnt result in any significant changes in the severity of the disease, nor did it substantially help patients muscle strength or respiratory function.Denali plans to further examine the data and look at biological markers of the disease, including one, neurofilament light chain, thats become increasingly important to researchers focused on amyotrophic lateral sclerosis. The company expects to conduct those analyses later this year.Though the initial top-line clinical results of this trial were not what we hoped, the data collected is valuable in helping to understand the next stage of ALS research, said Merit Cudkowicz, director of the Sean M. Healey & AMG Center for ALS at Massachusetts General Hospital, in a statement.Cudkowicz and her team came up with and for the last several years have been running the Healey platform trial, an innovative experiment structured to quickly test a variety of potential ALS therapies. The trial has so far evaluated more than half a dozen drugs, but none have successfully hit its main goals.Alongside the Denali news, the Healey center announced a similar medicine from Calico and AbbVie had failed, too. Both Denalis and Calicos drugs are supposed to activate eIF2B, a complex molecule cells use to make proteins. Research indicates stress and disease inhibits this molecule, which in turn can exacerbate the accumulation of stress-related proteins like TDP-43.While helpful when functioning normally, TDP-43 can, under certain conditions, become a bad actor in nerve cells. It is tied to ALS and other neurodegenerative diseases, and has therefore attracted interest from a handful of brain-focused biotechnology companies. Just two months ago, a San Francisco-area startup launched with a drug designed to work around this TDP-43 problem. Named Trace Neuroscience, the startup came equipped with $101 million from a group of prominent life sciences investors that includes Third Rock Ventures, Atlas Venture, RA Capital Management and Alphabets venture capital arm, GV.Cudkowicz said the Healey team remains deeply committed to fully understanding the effects of Denalis drug and will further evaluate the data before determining next steps.Some Denali investors may not be willing to wait, however. Shares of the company, which had already dipped more than 6% while the stock market was open Monday, fell further in after-hours trading. Calico is a privately held subsidiary of Google parent Alphabet.This was always a low expectations, high-risk study for Denali,wrote Michael Yee, an analyst at the investment bank Jefferies, in a note to clients. The failure of AbbVie and Calicos therapy to also hit the same goals in its own study arm points to a difficulty with the drug class in a challenging disease.In its own statement, Calico pointed to an assessment of muscle strength that hinted at slower deterioration among those given the companys drug. Bill Cho, the companys head of clinical sciences, said the finding supports further investigation.Like many brain diseases, ALS has been exceptionally difficult to crack for even the worlds most powerful drug developers. Only a few medicines have received approval from the Food and Drug Administration, and their effects are considered modest. Patients still typically live just two to five years following a diagnosis.The list of approved therapies got shorter last spring, when Amylyx Pharmaceuticals voluntarily removed its once-promising medication Relyvrio from the market. Amylyx made that decision after a key study meant to confirm the Relyvrio was an effective ALS treatment instead found it no better than a placebo. '