** Shares of GlaxoSmithKline Pharmaceuticals GLAX.NS fall 6.7% to 2,956 rupees
** Stock on track to fall most in a session since March 23, 2020
** Indian unit of British drugmaker GSK Plc GSK.L posts 1.2% decline in Q1 rev from ops to 8.05 bln rupees ($92.1 mln), first decrease in revenue since March 2023
** "Performance was below anticipated levels," the company said, citing "seasonal disruption"
** Nearly 150,000 shares traded, 1.5x its 30-day moving avg
** YTD, GLAX up 31%
($1 = 87.4300 Indian rupees)
(Reporting by Anuran Sadhu in Bengaluru)
((Anuran.Sadhu@thomsonreuters.com; +91 8697274436;))