$re = '/(.*=)([0-9.].+\|)+(.*)/';
$str = 'chr1 69511 rs75062661 A G . QSS_ref ASP;BaseCounts=375,3,118,4;CAF=[0.348,0.652];COMMON=1;EFF=NON_SYNONYMOUS_CODING(MODERATE|MISSENSE|Aca/Gca|T141A|305|OR4F5|protein_coding|CODING|ENST00000335137|1|1);GNO;HRun=0;HaplotypeScore=0.0000;KGPROD;KGPhase1;LowMQ=0.0280,0.0580,500;MQ=49.32;MQ0=14;MSigDb=ACEVEDO_METHYLATED_IN_LIVER_CANCER_DN,KEGG_OLFACTORY_TRANSDUCTION,REACTOME_GPCR_DOWNSTREAM_SIGNALING,REACTOME_OLFACTORY_SIGNALING_PATHWAY,REACTOME_SIGNALING_BY_GPCR,chr1p36;NORMALT=86;NORMREF=228;NSM;NT=het;OTHERKG;QSS=8;QSS_NT=6;REF;RS=75062661;RSPOS=69511;S3D;SAO=0;SGT=AG->AG;SOMATIC;SSR=0;TQSS=1;TQSS_NT=2;TUMALT=15;TUMREF=227;TUMVAF=0.06198347107438017;TUMVARFRACTION=0.1485148514851485;VC=SNV;VLD;VP=0x050200000a05140116000100;WGT=1;dbNSFP_1000Gp1_AC=1424;dbNSFP_1000Gp1_AF=0.652014652014652;dbNSFP_1000Gp1_AFR_AC=162;dbNSFP_1000Gp1_AFR_AF=0.32926829268292684;dbNSFP_1000Gp1_AMR_AC=235;dbNSFP_1000Gp1_AMR_AF=0.649171270718232;dbNSFP_1000Gp1_ASN_AC=500;dbNSFP_1000Gp1_ASN_AF=0.8741258741258742;dbNSFP_1000Gp1_EUR_AC=527;dbNSFP_1000Gp1_EUR_AF=0.6952506596306068;dbNSFP_29way_logOdds=4.1978;dbNSFP_29way_pi=0.1516:0.0:0.6258:0.2226;dbNSFP_ESP6500_AA_AF=0.544101;dbNSFP_ESP6500_EA_AF=0.887429;dbNSFP_Ensembl_geneid=ENSG00000186092;dbNSFP_Ensembl_transcriptid=ENST00000534990|ENST00000335137;dbNSFP_FATHMM_score=0.51;dbNSFP_GERP++_NR=2.31;dbNSFP_GERP++_RS=1.15;dbNSFP_Interpro_domain=GPCR|_rhodopsin-like_superfamily_(1)|;dbNSFP_LRT_Omega=0.000000;dbNSFP_LRT_pred=N;dbNSFP_LRT_score=0.000427;dbNSFP_MutationAssessor_pred=neutral;dbNSFP_MutationAssessor_score=-1.295;dbNSFP_MutationTaster_pred=N;dbNSFP_MutationTaster_score=0.000162;dbNSFP_Polyphen2_HDIV_pred=B;dbNSFP_Polyphen2_HVAR_pred=B;dbNSFP_SIFT_score=0.950000;dbNSFP_Uniprot_aapos=141;dbNSFP_Uniprot_acc=Q8NH21;dbNSFP_Uniprot_id=OR4F5_HUMAN;dbNSFP_aaalt=A;dbNSFP_aapos=189|141|142;dbNSFP_aaref=T;dbNSFP_cds_strand=+;dbNSFP_codonpos=1;dbNSFP_fold-degenerate=0;dbNSFP_phyloP=0.267000;dbNSFP_refcodon=ACA;dbSNPBuildID=131 AU:CU:DP:FDP:GU:SDP:SUBDP:TU 228,232:3,3:322:4:86,109:0:0:1,2 227,228:0,0:244:1:15,16:0:0:1,2';
$subst = "";
$result = preg_replace($re, $subst, $str, 1);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php