# Armstrong 2018 PREVAIL Cox Linear Predictor for mCRPC Overall Survival > Armstrong 2018 PREVAIL Cox Linear Predictor for mCRPC Overall Survival is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14). Computes the Armstrong 2018 PREVAIL trial Cox linear predictor score for overall survival in chemotherapy-naïve metastatic castration-resistant prostate cancer given 11 clinical variables ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/prevail - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-14 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/armstrong-2018-prevail-cox-linear-predictor-for-mcrpc-overall-survival-844b22f4 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_k3cFCeS_X3tQWtnDKqHAk Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability armstrong-2018-prevail-cox-linear-predictor-for-mcrpc-overall-survival-844b22f4 ``` Example prompt: Compute the Armstrong 2018 PREVAIL Cox linear predictor for a chemotherapy-naïve mCRPC patient: albumin 3.8 g/dL, ALP below ULN, fewer than 10 bone mets, hemoglobin 12.1 g/dL, LDH below ULN, NLR less than 2.5, pain score 0–1, no liver metastases, PSA 45 ng/mL, 18 months since diagnosis, on enzalutamide. ## When to prefer this Use this endpoint when you need the validated Armstrong 2018 PREVAIL trial Cox linear predictor for chemotherapy-naïve mCRPC patients and have all 11 clinical variables available as caller-assigned values. Prefer this over generic survival calculators when you specifically want the PREVAIL trial-derived hazard ratio coefficients from Table 1. Do not use it to obtain OS percentages, to read bone scans, to assay lab values, or to assign pain/NLR scores — those must be provided by the caller. ## Known failure modes - Missing required query parameters returns a 400 error - PSA value outside the 0.1–10000 ng/mL range may be rejected or yield out-of-range results - Boolean flags (NLR, pain, ALP, LDH, bone mets, liver mets, treatment) must be true/false; string or numeric values will fail validation - albumin or hemoglobin outside physiological bounds may cause errors - Payment not included or insufficient USDC will result in a 402 Payment Required response ## How this service works Armstrong 2018 PREVAIL Cox linear predictor for overall survival in chemotherapy-naïve metastatic castration-resistant prostate cancer from albumin, ALP versus ULN, bone metastases under 10, hemoglobin, LDH versus ULN, NLR under 2.5, pain 0-1, liver metastases, ln(PSA), months from diagnosis, and enzalutamide versus placebo. Table 1 HRs as ln(HR). Not a 1-/2-/3-year OS percent (no published S0). magent does not read bone scans. Not a dose or treatment order. ## Output Returns the Armstrong 2018 PREVAIL Cox linear predictor value expressed as ln(HR), computed from the 11 caller-supplied clinical variables using the Table 1 hazard ratios. Does not return a 1-, 2-, or 3-year OS percentage (no published S0 baseline survival function is applied). This is a continuous risk score, not a treatment recommendation. ## Request schema (JSON Schema) ```json { "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "input" ], "properties": { "input": { "type": "object", "required": [ "type", "method" ], "properties": { "type": { "type": "string", "const": "http" }, "method": { "enum": [ "GET", "HEAD", "DELETE" ], "type": "string" }, "headers": { "type": "object", "additionalProperties": { "type": "string" } }, "queryParams": { "type": "object", "required": [ "albumin_g_dl", "alp_below_uln", "bone_mets_lt_10", "hemoglobin_g_dl", "ldh_below_uln", "nlr_lt_2_5", "pain_0_to_1", "no_liver_metastases", "psa_ng_ml", "months_since_diagnosis", "treatment_enzalutamide" ], "properties": { "psa_ng_ml": { "type": "number", "description": "Baseline PSA in ng/mL (0.1-10000). Table 1: continuous log_e PSA, HR 1.23 per ln(ng/mL). magent does not assay PSA." }, "nlr_lt_2_5": { "type": "boolean", "description": "Neutrophil-to-lymphocyte ratio <2.5 as assigned by the caller (true or false). Table 1: true (<2.5 versus ≥2.5) has HR 0.69. magent does not compute NLR from counts." }, "pain_0_to_1": { "type": "boolean", "description": "Pain score 0-1 versus ≥2 on the paper's linear scale, as assigned by the caller (true or false). Table 1: true (0-1 versus ≥2) has HR 0.77. magent does not assign pain scores." }, "albumin_g_dl": { "type": "number", "description": "Serum albumin in g/dL (1.0-6.5). Armstrong 2018 Table 1: continuous, HR 0.71 per g/dL. magent does not assay albumin." }, "alp_below_uln": { "type": "boolean", "description": "Alkaline phosphatase below the institutional ULN as assigned by the caller (true or false). Table 1: true (